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d8e328b3bd
The modalias attribute of spi devices doesn't have the "spi:" prefix that is used in the UEVENT and in spi device drivers. This patch adds the prefix so the modprobe can correctly match modules to devices. Reported-by: David Daney <david.daney@cavium.com> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
1573 lines
43 KiB
C
1573 lines
43 KiB
C
/*
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* SPI init/core code
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*
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* Copyright (C) 2005 David Brownell
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* Copyright (C) 2008 Secret Lab Technologies Ltd.
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
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*/
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#include <linux/kernel.h>
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#include <linux/kmod.h>
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#include <linux/device.h>
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#include <linux/init.h>
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#include <linux/cache.h>
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#include <linux/mutex.h>
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#include <linux/of_device.h>
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#include <linux/of_irq.h>
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#include <linux/slab.h>
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#include <linux/mod_devicetable.h>
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#include <linux/spi/spi.h>
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#include <linux/pm_runtime.h>
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#include <linux/export.h>
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#include <linux/sched.h>
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#include <linux/delay.h>
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#include <linux/kthread.h>
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static void spidev_release(struct device *dev)
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{
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struct spi_device *spi = to_spi_device(dev);
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/* spi masters may cleanup for released devices */
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if (spi->master->cleanup)
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spi->master->cleanup(spi);
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spi_master_put(spi->master);
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kfree(spi);
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}
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static ssize_t
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modalias_show(struct device *dev, struct device_attribute *a, char *buf)
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{
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const struct spi_device *spi = to_spi_device(dev);
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return sprintf(buf, "%s%s\n", SPI_MODULE_PREFIX, spi->modalias);
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}
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static struct device_attribute spi_dev_attrs[] = {
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__ATTR_RO(modalias),
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__ATTR_NULL,
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};
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/* modalias support makes "modprobe $MODALIAS" new-style hotplug work,
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* and the sysfs version makes coldplug work too.
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*/
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static const struct spi_device_id *spi_match_id(const struct spi_device_id *id,
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const struct spi_device *sdev)
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{
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while (id->name[0]) {
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if (!strcmp(sdev->modalias, id->name))
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return id;
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id++;
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}
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return NULL;
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}
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const struct spi_device_id *spi_get_device_id(const struct spi_device *sdev)
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{
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const struct spi_driver *sdrv = to_spi_driver(sdev->dev.driver);
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return spi_match_id(sdrv->id_table, sdev);
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}
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EXPORT_SYMBOL_GPL(spi_get_device_id);
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static int spi_match_device(struct device *dev, struct device_driver *drv)
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{
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const struct spi_device *spi = to_spi_device(dev);
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const struct spi_driver *sdrv = to_spi_driver(drv);
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/* Attempt an OF style match */
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if (of_driver_match_device(dev, drv))
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return 1;
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if (sdrv->id_table)
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return !!spi_match_id(sdrv->id_table, spi);
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return strcmp(spi->modalias, drv->name) == 0;
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}
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static int spi_uevent(struct device *dev, struct kobj_uevent_env *env)
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{
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const struct spi_device *spi = to_spi_device(dev);
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add_uevent_var(env, "MODALIAS=%s%s", SPI_MODULE_PREFIX, spi->modalias);
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return 0;
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}
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#ifdef CONFIG_PM_SLEEP
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static int spi_legacy_suspend(struct device *dev, pm_message_t message)
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{
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int value = 0;
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struct spi_driver *drv = to_spi_driver(dev->driver);
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/* suspend will stop irqs and dma; no more i/o */
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if (drv) {
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if (drv->suspend)
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value = drv->suspend(to_spi_device(dev), message);
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else
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dev_dbg(dev, "... can't suspend\n");
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}
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return value;
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}
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static int spi_legacy_resume(struct device *dev)
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{
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int value = 0;
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struct spi_driver *drv = to_spi_driver(dev->driver);
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/* resume may restart the i/o queue */
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if (drv) {
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if (drv->resume)
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value = drv->resume(to_spi_device(dev));
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else
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dev_dbg(dev, "... can't resume\n");
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}
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return value;
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}
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static int spi_pm_suspend(struct device *dev)
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{
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const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
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if (pm)
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return pm_generic_suspend(dev);
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else
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return spi_legacy_suspend(dev, PMSG_SUSPEND);
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}
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static int spi_pm_resume(struct device *dev)
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{
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const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
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if (pm)
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return pm_generic_resume(dev);
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else
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return spi_legacy_resume(dev);
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}
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static int spi_pm_freeze(struct device *dev)
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{
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const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
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if (pm)
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return pm_generic_freeze(dev);
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else
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return spi_legacy_suspend(dev, PMSG_FREEZE);
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}
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static int spi_pm_thaw(struct device *dev)
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{
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const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
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if (pm)
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return pm_generic_thaw(dev);
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else
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return spi_legacy_resume(dev);
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}
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static int spi_pm_poweroff(struct device *dev)
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{
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const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
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if (pm)
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return pm_generic_poweroff(dev);
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else
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return spi_legacy_suspend(dev, PMSG_HIBERNATE);
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}
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static int spi_pm_restore(struct device *dev)
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{
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const struct dev_pm_ops *pm = dev->driver ? dev->driver->pm : NULL;
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if (pm)
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return pm_generic_restore(dev);
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else
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return spi_legacy_resume(dev);
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}
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#else
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#define spi_pm_suspend NULL
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#define spi_pm_resume NULL
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#define spi_pm_freeze NULL
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#define spi_pm_thaw NULL
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#define spi_pm_poweroff NULL
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#define spi_pm_restore NULL
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#endif
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static const struct dev_pm_ops spi_pm = {
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.suspend = spi_pm_suspend,
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.resume = spi_pm_resume,
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.freeze = spi_pm_freeze,
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.thaw = spi_pm_thaw,
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.poweroff = spi_pm_poweroff,
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.restore = spi_pm_restore,
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SET_RUNTIME_PM_OPS(
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pm_generic_runtime_suspend,
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pm_generic_runtime_resume,
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pm_generic_runtime_idle
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)
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};
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struct bus_type spi_bus_type = {
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.name = "spi",
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.dev_attrs = spi_dev_attrs,
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.match = spi_match_device,
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.uevent = spi_uevent,
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.pm = &spi_pm,
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};
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EXPORT_SYMBOL_GPL(spi_bus_type);
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static int spi_drv_probe(struct device *dev)
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{
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const struct spi_driver *sdrv = to_spi_driver(dev->driver);
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return sdrv->probe(to_spi_device(dev));
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}
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static int spi_drv_remove(struct device *dev)
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{
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const struct spi_driver *sdrv = to_spi_driver(dev->driver);
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return sdrv->remove(to_spi_device(dev));
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}
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static void spi_drv_shutdown(struct device *dev)
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{
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const struct spi_driver *sdrv = to_spi_driver(dev->driver);
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sdrv->shutdown(to_spi_device(dev));
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}
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/**
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* spi_register_driver - register a SPI driver
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* @sdrv: the driver to register
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* Context: can sleep
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*/
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int spi_register_driver(struct spi_driver *sdrv)
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{
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sdrv->driver.bus = &spi_bus_type;
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if (sdrv->probe)
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sdrv->driver.probe = spi_drv_probe;
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if (sdrv->remove)
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sdrv->driver.remove = spi_drv_remove;
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if (sdrv->shutdown)
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sdrv->driver.shutdown = spi_drv_shutdown;
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return driver_register(&sdrv->driver);
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}
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EXPORT_SYMBOL_GPL(spi_register_driver);
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/*-------------------------------------------------------------------------*/
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/* SPI devices should normally not be created by SPI device drivers; that
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* would make them board-specific. Similarly with SPI master drivers.
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* Device registration normally goes into like arch/.../mach.../board-YYY.c
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* with other readonly (flashable) information about mainboard devices.
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*/
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struct boardinfo {
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struct list_head list;
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struct spi_board_info board_info;
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};
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static LIST_HEAD(board_list);
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static LIST_HEAD(spi_master_list);
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/*
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* Used to protect add/del opertion for board_info list and
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* spi_master list, and their matching process
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*/
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static DEFINE_MUTEX(board_lock);
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/**
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* spi_alloc_device - Allocate a new SPI device
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* @master: Controller to which device is connected
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* Context: can sleep
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*
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* Allows a driver to allocate and initialize a spi_device without
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* registering it immediately. This allows a driver to directly
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* fill the spi_device with device parameters before calling
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* spi_add_device() on it.
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*
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* Caller is responsible to call spi_add_device() on the returned
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* spi_device structure to add it to the SPI master. If the caller
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* needs to discard the spi_device without adding it, then it should
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* call spi_dev_put() on it.
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*
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* Returns a pointer to the new device, or NULL.
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*/
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struct spi_device *spi_alloc_device(struct spi_master *master)
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{
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struct spi_device *spi;
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struct device *dev = master->dev.parent;
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if (!spi_master_get(master))
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return NULL;
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spi = kzalloc(sizeof *spi, GFP_KERNEL);
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if (!spi) {
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dev_err(dev, "cannot alloc spi_device\n");
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spi_master_put(master);
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return NULL;
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}
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spi->master = master;
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spi->dev.parent = &master->dev;
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spi->dev.bus = &spi_bus_type;
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spi->dev.release = spidev_release;
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device_initialize(&spi->dev);
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return spi;
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}
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EXPORT_SYMBOL_GPL(spi_alloc_device);
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/**
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* spi_add_device - Add spi_device allocated with spi_alloc_device
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* @spi: spi_device to register
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*
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* Companion function to spi_alloc_device. Devices allocated with
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* spi_alloc_device can be added onto the spi bus with this function.
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*
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* Returns 0 on success; negative errno on failure
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*/
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int spi_add_device(struct spi_device *spi)
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{
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static DEFINE_MUTEX(spi_add_lock);
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struct device *dev = spi->master->dev.parent;
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struct device *d;
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int status;
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/* Chipselects are numbered 0..max; validate. */
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if (spi->chip_select >= spi->master->num_chipselect) {
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dev_err(dev, "cs%d >= max %d\n",
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spi->chip_select,
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spi->master->num_chipselect);
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return -EINVAL;
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}
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/* Set the bus ID string */
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dev_set_name(&spi->dev, "%s.%u", dev_name(&spi->master->dev),
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spi->chip_select);
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/* We need to make sure there's no other device with this
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* chipselect **BEFORE** we call setup(), else we'll trash
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* its configuration. Lock against concurrent add() calls.
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*/
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mutex_lock(&spi_add_lock);
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d = bus_find_device_by_name(&spi_bus_type, NULL, dev_name(&spi->dev));
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if (d != NULL) {
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dev_err(dev, "chipselect %d already in use\n",
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spi->chip_select);
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put_device(d);
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status = -EBUSY;
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goto done;
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}
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/* Drivers may modify this initial i/o setup, but will
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* normally rely on the device being setup. Devices
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* using SPI_CS_HIGH can't coexist well otherwise...
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*/
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status = spi_setup(spi);
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if (status < 0) {
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dev_err(dev, "can't setup %s, status %d\n",
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dev_name(&spi->dev), status);
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goto done;
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}
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/* Device may be bound to an active driver when this returns */
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status = device_add(&spi->dev);
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if (status < 0)
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dev_err(dev, "can't add %s, status %d\n",
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dev_name(&spi->dev), status);
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else
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dev_dbg(dev, "registered child %s\n", dev_name(&spi->dev));
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done:
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mutex_unlock(&spi_add_lock);
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return status;
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}
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EXPORT_SYMBOL_GPL(spi_add_device);
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/**
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* spi_new_device - instantiate one new SPI device
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* @master: Controller to which device is connected
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* @chip: Describes the SPI device
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* Context: can sleep
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*
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* On typical mainboards, this is purely internal; and it's not needed
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* after board init creates the hard-wired devices. Some development
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* platforms may not be able to use spi_register_board_info though, and
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* this is exported so that for example a USB or parport based adapter
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* driver could add devices (which it would learn about out-of-band).
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*
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* Returns the new device, or NULL.
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*/
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struct spi_device *spi_new_device(struct spi_master *master,
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struct spi_board_info *chip)
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{
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struct spi_device *proxy;
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int status;
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/* NOTE: caller did any chip->bus_num checks necessary.
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*
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* Also, unless we change the return value convention to use
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* error-or-pointer (not NULL-or-pointer), troubleshootability
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* suggests syslogged diagnostics are best here (ugh).
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*/
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proxy = spi_alloc_device(master);
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if (!proxy)
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return NULL;
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WARN_ON(strlen(chip->modalias) >= sizeof(proxy->modalias));
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proxy->chip_select = chip->chip_select;
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proxy->max_speed_hz = chip->max_speed_hz;
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proxy->mode = chip->mode;
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proxy->irq = chip->irq;
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strlcpy(proxy->modalias, chip->modalias, sizeof(proxy->modalias));
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proxy->dev.platform_data = (void *) chip->platform_data;
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proxy->controller_data = chip->controller_data;
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proxy->controller_state = NULL;
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status = spi_add_device(proxy);
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if (status < 0) {
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spi_dev_put(proxy);
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return NULL;
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}
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return proxy;
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}
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EXPORT_SYMBOL_GPL(spi_new_device);
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static void spi_match_master_to_boardinfo(struct spi_master *master,
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struct spi_board_info *bi)
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{
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struct spi_device *dev;
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if (master->bus_num != bi->bus_num)
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return;
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dev = spi_new_device(master, bi);
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if (!dev)
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dev_err(master->dev.parent, "can't create new device for %s\n",
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bi->modalias);
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}
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|
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/**
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* spi_register_board_info - register SPI devices for a given board
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* @info: array of chip descriptors
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* @n: how many descriptors are provided
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* Context: can sleep
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*
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* Board-specific early init code calls this (probably during arch_initcall)
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* with segments of the SPI device table. Any device nodes are created later,
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* after the relevant parent SPI controller (bus_num) is defined. We keep
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* this table of devices forever, so that reloading a controller driver will
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* not make Linux forget about these hard-wired devices.
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*
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* Other code can also call this, e.g. a particular add-on board might provide
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* SPI devices through its expansion connector, so code initializing that board
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* would naturally declare its SPI devices.
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*
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* The board info passed can safely be __initdata ... but be careful of
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* any embedded pointers (platform_data, etc), they're copied as-is.
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*/
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int __devinit
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spi_register_board_info(struct spi_board_info const *info, unsigned n)
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{
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struct boardinfo *bi;
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int i;
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bi = kzalloc(n * sizeof(*bi), GFP_KERNEL);
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if (!bi)
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return -ENOMEM;
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|
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for (i = 0; i < n; i++, bi++, info++) {
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struct spi_master *master;
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memcpy(&bi->board_info, info, sizeof(*info));
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mutex_lock(&board_lock);
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list_add_tail(&bi->list, &board_list);
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list_for_each_entry(master, &spi_master_list, list)
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spi_match_master_to_boardinfo(master, &bi->board_info);
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mutex_unlock(&board_lock);
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}
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|
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return 0;
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}
|
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|
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/*-------------------------------------------------------------------------*/
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|
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/**
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* spi_pump_messages - kthread work function which processes spi message queue
|
|
* @work: pointer to kthread work struct contained in the master struct
|
|
*
|
|
* This function checks if there is any spi message in the queue that
|
|
* needs processing and if so call out to the driver to initialize hardware
|
|
* and transfer each message.
|
|
*
|
|
*/
|
|
static void spi_pump_messages(struct kthread_work *work)
|
|
{
|
|
struct spi_master *master =
|
|
container_of(work, struct spi_master, pump_messages);
|
|
unsigned long flags;
|
|
bool was_busy = false;
|
|
int ret;
|
|
|
|
/* Lock queue and check for queue work */
|
|
spin_lock_irqsave(&master->queue_lock, flags);
|
|
if (list_empty(&master->queue) || !master->running) {
|
|
if (master->busy && master->unprepare_transfer_hardware) {
|
|
ret = master->unprepare_transfer_hardware(master);
|
|
if (ret) {
|
|
spin_unlock_irqrestore(&master->queue_lock, flags);
|
|
dev_err(&master->dev,
|
|
"failed to unprepare transfer hardware\n");
|
|
return;
|
|
}
|
|
}
|
|
master->busy = false;
|
|
spin_unlock_irqrestore(&master->queue_lock, flags);
|
|
return;
|
|
}
|
|
|
|
/* Make sure we are not already running a message */
|
|
if (master->cur_msg) {
|
|
spin_unlock_irqrestore(&master->queue_lock, flags);
|
|
return;
|
|
}
|
|
/* Extract head of queue */
|
|
master->cur_msg =
|
|
list_entry(master->queue.next, struct spi_message, queue);
|
|
|
|
list_del_init(&master->cur_msg->queue);
|
|
if (master->busy)
|
|
was_busy = true;
|
|
else
|
|
master->busy = true;
|
|
spin_unlock_irqrestore(&master->queue_lock, flags);
|
|
|
|
if (!was_busy && master->prepare_transfer_hardware) {
|
|
ret = master->prepare_transfer_hardware(master);
|
|
if (ret) {
|
|
dev_err(&master->dev,
|
|
"failed to prepare transfer hardware\n");
|
|
return;
|
|
}
|
|
}
|
|
|
|
ret = master->transfer_one_message(master, master->cur_msg);
|
|
if (ret) {
|
|
dev_err(&master->dev,
|
|
"failed to transfer one message from queue\n");
|
|
return;
|
|
}
|
|
}
|
|
|
|
static int spi_init_queue(struct spi_master *master)
|
|
{
|
|
struct sched_param param = { .sched_priority = MAX_RT_PRIO - 1 };
|
|
|
|
INIT_LIST_HEAD(&master->queue);
|
|
spin_lock_init(&master->queue_lock);
|
|
|
|
master->running = false;
|
|
master->busy = false;
|
|
|
|
init_kthread_worker(&master->kworker);
|
|
master->kworker_task = kthread_run(kthread_worker_fn,
|
|
&master->kworker,
|
|
dev_name(&master->dev));
|
|
if (IS_ERR(master->kworker_task)) {
|
|
dev_err(&master->dev, "failed to create message pump task\n");
|
|
return -ENOMEM;
|
|
}
|
|
init_kthread_work(&master->pump_messages, spi_pump_messages);
|
|
|
|
/*
|
|
* Master config will indicate if this controller should run the
|
|
* message pump with high (realtime) priority to reduce the transfer
|
|
* latency on the bus by minimising the delay between a transfer
|
|
* request and the scheduling of the message pump thread. Without this
|
|
* setting the message pump thread will remain at default priority.
|
|
*/
|
|
if (master->rt) {
|
|
dev_info(&master->dev,
|
|
"will run message pump with realtime priority\n");
|
|
sched_setscheduler(master->kworker_task, SCHED_FIFO, ¶m);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* spi_get_next_queued_message() - called by driver to check for queued
|
|
* messages
|
|
* @master: the master to check for queued messages
|
|
*
|
|
* If there are more messages in the queue, the next message is returned from
|
|
* this call.
|
|
*/
|
|
struct spi_message *spi_get_next_queued_message(struct spi_master *master)
|
|
{
|
|
struct spi_message *next;
|
|
unsigned long flags;
|
|
|
|
/* get a pointer to the next message, if any */
|
|
spin_lock_irqsave(&master->queue_lock, flags);
|
|
if (list_empty(&master->queue))
|
|
next = NULL;
|
|
else
|
|
next = list_entry(master->queue.next,
|
|
struct spi_message, queue);
|
|
spin_unlock_irqrestore(&master->queue_lock, flags);
|
|
|
|
return next;
|
|
}
|
|
EXPORT_SYMBOL_GPL(spi_get_next_queued_message);
|
|
|
|
/**
|
|
* spi_finalize_current_message() - the current message is complete
|
|
* @master: the master to return the message to
|
|
*
|
|
* Called by the driver to notify the core that the message in the front of the
|
|
* queue is complete and can be removed from the queue.
|
|
*/
|
|
void spi_finalize_current_message(struct spi_master *master)
|
|
{
|
|
struct spi_message *mesg;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&master->queue_lock, flags);
|
|
mesg = master->cur_msg;
|
|
master->cur_msg = NULL;
|
|
|
|
queue_kthread_work(&master->kworker, &master->pump_messages);
|
|
spin_unlock_irqrestore(&master->queue_lock, flags);
|
|
|
|
mesg->state = NULL;
|
|
if (mesg->complete)
|
|
mesg->complete(mesg->context);
|
|
}
|
|
EXPORT_SYMBOL_GPL(spi_finalize_current_message);
|
|
|
|
static int spi_start_queue(struct spi_master *master)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&master->queue_lock, flags);
|
|
|
|
if (master->running || master->busy) {
|
|
spin_unlock_irqrestore(&master->queue_lock, flags);
|
|
return -EBUSY;
|
|
}
|
|
|
|
master->running = true;
|
|
master->cur_msg = NULL;
|
|
spin_unlock_irqrestore(&master->queue_lock, flags);
|
|
|
|
queue_kthread_work(&master->kworker, &master->pump_messages);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int spi_stop_queue(struct spi_master *master)
|
|
{
|
|
unsigned long flags;
|
|
unsigned limit = 500;
|
|
int ret = 0;
|
|
|
|
spin_lock_irqsave(&master->queue_lock, flags);
|
|
|
|
/*
|
|
* This is a bit lame, but is optimized for the common execution path.
|
|
* A wait_queue on the master->busy could be used, but then the common
|
|
* execution path (pump_messages) would be required to call wake_up or
|
|
* friends on every SPI message. Do this instead.
|
|
*/
|
|
while ((!list_empty(&master->queue) || master->busy) && limit--) {
|
|
spin_unlock_irqrestore(&master->queue_lock, flags);
|
|
msleep(10);
|
|
spin_lock_irqsave(&master->queue_lock, flags);
|
|
}
|
|
|
|
if (!list_empty(&master->queue) || master->busy)
|
|
ret = -EBUSY;
|
|
else
|
|
master->running = false;
|
|
|
|
spin_unlock_irqrestore(&master->queue_lock, flags);
|
|
|
|
if (ret) {
|
|
dev_warn(&master->dev,
|
|
"could not stop message queue\n");
|
|
return ret;
|
|
}
|
|
return ret;
|
|
}
|
|
|
|
static int spi_destroy_queue(struct spi_master *master)
|
|
{
|
|
int ret;
|
|
|
|
ret = spi_stop_queue(master);
|
|
|
|
/*
|
|
* flush_kthread_worker will block until all work is done.
|
|
* If the reason that stop_queue timed out is that the work will never
|
|
* finish, then it does no good to call flush/stop thread, so
|
|
* return anyway.
|
|
*/
|
|
if (ret) {
|
|
dev_err(&master->dev, "problem destroying queue\n");
|
|
return ret;
|
|
}
|
|
|
|
flush_kthread_worker(&master->kworker);
|
|
kthread_stop(master->kworker_task);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* spi_queued_transfer - transfer function for queued transfers
|
|
* @spi: spi device which is requesting transfer
|
|
* @msg: spi message which is to handled is queued to driver queue
|
|
*/
|
|
static int spi_queued_transfer(struct spi_device *spi, struct spi_message *msg)
|
|
{
|
|
struct spi_master *master = spi->master;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&master->queue_lock, flags);
|
|
|
|
if (!master->running) {
|
|
spin_unlock_irqrestore(&master->queue_lock, flags);
|
|
return -ESHUTDOWN;
|
|
}
|
|
msg->actual_length = 0;
|
|
msg->status = -EINPROGRESS;
|
|
|
|
list_add_tail(&msg->queue, &master->queue);
|
|
if (master->running && !master->busy)
|
|
queue_kthread_work(&master->kworker, &master->pump_messages);
|
|
|
|
spin_unlock_irqrestore(&master->queue_lock, flags);
|
|
return 0;
|
|
}
|
|
|
|
static int spi_master_initialize_queue(struct spi_master *master)
|
|
{
|
|
int ret;
|
|
|
|
master->queued = true;
|
|
master->transfer = spi_queued_transfer;
|
|
|
|
/* Initialize and start queue */
|
|
ret = spi_init_queue(master);
|
|
if (ret) {
|
|
dev_err(&master->dev, "problem initializing queue\n");
|
|
goto err_init_queue;
|
|
}
|
|
ret = spi_start_queue(master);
|
|
if (ret) {
|
|
dev_err(&master->dev, "problem starting queue\n");
|
|
goto err_start_queue;
|
|
}
|
|
|
|
return 0;
|
|
|
|
err_start_queue:
|
|
err_init_queue:
|
|
spi_destroy_queue(master);
|
|
return ret;
|
|
}
|
|
|
|
/*-------------------------------------------------------------------------*/
|
|
|
|
#if defined(CONFIG_OF) && !defined(CONFIG_SPARC)
|
|
/**
|
|
* of_register_spi_devices() - Register child devices onto the SPI bus
|
|
* @master: Pointer to spi_master device
|
|
*
|
|
* Registers an spi_device for each child node of master node which has a 'reg'
|
|
* property.
|
|
*/
|
|
static void of_register_spi_devices(struct spi_master *master)
|
|
{
|
|
struct spi_device *spi;
|
|
struct device_node *nc;
|
|
const __be32 *prop;
|
|
int rc;
|
|
int len;
|
|
|
|
if (!master->dev.of_node)
|
|
return;
|
|
|
|
for_each_child_of_node(master->dev.of_node, nc) {
|
|
/* Alloc an spi_device */
|
|
spi = spi_alloc_device(master);
|
|
if (!spi) {
|
|
dev_err(&master->dev, "spi_device alloc error for %s\n",
|
|
nc->full_name);
|
|
spi_dev_put(spi);
|
|
continue;
|
|
}
|
|
|
|
/* Select device driver */
|
|
if (of_modalias_node(nc, spi->modalias,
|
|
sizeof(spi->modalias)) < 0) {
|
|
dev_err(&master->dev, "cannot find modalias for %s\n",
|
|
nc->full_name);
|
|
spi_dev_put(spi);
|
|
continue;
|
|
}
|
|
|
|
/* Device address */
|
|
prop = of_get_property(nc, "reg", &len);
|
|
if (!prop || len < sizeof(*prop)) {
|
|
dev_err(&master->dev, "%s has no 'reg' property\n",
|
|
nc->full_name);
|
|
spi_dev_put(spi);
|
|
continue;
|
|
}
|
|
spi->chip_select = be32_to_cpup(prop);
|
|
|
|
/* Mode (clock phase/polarity/etc.) */
|
|
if (of_find_property(nc, "spi-cpha", NULL))
|
|
spi->mode |= SPI_CPHA;
|
|
if (of_find_property(nc, "spi-cpol", NULL))
|
|
spi->mode |= SPI_CPOL;
|
|
if (of_find_property(nc, "spi-cs-high", NULL))
|
|
spi->mode |= SPI_CS_HIGH;
|
|
|
|
/* Device speed */
|
|
prop = of_get_property(nc, "spi-max-frequency", &len);
|
|
if (!prop || len < sizeof(*prop)) {
|
|
dev_err(&master->dev, "%s has no 'spi-max-frequency' property\n",
|
|
nc->full_name);
|
|
spi_dev_put(spi);
|
|
continue;
|
|
}
|
|
spi->max_speed_hz = be32_to_cpup(prop);
|
|
|
|
/* IRQ */
|
|
spi->irq = irq_of_parse_and_map(nc, 0);
|
|
|
|
/* Store a pointer to the node in the device structure */
|
|
of_node_get(nc);
|
|
spi->dev.of_node = nc;
|
|
|
|
/* Register the new device */
|
|
request_module(spi->modalias);
|
|
rc = spi_add_device(spi);
|
|
if (rc) {
|
|
dev_err(&master->dev, "spi_device register error %s\n",
|
|
nc->full_name);
|
|
spi_dev_put(spi);
|
|
}
|
|
|
|
}
|
|
}
|
|
#else
|
|
static void of_register_spi_devices(struct spi_master *master) { }
|
|
#endif
|
|
|
|
static void spi_master_release(struct device *dev)
|
|
{
|
|
struct spi_master *master;
|
|
|
|
master = container_of(dev, struct spi_master, dev);
|
|
kfree(master);
|
|
}
|
|
|
|
static struct class spi_master_class = {
|
|
.name = "spi_master",
|
|
.owner = THIS_MODULE,
|
|
.dev_release = spi_master_release,
|
|
};
|
|
|
|
|
|
|
|
/**
|
|
* spi_alloc_master - allocate SPI master controller
|
|
* @dev: the controller, possibly using the platform_bus
|
|
* @size: how much zeroed driver-private data to allocate; the pointer to this
|
|
* memory is in the driver_data field of the returned device,
|
|
* accessible with spi_master_get_devdata().
|
|
* Context: can sleep
|
|
*
|
|
* This call is used only by SPI master controller drivers, which are the
|
|
* only ones directly touching chip registers. It's how they allocate
|
|
* an spi_master structure, prior to calling spi_register_master().
|
|
*
|
|
* This must be called from context that can sleep. It returns the SPI
|
|
* master structure on success, else NULL.
|
|
*
|
|
* The caller is responsible for assigning the bus number and initializing
|
|
* the master's methods before calling spi_register_master(); and (after errors
|
|
* adding the device) calling spi_master_put() and kfree() to prevent a memory
|
|
* leak.
|
|
*/
|
|
struct spi_master *spi_alloc_master(struct device *dev, unsigned size)
|
|
{
|
|
struct spi_master *master;
|
|
|
|
if (!dev)
|
|
return NULL;
|
|
|
|
master = kzalloc(size + sizeof *master, GFP_KERNEL);
|
|
if (!master)
|
|
return NULL;
|
|
|
|
device_initialize(&master->dev);
|
|
master->bus_num = -1;
|
|
master->num_chipselect = 1;
|
|
master->dev.class = &spi_master_class;
|
|
master->dev.parent = get_device(dev);
|
|
spi_master_set_devdata(master, &master[1]);
|
|
|
|
return master;
|
|
}
|
|
EXPORT_SYMBOL_GPL(spi_alloc_master);
|
|
|
|
/**
|
|
* spi_register_master - register SPI master controller
|
|
* @master: initialized master, originally from spi_alloc_master()
|
|
* Context: can sleep
|
|
*
|
|
* SPI master controllers connect to their drivers using some non-SPI bus,
|
|
* such as the platform bus. The final stage of probe() in that code
|
|
* includes calling spi_register_master() to hook up to this SPI bus glue.
|
|
*
|
|
* SPI controllers use board specific (often SOC specific) bus numbers,
|
|
* and board-specific addressing for SPI devices combines those numbers
|
|
* with chip select numbers. Since SPI does not directly support dynamic
|
|
* device identification, boards need configuration tables telling which
|
|
* chip is at which address.
|
|
*
|
|
* This must be called from context that can sleep. It returns zero on
|
|
* success, else a negative error code (dropping the master's refcount).
|
|
* After a successful return, the caller is responsible for calling
|
|
* spi_unregister_master().
|
|
*/
|
|
int spi_register_master(struct spi_master *master)
|
|
{
|
|
static atomic_t dyn_bus_id = ATOMIC_INIT((1<<15) - 1);
|
|
struct device *dev = master->dev.parent;
|
|
struct boardinfo *bi;
|
|
int status = -ENODEV;
|
|
int dynamic = 0;
|
|
|
|
if (!dev)
|
|
return -ENODEV;
|
|
|
|
/* even if it's just one always-selected device, there must
|
|
* be at least one chipselect
|
|
*/
|
|
if (master->num_chipselect == 0)
|
|
return -EINVAL;
|
|
|
|
/* convention: dynamically assigned bus IDs count down from the max */
|
|
if (master->bus_num < 0) {
|
|
/* FIXME switch to an IDR based scheme, something like
|
|
* I2C now uses, so we can't run out of "dynamic" IDs
|
|
*/
|
|
master->bus_num = atomic_dec_return(&dyn_bus_id);
|
|
dynamic = 1;
|
|
}
|
|
|
|
spin_lock_init(&master->bus_lock_spinlock);
|
|
mutex_init(&master->bus_lock_mutex);
|
|
master->bus_lock_flag = 0;
|
|
|
|
/* register the device, then userspace will see it.
|
|
* registration fails if the bus ID is in use.
|
|
*/
|
|
dev_set_name(&master->dev, "spi%u", master->bus_num);
|
|
status = device_add(&master->dev);
|
|
if (status < 0)
|
|
goto done;
|
|
dev_dbg(dev, "registered master %s%s\n", dev_name(&master->dev),
|
|
dynamic ? " (dynamic)" : "");
|
|
|
|
/* If we're using a queued driver, start the queue */
|
|
if (master->transfer)
|
|
dev_info(dev, "master is unqueued, this is deprecated\n");
|
|
else {
|
|
status = spi_master_initialize_queue(master);
|
|
if (status) {
|
|
device_unregister(&master->dev);
|
|
goto done;
|
|
}
|
|
}
|
|
|
|
mutex_lock(&board_lock);
|
|
list_add_tail(&master->list, &spi_master_list);
|
|
list_for_each_entry(bi, &board_list, list)
|
|
spi_match_master_to_boardinfo(master, &bi->board_info);
|
|
mutex_unlock(&board_lock);
|
|
|
|
/* Register devices from the device tree */
|
|
of_register_spi_devices(master);
|
|
done:
|
|
return status;
|
|
}
|
|
EXPORT_SYMBOL_GPL(spi_register_master);
|
|
|
|
static int __unregister(struct device *dev, void *null)
|
|
{
|
|
spi_unregister_device(to_spi_device(dev));
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* spi_unregister_master - unregister SPI master controller
|
|
* @master: the master being unregistered
|
|
* Context: can sleep
|
|
*
|
|
* This call is used only by SPI master controller drivers, which are the
|
|
* only ones directly touching chip registers.
|
|
*
|
|
* This must be called from context that can sleep.
|
|
*/
|
|
void spi_unregister_master(struct spi_master *master)
|
|
{
|
|
int dummy;
|
|
|
|
if (master->queued) {
|
|
if (spi_destroy_queue(master))
|
|
dev_err(&master->dev, "queue remove failed\n");
|
|
}
|
|
|
|
mutex_lock(&board_lock);
|
|
list_del(&master->list);
|
|
mutex_unlock(&board_lock);
|
|
|
|
dummy = device_for_each_child(&master->dev, NULL, __unregister);
|
|
device_unregister(&master->dev);
|
|
}
|
|
EXPORT_SYMBOL_GPL(spi_unregister_master);
|
|
|
|
int spi_master_suspend(struct spi_master *master)
|
|
{
|
|
int ret;
|
|
|
|
/* Basically no-ops for non-queued masters */
|
|
if (!master->queued)
|
|
return 0;
|
|
|
|
ret = spi_stop_queue(master);
|
|
if (ret)
|
|
dev_err(&master->dev, "queue stop failed\n");
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(spi_master_suspend);
|
|
|
|
int spi_master_resume(struct spi_master *master)
|
|
{
|
|
int ret;
|
|
|
|
if (!master->queued)
|
|
return 0;
|
|
|
|
ret = spi_start_queue(master);
|
|
if (ret)
|
|
dev_err(&master->dev, "queue restart failed\n");
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(spi_master_resume);
|
|
|
|
static int __spi_master_match(struct device *dev, void *data)
|
|
{
|
|
struct spi_master *m;
|
|
u16 *bus_num = data;
|
|
|
|
m = container_of(dev, struct spi_master, dev);
|
|
return m->bus_num == *bus_num;
|
|
}
|
|
|
|
/**
|
|
* spi_busnum_to_master - look up master associated with bus_num
|
|
* @bus_num: the master's bus number
|
|
* Context: can sleep
|
|
*
|
|
* This call may be used with devices that are registered after
|
|
* arch init time. It returns a refcounted pointer to the relevant
|
|
* spi_master (which the caller must release), or NULL if there is
|
|
* no such master registered.
|
|
*/
|
|
struct spi_master *spi_busnum_to_master(u16 bus_num)
|
|
{
|
|
struct device *dev;
|
|
struct spi_master *master = NULL;
|
|
|
|
dev = class_find_device(&spi_master_class, NULL, &bus_num,
|
|
__spi_master_match);
|
|
if (dev)
|
|
master = container_of(dev, struct spi_master, dev);
|
|
/* reference got in class_find_device */
|
|
return master;
|
|
}
|
|
EXPORT_SYMBOL_GPL(spi_busnum_to_master);
|
|
|
|
|
|
/*-------------------------------------------------------------------------*/
|
|
|
|
/* Core methods for SPI master protocol drivers. Some of the
|
|
* other core methods are currently defined as inline functions.
|
|
*/
|
|
|
|
/**
|
|
* spi_setup - setup SPI mode and clock rate
|
|
* @spi: the device whose settings are being modified
|
|
* Context: can sleep, and no requests are queued to the device
|
|
*
|
|
* SPI protocol drivers may need to update the transfer mode if the
|
|
* device doesn't work with its default. They may likewise need
|
|
* to update clock rates or word sizes from initial values. This function
|
|
* changes those settings, and must be called from a context that can sleep.
|
|
* Except for SPI_CS_HIGH, which takes effect immediately, the changes take
|
|
* effect the next time the device is selected and data is transferred to
|
|
* or from it. When this function returns, the spi device is deselected.
|
|
*
|
|
* Note that this call will fail if the protocol driver specifies an option
|
|
* that the underlying controller or its driver does not support. For
|
|
* example, not all hardware supports wire transfers using nine bit words,
|
|
* LSB-first wire encoding, or active-high chipselects.
|
|
*/
|
|
int spi_setup(struct spi_device *spi)
|
|
{
|
|
unsigned bad_bits;
|
|
int status;
|
|
|
|
/* help drivers fail *cleanly* when they need options
|
|
* that aren't supported with their current master
|
|
*/
|
|
bad_bits = spi->mode & ~spi->master->mode_bits;
|
|
if (bad_bits) {
|
|
dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
|
|
bad_bits);
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (!spi->bits_per_word)
|
|
spi->bits_per_word = 8;
|
|
|
|
status = spi->master->setup(spi);
|
|
|
|
dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s"
|
|
"%u bits/w, %u Hz max --> %d\n",
|
|
(int) (spi->mode & (SPI_CPOL | SPI_CPHA)),
|
|
(spi->mode & SPI_CS_HIGH) ? "cs_high, " : "",
|
|
(spi->mode & SPI_LSB_FIRST) ? "lsb, " : "",
|
|
(spi->mode & SPI_3WIRE) ? "3wire, " : "",
|
|
(spi->mode & SPI_LOOP) ? "loopback, " : "",
|
|
spi->bits_per_word, spi->max_speed_hz,
|
|
status);
|
|
|
|
return status;
|
|
}
|
|
EXPORT_SYMBOL_GPL(spi_setup);
|
|
|
|
static int __spi_async(struct spi_device *spi, struct spi_message *message)
|
|
{
|
|
struct spi_master *master = spi->master;
|
|
|
|
/* Half-duplex links include original MicroWire, and ones with
|
|
* only one data pin like SPI_3WIRE (switches direction) or where
|
|
* either MOSI or MISO is missing. They can also be caused by
|
|
* software limitations.
|
|
*/
|
|
if ((master->flags & SPI_MASTER_HALF_DUPLEX)
|
|
|| (spi->mode & SPI_3WIRE)) {
|
|
struct spi_transfer *xfer;
|
|
unsigned flags = master->flags;
|
|
|
|
list_for_each_entry(xfer, &message->transfers, transfer_list) {
|
|
if (xfer->rx_buf && xfer->tx_buf)
|
|
return -EINVAL;
|
|
if ((flags & SPI_MASTER_NO_TX) && xfer->tx_buf)
|
|
return -EINVAL;
|
|
if ((flags & SPI_MASTER_NO_RX) && xfer->rx_buf)
|
|
return -EINVAL;
|
|
}
|
|
}
|
|
|
|
message->spi = spi;
|
|
message->status = -EINPROGRESS;
|
|
return master->transfer(spi, message);
|
|
}
|
|
|
|
/**
|
|
* spi_async - asynchronous SPI transfer
|
|
* @spi: device with which data will be exchanged
|
|
* @message: describes the data transfers, including completion callback
|
|
* Context: any (irqs may be blocked, etc)
|
|
*
|
|
* This call may be used in_irq and other contexts which can't sleep,
|
|
* as well as from task contexts which can sleep.
|
|
*
|
|
* The completion callback is invoked in a context which can't sleep.
|
|
* Before that invocation, the value of message->status is undefined.
|
|
* When the callback is issued, message->status holds either zero (to
|
|
* indicate complete success) or a negative error code. After that
|
|
* callback returns, the driver which issued the transfer request may
|
|
* deallocate the associated memory; it's no longer in use by any SPI
|
|
* core or controller driver code.
|
|
*
|
|
* Note that although all messages to a spi_device are handled in
|
|
* FIFO order, messages may go to different devices in other orders.
|
|
* Some device might be higher priority, or have various "hard" access
|
|
* time requirements, for example.
|
|
*
|
|
* On detection of any fault during the transfer, processing of
|
|
* the entire message is aborted, and the device is deselected.
|
|
* Until returning from the associated message completion callback,
|
|
* no other spi_message queued to that device will be processed.
|
|
* (This rule applies equally to all the synchronous transfer calls,
|
|
* which are wrappers around this core asynchronous primitive.)
|
|
*/
|
|
int spi_async(struct spi_device *spi, struct spi_message *message)
|
|
{
|
|
struct spi_master *master = spi->master;
|
|
int ret;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&master->bus_lock_spinlock, flags);
|
|
|
|
if (master->bus_lock_flag)
|
|
ret = -EBUSY;
|
|
else
|
|
ret = __spi_async(spi, message);
|
|
|
|
spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
|
|
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL_GPL(spi_async);
|
|
|
|
/**
|
|
* spi_async_locked - version of spi_async with exclusive bus usage
|
|
* @spi: device with which data will be exchanged
|
|
* @message: describes the data transfers, including completion callback
|
|
* Context: any (irqs may be blocked, etc)
|
|
*
|
|
* This call may be used in_irq and other contexts which can't sleep,
|
|
* as well as from task contexts which can sleep.
|
|
*
|
|
* The completion callback is invoked in a context which can't sleep.
|
|
* Before that invocation, the value of message->status is undefined.
|
|
* When the callback is issued, message->status holds either zero (to
|
|
* indicate complete success) or a negative error code. After that
|
|
* callback returns, the driver which issued the transfer request may
|
|
* deallocate the associated memory; it's no longer in use by any SPI
|
|
* core or controller driver code.
|
|
*
|
|
* Note that although all messages to a spi_device are handled in
|
|
* FIFO order, messages may go to different devices in other orders.
|
|
* Some device might be higher priority, or have various "hard" access
|
|
* time requirements, for example.
|
|
*
|
|
* On detection of any fault during the transfer, processing of
|
|
* the entire message is aborted, and the device is deselected.
|
|
* Until returning from the associated message completion callback,
|
|
* no other spi_message queued to that device will be processed.
|
|
* (This rule applies equally to all the synchronous transfer calls,
|
|
* which are wrappers around this core asynchronous primitive.)
|
|
*/
|
|
int spi_async_locked(struct spi_device *spi, struct spi_message *message)
|
|
{
|
|
struct spi_master *master = spi->master;
|
|
int ret;
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&master->bus_lock_spinlock, flags);
|
|
|
|
ret = __spi_async(spi, message);
|
|
|
|
spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
|
|
|
|
return ret;
|
|
|
|
}
|
|
EXPORT_SYMBOL_GPL(spi_async_locked);
|
|
|
|
|
|
/*-------------------------------------------------------------------------*/
|
|
|
|
/* Utility methods for SPI master protocol drivers, layered on
|
|
* top of the core. Some other utility methods are defined as
|
|
* inline functions.
|
|
*/
|
|
|
|
static void spi_complete(void *arg)
|
|
{
|
|
complete(arg);
|
|
}
|
|
|
|
static int __spi_sync(struct spi_device *spi, struct spi_message *message,
|
|
int bus_locked)
|
|
{
|
|
DECLARE_COMPLETION_ONSTACK(done);
|
|
int status;
|
|
struct spi_master *master = spi->master;
|
|
|
|
message->complete = spi_complete;
|
|
message->context = &done;
|
|
|
|
if (!bus_locked)
|
|
mutex_lock(&master->bus_lock_mutex);
|
|
|
|
status = spi_async_locked(spi, message);
|
|
|
|
if (!bus_locked)
|
|
mutex_unlock(&master->bus_lock_mutex);
|
|
|
|
if (status == 0) {
|
|
wait_for_completion(&done);
|
|
status = message->status;
|
|
}
|
|
message->context = NULL;
|
|
return status;
|
|
}
|
|
|
|
/**
|
|
* spi_sync - blocking/synchronous SPI data transfers
|
|
* @spi: device with which data will be exchanged
|
|
* @message: describes the data transfers
|
|
* Context: can sleep
|
|
*
|
|
* This call may only be used from a context that may sleep. The sleep
|
|
* is non-interruptible, and has no timeout. Low-overhead controller
|
|
* drivers may DMA directly into and out of the message buffers.
|
|
*
|
|
* Note that the SPI device's chip select is active during the message,
|
|
* and then is normally disabled between messages. Drivers for some
|
|
* frequently-used devices may want to minimize costs of selecting a chip,
|
|
* by leaving it selected in anticipation that the next message will go
|
|
* to the same chip. (That may increase power usage.)
|
|
*
|
|
* Also, the caller is guaranteeing that the memory associated with the
|
|
* message will not be freed before this call returns.
|
|
*
|
|
* It returns zero on success, else a negative error code.
|
|
*/
|
|
int spi_sync(struct spi_device *spi, struct spi_message *message)
|
|
{
|
|
return __spi_sync(spi, message, 0);
|
|
}
|
|
EXPORT_SYMBOL_GPL(spi_sync);
|
|
|
|
/**
|
|
* spi_sync_locked - version of spi_sync with exclusive bus usage
|
|
* @spi: device with which data will be exchanged
|
|
* @message: describes the data transfers
|
|
* Context: can sleep
|
|
*
|
|
* This call may only be used from a context that may sleep. The sleep
|
|
* is non-interruptible, and has no timeout. Low-overhead controller
|
|
* drivers may DMA directly into and out of the message buffers.
|
|
*
|
|
* This call should be used by drivers that require exclusive access to the
|
|
* SPI bus. It has to be preceded by a spi_bus_lock call. The SPI bus must
|
|
* be released by a spi_bus_unlock call when the exclusive access is over.
|
|
*
|
|
* It returns zero on success, else a negative error code.
|
|
*/
|
|
int spi_sync_locked(struct spi_device *spi, struct spi_message *message)
|
|
{
|
|
return __spi_sync(spi, message, 1);
|
|
}
|
|
EXPORT_SYMBOL_GPL(spi_sync_locked);
|
|
|
|
/**
|
|
* spi_bus_lock - obtain a lock for exclusive SPI bus usage
|
|
* @master: SPI bus master that should be locked for exclusive bus access
|
|
* Context: can sleep
|
|
*
|
|
* This call may only be used from a context that may sleep. The sleep
|
|
* is non-interruptible, and has no timeout.
|
|
*
|
|
* This call should be used by drivers that require exclusive access to the
|
|
* SPI bus. The SPI bus must be released by a spi_bus_unlock call when the
|
|
* exclusive access is over. Data transfer must be done by spi_sync_locked
|
|
* and spi_async_locked calls when the SPI bus lock is held.
|
|
*
|
|
* It returns zero on success, else a negative error code.
|
|
*/
|
|
int spi_bus_lock(struct spi_master *master)
|
|
{
|
|
unsigned long flags;
|
|
|
|
mutex_lock(&master->bus_lock_mutex);
|
|
|
|
spin_lock_irqsave(&master->bus_lock_spinlock, flags);
|
|
master->bus_lock_flag = 1;
|
|
spin_unlock_irqrestore(&master->bus_lock_spinlock, flags);
|
|
|
|
/* mutex remains locked until spi_bus_unlock is called */
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(spi_bus_lock);
|
|
|
|
/**
|
|
* spi_bus_unlock - release the lock for exclusive SPI bus usage
|
|
* @master: SPI bus master that was locked for exclusive bus access
|
|
* Context: can sleep
|
|
*
|
|
* This call may only be used from a context that may sleep. The sleep
|
|
* is non-interruptible, and has no timeout.
|
|
*
|
|
* This call releases an SPI bus lock previously obtained by an spi_bus_lock
|
|
* call.
|
|
*
|
|
* It returns zero on success, else a negative error code.
|
|
*/
|
|
int spi_bus_unlock(struct spi_master *master)
|
|
{
|
|
master->bus_lock_flag = 0;
|
|
|
|
mutex_unlock(&master->bus_lock_mutex);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(spi_bus_unlock);
|
|
|
|
/* portable code must never pass more than 32 bytes */
|
|
#define SPI_BUFSIZ max(32,SMP_CACHE_BYTES)
|
|
|
|
static u8 *buf;
|
|
|
|
/**
|
|
* spi_write_then_read - SPI synchronous write followed by read
|
|
* @spi: device with which data will be exchanged
|
|
* @txbuf: data to be written (need not be dma-safe)
|
|
* @n_tx: size of txbuf, in bytes
|
|
* @rxbuf: buffer into which data will be read (need not be dma-safe)
|
|
* @n_rx: size of rxbuf, in bytes
|
|
* Context: can sleep
|
|
*
|
|
* This performs a half duplex MicroWire style transaction with the
|
|
* device, sending txbuf and then reading rxbuf. The return value
|
|
* is zero for success, else a negative errno status code.
|
|
* This call may only be used from a context that may sleep.
|
|
*
|
|
* Parameters to this routine are always copied using a small buffer;
|
|
* portable code should never use this for more than 32 bytes.
|
|
* Performance-sensitive or bulk transfer code should instead use
|
|
* spi_{async,sync}() calls with dma-safe buffers.
|
|
*/
|
|
int spi_write_then_read(struct spi_device *spi,
|
|
const void *txbuf, unsigned n_tx,
|
|
void *rxbuf, unsigned n_rx)
|
|
{
|
|
static DEFINE_MUTEX(lock);
|
|
|
|
int status;
|
|
struct spi_message message;
|
|
struct spi_transfer x[2];
|
|
u8 *local_buf;
|
|
|
|
/* Use preallocated DMA-safe buffer. We can't avoid copying here,
|
|
* (as a pure convenience thing), but we can keep heap costs
|
|
* out of the hot path ...
|
|
*/
|
|
if ((n_tx + n_rx) > SPI_BUFSIZ)
|
|
return -EINVAL;
|
|
|
|
spi_message_init(&message);
|
|
memset(x, 0, sizeof x);
|
|
if (n_tx) {
|
|
x[0].len = n_tx;
|
|
spi_message_add_tail(&x[0], &message);
|
|
}
|
|
if (n_rx) {
|
|
x[1].len = n_rx;
|
|
spi_message_add_tail(&x[1], &message);
|
|
}
|
|
|
|
/* ... unless someone else is using the pre-allocated buffer */
|
|
if (!mutex_trylock(&lock)) {
|
|
local_buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
|
|
if (!local_buf)
|
|
return -ENOMEM;
|
|
} else
|
|
local_buf = buf;
|
|
|
|
memcpy(local_buf, txbuf, n_tx);
|
|
x[0].tx_buf = local_buf;
|
|
x[1].rx_buf = local_buf + n_tx;
|
|
|
|
/* do the i/o */
|
|
status = spi_sync(spi, &message);
|
|
if (status == 0)
|
|
memcpy(rxbuf, x[1].rx_buf, n_rx);
|
|
|
|
if (x[0].tx_buf == buf)
|
|
mutex_unlock(&lock);
|
|
else
|
|
kfree(local_buf);
|
|
|
|
return status;
|
|
}
|
|
EXPORT_SYMBOL_GPL(spi_write_then_read);
|
|
|
|
/*-------------------------------------------------------------------------*/
|
|
|
|
static int __init spi_init(void)
|
|
{
|
|
int status;
|
|
|
|
buf = kmalloc(SPI_BUFSIZ, GFP_KERNEL);
|
|
if (!buf) {
|
|
status = -ENOMEM;
|
|
goto err0;
|
|
}
|
|
|
|
status = bus_register(&spi_bus_type);
|
|
if (status < 0)
|
|
goto err1;
|
|
|
|
status = class_register(&spi_master_class);
|
|
if (status < 0)
|
|
goto err2;
|
|
return 0;
|
|
|
|
err2:
|
|
bus_unregister(&spi_bus_type);
|
|
err1:
|
|
kfree(buf);
|
|
buf = NULL;
|
|
err0:
|
|
return status;
|
|
}
|
|
|
|
/* board_info is normally registered in arch_initcall(),
|
|
* but even essential drivers wait till later
|
|
*
|
|
* REVISIT only boardinfo really needs static linking. the rest (device and
|
|
* driver registration) _could_ be dynamically linked (modular) ... costs
|
|
* include needing to have boardinfo data structures be much more public.
|
|
*/
|
|
postcore_initcall(spi_init);
|
|
|