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linux/drivers/i2c/busses/i2c-at91-core.c
Codrin Ciubotariu 73371d5f31 i2c: at91: Send bus clear command if SDA is down 
After a transfer timeout, some faulty I2C slave devices might hold down
the SDA pin. We can generate a bus clear command, hoping that the slave
might release the pins.
If the CLEAR command is not supported, we will use gpio recovery, if
available, to reset the bus.

Signed-off-by: Codrin Ciubotariu <codrin.ciubotariu@microchip.com>
Acked-by: Ludovic Desroches <ludovic.desroches@microchip.com>
Signed-off-by: Wolfram Sang <wsa@kernel.org>
2020-05-05 16:37:21 +02:00

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// SPDX-License-Identifier: GPL-2.0
/*
* i2c Support for Atmel's AT91 Two-Wire Interface (TWI)
*
* Copyright (C) 2011 Weinmann Medical GmbH
* Author: Nikolaus Voss <n.voss@weinmann.de>
*
* Evolved from original work by:
* Copyright (C) 2004 Rick Bronson
* Converted to 2.6 by Andrew Victor <andrew@sanpeople.com>
*
* Borrowed heavily from original work by:
* Copyright (C) 2000 Philip Edelbrock <phil@stimpy.netroedge.com>
*/
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/i2c.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_device.h>
#include <linux/platform_device.h>
#include <linux/pm_runtime.h>
#include <linux/pinctrl/consumer.h>
#include "i2c-at91.h"
unsigned at91_twi_read(struct at91_twi_dev *dev, unsigned reg)
{
return readl_relaxed(dev->base + reg);
}
void at91_twi_write(struct at91_twi_dev *dev, unsigned reg, unsigned val)
{
writel_relaxed(val, dev->base + reg);
}
void at91_disable_twi_interrupts(struct at91_twi_dev *dev)
{
at91_twi_write(dev, AT91_TWI_IDR, AT91_TWI_INT_MASK);
}
void at91_twi_irq_save(struct at91_twi_dev *dev)
{
dev->imr = at91_twi_read(dev, AT91_TWI_IMR) & AT91_TWI_INT_MASK;
at91_disable_twi_interrupts(dev);
}
void at91_twi_irq_restore(struct at91_twi_dev *dev)
{
at91_twi_write(dev, AT91_TWI_IER, dev->imr);
}
void at91_init_twi_bus(struct at91_twi_dev *dev)
{
at91_disable_twi_interrupts(dev);
at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SWRST);
if (dev->slave_detected)
at91_init_twi_bus_slave(dev);
else
at91_init_twi_bus_master(dev);
}
static struct at91_twi_pdata at91rm9200_config = {
.clk_max_div = 5,
.clk_offset = 3,
.has_unre_flag = true,
};
static struct at91_twi_pdata at91sam9261_config = {
.clk_max_div = 5,
.clk_offset = 4,
};
static struct at91_twi_pdata at91sam9260_config = {
.clk_max_div = 7,
.clk_offset = 4,
};
static struct at91_twi_pdata at91sam9g20_config = {
.clk_max_div = 7,
.clk_offset = 4,
};
static struct at91_twi_pdata at91sam9g10_config = {
.clk_max_div = 7,
.clk_offset = 4,
};
static const struct platform_device_id at91_twi_devtypes[] = {
{
.name = "i2c-at91rm9200",
.driver_data = (unsigned long) &at91rm9200_config,
}, {
.name = "i2c-at91sam9261",
.driver_data = (unsigned long) &at91sam9261_config,
}, {
.name = "i2c-at91sam9260",
.driver_data = (unsigned long) &at91sam9260_config,
}, {
.name = "i2c-at91sam9g20",
.driver_data = (unsigned long) &at91sam9g20_config,
}, {
.name = "i2c-at91sam9g10",
.driver_data = (unsigned long) &at91sam9g10_config,
}, {
/* sentinel */
}
};
#if defined(CONFIG_OF)
static struct at91_twi_pdata at91sam9x5_config = {
.clk_max_div = 7,
.clk_offset = 4,
};
static struct at91_twi_pdata sama5d4_config = {
.clk_max_div = 7,
.clk_offset = 4,
.has_hold_field = true,
.has_dig_filtr = true,
};
static struct at91_twi_pdata sama5d2_config = {
.clk_max_div = 7,
.clk_offset = 3,
.has_unre_flag = true,
.has_alt_cmd = true,
.has_hold_field = true,
.has_dig_filtr = true,
.has_adv_dig_filtr = true,
.has_ana_filtr = true,
.has_clear_cmd = false, /* due to errata, CLEAR cmd is not working */
};
static struct at91_twi_pdata sam9x60_config = {
.clk_max_div = 7,
.clk_offset = 3,
.has_unre_flag = true,
.has_alt_cmd = true,
.has_hold_field = true,
.has_dig_filtr = true,
.has_adv_dig_filtr = true,
.has_ana_filtr = true,
.has_clear_cmd = true,
};
static const struct of_device_id atmel_twi_dt_ids[] = {
{
.compatible = "atmel,at91rm9200-i2c",
.data = &at91rm9200_config,
}, {
.compatible = "atmel,at91sam9260-i2c",
.data = &at91sam9260_config,
}, {
.compatible = "atmel,at91sam9261-i2c",
.data = &at91sam9261_config,
}, {
.compatible = "atmel,at91sam9g20-i2c",
.data = &at91sam9g20_config,
}, {
.compatible = "atmel,at91sam9g10-i2c",
.data = &at91sam9g10_config,
}, {
.compatible = "atmel,at91sam9x5-i2c",
.data = &at91sam9x5_config,
}, {
.compatible = "atmel,sama5d4-i2c",
.data = &sama5d4_config,
}, {
.compatible = "atmel,sama5d2-i2c",
.data = &sama5d2_config,
}, {
.compatible = "microchip,sam9x60-i2c",
.data = &sam9x60_config,
}, {
/* sentinel */
}
};
MODULE_DEVICE_TABLE(of, atmel_twi_dt_ids);
#endif
static struct at91_twi_pdata *at91_twi_get_driver_data(
struct platform_device *pdev)
{
if (pdev->dev.of_node) {
const struct of_device_id *match;
match = of_match_node(atmel_twi_dt_ids, pdev->dev.of_node);
if (!match)
return NULL;
return (struct at91_twi_pdata *)match->data;
}
return (struct at91_twi_pdata *) platform_get_device_id(pdev)->driver_data;
}
static int at91_twi_probe(struct platform_device *pdev)
{
struct at91_twi_dev *dev;
struct resource *mem;
int rc;
u32 phy_addr;
dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
if (!dev)
return -ENOMEM;
dev->dev = &pdev->dev;
mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!mem)
return -ENODEV;
phy_addr = mem->start;
dev->pdata = at91_twi_get_driver_data(pdev);
if (!dev->pdata)
return -ENODEV;
dev->base = devm_ioremap_resource(&pdev->dev, mem);
if (IS_ERR(dev->base))
return PTR_ERR(dev->base);
dev->irq = platform_get_irq(pdev, 0);
if (dev->irq < 0)
return dev->irq;
platform_set_drvdata(pdev, dev);
dev->clk = devm_clk_get(dev->dev, NULL);
if (IS_ERR(dev->clk)) {
dev_err(dev->dev, "no clock defined\n");
return -ENODEV;
}
clk_prepare_enable(dev->clk);
snprintf(dev->adapter.name, sizeof(dev->adapter.name), "AT91");
i2c_set_adapdata(&dev->adapter, dev);
dev->adapter.owner = THIS_MODULE;
dev->adapter.class = I2C_CLASS_DEPRECATED;
dev->adapter.dev.parent = dev->dev;
dev->adapter.nr = pdev->id;
dev->adapter.timeout = AT91_I2C_TIMEOUT;
dev->adapter.dev.of_node = pdev->dev.of_node;
dev->slave_detected = i2c_detect_slave_mode(&pdev->dev);
if (dev->slave_detected)
rc = at91_twi_probe_slave(pdev, phy_addr, dev);
else
rc = at91_twi_probe_master(pdev, phy_addr, dev);
if (rc)
return rc;
at91_init_twi_bus(dev);
pm_runtime_set_autosuspend_delay(dev->dev, AUTOSUSPEND_TIMEOUT);
pm_runtime_use_autosuspend(dev->dev);
pm_runtime_set_active(dev->dev);
pm_runtime_enable(dev->dev);
rc = i2c_add_numbered_adapter(&dev->adapter);
if (rc) {
clk_disable_unprepare(dev->clk);
pm_runtime_disable(dev->dev);
pm_runtime_set_suspended(dev->dev);
return rc;
}
dev_info(dev->dev, "AT91 i2c bus driver (hw version: %#x).\n",
at91_twi_read(dev, AT91_TWI_VER));
return 0;
}
static int at91_twi_remove(struct platform_device *pdev)
{
struct at91_twi_dev *dev = platform_get_drvdata(pdev);
i2c_del_adapter(&dev->adapter);
clk_disable_unprepare(dev->clk);
pm_runtime_disable(dev->dev);
pm_runtime_set_suspended(dev->dev);
return 0;
}
#ifdef CONFIG_PM
static int at91_twi_runtime_suspend(struct device *dev)
{
struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
clk_disable_unprepare(twi_dev->clk);
pinctrl_pm_select_sleep_state(dev);
return 0;
}
static int at91_twi_runtime_resume(struct device *dev)
{
struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
pinctrl_pm_select_default_state(dev);
return clk_prepare_enable(twi_dev->clk);
}
static int at91_twi_suspend_noirq(struct device *dev)
{
if (!pm_runtime_status_suspended(dev))
at91_twi_runtime_suspend(dev);
return 0;
}
static int at91_twi_resume_noirq(struct device *dev)
{
struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
int ret;
if (!pm_runtime_status_suspended(dev)) {
ret = at91_twi_runtime_resume(dev);
if (ret)
return ret;
}
pm_runtime_mark_last_busy(dev);
pm_request_autosuspend(dev);
at91_init_twi_bus(twi_dev);
return 0;
}
static const struct dev_pm_ops at91_twi_pm = {
.suspend_noirq = at91_twi_suspend_noirq,
.resume_noirq = at91_twi_resume_noirq,
.runtime_suspend = at91_twi_runtime_suspend,
.runtime_resume = at91_twi_runtime_resume,
};
#define at91_twi_pm_ops (&at91_twi_pm)
#else
#define at91_twi_pm_ops NULL
#endif
static struct platform_driver at91_twi_driver = {
.probe = at91_twi_probe,
.remove = at91_twi_remove,
.id_table = at91_twi_devtypes,
.driver = {
.name = "at91_i2c",
.of_match_table = of_match_ptr(atmel_twi_dt_ids),
.pm = at91_twi_pm_ops,
},
};
static int __init at91_twi_init(void)
{
return platform_driver_register(&at91_twi_driver);
}
static void __exit at91_twi_exit(void)
{
platform_driver_unregister(&at91_twi_driver);
}
subsys_initcall(at91_twi_init);
module_exit(at91_twi_exit);
MODULE_AUTHOR("Nikolaus Voss <n.voss@weinmann.de>");
MODULE_DESCRIPTION("I2C (TWI) driver for Atmel AT91");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:at91_i2c");
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