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The of_find_i2c_device_by_node function allows you to follow a reference in the device tree to an i2c device node and then locate the linux device instantiated by the device tree. Example use: an I2S bus driver finding the i2c_device instance for a codec described by a device tree node. This was waiting for Anton's i2c patches that were just added. Signed-off-by: Jon Smirl <jonsmirl@gmail.com> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
89 lines
2.1 KiB
C
89 lines
2.1 KiB
C
/*
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* OF helpers for the I2C API
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*
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* Copyright (c) 2008 Jochen Friedrich <jochen@scram.de>
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*
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* Based on a previous patch from Jon Smirl <jonsmirl@gmail.com>
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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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#include <linux/i2c.h>
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#include <linux/of.h>
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#include <linux/of_i2c.h>
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#include <linux/module.h>
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void of_register_i2c_devices(struct i2c_adapter *adap,
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struct device_node *adap_node)
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{
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void *result;
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struct device_node *node;
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for_each_child_of_node(adap_node, node) {
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struct i2c_board_info info = {};
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struct dev_archdata dev_ad = {};
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const u32 *addr;
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int len;
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if (of_modalias_node(node, info.type, sizeof(info.type)) < 0)
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continue;
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addr = of_get_property(node, "reg", &len);
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if (!addr || len < sizeof(int) || *addr > (1 << 10) - 1) {
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printk(KERN_ERR
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"of-i2c: invalid i2c device entry\n");
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continue;
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}
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info.irq = irq_of_parse_and_map(node, 0);
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info.addr = *addr;
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dev_archdata_set_node(&dev_ad, node);
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info.archdata = &dev_ad;
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request_module("%s", info.type);
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result = i2c_new_device(adap, &info);
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if (result == NULL) {
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printk(KERN_ERR
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"of-i2c: Failed to load driver for %s\n",
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info.type);
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irq_dispose_mapping(info.irq);
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continue;
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}
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/*
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* Get the node to not lose the dev_archdata->of_node.
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* Currently there is no way to put it back, as well as no
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* of_unregister_i2c_devices() call.
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*/
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of_node_get(node);
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}
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}
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EXPORT_SYMBOL(of_register_i2c_devices);
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static int of_dev_node_match(struct device *dev, void *data)
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{
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return dev_archdata_get_node(&dev->archdata) == data;
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}
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/* must call put_device() when done with returned i2c_client device */
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struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
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{
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struct device *dev;
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dev = bus_find_device(&i2c_bus_type, NULL, node,
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of_dev_node_match);
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if (!dev)
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return NULL;
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return to_i2c_client(dev);
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}
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EXPORT_SYMBOL(of_find_i2c_device_by_node);
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MODULE_LICENSE("GPL");
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