0208626484
If we are registering an i2c device that has a device tree node like
this real-world example:
rtc@68 {
compatible = "dallas,ds1337";
reg = <0x68>;
};
of_i2c_register_devices() will try to load a module called ds1337.ko.
There is no such module, so it will fail. If we look in modules.alias
we will find entries like these:
.
.
.
alias i2c:ds1339 rtc_ds1307
alias i2c:ds1338 rtc_ds1307
alias i2c:ds1337 rtc_ds1307
alias i2c:ds1307 rtc_ds1307
alias i2c:ds1374 rtc_ds1374
.
.
.
The module we want is really called rtc_ds1307.ko. If we request a
module called "i2c:ds1337", the userspace module loader will do the
right thing (unless it is busybox) and load rtc_ds1307.ko. So we add
the I2C_MODULE_PREFIX to the request_module() string.
Signed-off-by: David Daney <ddaney@caviumnetworks.com>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
98 lines
2.4 KiB
C
98 lines
2.4 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/irq.h>
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#include <linux/of.h>
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#include <linux/of_i2c.h>
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#include <linux/of_irq.h>
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#include <linux/module.h>
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void of_i2c_register_devices(struct i2c_adapter *adap)
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{
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void *result;
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struct device_node *node;
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/* Only register child devices if the adapter has a node pointer set */
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if (!adap->dev.of_node)
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return;
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dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
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for_each_child_of_node(adap->dev.of_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 __be32 *addr;
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int len;
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dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
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if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
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dev_err(&adap->dev, "of_i2c: modalias failure on %s\n",
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node->full_name);
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continue;
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}
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addr = of_get_property(node, "reg", &len);
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if (!addr || (len < sizeof(int))) {
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dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
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node->full_name);
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continue;
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}
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info.addr = be32_to_cpup(addr);
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if (info.addr > (1 << 10) - 1) {
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dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
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info.addr, node->full_name);
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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.of_node = of_node_get(node);
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info.archdata = &dev_ad;
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request_module("%s%s", I2C_MODULE_PREFIX, info.type);
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result = i2c_new_device(adap, &info);
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if (result == NULL) {
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dev_err(&adap->dev, "of_i2c: Failure registering %s\n",
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node->full_name);
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of_node_put(node);
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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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}
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EXPORT_SYMBOL(of_i2c_register_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->of_node == 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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