drivers/of/of_i2c.c

   1 /*
   2  * OF helpers for the I2C API
   3  *
   4  * Copyright (c) 2008 Jochen Friedrich <jochen@scram.de>
   5  *
   6  * Based on a previous patch from Jon Smirl <jonsmirl@gmail.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License as published by
  10  * the Free Software Foundation; either version 2 of the License, or
  11  * (at your option) any later version.
  12  */
  13
  14 #include <linux/i2c.h>
  15 #include <linux/of.h>
  16 #include <linux/of_i2c.h>
  17 #include <linux/module.h>
  18
  19 void of_register_i2c_devices(struct i2c_adapter *adap,
  20                              struct device_node *adap_node)
  21 {
  22         void *result;
  23         struct device_node *node;
  24
  25         for_each_child_of_node(adap_node, node) {
  26                 struct i2c_board_info info = {};
  27                 struct dev_archdata dev_ad = {};
  28                 const __be32 *addr;
  29                 int len;
  30
  31                 if (of_modalias_node(node, info.type, sizeof(info.type)) < 0)
  32                         continue;
  33
  34                 addr = of_get_property(node, "reg", &len);
  35                 if (!addr || len < sizeof(int) || *addr > (1 << 10) - 1) {
  36                         printk(KERN_ERR
  37                                "of-i2c: invalid i2c device entry\n");
  38                         continue;
  39                 }
  40
  41                 info.irq = irq_of_parse_and_map(node, 0);
  42
  43                 info.addr = be32_to_cpup(addr);
  44
  45                 dev_archdata_set_node(&dev_ad, node);
  46                 info.archdata = &dev_ad;
  47
  48                 request_module("%s", info.type);
  49
  50                 result = i2c_new_device(adap, &info);
  51                 if (result == NULL) {
  52                         printk(KERN_ERR
  53                                "of-i2c: Failed to load driver for %s\n",
  54                                info.type);
  55                         irq_dispose_mapping(info.irq);
  56                         continue;
  57                 }
  58
  59                 /*
  60                  * Get the node to not lose the dev_archdata->of_node.
  61                  * Currently there is no way to put it back, as well as no
  62                  * of_unregister_i2c_devices() call.
  63                  */
  64                 of_node_get(node);
  65         }
  66 }
  67 EXPORT_SYMBOL(of_register_i2c_devices);
  68
  69 static int of_dev_node_match(struct device *dev, void *data)
  70 {
  71         return dev_archdata_get_node(&dev->archdata) == data;
  72 }
  73
  74 /* must call put_device() when done with returned i2c_client device */
  75 struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
  76 {
  77         struct device *dev;
  78
  79         dev = bus_find_device(&i2c_bus_type, NULL, node,
  80                                          of_dev_node_match);
  81         if (!dev)
  82                 return NULL;
  83
  84         return to_i2c_client(dev);
  85 }
  86 EXPORT_SYMBOL(of_find_i2c_device_by_node);
  87
  88 MODULE_LICENSE("GPL");