release/src-rt-6.x.4708/linux/linux-2.6.36/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/of_irq.h>
  18 #include <linux/module.h>
  19
  20 void of_i2c_register_devices(struct i2c_adapter *adap)
  21 {
  22         void *result;
  23         struct device_node *node;
  24
  25         /* Only register child devices if the adapter has a node pointer set */
  26         if (!adap->dev.of_node)
  27                 return;
  28
  29         dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
  30
  31         for_each_child_of_node(adap->dev.of_node, node) {
  32                 struct i2c_board_info info = {};
  33                 struct dev_archdata dev_ad = {};
  34                 const __be32 *addr;
  35                 int len;
  36
  37                 dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
  38
  39                 if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
  40                         dev_err(&adap->dev, "of_i2c: modalias failure on %s\n",
  41                                 node->full_name);
  42                         continue;
  43                 }
  44
  45                 addr = of_get_property(node, "reg", &len);
  46                 if (!addr || (len < sizeof(int))) {
  47                         dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
  48                                 node->full_name);
  49                         continue;
  50                 }
  51
  52                 info.addr = be32_to_cpup(addr);
  53                 if (info.addr > (1 << 10) - 1) {
  54                         dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
  55                                 info.addr, node->full_name);
  56                         continue;
  57                 }
  58
  59                 info.irq = irq_of_parse_and_map(node, 0);
  60                 info.of_node = of_node_get(node);
  61                 info.archdata = &dev_ad;
  62
  63                 request_module("%s", info.type);
  64
  65                 result = i2c_new_device(adap, &info);
  66                 if (result == NULL) {
  67                         dev_err(&adap->dev, "of_i2c: Failure registering %s\n",
  68                                 node->full_name);
  69                         of_node_put(node);
  70                         irq_dispose_mapping(info.irq);
  71                         continue;
  72                 }
  73         }
  74 }
  75 EXPORT_SYMBOL(of_i2c_register_devices);
  76
  77 static int of_dev_node_match(struct device *dev, void *data)
  78 {
  79         return dev->of_node == data;
  80 }
  81
  82 /* must call put_device() when done with returned i2c_client device */
  83 struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
  84 {
  85         struct device *dev;
  86
  87         dev = bus_find_device(&i2c_bus_type, NULL, node,
  88                                          of_dev_node_match);
  89         if (!dev)
  90                 return NULL;
  91
  92         return to_i2c_client(dev);
  93 }
  94 EXPORT_SYMBOL(of_find_i2c_device_by_node);
  95
  96 MODULE_LICENSE("GPL");