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/irq.h>
  16 #include <linux/of.h>
  17 #include <linux/of_i2c.h>
  18 #include <linux/of_irq.h>
  19 #include <linux/module.h>
  20
  21 void of_i2c_register_devices(struct i2c_adapter *adap)
  22 {
  23         void *result;
  24         struct device_node *node;
  25
  26         /* Only register child devices if the adapter has a node pointer set */
  27         if (!adap->dev.of_node)
  28                 return;
  29
  30         dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
  31
  32         for_each_child_of_node(adap->dev.of_node, node) {
  33                 struct i2c_board_info info = {};
  34                 struct dev_archdata dev_ad = {};
  35                 const __be32 *addr;
  36                 int len;
  37
  38                 dev_dbg(&adap->dev, "of_i2c: register %s\n", node->full_name);
  39
  40                 if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
  41                         dev_err(&adap->dev, "of_i2c: modalias failure on %s\n",
  42                                 node->full_name);
  43                         continue;
  44                 }
  45
  46                 addr = of_get_property(node, "reg", &len);
  47                 if (!addr || (len < sizeof(int))) {
  48                         dev_err(&adap->dev, "of_i2c: invalid reg on %s\n",
  49                                 node->full_name);
  50                         continue;
  51                 }
  52
  53                 info.addr = be32_to_cpup(addr);
  54                 if (info.addr > (1 << 10) - 1) {
  55                         dev_err(&adap->dev, "of_i2c: invalid addr=%x on %s\n",
  56                                 info.addr, node->full_name);
  57                         continue;
  58                 }
  59
  60                 info.irq = irq_of_parse_and_map(node, 0);
  61                 info.of_node = of_node_get(node);
  62                 info.archdata = &dev_ad;
  63
  64                 request_module("%s%s", I2C_MODULE_PREFIX, info.type);
  65
  66                 result = i2c_new_device(adap, &info);
  67                 if (result == NULL) {
  68                         dev_err(&adap->dev, "of_i2c: Failure registering %s\n",
  69                                 node->full_name);
  70                         of_node_put(node);
  71                         irq_dispose_mapping(info.irq);
  72                         continue;
  73                 }
  74         }
  75 }
  76 EXPORT_SYMBOL(of_i2c_register_devices);
  77
  78 static int of_dev_node_match(struct device *dev, void *data)
  79 {
  80         return dev->of_node == data;
  81 }
  82
  83 /* must call put_device() when done with returned i2c_client device */
  84 struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
  85 {
  86         struct device *dev;
  87
  88         dev = bus_find_device(&i2c_bus_type, NULL, node,
  89                                          of_dev_node_match);
  90         if (!dev)
  91                 return NULL;
  92
  93         return to_i2c_client(dev);
  94 }
  95 EXPORT_SYMBOL(of_find_i2c_device_by_node);
  96
  97 MODULE_LICENSE("GPL");