drivers/i2c/i2c-core-of.c

   1 /*
   2  * Linux I2C core OF support code
   3  *
   4  * Copyright (C) 2008 Jochen Friedrich <jochen@scram.de>
   5  * based on a previous patch from Jon Smirl <jonsmirl@gmail.com>
   6  *
   7  * Copyright (C) 2013 Wolfram Sang <wsa@the-dreams.de>
   8  *
   9  * This program is free software; you can redistribute it and/or modify it
  10  * under the terms of the GNU General Public License as published by the Free
  11  * Software Foundation; either version 2 of the License, or (at your option)
  12  * any later version.
  13  */
  14
  15 #include <dt-bindings/i2c/i2c.h>
  16 #include <linux/device.h>
  17 #include <linux/err.h>
  18 #include <linux/i2c.h>
  19 #include <linux/module.h>
  20 #include <linux/of.h>
  21 #include <linux/of_device.h>
  22
  23 #include "i2c-core.h"
  24
  25 static struct i2c_client *of_i2c_register_device(struct i2c_adapter *adap,
  26                                                  struct device_node *node)
  27 {
  28         struct i2c_client *result;
  29         struct i2c_board_info info = {};
  30         struct dev_archdata dev_ad = {};
  31         const __be32 *addr_be;
  32         u32 addr;
  33         int len;
  34
  35         dev_dbg(&adap->dev, "of_i2c: register %pOF\n", node);
  36
  37         if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
  38                 dev_err(&adap->dev, "of_i2c: modalias failure on %pOF\n",
  39                         node);
  40                 return ERR_PTR(-EINVAL);
  41         }
  42
  43         addr_be = of_get_property(node, "reg", &len);
  44         if (!addr_be || (len < sizeof(*addr_be))) {
  45                 dev_err(&adap->dev, "of_i2c: invalid reg on %pOF\n", node);
  46                 return ERR_PTR(-EINVAL);
  47         }
  48
  49         addr = be32_to_cpup(addr_be);
  50         if (addr & I2C_TEN_BIT_ADDRESS) {
  51                 addr &= ~I2C_TEN_BIT_ADDRESS;
  52                 info.flags |= I2C_CLIENT_TEN;
  53         }
  54
  55         if (addr & I2C_OWN_SLAVE_ADDRESS) {
  56                 addr &= ~I2C_OWN_SLAVE_ADDRESS;
  57                 info.flags |= I2C_CLIENT_SLAVE;
  58         }
  59
  60         if (i2c_check_addr_validity(addr, info.flags)) {
  61                 dev_err(&adap->dev, "of_i2c: invalid addr=%x on %pOF\n",
  62                         addr, node);
  63                 return ERR_PTR(-EINVAL);
  64         }
  65
  66         info.addr = addr;
  67         info.of_node = of_node_get(node);
  68         info.archdata = &dev_ad;
  69
  70         if (of_property_read_bool(node, "host-notify"))
  71                 info.flags |= I2C_CLIENT_HOST_NOTIFY;
  72
  73         if (of_get_property(node, "wakeup-source", NULL))
  74                 info.flags |= I2C_CLIENT_WAKE;
  75
  76         result = i2c_new_device(adap, &info);
  77         if (result == NULL) {
  78                 dev_err(&adap->dev, "of_i2c: Failure registering %pOF\n", node);
  79                 of_node_put(node);
  80                 return ERR_PTR(-EINVAL);
  81         }
  82         return result;
  83 }
  84
  85 void of_i2c_register_devices(struct i2c_adapter *adap)
  86 {
  87         struct device_node *bus, *node;
  88         struct i2c_client *client;
  89
  90         /* Only register child devices if the adapter has a node pointer set */
  91         if (!adap->dev.of_node)
  92                 return;
  93
  94         dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
  95
  96         bus = of_get_child_by_name(adap->dev.of_node, "i2c-bus");
  97         if (!bus)
  98                 bus = of_node_get(adap->dev.of_node);
  99
 100         for_each_available_child_of_node(bus, node) {
 101                 if (of_node_test_and_set_flag(node, OF_POPULATED))
 102                         continue;
 103
 104                 client = of_i2c_register_device(adap, node);
 105                 if (IS_ERR(client)) {
 106                         dev_warn(&adap->dev,
 107                                  "Failed to create I2C device for %pOF\n",
 108                                  node);
 109                         of_node_clear_flag(node, OF_POPULATED);
 110                 }
 111         }
 112
 113         of_node_put(bus);
 114 }
 115
 116 static int of_dev_node_match(struct device *dev, void *data)
 117 {
 118         return dev->of_node == data;
 119 }
 120
 121 /* must call put_device() when done with returned i2c_client device */
 122 struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
 123 {
 124         struct device *dev;
 125         struct i2c_client *client;
 126
 127         dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
 128         if (!dev)
 129                 return NULL;
 130
 131         client = i2c_verify_client(dev);
 132         if (!client)
 133                 put_device(dev);
 134
 135         return client;
 136 }
 137 EXPORT_SYMBOL(of_find_i2c_device_by_node);
 138
 139 /* must call put_device() when done with returned i2c_adapter device */
 140 struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
 141 {
 142         struct device *dev;
 143         struct i2c_adapter *adapter;
 144
 145         dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
 146         if (!dev)
 147                 return NULL;
 148
 149         adapter = i2c_verify_adapter(dev);
 150         if (!adapter)
 151                 put_device(dev);
 152
 153         return adapter;
 154 }
 155 EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
 156
 157 /* must call i2c_put_adapter() when done with returned i2c_adapter device */
 158 struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
 159 {
 160         struct i2c_adapter *adapter;
 161
 162         adapter = of_find_i2c_adapter_by_node(node);
 163         if (!adapter)
 164                 return NULL;
 165
 166         if (!try_module_get(adapter->owner)) {
 167                 put_device(&adapter->dev);
 168                 adapter = NULL;
 169         }
 170
 171         return adapter;
 172 }
 173 EXPORT_SYMBOL(of_get_i2c_adapter_by_node);
 174
 175 static const struct of_device_id*
 176 i2c_of_match_device_sysfs(const struct of_device_id *matches,
 177                                   struct i2c_client *client)
 178 {
 179         const char *name;
 180
 181         for (; matches->compatible[0]; matches++) {
 182                 /*
 183                  * Adding devices through the i2c sysfs interface provides us
 184                  * a string to match which may be compatible with the device
 185                  * tree compatible strings, however with no actual of_node the
 186                  * of_match_device() will not match
 187                  */
 188                 if (sysfs_streq(client->name, matches->compatible))
 189                         return matches;
 190
 191                 name = strchr(matches->compatible, ',');
 192                 if (!name)
 193                         name = matches->compatible;
 194                 else
 195                         name++;
 196
 197                 if (sysfs_streq(client->name, name))
 198                         return matches;
 199         }
 200
 201         return NULL;
 202 }
 203
 204 const struct of_device_id
 205 *i2c_of_match_device(const struct of_device_id *matches,
 206                      struct i2c_client *client)
 207 {
 208         const struct of_device_id *match;
 209
 210         if (!(client && matches))
 211                 return NULL;
 212
 213         match = of_match_device(matches, &client->dev);
 214         if (match)
 215                 return match;
 216
 217         return i2c_of_match_device_sysfs(matches, client);
 218 }
 219 EXPORT_SYMBOL_GPL(i2c_of_match_device);
 220
 221 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
 222 static int of_i2c_notify(struct notifier_block *nb, unsigned long action,
 223                          void *arg)
 224 {
 225         struct of_reconfig_data *rd = arg;
 226         struct i2c_adapter *adap;
 227         struct i2c_client *client;
 228
 229         switch (of_reconfig_get_state_change(action, rd)) {
 230         case OF_RECONFIG_CHANGE_ADD:
 231                 adap = of_find_i2c_adapter_by_node(rd->dn->parent);
 232                 if (adap == NULL)
 233                         return NOTIFY_OK;       /* not for us */
 234
 235                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
 236                         put_device(&adap->dev);
 237                         return NOTIFY_OK;
 238                 }
 239
 240                 client = of_i2c_register_device(adap, rd->dn);
 241                 put_device(&adap->dev);
 242
 243                 if (IS_ERR(client)) {
 244                         dev_err(&adap->dev, "failed to create client for '%pOF'\n",
 245                                  rd->dn);
 246                         of_node_clear_flag(rd->dn, OF_POPULATED);
 247                         return notifier_from_errno(PTR_ERR(client));
 248                 }
 249                 break;
 250         case OF_RECONFIG_CHANGE_REMOVE:
 251                 /* already depopulated? */
 252                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
 253                         return NOTIFY_OK;
 254
 255                 /* find our device by node */
 256                 client = of_find_i2c_device_by_node(rd->dn);
 257                 if (client == NULL)
 258                         return NOTIFY_OK;       /* no? not meant for us */
 259
 260                 /* unregister takes one ref away */
 261                 i2c_unregister_device(client);
 262
 263                 /* and put the reference of the find */
 264                 put_device(&client->dev);
 265                 break;
 266         }
 267
 268         return NOTIFY_OK;
 269 }
 270
 271 struct notifier_block i2c_of_notifier = {
 272         .notifier_call = of_i2c_notify,
 273 };
 274 #endif /* CONFIG_OF_DYNAMIC */