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, 2018 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 *client;
  29         struct i2c_board_info info = {};
  30         u32 addr;
  31         int ret;
  32
  33         dev_dbg(&adap->dev, "of_i2c: register %pOF\n", node);
  34
  35         if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
  36                 dev_err(&adap->dev, "of_i2c: modalias failure on %pOF\n",
  37                         node);
  38                 return ERR_PTR(-EINVAL);
  39         }
  40
  41         ret = of_property_read_u32(node, "reg", &addr);
  42         if (ret) {
  43                 dev_err(&adap->dev, "of_i2c: invalid reg on %pOF\n", node);
  44                 return ERR_PTR(ret);
  45         }
  46
  47         if (addr & I2C_TEN_BIT_ADDRESS) {
  48                 addr &= ~I2C_TEN_BIT_ADDRESS;
  49                 info.flags |= I2C_CLIENT_TEN;
  50         }
  51
  52         if (addr & I2C_OWN_SLAVE_ADDRESS) {
  53                 addr &= ~I2C_OWN_SLAVE_ADDRESS;
  54                 info.flags |= I2C_CLIENT_SLAVE;
  55         }
  56
  57         info.addr = addr;
  58         info.of_node = of_node_get(node);
  59
  60         if (of_property_read_bool(node, "host-notify"))
  61                 info.flags |= I2C_CLIENT_HOST_NOTIFY;
  62
  63         if (of_get_property(node, "wakeup-source", NULL))
  64                 info.flags |= I2C_CLIENT_WAKE;
  65
  66         client = i2c_new_device(adap, &info);
  67         if (!client) {
  68                 dev_err(&adap->dev, "of_i2c: Failure registering %pOF\n", node);
  69                 of_node_put(node);
  70                 return ERR_PTR(-EINVAL);
  71         }
  72         return client;
  73 }
  74
  75 void of_i2c_register_devices(struct i2c_adapter *adap)
  76 {
  77         struct device_node *bus, *node;
  78         struct i2c_client *client;
  79
  80         /* Only register child devices if the adapter has a node pointer set */
  81         if (!adap->dev.of_node)
  82                 return;
  83
  84         dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
  85
  86         bus = of_get_child_by_name(adap->dev.of_node, "i2c-bus");
  87         if (!bus)
  88                 bus = of_node_get(adap->dev.of_node);
  89
  90         for_each_available_child_of_node(bus, node) {
  91                 if (of_node_test_and_set_flag(node, OF_POPULATED))
  92                         continue;
  93
  94                 client = of_i2c_register_device(adap, node);
  95                 if (IS_ERR(client)) {
  96                         dev_err(&adap->dev,
  97                                  "Failed to create I2C device for %pOF\n",
  98                                  node);
  99                         of_node_clear_flag(node, OF_POPULATED);
 100                 }
 101         }
 102
 103         of_node_put(bus);
 104 }
 105
 106 static int of_dev_node_match(struct device *dev, void *data)
 107 {
 108         return dev->of_node == data;
 109 }
 110
 111 /* must call put_device() when done with returned i2c_client device */
 112 struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
 113 {
 114         struct device *dev;
 115         struct i2c_client *client;
 116
 117         dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
 118         if (!dev)
 119                 return NULL;
 120
 121         client = i2c_verify_client(dev);
 122         if (!client)
 123                 put_device(dev);
 124
 125         return client;
 126 }
 127 EXPORT_SYMBOL(of_find_i2c_device_by_node);
 128
 129 /* must call put_device() when done with returned i2c_adapter device */
 130 struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
 131 {
 132         struct device *dev;
 133         struct i2c_adapter *adapter;
 134
 135         dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
 136         if (!dev)
 137                 return NULL;
 138
 139         adapter = i2c_verify_adapter(dev);
 140         if (!adapter)
 141                 put_device(dev);
 142
 143         return adapter;
 144 }
 145 EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
 146
 147 /* must call i2c_put_adapter() when done with returned i2c_adapter device */
 148 struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
 149 {
 150         struct i2c_adapter *adapter;
 151
 152         adapter = of_find_i2c_adapter_by_node(node);
 153         if (!adapter)
 154                 return NULL;
 155
 156         if (!try_module_get(adapter->owner)) {
 157                 put_device(&adapter->dev);
 158                 adapter = NULL;
 159         }
 160
 161         return adapter;
 162 }
 163 EXPORT_SYMBOL(of_get_i2c_adapter_by_node);
 164
 165 static const struct of_device_id*
 166 i2c_of_match_device_sysfs(const struct of_device_id *matches,
 167                                   struct i2c_client *client)
 168 {
 169         const char *name;
 170
 171         for (; matches->compatible[0]; matches++) {
 172                 /*
 173                  * Adding devices through the i2c sysfs interface provides us
 174                  * a string to match which may be compatible with the device
 175                  * tree compatible strings, however with no actual of_node the
 176                  * of_match_device() will not match
 177                  */
 178                 if (sysfs_streq(client->name, matches->compatible))
 179                         return matches;
 180
 181                 name = strchr(matches->compatible, ',');
 182                 if (!name)
 183                         name = matches->compatible;
 184                 else
 185                         name++;
 186
 187                 if (sysfs_streq(client->name, name))
 188                         return matches;
 189         }
 190
 191         return NULL;
 192 }
 193
 194 const struct of_device_id
 195 *i2c_of_match_device(const struct of_device_id *matches,
 196                      struct i2c_client *client)
 197 {
 198         const struct of_device_id *match;
 199
 200         if (!(client && matches))
 201                 return NULL;
 202
 203         match = of_match_device(matches, &client->dev);
 204         if (match)
 205                 return match;
 206
 207         return i2c_of_match_device_sysfs(matches, client);
 208 }
 209 EXPORT_SYMBOL_GPL(i2c_of_match_device);
 210
 211 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
 212 static int of_i2c_notify(struct notifier_block *nb, unsigned long action,
 213                          void *arg)
 214 {
 215         struct of_reconfig_data *rd = arg;
 216         struct i2c_adapter *adap;
 217         struct i2c_client *client;
 218
 219         switch (of_reconfig_get_state_change(action, rd)) {
 220         case OF_RECONFIG_CHANGE_ADD:
 221                 adap = of_find_i2c_adapter_by_node(rd->dn->parent);
 222                 if (adap == NULL)
 223                         return NOTIFY_OK;       /* not for us */
 224
 225                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
 226                         put_device(&adap->dev);
 227                         return NOTIFY_OK;
 228                 }
 229
 230                 client = of_i2c_register_device(adap, rd->dn);
 231                 put_device(&adap->dev);
 232
 233                 if (IS_ERR(client)) {
 234                         dev_err(&adap->dev, "failed to create client for '%pOF'\n",
 235                                  rd->dn);
 236                         of_node_clear_flag(rd->dn, OF_POPULATED);
 237                         return notifier_from_errno(PTR_ERR(client));
 238                 }
 239                 break;
 240         case OF_RECONFIG_CHANGE_REMOVE:
 241                 /* already depopulated? */
 242                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
 243                         return NOTIFY_OK;
 244
 245                 /* find our device by node */
 246                 client = of_find_i2c_device_by_node(rd->dn);
 247                 if (client == NULL)
 248                         return NOTIFY_OK;       /* no? not meant for us */
 249
 250                 /* unregister takes one ref away */
 251                 i2c_unregister_device(client);
 252
 253                 /* and put the reference of the find */
 254                 put_device(&client->dev);
 255                 break;
 256         }
 257
 258         return NOTIFY_OK;
 259 }
 260
 261 struct notifier_block i2c_of_notifier = {
 262         .notifier_call = of_i2c_notify,
 263 };
 264 #endif /* CONFIG_OF_DYNAMIC */