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