drivers/i2c/i2c-core-of.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Linux I2C core OF support code
   4  *
   5  * Copyright (C) 2008 Jochen Friedrich <jochen@scram.de>
   6  * based on a previous patch from Jon Smirl <jonsmirl@gmail.com>
   7  *
   8  * Copyright (C) 2013, 2018 Wolfram Sang <wsa@the-dreams.de>
   9  */
  10
  11 #include <dt-bindings/i2c/i2c.h>
  12 #include <linux/device.h>
  13 #include <linux/err.h>
  14 #include <linux/i2c.h>
  15 #include <linux/module.h>
  16 #include <linux/of.h>
  17 #include <linux/of_device.h>
  18 #include <linux/sysfs.h>
  19
  20 #include "i2c-core.h"
  21
  22 int of_i2c_get_board_info(struct device *dev, struct device_node *node,
  23                           struct i2c_board_info *info)
  24 {
  25         u32 addr;
  26         int ret;
  27
  28         memset(info, 0, sizeof(*info));
  29
  30         if (of_modalias_node(node, info->type, sizeof(info->type)) < 0) {
  31                 dev_err(dev, "of_i2c: modalias failure on %pOF\n", node);
  32                 return -EINVAL;
  33         }
  34
  35         ret = of_property_read_u32(node, "reg", &addr);
  36         if (ret) {
  37                 dev_err(dev, "of_i2c: invalid reg on %pOF\n", node);
  38                 return ret;
  39         }
  40
  41         if (addr & I2C_TEN_BIT_ADDRESS) {
  42                 addr &= ~I2C_TEN_BIT_ADDRESS;
  43                 info->flags |= I2C_CLIENT_TEN;
  44         }
  45
  46         if (addr & I2C_OWN_SLAVE_ADDRESS) {
  47                 addr &= ~I2C_OWN_SLAVE_ADDRESS;
  48                 info->flags |= I2C_CLIENT_SLAVE;
  49         }
  50
  51         info->addr = addr;
  52         info->of_node = node;
  53
  54         if (of_property_read_bool(node, "host-notify"))
  55                 info->flags |= I2C_CLIENT_HOST_NOTIFY;
  56
  57         if (of_get_property(node, "wakeup-source", NULL))
  58                 info->flags |= I2C_CLIENT_WAKE;
  59
  60         return 0;
  61 }
  62 EXPORT_SYMBOL_GPL(of_i2c_get_board_info);
  63
  64 static struct i2c_client *of_i2c_register_device(struct i2c_adapter *adap,
  65                                                  struct device_node *node)
  66 {
  67         struct i2c_client *client;
  68         struct i2c_board_info info;
  69         int ret;
  70
  71         dev_dbg(&adap->dev, "of_i2c: register %pOF\n", node);
  72
  73         ret = of_i2c_get_board_info(&adap->dev, node, &info);
  74         if (ret)
  75                 return ERR_PTR(ret);
  76
  77         client = i2c_new_device(adap, &info);
  78         if (!client) {
  79                 dev_err(&adap->dev, "of_i2c: Failure registering %pOF\n", node);
  80                 return ERR_PTR(-EINVAL);
  81         }
  82         return client;
  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_err(&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, const void *data)
 117 {
 118         return dev->of_node == data;
 119 }
 120
 121 static int of_dev_or_parent_node_match(struct device *dev, const void *data)
 122 {
 123         if (dev->of_node == data)
 124                 return 1;
 125
 126         if (dev->parent)
 127                 return dev->parent->of_node == data;
 128
 129         return 0;
 130 }
 131
 132 /* must call put_device() when done with returned i2c_client device */
 133 struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
 134 {
 135         struct device *dev;
 136         struct i2c_client *client;
 137
 138         dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
 139         if (!dev)
 140                 return NULL;
 141
 142         client = i2c_verify_client(dev);
 143         if (!client)
 144                 put_device(dev);
 145
 146         return client;
 147 }
 148 EXPORT_SYMBOL(of_find_i2c_device_by_node);
 149
 150 /* must call put_device() when done with returned i2c_adapter device */
 151 struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
 152 {
 153         struct device *dev;
 154         struct i2c_adapter *adapter;
 155
 156         dev = bus_find_device(&i2c_bus_type, NULL, node,
 157                               of_dev_or_parent_node_match);
 158         if (!dev)
 159                 return NULL;
 160
 161         adapter = i2c_verify_adapter(dev);
 162         if (!adapter)
 163                 put_device(dev);
 164
 165         return adapter;
 166 }
 167 EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
 168
 169 /* must call i2c_put_adapter() when done with returned i2c_adapter device */
 170 struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
 171 {
 172         struct i2c_adapter *adapter;
 173
 174         adapter = of_find_i2c_adapter_by_node(node);
 175         if (!adapter)
 176                 return NULL;
 177
 178         if (!try_module_get(adapter->owner)) {
 179                 put_device(&adapter->dev);
 180                 adapter = NULL;
 181         }
 182
 183         return adapter;
 184 }
 185 EXPORT_SYMBOL(of_get_i2c_adapter_by_node);
 186
 187 static const struct of_device_id*
 188 i2c_of_match_device_sysfs(const struct of_device_id *matches,
 189                                   struct i2c_client *client)
 190 {
 191         const char *name;
 192
 193         for (; matches->compatible[0]; matches++) {
 194                 /*
 195                  * Adding devices through the i2c sysfs interface provides us
 196                  * a string to match which may be compatible with the device
 197                  * tree compatible strings, however with no actual of_node the
 198                  * of_match_device() will not match
 199                  */
 200                 if (sysfs_streq(client->name, matches->compatible))
 201                         return matches;
 202
 203                 name = strchr(matches->compatible, ',');
 204                 if (!name)
 205                         name = matches->compatible;
 206                 else
 207                         name++;
 208
 209                 if (sysfs_streq(client->name, name))
 210                         return matches;
 211         }
 212
 213         return NULL;
 214 }
 215
 216 const struct of_device_id
 217 *i2c_of_match_device(const struct of_device_id *matches,
 218                      struct i2c_client *client)
 219 {
 220         const struct of_device_id *match;
 221
 222         if (!(client && matches))
 223                 return NULL;
 224
 225         match = of_match_device(matches, &client->dev);
 226         if (match)
 227                 return match;
 228
 229         return i2c_of_match_device_sysfs(matches, client);
 230 }
 231 EXPORT_SYMBOL_GPL(i2c_of_match_device);
 232
 233 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
 234 static int of_i2c_notify(struct notifier_block *nb, unsigned long action,
 235                          void *arg)
 236 {
 237         struct of_reconfig_data *rd = arg;
 238         struct i2c_adapter *adap;
 239         struct i2c_client *client;
 240
 241         switch (of_reconfig_get_state_change(action, rd)) {
 242         case OF_RECONFIG_CHANGE_ADD:
 243                 adap = of_find_i2c_adapter_by_node(rd->dn->parent);
 244                 if (adap == NULL)
 245                         return NOTIFY_OK;       /* not for us */
 246
 247                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
 248                         put_device(&adap->dev);
 249                         return NOTIFY_OK;
 250                 }
 251
 252                 client = of_i2c_register_device(adap, rd->dn);
 253                 put_device(&adap->dev);
 254
 255                 if (IS_ERR(client)) {
 256                         dev_err(&adap->dev, "failed to create client for '%pOF'\n",
 257                                  rd->dn);
 258                         of_node_clear_flag(rd->dn, OF_POPULATED);
 259                         return notifier_from_errno(PTR_ERR(client));
 260                 }
 261                 break;
 262         case OF_RECONFIG_CHANGE_REMOVE:
 263                 /* already depopulated? */
 264                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
 265                         return NOTIFY_OK;
 266
 267                 /* find our device by node */
 268                 client = of_find_i2c_device_by_node(rd->dn);
 269                 if (client == NULL)
 270                         return NOTIFY_OK;       /* no? not meant for us */
 271
 272                 /* unregister takes one ref away */
 273                 i2c_unregister_device(client);
 274
 275                 /* and put the reference of the find */
 276                 put_device(&client->dev);
 277                 break;
 278         }
 279
 280         return NOTIFY_OK;
 281 }
 282
 283 struct notifier_block i2c_of_notifier = {
 284         .notifier_call = of_i2c_notify,
 285 };
 286 #endif /* CONFIG_OF_DYNAMIC */