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         info->fwnode = of_fwnode_handle(node);
  54
  55         if (of_property_read_bool(node, "host-notify"))
  56                 info->flags |= I2C_CLIENT_HOST_NOTIFY;
  57
  58         if (of_get_property(node, "wakeup-source", NULL))
  59                 info->flags |= I2C_CLIENT_WAKE;
  60
  61         return 0;
  62 }
  63 EXPORT_SYMBOL_GPL(of_i2c_get_board_info);
  64
  65 static struct i2c_client *of_i2c_register_device(struct i2c_adapter *adap,
  66                                                  struct device_node *node)
  67 {
  68         struct i2c_client *client;
  69         struct i2c_board_info info;
  70         int ret;
  71
  72         dev_dbg(&adap->dev, "of_i2c: register %pOF\n", node);
  73
  74         ret = of_i2c_get_board_info(&adap->dev, node, &info);
  75         if (ret)
  76                 return ERR_PTR(ret);
  77
  78         client = i2c_new_device(adap, &info);
  79         if (!client) {
  80                 dev_err(&adap->dev, "of_i2c: Failure registering %pOF\n", node);
  81                 return ERR_PTR(-EINVAL);
  82         }
  83         return client;
  84 }
  85
  86 void of_i2c_register_devices(struct i2c_adapter *adap)
  87 {
  88         struct device_node *bus, *node;
  89         struct i2c_client *client;
  90
  91         /* Only register child devices if the adapter has a node pointer set */
  92         if (!adap->dev.of_node)
  93                 return;
  94
  95         dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
  96
  97         bus = of_get_child_by_name(adap->dev.of_node, "i2c-bus");
  98         if (!bus)
  99                 bus = of_node_get(adap->dev.of_node);
 100
 101         for_each_available_child_of_node(bus, node) {
 102                 if (of_node_test_and_set_flag(node, OF_POPULATED))
 103                         continue;
 104
 105                 client = of_i2c_register_device(adap, node);
 106                 if (IS_ERR(client)) {
 107                         dev_err(&adap->dev,
 108                                  "Failed to create I2C device for %pOF\n",
 109                                  node);
 110                         of_node_clear_flag(node, OF_POPULATED);
 111                 }
 112         }
 113
 114         of_node_put(bus);
 115 }
 116
 117 static int of_dev_or_parent_node_match(struct device *dev, const void *data)
 118 {
 119         if (dev->of_node == data)
 120                 return 1;
 121
 122         if (dev->parent)
 123                 return dev->parent->of_node == data;
 124
 125         return 0;
 126 }
 127
 128 /* must call put_device() when done with returned i2c_client device */
 129 struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
 130 {
 131         struct device *dev;
 132         struct i2c_client *client;
 133
 134         dev = bus_find_device_by_of_node(&i2c_bus_type, node);
 135         if (!dev)
 136                 return NULL;
 137
 138         client = i2c_verify_client(dev);
 139         if (!client)
 140                 put_device(dev);
 141
 142         return client;
 143 }
 144 EXPORT_SYMBOL(of_find_i2c_device_by_node);
 145
 146 /* must call put_device() when done with returned i2c_adapter device */
 147 struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
 148 {
 149         struct device *dev;
 150         struct i2c_adapter *adapter;
 151
 152         dev = bus_find_device(&i2c_bus_type, NULL, node,
 153                               of_dev_or_parent_node_match);
 154         if (!dev)
 155                 return NULL;
 156
 157         adapter = i2c_verify_adapter(dev);
 158         if (!adapter)
 159                 put_device(dev);
 160
 161         return adapter;
 162 }
 163 EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
 164
 165 /* must call i2c_put_adapter() when done with returned i2c_adapter device */
 166 struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
 167 {
 168         struct i2c_adapter *adapter;
 169
 170         adapter = of_find_i2c_adapter_by_node(node);
 171         if (!adapter)
 172                 return NULL;
 173
 174         if (!try_module_get(adapter->owner)) {
 175                 put_device(&adapter->dev);
 176                 adapter = NULL;
 177         }
 178
 179         return adapter;
 180 }
 181 EXPORT_SYMBOL(of_get_i2c_adapter_by_node);
 182
 183 static const struct of_device_id*
 184 i2c_of_match_device_sysfs(const struct of_device_id *matches,
 185                                   struct i2c_client *client)
 186 {
 187         const char *name;
 188
 189         for (; matches->compatible[0]; matches++) {
 190                 /*
 191                  * Adding devices through the i2c sysfs interface provides us
 192                  * a string to match which may be compatible with the device
 193                  * tree compatible strings, however with no actual of_node the
 194                  * of_match_device() will not match
 195                  */
 196                 if (sysfs_streq(client->name, matches->compatible))
 197                         return matches;
 198
 199                 name = strchr(matches->compatible, ',');
 200                 if (!name)
 201                         name = matches->compatible;
 202                 else
 203                         name++;
 204
 205                 if (sysfs_streq(client->name, name))
 206                         return matches;
 207         }
 208
 209         return NULL;
 210 }
 211
 212 const struct of_device_id
 213 *i2c_of_match_device(const struct of_device_id *matches,
 214                      struct i2c_client *client)
 215 {
 216         const struct of_device_id *match;
 217
 218         if (!(client && matches))
 219                 return NULL;
 220
 221         match = of_match_device(matches, &client->dev);
 222         if (match)
 223                 return match;
 224
 225         return i2c_of_match_device_sysfs(matches, client);
 226 }
 227 EXPORT_SYMBOL_GPL(i2c_of_match_device);
 228
 229 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
 230 static int of_i2c_notify(struct notifier_block *nb, unsigned long action,
 231                          void *arg)
 232 {
 233         struct of_reconfig_data *rd = arg;
 234         struct i2c_adapter *adap;
 235         struct i2c_client *client;
 236
 237         switch (of_reconfig_get_state_change(action, rd)) {
 238         case OF_RECONFIG_CHANGE_ADD:
 239                 adap = of_find_i2c_adapter_by_node(rd->dn->parent);
 240                 if (adap == NULL)
 241                         return NOTIFY_OK;       /* not for us */
 242
 243                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
 244                         put_device(&adap->dev);
 245                         return NOTIFY_OK;
 246                 }
 247
 248                 client = of_i2c_register_device(adap, rd->dn);
 249                 if (IS_ERR(client)) {
 250                         dev_err(&adap->dev, "failed to create client for '%pOF'\n",
 251                                  rd->dn);
 252                         put_device(&adap->dev);
 253                         of_node_clear_flag(rd->dn, OF_POPULATED);
 254                         return notifier_from_errno(PTR_ERR(client));
 255                 }
 256                 put_device(&adap->dev);
 257                 break;
 258         case OF_RECONFIG_CHANGE_REMOVE:
 259                 /* already depopulated? */
 260                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
 261                         return NOTIFY_OK;
 262
 263                 /* find our device by node */
 264                 client = of_find_i2c_device_by_node(rd->dn);
 265                 if (client == NULL)
 266                         return NOTIFY_OK;       /* no? not meant for us */
 267
 268                 /* unregister takes one ref away */
 269                 i2c_unregister_device(client);
 270
 271                 /* and put the reference of the find */
 272                 put_device(&client->dev);
 273                 break;
 274         }
 275
 276         return NOTIFY_OK;
 277 }
 278
 279 struct notifier_block i2c_of_notifier = {
 280         .notifier_call = of_i2c_notify,
 281 };
 282 #endif /* CONFIG_OF_DYNAMIC */