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         struct dev_archdata dev_ad = {};
  31         u32 addr;
  32         int ret;
  33
  34         dev_dbg(&adap->dev, "of_i2c: register %pOF\n", node);
  35
  36         if (of_modalias_node(node, info.type, sizeof(info.type)) < 0) {
  37                 dev_err(&adap->dev, "of_i2c: modalias failure on %pOF\n",
  38                         node);
  39                 return ERR_PTR(-EINVAL);
  40         }
  41
  42         ret = of_property_read_u32(node, "reg", &addr);
  43         if (ret) {
  44                 dev_err(&adap->dev, "of_i2c: invalid reg on %pOF\n", node);
  45                 return ERR_PTR(ret);
  46         }
  47
  48         if (addr & I2C_TEN_BIT_ADDRESS) {
  49                 addr &= ~I2C_TEN_BIT_ADDRESS;
  50                 info.flags |= I2C_CLIENT_TEN;
  51         }
  52
  53         if (addr & I2C_OWN_SLAVE_ADDRESS) {
  54                 addr &= ~I2C_OWN_SLAVE_ADDRESS;
  55                 info.flags |= I2C_CLIENT_SLAVE;
  56         }
  57
  58         info.addr = addr;
  59         info.archdata = &dev_ad;
  60         info.of_node = of_node_get(node);
  61
  62         if (of_property_read_bool(node, "host-notify"))
  63                 info.flags |= I2C_CLIENT_HOST_NOTIFY;
  64
  65         if (of_get_property(node, "wakeup-source", NULL))
  66                 info.flags |= I2C_CLIENT_WAKE;
  67
  68         client = i2c_new_device(adap, &info);
  69         if (!client) {
  70                 dev_err(&adap->dev, "of_i2c: Failure registering %pOF\n", node);
  71                 of_node_put(node);
  72                 return ERR_PTR(-EINVAL);
  73         }
  74         return client;
  75 }
  76
  77 void of_i2c_register_devices(struct i2c_adapter *adap)
  78 {
  79         struct device_node *bus, *node;
  80         struct i2c_client *client;
  81
  82         /* Only register child devices if the adapter has a node pointer set */
  83         if (!adap->dev.of_node)
  84                 return;
  85
  86         dev_dbg(&adap->dev, "of_i2c: walking child nodes\n");
  87
  88         bus = of_get_child_by_name(adap->dev.of_node, "i2c-bus");
  89         if (!bus)
  90                 bus = of_node_get(adap->dev.of_node);
  91
  92         for_each_available_child_of_node(bus, node) {
  93                 if (of_node_test_and_set_flag(node, OF_POPULATED))
  94                         continue;
  95
  96                 client = of_i2c_register_device(adap, node);
  97                 if (IS_ERR(client)) {
  98                         dev_err(&adap->dev,
  99                                  "Failed to create I2C device for %pOF\n",
 100                                  node);
 101                         of_node_clear_flag(node, OF_POPULATED);
 102                 }
 103         }
 104
 105         of_node_put(bus);
 106 }
 107
 108 static int of_dev_node_match(struct device *dev, void *data)
 109 {
 110         return dev->of_node == data;
 111 }
 112
 113 /* must call put_device() when done with returned i2c_client device */
 114 struct i2c_client *of_find_i2c_device_by_node(struct device_node *node)
 115 {
 116         struct device *dev;
 117         struct i2c_client *client;
 118
 119         dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
 120         if (!dev)
 121                 return NULL;
 122
 123         client = i2c_verify_client(dev);
 124         if (!client)
 125                 put_device(dev);
 126
 127         return client;
 128 }
 129 EXPORT_SYMBOL(of_find_i2c_device_by_node);
 130
 131 /* must call put_device() when done with returned i2c_adapter device */
 132 struct i2c_adapter *of_find_i2c_adapter_by_node(struct device_node *node)
 133 {
 134         struct device *dev;
 135         struct i2c_adapter *adapter;
 136
 137         dev = bus_find_device(&i2c_bus_type, NULL, node, of_dev_node_match);
 138         if (!dev)
 139                 return NULL;
 140
 141         adapter = i2c_verify_adapter(dev);
 142         if (!adapter)
 143                 put_device(dev);
 144
 145         return adapter;
 146 }
 147 EXPORT_SYMBOL(of_find_i2c_adapter_by_node);
 148
 149 /* must call i2c_put_adapter() when done with returned i2c_adapter device */
 150 struct i2c_adapter *of_get_i2c_adapter_by_node(struct device_node *node)
 151 {
 152         struct i2c_adapter *adapter;
 153
 154         adapter = of_find_i2c_adapter_by_node(node);
 155         if (!adapter)
 156                 return NULL;
 157
 158         if (!try_module_get(adapter->owner)) {
 159                 put_device(&adapter->dev);
 160                 adapter = NULL;
 161         }
 162
 163         return adapter;
 164 }
 165 EXPORT_SYMBOL(of_get_i2c_adapter_by_node);
 166
 167 static const struct of_device_id*
 168 i2c_of_match_device_sysfs(const struct of_device_id *matches,
 169                                   struct i2c_client *client)
 170 {
 171         const char *name;
 172
 173         for (; matches->compatible[0]; matches++) {
 174                 /*
 175                  * Adding devices through the i2c sysfs interface provides us
 176                  * a string to match which may be compatible with the device
 177                  * tree compatible strings, however with no actual of_node the
 178                  * of_match_device() will not match
 179                  */
 180                 if (sysfs_streq(client->name, matches->compatible))
 181                         return matches;
 182
 183                 name = strchr(matches->compatible, ',');
 184                 if (!name)
 185                         name = matches->compatible;
 186                 else
 187                         name++;
 188
 189                 if (sysfs_streq(client->name, name))
 190                         return matches;
 191         }
 192
 193         return NULL;
 194 }
 195
 196 const struct of_device_id
 197 *i2c_of_match_device(const struct of_device_id *matches,
 198                      struct i2c_client *client)
 199 {
 200         const struct of_device_id *match;
 201
 202         if (!(client && matches))
 203                 return NULL;
 204
 205         match = of_match_device(matches, &client->dev);
 206         if (match)
 207                 return match;
 208
 209         return i2c_of_match_device_sysfs(matches, client);
 210 }
 211 EXPORT_SYMBOL_GPL(i2c_of_match_device);
 212
 213 #if IS_ENABLED(CONFIG_OF_DYNAMIC)
 214 static int of_i2c_notify(struct notifier_block *nb, unsigned long action,
 215                          void *arg)
 216 {
 217         struct of_reconfig_data *rd = arg;
 218         struct i2c_adapter *adap;
 219         struct i2c_client *client;
 220
 221         switch (of_reconfig_get_state_change(action, rd)) {
 222         case OF_RECONFIG_CHANGE_ADD:
 223                 adap = of_find_i2c_adapter_by_node(rd->dn->parent);
 224                 if (adap == NULL)
 225                         return NOTIFY_OK;       /* not for us */
 226
 227                 if (of_node_test_and_set_flag(rd->dn, OF_POPULATED)) {
 228                         put_device(&adap->dev);
 229                         return NOTIFY_OK;
 230                 }
 231
 232                 client = of_i2c_register_device(adap, rd->dn);
 233                 put_device(&adap->dev);
 234
 235                 if (IS_ERR(client)) {
 236                         dev_err(&adap->dev, "failed to create client for '%pOF'\n",
 237                                  rd->dn);
 238                         of_node_clear_flag(rd->dn, OF_POPULATED);
 239                         return notifier_from_errno(PTR_ERR(client));
 240                 }
 241                 break;
 242         case OF_RECONFIG_CHANGE_REMOVE:
 243                 /* already depopulated? */
 244                 if (!of_node_check_flag(rd->dn, OF_POPULATED))
 245                         return NOTIFY_OK;
 246
 247                 /* find our device by node */
 248                 client = of_find_i2c_device_by_node(rd->dn);
 249                 if (client == NULL)
 250                         return NOTIFY_OK;       /* no? not meant for us */
 251
 252                 /* unregister takes one ref away */
 253                 i2c_unregister_device(client);
 254
 255                 /* and put the reference of the find */
 256                 put_device(&client->dev);
 257                 break;
 258         }
 259
 260         return NOTIFY_OK;
 261 }
 262
 263 struct notifier_block i2c_of_notifier = {
 264         .notifier_call = of_i2c_notify,
 265 };
 266 #endif /* CONFIG_OF_DYNAMIC */