drivers/i2c/i2c-acpi.c

   1 /*
   2  * I2C ACPI code
   3  *
   4  * Copyright (C) 2014 Intel Corp
   5  *
   6  * Author: Lan Tianyu <tianyu.lan@intel.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but
  13  * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
  14  * or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
  15  * for more details.
  16  */
  17 #define pr_fmt(fmt) "I2C/ACPI : " fmt
  18
  19 #include <linux/kernel.h>
  20 #include <linux/errno.h>
  21 #include <linux/err.h>
  22 #include <linux/i2c.h>
  23 #include <linux/acpi.h>
  24
  25 struct acpi_i2c_handler_data {
  26         struct acpi_connection_info info;
  27         struct i2c_adapter *adapter;
  28 };
  29
  30 struct gsb_buffer {
  31         u8      status;
  32         u8      len;
  33         union {
  34                 u16     wdata;
  35                 u8      bdata;
  36                 u8      data[0];
  37         };
  38 } __packed;
  39
  40 static int acpi_i2c_add_resource(struct acpi_resource *ares, void *data)
  41 {
  42         struct i2c_board_info *info = data;
  43
  44         if (ares->type == ACPI_RESOURCE_TYPE_SERIAL_BUS) {
  45                 struct acpi_resource_i2c_serialbus *sb;
  46
  47                 sb = &ares->data.i2c_serial_bus;
  48                 if (sb->type == ACPI_RESOURCE_SERIAL_TYPE_I2C) {
  49                         info->addr = sb->slave_address;
  50                         if (sb->access_mode == ACPI_I2C_10BIT_MODE)
  51                                 info->flags |= I2C_CLIENT_TEN;
  52                 }
  53         } else if (info->irq < 0) {
  54                 struct resource r;
  55
  56                 if (acpi_dev_resource_interrupt(ares, 0, &r))
  57                         info->irq = r.start;
  58         }
  59
  60         /* Tell the ACPI core to skip this resource */
  61         return 1;
  62 }
  63
  64 static acpi_status acpi_i2c_add_device(acpi_handle handle, u32 level,
  65                                        void *data, void **return_value)
  66 {
  67         struct i2c_adapter *adapter = data;
  68         struct list_head resource_list;
  69         struct i2c_board_info info;
  70         struct acpi_device *adev;
  71         int ret;
  72
  73         if (acpi_bus_get_device(handle, &adev))
  74                 return AE_OK;
  75         if (acpi_bus_get_status(adev) || !adev->status.present)
  76                 return AE_OK;
  77
  78         memset(&info, 0, sizeof(info));
  79         info.acpi_node.companion = adev;
  80         info.irq = -1;
  81
  82         INIT_LIST_HEAD(&resource_list);
  83         ret = acpi_dev_get_resources(adev, &resource_list,
  84                                      acpi_i2c_add_resource, &info);
  85         acpi_dev_free_resource_list(&resource_list);
  86
  87         if (ret < 0 || !info.addr)
  88                 return AE_OK;
  89
  90         adev->power.flags.ignore_parent = true;
  91         strlcpy(info.type, dev_name(&adev->dev), sizeof(info.type));
  92         if (!i2c_new_device(adapter, &info)) {
  93                 adev->power.flags.ignore_parent = false;
  94                 dev_err(&adapter->dev,
  95                         "failed to add I2C device %s from ACPI\n",
  96                         dev_name(&adev->dev));
  97         }
  98
  99         return AE_OK;
 100 }
 101
 102 /**
 103  * acpi_i2c_register_devices - enumerate I2C slave devices behind adapter
 104  * @adap: pointer to adapter
 105  *
 106  * Enumerate all I2C slave devices behind this adapter by walking the ACPI
 107  * namespace. When a device is found it will be added to the Linux device
 108  * model and bound to the corresponding ACPI handle.
 109  */
 110 void acpi_i2c_register_devices(struct i2c_adapter *adap)
 111 {
 112         acpi_handle handle;
 113         acpi_status status;
 114
 115         if (!adap->dev.parent)
 116                 return;
 117
 118         handle = ACPI_HANDLE(adap->dev.parent);
 119         if (!handle)
 120                 return;
 121
 122         status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
 123                                      acpi_i2c_add_device, NULL,
 124                                      adap, NULL);
 125         if (ACPI_FAILURE(status))
 126                 dev_warn(&adap->dev, "failed to enumerate I2C slaves\n");
 127 }
 128
 129 static int acpi_gsb_i2c_read_bytes(struct i2c_client *client,
 130                 u8 cmd, u8 *data, u8 data_len)
 131 {
 132
 133         struct i2c_msg msgs[2];
 134         int ret;
 135         u8 *buffer;
 136
 137         buffer = kzalloc(data_len, GFP_KERNEL);
 138         if (!buffer)
 139                 return AE_NO_MEMORY;
 140
 141         msgs[0].addr = client->addr;
 142         msgs[0].flags = client->flags;
 143         msgs[0].len = 1;
 144         msgs[0].buf = &cmd;
 145
 146         msgs[1].addr = client->addr;
 147         msgs[1].flags = client->flags | I2C_M_RD;
 148         msgs[1].len = data_len;
 149         msgs[1].buf = buffer;
 150
 151         ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
 152         if (ret < 0)
 153                 dev_err(&client->adapter->dev, "i2c read failed\n");
 154         else
 155                 memcpy(data, buffer, data_len);
 156
 157         kfree(buffer);
 158         return ret;
 159 }
 160
 161 static int acpi_gsb_i2c_write_bytes(struct i2c_client *client,
 162                 u8 cmd, u8 *data, u8 data_len)
 163 {
 164
 165         struct i2c_msg msgs[1];
 166         u8 *buffer;
 167         int ret = AE_OK;
 168
 169         buffer = kzalloc(data_len + 1, GFP_KERNEL);
 170         if (!buffer)
 171                 return AE_NO_MEMORY;
 172
 173         buffer[0] = cmd;
 174         memcpy(buffer + 1, data, data_len);
 175
 176         msgs[0].addr = client->addr;
 177         msgs[0].flags = client->flags;
 178         msgs[0].len = data_len + 1;
 179         msgs[0].buf = buffer;
 180
 181         ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
 182         if (ret < 0)
 183                 dev_err(&client->adapter->dev, "i2c write failed\n");
 184
 185         kfree(buffer);
 186         return ret;
 187 }
 188
 189 static acpi_status
 190 acpi_i2c_space_handler(u32 function, acpi_physical_address command,
 191                         u32 bits, u64 *value64,
 192                         void *handler_context, void *region_context)
 193 {
 194         struct gsb_buffer *gsb = (struct gsb_buffer *)value64;
 195         struct acpi_i2c_handler_data *data = handler_context;
 196         struct acpi_connection_info *info = &data->info;
 197         struct acpi_resource_i2c_serialbus *sb;
 198         struct i2c_adapter *adapter = data->adapter;
 199         struct i2c_client client;
 200         struct acpi_resource *ares;
 201         u32 accessor_type = function >> 16;
 202         u8 action = function & ACPI_IO_MASK;
 203         acpi_status ret = AE_OK;
 204         int status;
 205
 206         ret = acpi_buffer_to_resource(info->connection, info->length, &ares);
 207         if (ACPI_FAILURE(ret))
 208                 return ret;
 209
 210         if (!value64 || ares->type != ACPI_RESOURCE_TYPE_SERIAL_BUS) {
 211                 ret = AE_BAD_PARAMETER;
 212                 goto err;
 213         }
 214
 215         sb = &ares->data.i2c_serial_bus;
 216         if (sb->type != ACPI_RESOURCE_SERIAL_TYPE_I2C) {
 217                 ret = AE_BAD_PARAMETER;
 218                 goto err;
 219         }
 220
 221         memset(&client, 0, sizeof(client));
 222         client.adapter = adapter;
 223         client.addr = sb->slave_address;
 224         client.flags = 0;
 225
 226         if (sb->access_mode == ACPI_I2C_10BIT_MODE)
 227                 client.flags |= I2C_CLIENT_TEN;
 228
 229         switch (accessor_type) {
 230         case ACPI_GSB_ACCESS_ATTRIB_SEND_RCV:
 231                 if (action == ACPI_READ) {
 232                         status = i2c_smbus_read_byte(&client);
 233                         if (status >= 0) {
 234                                 gsb->bdata = status;
 235                                 status = 0;
 236                         }
 237                 } else {
 238                         status = i2c_smbus_write_byte(&client, gsb->bdata);
 239                 }
 240                 break;
 241
 242         case ACPI_GSB_ACCESS_ATTRIB_BYTE:
 243                 if (action == ACPI_READ) {
 244                         status = i2c_smbus_read_byte_data(&client, command);
 245                         if (status >= 0) {
 246                                 gsb->bdata = status;
 247                                 status = 0;
 248                         }
 249                 } else {
 250                         status = i2c_smbus_write_byte_data(&client, command,
 251                                         gsb->bdata);
 252                 }
 253                 break;
 254
 255         case ACPI_GSB_ACCESS_ATTRIB_WORD:
 256                 if (action == ACPI_READ) {
 257                         status = i2c_smbus_read_word_data(&client, command);
 258                         if (status >= 0) {
 259                                 gsb->wdata = status;
 260                                 status = 0;
 261                         }
 262                 } else {
 263                         status = i2c_smbus_write_word_data(&client, command,
 264                                         gsb->wdata);
 265                 }
 266                 break;
 267
 268         case ACPI_GSB_ACCESS_ATTRIB_BLOCK:
 269                 if (action == ACPI_READ) {
 270                         status = i2c_smbus_read_block_data(&client, command,
 271                                         gsb->data);
 272                         if (status >= 0) {
 273                                 gsb->len = status;
 274                                 status = 0;
 275                         }
 276                 } else {
 277                         status = i2c_smbus_write_block_data(&client, command,
 278                                         gsb->len, gsb->data);
 279                 }
 280                 break;
 281
 282         case ACPI_GSB_ACCESS_ATTRIB_MULTIBYTE:
 283                 if (action == ACPI_READ) {
 284                         status = acpi_gsb_i2c_read_bytes(&client, command,
 285                                         gsb->data, info->access_length);
 286                         if (status > 0)
 287                                 status = 0;
 288                 } else {
 289                         status = acpi_gsb_i2c_write_bytes(&client, command,
 290                                         gsb->data, info->access_length);
 291                 }
 292                 break;
 293
 294         default:
 295                 pr_info("protocol(0x%02x) is not supported.\n", accessor_type);
 296                 ret = AE_BAD_PARAMETER;
 297                 goto err;
 298         }
 299
 300         gsb->status = status;
 301
 302  err:
 303         ACPI_FREE(ares);
 304         return ret;
 305 }
 306
 307
 308 int acpi_i2c_install_space_handler(struct i2c_adapter *adapter)
 309 {
 310         acpi_handle handle = ACPI_HANDLE(adapter->dev.parent);
 311         struct acpi_i2c_handler_data *data;
 312         acpi_status status;
 313
 314         if (!handle)
 315                 return -ENODEV;
 316
 317         data = kzalloc(sizeof(struct acpi_i2c_handler_data),
 318                             GFP_KERNEL);
 319         if (!data)
 320                 return -ENOMEM;
 321
 322         data->adapter = adapter;
 323         status = acpi_bus_attach_private_data(handle, (void *)data);
 324         if (ACPI_FAILURE(status)) {
 325                 kfree(data);
 326                 return -ENOMEM;
 327         }
 328
 329         status = acpi_install_address_space_handler(handle,
 330                                 ACPI_ADR_SPACE_GSBUS,
 331                                 &acpi_i2c_space_handler,
 332                                 NULL,
 333                                 data);
 334         if (ACPI_FAILURE(status)) {
 335                 dev_err(&adapter->dev, "Error installing i2c space handler\n");
 336                 acpi_bus_detach_private_data(handle);
 337                 kfree(data);
 338                 return -ENOMEM;
 339         }
 340
 341         return 0;
 342 }
 343
 344 void acpi_i2c_remove_space_handler(struct i2c_adapter *adapter)
 345 {
 346         acpi_handle handle = ACPI_HANDLE(adapter->dev.parent);
 347         struct acpi_i2c_handler_data *data;
 348         acpi_status status;
 349
 350         if (!handle)
 351                 return;
 352
 353         acpi_remove_address_space_handler(handle,
 354                                 ACPI_ADR_SPACE_GSBUS,
 355                                 &acpi_i2c_space_handler);
 356
 357         status = acpi_bus_get_private_data(handle, (void **)&data);
 358         if (ACPI_SUCCESS(status))
 359                 kfree(data);
 360
 361         acpi_bus_detach_private_data(handle);
 362 }