drivers/iio/magnetometer/ak09911.c

   1 /*
   2  * AK09911 3-axis compass driver
   3  * Copyright (c) 2014, Intel Corporation.
   4  *
   5  * This program is free software; you can redistribute it and/or modify it
   6  * under the terms and conditions of the GNU General Public License,
   7  * version 2, as published by the Free Software Foundation.
   8  *
   9  * This program is distributed in the hope it will be useful, but WITHOUT
  10  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  11  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  12  * more details.
  13  */
  14
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/init.h>
  18 #include <linux/types.h>
  19 #include <linux/slab.h>
  20 #include <linux/delay.h>
  21 #include <linux/i2c.h>
  22 #include <linux/acpi.h>
  23 #include <linux/iio/iio.h>
  24
  25 #define AK09911_REG_WIA1                0x00
  26 #define AK09911_REG_WIA2                0x01
  27 #define AK09911_WIA1_VALUE              0x48
  28 #define AK09911_WIA2_VALUE              0x05
  29
  30 #define AK09911_REG_ST1                 0x10
  31 #define AK09911_REG_HXL                 0x11
  32 #define AK09911_REG_HXH                 0x12
  33 #define AK09911_REG_HYL                 0x13
  34 #define AK09911_REG_HYH                 0x14
  35 #define AK09911_REG_HZL                 0x15
  36 #define AK09911_REG_HZH                 0x16
  37
  38 #define AK09911_REG_ASAX                0x60
  39 #define AK09911_REG_ASAY                0x61
  40 #define AK09911_REG_ASAZ                0x62
  41
  42 #define AK09911_REG_CNTL1               0x30
  43 #define AK09911_REG_CNTL2               0x31
  44 #define AK09911_REG_CNTL3               0x32
  45
  46 #define AK09911_MODE_SNG_MEASURE        0x01
  47 #define AK09911_MODE_SELF_TEST          0x10
  48 #define AK09911_MODE_FUSE_ACCESS        0x1F
  49 #define AK09911_MODE_POWERDOWN          0x00
  50 #define AK09911_RESET_DATA              0x01
  51
  52 #define AK09911_REG_CNTL1               0x30
  53 #define AK09911_REG_CNTL2               0x31
  54 #define AK09911_REG_CNTL3               0x32
  55
  56 #define AK09911_RAW_TO_GAUSS(asa)       ((((asa) + 128) * 6000) / 256)
  57
  58 #define AK09911_MAX_CONVERSION_TIMEOUT_MS       500
  59 #define AK09911_CONVERSION_DONE_POLL_TIME_MS    10
  60
  61 struct ak09911_data {
  62         struct i2c_client       *client;
  63         struct mutex            lock;
  64         u8                      asa[3];
  65         long                    raw_to_gauss[3];
  66 };
  67
  68 static const int ak09911_index_to_reg[] = {
  69         AK09911_REG_HXL, AK09911_REG_HYL, AK09911_REG_HZL,
  70 };
  71
  72 static int ak09911_set_mode(struct i2c_client *client, u8 mode)
  73 {
  74         int ret;
  75
  76         switch (mode) {
  77         case AK09911_MODE_SNG_MEASURE:
  78         case AK09911_MODE_SELF_TEST:
  79         case AK09911_MODE_FUSE_ACCESS:
  80         case AK09911_MODE_POWERDOWN:
  81                 ret = i2c_smbus_write_byte_data(client,
  82                                                 AK09911_REG_CNTL2, mode);
  83                 if (ret < 0) {
  84                         dev_err(&client->dev, "set_mode error\n");
  85                         return ret;
  86                 }
  87                 /* After mode change wait atleast 100us */
  88                 usleep_range(100, 500);
  89                 break;
  90         default:
  91                 dev_err(&client->dev,
  92                         "%s: Unknown mode(%d).", __func__, mode);
  93                 return -EINVAL;
  94         }
  95
  96         return ret;
  97 }
  98
  99 /* Get Sensitivity Adjustment value */
 100 static int ak09911_get_asa(struct i2c_client *client)
 101 {
 102         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 103         struct ak09911_data *data = iio_priv(indio_dev);
 104         int ret;
 105
 106         ret = ak09911_set_mode(client, AK09911_MODE_FUSE_ACCESS);
 107         if (ret < 0)
 108                 return ret;
 109
 110         /* Get asa data and store in the device data. */
 111         ret = i2c_smbus_read_i2c_block_data(client, AK09911_REG_ASAX,
 112                                             3, data->asa);
 113         if (ret < 0) {
 114                 dev_err(&client->dev, "Not able to read asa data\n");
 115                 return ret;
 116         }
 117
 118         ret = ak09911_set_mode(client,  AK09911_MODE_POWERDOWN);
 119         if (ret < 0)
 120                 return ret;
 121
 122         data->raw_to_gauss[0] = AK09911_RAW_TO_GAUSS(data->asa[0]);
 123         data->raw_to_gauss[1] = AK09911_RAW_TO_GAUSS(data->asa[1]);
 124         data->raw_to_gauss[2] = AK09911_RAW_TO_GAUSS(data->asa[2]);
 125
 126         return 0;
 127 }
 128
 129 static int ak09911_verify_chip_id(struct i2c_client *client)
 130 {
 131         u8 wia_val[2];
 132         int ret;
 133
 134         ret = i2c_smbus_read_i2c_block_data(client, AK09911_REG_WIA1,
 135                                             2, wia_val);
 136         if (ret < 0) {
 137                 dev_err(&client->dev, "Error reading WIA\n");
 138                 return ret;
 139         }
 140
 141         dev_dbg(&client->dev, "WIA %02x %02x\n", wia_val[0], wia_val[1]);
 142
 143         if (wia_val[0] != AK09911_WIA1_VALUE ||
 144                 wia_val[1] != AK09911_WIA2_VALUE) {
 145                 dev_err(&client->dev, "Device ak09911 not found\n");
 146                 return -ENODEV;
 147         }
 148
 149         return 0;
 150 }
 151
 152 static int wait_conversion_complete_polled(struct ak09911_data *data)
 153 {
 154         struct i2c_client *client = data->client;
 155         u8 read_status;
 156         u32 timeout_ms = AK09911_MAX_CONVERSION_TIMEOUT_MS;
 157         int ret;
 158
 159         /* Wait for the conversion to complete. */
 160         while (timeout_ms) {
 161                 msleep_interruptible(AK09911_CONVERSION_DONE_POLL_TIME_MS);
 162                 ret = i2c_smbus_read_byte_data(client, AK09911_REG_ST1);
 163                 if (ret < 0) {
 164                         dev_err(&client->dev, "Error in reading ST1\n");
 165                         return ret;
 166                 }
 167                 read_status = ret & 0x01;
 168                 if (read_status)
 169                         break;
 170                 timeout_ms -= AK09911_CONVERSION_DONE_POLL_TIME_MS;
 171         }
 172         if (!timeout_ms) {
 173                 dev_err(&client->dev, "Conversion timeout happened\n");
 174                 return -EIO;
 175         }
 176
 177         return read_status;
 178 }
 179
 180 static int ak09911_read_axis(struct iio_dev *indio_dev, int index, int *val)
 181 {
 182         struct ak09911_data *data = iio_priv(indio_dev);
 183         struct i2c_client *client = data->client;
 184         int ret;
 185
 186         mutex_lock(&data->lock);
 187
 188         ret = ak09911_set_mode(client, AK09911_MODE_SNG_MEASURE);
 189         if (ret < 0)
 190                 goto fn_exit;
 191
 192         ret = wait_conversion_complete_polled(data);
 193         if (ret < 0)
 194                 goto fn_exit;
 195
 196         /* Read data */
 197         ret = i2c_smbus_read_word_data(client, ak09911_index_to_reg[index]);
 198         if (ret < 0) {
 199                 dev_err(&client->dev, "Read axis data fails\n");
 200                 goto fn_exit;
 201         }
 202
 203         mutex_unlock(&data->lock);
 204
 205         /* Clamp to valid range. */
 206         *val = sign_extend32(clamp_t(s16, ret, -8192, 8191), 13);
 207
 208         return IIO_VAL_INT;
 209
 210 fn_exit:
 211         mutex_unlock(&data->lock);
 212
 213         return ret;
 214 }
 215
 216 static int ak09911_read_raw(struct iio_dev *indio_dev,
 217                             struct iio_chan_spec const *chan,
 218                             int *val, int *val2,
 219                             long mask)
 220 {
 221         struct ak09911_data *data = iio_priv(indio_dev);
 222
 223         switch (mask) {
 224         case IIO_CHAN_INFO_RAW:
 225                 return ak09911_read_axis(indio_dev, chan->address, val);
 226         case IIO_CHAN_INFO_SCALE:
 227                 *val = 0;
 228                 *val2 = data->raw_to_gauss[chan->address];
 229                 return IIO_VAL_INT_PLUS_MICRO;
 230         }
 231
 232         return -EINVAL;
 233 }
 234
 235 #define AK09911_CHANNEL(axis, index)                                    \
 236         {                                                               \
 237                 .type = IIO_MAGN,                                       \
 238                 .modified = 1,                                          \
 239                 .channel2 = IIO_MOD_##axis,                             \
 240                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |          \
 241                              BIT(IIO_CHAN_INFO_SCALE),                  \
 242                 .address = index,                                       \
 243         }
 244
 245 static const struct iio_chan_spec ak09911_channels[] = {
 246         AK09911_CHANNEL(X, 0), AK09911_CHANNEL(Y, 1), AK09911_CHANNEL(Z, 2),
 247 };
 248
 249 static const struct iio_info ak09911_info = {
 250         .read_raw = &ak09911_read_raw,
 251         .driver_module = THIS_MODULE,
 252 };
 253
 254 static const struct acpi_device_id ak_acpi_match[] = {
 255         {"AK009911", 0},
 256         { },
 257 };
 258 MODULE_DEVICE_TABLE(acpi, ak_acpi_match);
 259
 260 static int ak09911_probe(struct i2c_client *client,
 261                          const struct i2c_device_id *id)
 262 {
 263         struct iio_dev *indio_dev;
 264         struct ak09911_data *data;
 265         const char *name;
 266         int ret;
 267
 268         ret = ak09911_verify_chip_id(client);
 269         if (ret) {
 270                 dev_err(&client->dev, "AK00911 not detected\n");
 271                 return -ENODEV;
 272         }
 273
 274         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 275         if (indio_dev == NULL)
 276                 return -ENOMEM;
 277
 278         data = iio_priv(indio_dev);
 279         i2c_set_clientdata(client, indio_dev);
 280
 281         data->client = client;
 282         mutex_init(&data->lock);
 283
 284         ret = ak09911_get_asa(client);
 285         if (ret)
 286                 return ret;
 287
 288         if (id)
 289                 name = id->name;
 290         else if (ACPI_HANDLE(&client->dev))
 291                 name = dev_name(&client->dev);
 292         else
 293                 return -ENODEV;
 294
 295         dev_dbg(&client->dev, "Asahi compass chip %s\n", name);
 296
 297         indio_dev->dev.parent = &client->dev;
 298         indio_dev->channels = ak09911_channels;
 299         indio_dev->num_channels = ARRAY_SIZE(ak09911_channels);
 300         indio_dev->info = &ak09911_info;
 301         indio_dev->modes = INDIO_DIRECT_MODE;
 302         indio_dev->name = name;
 303
 304         return devm_iio_device_register(&client->dev, indio_dev);
 305 }
 306
 307 static const struct i2c_device_id ak09911_id[] = {
 308         {"ak09911", 0},
 309         {}
 310 };
 311
 312 MODULE_DEVICE_TABLE(i2c, ak09911_id);
 313
 314 static struct i2c_driver ak09911_driver = {
 315         .driver = {
 316                 .name   = "ak09911",
 317                 .acpi_match_table = ACPI_PTR(ak_acpi_match),
 318         },
 319         .probe          = ak09911_probe,
 320         .id_table       = ak09911_id,
 321 };
 322 module_i2c_driver(ak09911_driver);
 323
 324 MODULE_AUTHOR("Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>");
 325 MODULE_LICENSE("GPL v2");
 326 MODULE_DESCRIPTION("AK09911 Compass driver");