drivers/iio/pressure/hp206c.c

   1 /*
   2  * hp206c.c - HOPERF HP206C precision barometer and altimeter sensor
   3  *
   4  * Copyright (c) 2016, Intel Corporation.
   5  *
   6  * This file is subject to the terms and conditions of version 2 of
   7  * the GNU General Public License.  See the file COPYING in the main
   8  * directory of this archive for more details.
   9  *
  10  * (7-bit I2C slave address 0x76)
  11  *
  12  * Datasheet:
  13  *  http://www.hoperf.com/upload/sensor/HP206C_DataSheet_EN_V2.0.pdf
  14  */
  15
  16 #include <linux/module.h>
  17 #include <linux/i2c.h>
  18 #include <linux/iio/iio.h>
  19 #include <linux/iio/sysfs.h>
  20 #include <linux/delay.h>
  21 #include <linux/util_macros.h>
  22 #include <linux/acpi.h>
  23
  24 /* I2C commands: */
  25 #define HP206C_CMD_SOFT_RST     0x06
  26
  27 #define HP206C_CMD_ADC_CVT      0x40
  28
  29 #define HP206C_CMD_ADC_CVT_OSR_4096     0x00
  30 #define HP206C_CMD_ADC_CVT_OSR_2048     0x04
  31 #define HP206C_CMD_ADC_CVT_OSR_1024     0x08
  32 #define HP206C_CMD_ADC_CVT_OSR_512      0x0c
  33 #define HP206C_CMD_ADC_CVT_OSR_256      0x10
  34 #define HP206C_CMD_ADC_CVT_OSR_128      0x14
  35
  36 #define HP206C_CMD_ADC_CVT_CHNL_PT      0x00
  37 #define HP206C_CMD_ADC_CVT_CHNL_T       0x02
  38
  39 #define HP206C_CMD_READ_P       0x30
  40 #define HP206C_CMD_READ_T       0x32
  41
  42 #define HP206C_CMD_READ_REG     0x80
  43 #define HP206C_CMD_WRITE_REG    0xc0
  44
  45 #define HP206C_REG_INT_EN       0x0b
  46 #define HP206C_REG_INT_CFG      0x0c
  47
  48 #define HP206C_REG_INT_SRC      0x0d
  49 #define HP206C_FLAG_DEV_RDY     0x40
  50
  51 #define HP206C_REG_PARA         0x0f
  52 #define HP206C_FLAG_CMPS_EN     0x80
  53
  54 /* Maximum spin for DEV_RDY */
  55 #define HP206C_MAX_DEV_RDY_WAIT_COUNT 20
  56 #define HP206C_DEV_RDY_WAIT_US    20000
  57
  58 struct hp206c_data {
  59         struct mutex mutex;
  60         struct i2c_client *client;
  61         int temp_osr_index;
  62         int pres_osr_index;
  63 };
  64
  65 struct hp206c_osr_setting {
  66         u8 osr_mask;
  67         unsigned int temp_conv_time_us;
  68         unsigned int pres_conv_time_us;
  69 };
  70
  71 /* Data from Table 5 in datasheet. */
  72 static const struct hp206c_osr_setting hp206c_osr_settings[] = {
  73         { HP206C_CMD_ADC_CVT_OSR_4096,  65600,  131100  },
  74         { HP206C_CMD_ADC_CVT_OSR_2048,  32800,  65600   },
  75         { HP206C_CMD_ADC_CVT_OSR_1024,  16400,  32800   },
  76         { HP206C_CMD_ADC_CVT_OSR_512,   8200,   16400   },
  77         { HP206C_CMD_ADC_CVT_OSR_256,   4100,   8200    },
  78         { HP206C_CMD_ADC_CVT_OSR_128,   2100,   4100    },
  79 };
  80 static const int hp206c_osr_rates[] = { 4096, 2048, 1024, 512, 256, 128 };
  81 static const char hp206c_osr_rates_str[] = "4096 2048 1024 512 256 128";
  82
  83 static inline int hp206c_read_reg(struct i2c_client *client, u8 reg)
  84 {
  85         return i2c_smbus_read_byte_data(client, HP206C_CMD_READ_REG | reg);
  86 }
  87
  88 static inline int hp206c_write_reg(struct i2c_client *client, u8 reg, u8 val)
  89 {
  90         return i2c_smbus_write_byte_data(client,
  91                         HP206C_CMD_WRITE_REG | reg, val);
  92 }
  93
  94 static int hp206c_read_20bit(struct i2c_client *client, u8 cmd)
  95 {
  96         int ret;
  97         u8 values[3];
  98
  99         ret = i2c_smbus_read_i2c_block_data(client, cmd, 3, values);
 100         if (ret < 0)
 101                 return ret;
 102         if (ret != 3)
 103                 return -EIO;
 104         return ((values[0] & 0xF) << 16) | (values[1] << 8) | (values[2]);
 105 }
 106
 107 /* Spin for max 160ms until DEV_RDY is 1, or return error. */
 108 static int hp206c_wait_dev_rdy(struct iio_dev *indio_dev)
 109 {
 110         int ret;
 111         int count = 0;
 112         struct hp206c_data *data = iio_priv(indio_dev);
 113         struct i2c_client *client = data->client;
 114
 115         while (++count <= HP206C_MAX_DEV_RDY_WAIT_COUNT) {
 116                 ret = hp206c_read_reg(client, HP206C_REG_INT_SRC);
 117                 if (ret < 0) {
 118                         dev_err(&indio_dev->dev, "Failed READ_REG INT_SRC: %d\n", ret);
 119                         return ret;
 120                 }
 121                 if (ret & HP206C_FLAG_DEV_RDY)
 122                         return 0;
 123                 usleep_range(HP206C_DEV_RDY_WAIT_US, HP206C_DEV_RDY_WAIT_US * 3 / 2);
 124         }
 125         return -ETIMEDOUT;
 126 }
 127
 128 static int hp206c_set_compensation(struct i2c_client *client, bool enabled)
 129 {
 130         int val;
 131
 132         val = hp206c_read_reg(client, HP206C_REG_PARA);
 133         if (val < 0)
 134                 return val;
 135         if (enabled)
 136                 val |= HP206C_FLAG_CMPS_EN;
 137         else
 138                 val &= ~HP206C_FLAG_CMPS_EN;
 139
 140         return hp206c_write_reg(client, HP206C_REG_PARA, val);
 141 }
 142
 143 /* Do a soft reset */
 144 static int hp206c_soft_reset(struct iio_dev *indio_dev)
 145 {
 146         int ret;
 147         struct hp206c_data *data = iio_priv(indio_dev);
 148         struct i2c_client *client = data->client;
 149
 150         ret = i2c_smbus_write_byte(client, HP206C_CMD_SOFT_RST);
 151         if (ret) {
 152                 dev_err(&client->dev, "Failed to reset device: %d\n", ret);
 153                 return ret;
 154         }
 155
 156         usleep_range(400, 600);
 157
 158         ret = hp206c_wait_dev_rdy(indio_dev);
 159         if (ret) {
 160                 dev_err(&client->dev, "Device not ready after soft reset: %d\n", ret);
 161                 return ret;
 162         }
 163
 164         ret = hp206c_set_compensation(client, true);
 165         if (ret)
 166                 dev_err(&client->dev, "Failed to enable compensation: %d\n", ret);
 167         return ret;
 168 }
 169
 170 static int hp206c_conv_and_read(struct iio_dev *indio_dev,
 171                                 u8 conv_cmd, u8 read_cmd,
 172                                 unsigned int sleep_us)
 173 {
 174         int ret;
 175         struct hp206c_data *data = iio_priv(indio_dev);
 176         struct i2c_client *client = data->client;
 177
 178         ret = hp206c_wait_dev_rdy(indio_dev);
 179         if (ret < 0) {
 180                 dev_err(&indio_dev->dev, "Device not ready: %d\n", ret);
 181                 return ret;
 182         }
 183
 184         ret = i2c_smbus_write_byte(client, conv_cmd);
 185         if (ret < 0) {
 186                 dev_err(&indio_dev->dev, "Failed convert: %d\n", ret);
 187                 return ret;
 188         }
 189
 190         usleep_range(sleep_us, sleep_us * 3 / 2);
 191
 192         ret = hp206c_wait_dev_rdy(indio_dev);
 193         if (ret < 0) {
 194                 dev_err(&indio_dev->dev, "Device not ready: %d\n", ret);
 195                 return ret;
 196         }
 197
 198         ret = hp206c_read_20bit(client, read_cmd);
 199         if (ret < 0)
 200                 dev_err(&indio_dev->dev, "Failed read: %d\n", ret);
 201
 202         return ret;
 203 }
 204
 205 static int hp206c_read_raw(struct iio_dev *indio_dev,
 206                            struct iio_chan_spec const *chan, int *val,
 207                            int *val2, long mask)
 208 {
 209         int ret;
 210         struct hp206c_data *data = iio_priv(indio_dev);
 211         const struct hp206c_osr_setting *osr_setting;
 212         u8 conv_cmd;
 213
 214         mutex_lock(&data->mutex);
 215
 216         switch (mask) {
 217         case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
 218                 switch (chan->type) {
 219                 case IIO_TEMP:
 220                         *val = hp206c_osr_rates[data->temp_osr_index];
 221                         ret = IIO_VAL_INT;
 222                         break;
 223
 224                 case IIO_PRESSURE:
 225                         *val = hp206c_osr_rates[data->pres_osr_index];
 226                         ret = IIO_VAL_INT;
 227                         break;
 228                 default:
 229                         ret = -EINVAL;
 230                 }
 231                 break;
 232
 233         case IIO_CHAN_INFO_RAW:
 234                 switch (chan->type) {
 235                 case IIO_TEMP:
 236                         osr_setting = &hp206c_osr_settings[data->temp_osr_index];
 237                         conv_cmd = HP206C_CMD_ADC_CVT |
 238                                         osr_setting->osr_mask |
 239                                         HP206C_CMD_ADC_CVT_CHNL_T;
 240                         ret = hp206c_conv_and_read(indio_dev,
 241                                         conv_cmd,
 242                                         HP206C_CMD_READ_T,
 243                                         osr_setting->temp_conv_time_us);
 244                         if (ret >= 0) {
 245                                 /* 20 significant bits are provided.
 246                                  * Extend sign over the rest.
 247                                  */
 248                                 *val = sign_extend32(ret, 19);
 249                                 ret = IIO_VAL_INT;
 250                         }
 251                         break;
 252
 253                 case IIO_PRESSURE:
 254                         osr_setting = &hp206c_osr_settings[data->pres_osr_index];
 255                         conv_cmd = HP206C_CMD_ADC_CVT |
 256                                         osr_setting->osr_mask |
 257                                         HP206C_CMD_ADC_CVT_CHNL_PT;
 258                         ret = hp206c_conv_and_read(indio_dev,
 259                                         conv_cmd,
 260                                         HP206C_CMD_READ_P,
 261                                         osr_setting->pres_conv_time_us);
 262                         if (ret >= 0) {
 263                                 *val = ret;
 264                                 ret = IIO_VAL_INT;
 265                         }
 266                         break;
 267                 default:
 268                         ret = -EINVAL;
 269                 }
 270                 break;
 271
 272         case IIO_CHAN_INFO_SCALE:
 273                 switch (chan->type) {
 274                 case IIO_TEMP:
 275                         *val = 0;
 276                         *val2 = 10000;
 277                         ret = IIO_VAL_INT_PLUS_MICRO;
 278                         break;
 279
 280                 case IIO_PRESSURE:
 281                         *val = 0;
 282                         *val2 = 1000;
 283                         ret = IIO_VAL_INT_PLUS_MICRO;
 284                         break;
 285                 default:
 286                         ret = -EINVAL;
 287                 }
 288                 break;
 289
 290         default:
 291                 ret = -EINVAL;
 292         }
 293
 294         mutex_unlock(&data->mutex);
 295         return ret;
 296 }
 297
 298 static int hp206c_write_raw(struct iio_dev *indio_dev,
 299                             struct iio_chan_spec const *chan,
 300                             int val, int val2, long mask)
 301 {
 302         int ret = 0;
 303         struct hp206c_data *data = iio_priv(indio_dev);
 304
 305         if (mask != IIO_CHAN_INFO_OVERSAMPLING_RATIO)
 306                 return -EINVAL;
 307         mutex_lock(&data->mutex);
 308         switch (chan->type) {
 309         case IIO_TEMP:
 310                 data->temp_osr_index = find_closest_descending(val,
 311                         hp206c_osr_rates, ARRAY_SIZE(hp206c_osr_rates));
 312                 break;
 313         case IIO_PRESSURE:
 314                 data->pres_osr_index = find_closest_descending(val,
 315                         hp206c_osr_rates, ARRAY_SIZE(hp206c_osr_rates));
 316                 break;
 317         default:
 318                 ret = -EINVAL;
 319         }
 320         mutex_unlock(&data->mutex);
 321         return ret;
 322 }
 323
 324 static const struct iio_chan_spec hp206c_channels[] = {
 325         {
 326                 .type = IIO_TEMP,
 327                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 328                                       BIT(IIO_CHAN_INFO_SCALE) |
 329                                       BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
 330         },
 331         {
 332                 .type = IIO_PRESSURE,
 333                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 334                                       BIT(IIO_CHAN_INFO_SCALE) |
 335                                       BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO),
 336         }
 337 };
 338
 339 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL(hp206c_osr_rates_str);
 340
 341 static struct attribute *hp206c_attributes[] = {
 342         &iio_const_attr_sampling_frequency_available.dev_attr.attr,
 343         NULL,
 344 };
 345
 346 static const struct attribute_group hp206c_attribute_group = {
 347         .attrs = hp206c_attributes,
 348 };
 349
 350 static const struct iio_info hp206c_info = {
 351         .attrs = &hp206c_attribute_group,
 352         .read_raw = hp206c_read_raw,
 353         .write_raw = hp206c_write_raw,
 354         .driver_module = THIS_MODULE,
 355 };
 356
 357 static int hp206c_probe(struct i2c_client *client,
 358                         const struct i2c_device_id *id)
 359 {
 360         struct iio_dev *indio_dev;
 361         struct hp206c_data *data;
 362         int ret;
 363
 364         if (!i2c_check_functionality(client->adapter,
 365                                      I2C_FUNC_SMBUS_BYTE |
 366                                      I2C_FUNC_SMBUS_BYTE_DATA |
 367                                      I2C_FUNC_SMBUS_READ_I2C_BLOCK)) {
 368                 dev_err(&client->dev, "Adapter does not support "
 369                                 "all required i2c functionality\n");
 370                 return -ENODEV;
 371         }
 372
 373         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 374         if (!indio_dev)
 375                 return -ENOMEM;
 376
 377         data = iio_priv(indio_dev);
 378         data->client = client;
 379         mutex_init(&data->mutex);
 380
 381         indio_dev->info = &hp206c_info;
 382         indio_dev->name = id->name;
 383         indio_dev->dev.parent = &client->dev;
 384         indio_dev->modes = INDIO_DIRECT_MODE;
 385         indio_dev->channels = hp206c_channels;
 386         indio_dev->num_channels = ARRAY_SIZE(hp206c_channels);
 387
 388         i2c_set_clientdata(client, indio_dev);
 389
 390         /* Do a soft reset on probe */
 391         ret = hp206c_soft_reset(indio_dev);
 392         if (ret) {
 393                 dev_err(&client->dev, "Failed to reset on startup: %d\n", ret);
 394                 return -ENODEV;
 395         }
 396
 397         return devm_iio_device_register(&client->dev, indio_dev);
 398 }
 399
 400 static const struct i2c_device_id hp206c_id[] = {
 401         {"hp206c"},
 402         {}
 403 };
 404
 405 #ifdef CONFIG_ACPI
 406 static const struct acpi_device_id hp206c_acpi_match[] = {
 407         {"HOP206C", 0},
 408         { },
 409 };
 410 MODULE_DEVICE_TABLE(acpi, hp206c_acpi_match);
 411 #endif
 412
 413 static struct i2c_driver hp206c_driver = {
 414         .probe = hp206c_probe,
 415         .id_table = hp206c_id,
 416         .driver = {
 417                 .name = "hp206c",
 418                 .acpi_match_table = ACPI_PTR(hp206c_acpi_match),
 419         },
 420 };
 421
 422 module_i2c_driver(hp206c_driver);
 423
 424 MODULE_DESCRIPTION("HOPERF HP206C precision barometer and altimeter sensor");
 425 MODULE_AUTHOR("Leonard Crestez <leonard.crestez@intel.com>");
 426 MODULE_LICENSE("GPL v2");