drivers/iio/accel/stk8ba50.c

   1 /**
   2  * Sensortek STK8BA50 3-Axis Accelerometer
   3  *
   4  * Copyright (c) 2015, 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  * STK8BA50 7-bit I2C address: 0x18.
  11  */
  12
  13 #include <linux/acpi.h>
  14 #include <linux/i2c.h>
  15 #include <linux/kernel.h>
  16 #include <linux/module.h>
  17 #include <linux/iio/iio.h>
  18 #include <linux/iio/sysfs.h>
  19
  20 #define STK8BA50_REG_XOUT                       0x02
  21 #define STK8BA50_REG_YOUT                       0x04
  22 #define STK8BA50_REG_ZOUT                       0x06
  23 #define STK8BA50_REG_RANGE                      0x0F
  24 #define STK8BA50_REG_POWMODE                    0x11
  25 #define STK8BA50_REG_SWRST                      0x14
  26
  27 #define STK8BA50_MODE_NORMAL                    0
  28 #define STK8BA50_MODE_SUSPEND                   1
  29 #define STK8BA50_MODE_POWERBIT                  BIT(7)
  30 #define STK8BA50_DATA_SHIFT                     6
  31 #define STK8BA50_RESET_CMD                      0xB6
  32
  33 #define STK8BA50_DRIVER_NAME                    "stk8ba50"
  34
  35 #define STK8BA50_SCALE_AVAIL                    "0.0384 0.0767 0.1534 0.3069"
  36
  37 /*
  38  * The accelerometer has four measurement ranges:
  39  * +/-2g; +/-4g; +/-8g; +/-16g
  40  *
  41  * Acceleration values are 10-bit, 2's complement.
  42  * Scales are calculated as following:
  43  *
  44  * scale1 = (2 + 2) * 9.81 / (2^10 - 1)   = 0.0384
  45  * scale2 = (4 + 4) * 9.81 / (2^10 - 1)   = 0.0767
  46  * etc.
  47  *
  48  * Scales are stored in this format:
  49  * { <register value>, <scale value> }
  50  *
  51  * Locally, the range is stored as a table index.
  52  */
  53 static const int stk8ba50_scale_table[][2] = {
  54         {3, 38400}, {5, 76700}, {8, 153400}, {12, 306900}
  55 };
  56
  57 struct stk8ba50_data {
  58         struct i2c_client *client;
  59         struct mutex lock;
  60         int range;
  61 };
  62
  63 #define STK8BA50_ACCEL_CHANNEL(reg, axis) {                     \
  64         .type = IIO_ACCEL,                                      \
  65         .address = reg,                                         \
  66         .modified = 1,                                          \
  67         .channel2 = IIO_MOD_##axis,                             \
  68         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
  69         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
  70 }
  71
  72 static const struct iio_chan_spec stk8ba50_channels[] = {
  73         STK8BA50_ACCEL_CHANNEL(STK8BA50_REG_XOUT, X),
  74         STK8BA50_ACCEL_CHANNEL(STK8BA50_REG_YOUT, Y),
  75         STK8BA50_ACCEL_CHANNEL(STK8BA50_REG_ZOUT, Z),
  76 };
  77
  78 static IIO_CONST_ATTR(in_accel_scale_available, STK8BA50_SCALE_AVAIL);
  79
  80 static struct attribute *stk8ba50_attributes[] = {
  81         &iio_const_attr_in_accel_scale_available.dev_attr.attr,
  82         NULL,
  83 };
  84
  85 static const struct attribute_group stk8ba50_attribute_group = {
  86         .attrs = stk8ba50_attributes
  87 };
  88
  89 static int stk8ba50_read_accel(struct stk8ba50_data *data, u8 reg)
  90 {
  91         int ret;
  92         struct i2c_client *client = data->client;
  93
  94         ret = i2c_smbus_read_word_data(client, reg);
  95         if (ret < 0) {
  96                 dev_err(&client->dev, "register read failed\n");
  97                 return ret;
  98         }
  99
 100         return sign_extend32(ret >> STK8BA50_DATA_SHIFT, 9);
 101 }
 102
 103 static int stk8ba50_read_raw(struct iio_dev *indio_dev,
 104                              struct iio_chan_spec const *chan,
 105                              int *val, int *val2, long mask)
 106 {
 107         struct stk8ba50_data *data = iio_priv(indio_dev);
 108
 109         switch (mask) {
 110         case IIO_CHAN_INFO_RAW:
 111                 mutex_lock(&data->lock);
 112                 *val = stk8ba50_read_accel(data, chan->address);
 113                 mutex_unlock(&data->lock);
 114                 return IIO_VAL_INT;
 115         case IIO_CHAN_INFO_SCALE:
 116                 *val = 0;
 117                 *val2 = stk8ba50_scale_table[data->range][1];
 118                 return IIO_VAL_INT_PLUS_MICRO;
 119         }
 120
 121         return -EINVAL;
 122 }
 123
 124 static int stk8ba50_write_raw(struct iio_dev *indio_dev,
 125                               struct iio_chan_spec const *chan,
 126                               int val, int val2, long mask)
 127 {
 128         int ret;
 129         int i;
 130         int index = -1;
 131         struct stk8ba50_data *data = iio_priv(indio_dev);
 132
 133         switch (mask) {
 134         case IIO_CHAN_INFO_SCALE:
 135                 if (val != 0)
 136                         return -EINVAL;
 137
 138                 for (i = 0; i < ARRAY_SIZE(stk8ba50_scale_table); i++)
 139                         if (val2 == stk8ba50_scale_table[i][1]) {
 140                                 index = i;
 141                                 break;
 142                         }
 143                 if (index < 0)
 144                         return -EINVAL;
 145
 146                 ret = i2c_smbus_write_byte_data(data->client,
 147                                 STK8BA50_REG_RANGE,
 148                                 stk8ba50_scale_table[index][0]);
 149                 if (ret < 0)
 150                         dev_err(&data->client->dev,
 151                                         "failed to set measurement range\n");
 152                 else
 153                         data->range = index;
 154
 155                 return ret;
 156         }
 157
 158         return -EINVAL;
 159 }
 160
 161 static const struct iio_info stk8ba50_info = {
 162         .driver_module          = THIS_MODULE,
 163         .read_raw               = stk8ba50_read_raw,
 164         .write_raw              = stk8ba50_write_raw,
 165         .attrs                  = &stk8ba50_attribute_group,
 166 };
 167
 168 static int stk8ba50_set_power(struct stk8ba50_data *data, bool mode)
 169 {
 170         int ret;
 171         u8 masked_reg;
 172         struct i2c_client *client = data->client;
 173
 174         ret = i2c_smbus_read_byte_data(client, STK8BA50_REG_POWMODE);
 175         if (ret < 0)
 176                 goto exit_err;
 177
 178         if (mode)
 179                 masked_reg = ret | STK8BA50_MODE_POWERBIT;
 180         else
 181                 masked_reg = ret & (~STK8BA50_MODE_POWERBIT);
 182
 183         ret = i2c_smbus_write_byte_data(client, STK8BA50_REG_POWMODE,
 184                                         masked_reg);
 185         if (ret < 0)
 186                 goto exit_err;
 187
 188         return ret;
 189
 190 exit_err:
 191         dev_err(&client->dev, "failed to change sensor mode\n");
 192         return ret;
 193 }
 194
 195 static int stk8ba50_probe(struct i2c_client *client,
 196                           const struct i2c_device_id *id)
 197 {
 198         int ret;
 199         struct iio_dev *indio_dev;
 200         struct stk8ba50_data *data;
 201
 202         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 203         if (!indio_dev) {
 204                 dev_err(&client->dev, "iio allocation failed!\n");
 205                 return -ENOMEM;
 206         }
 207
 208         data = iio_priv(indio_dev);
 209         data->client = client;
 210         i2c_set_clientdata(client, indio_dev);
 211         mutex_init(&data->lock);
 212
 213         indio_dev->dev.parent = &client->dev;
 214         indio_dev->info = &stk8ba50_info;
 215         indio_dev->name = STK8BA50_DRIVER_NAME;
 216         indio_dev->modes = INDIO_DIRECT_MODE;
 217         indio_dev->channels = stk8ba50_channels;
 218         indio_dev->num_channels = ARRAY_SIZE(stk8ba50_channels);
 219
 220         /* Reset all registers on startup */
 221         ret = i2c_smbus_write_byte_data(client,
 222                         STK8BA50_REG_SWRST, STK8BA50_RESET_CMD);
 223         if (ret < 0) {
 224                 dev_err(&client->dev, "failed to reset sensor\n");
 225                 return ret;
 226         }
 227
 228         /* The default range is +/-2g */
 229         data->range = 0;
 230
 231         ret = iio_device_register(indio_dev);
 232         if (ret < 0) {
 233                 dev_err(&client->dev, "device_register failed\n");
 234                 stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 235         }
 236
 237         return ret;
 238 }
 239
 240 static int stk8ba50_remove(struct i2c_client *client)
 241 {
 242         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 243
 244         iio_device_unregister(indio_dev);
 245
 246         return stk8ba50_set_power(iio_priv(indio_dev), STK8BA50_MODE_SUSPEND);
 247 }
 248
 249 #ifdef CONFIG_PM_SLEEP
 250 static int stk8ba50_suspend(struct device *dev)
 251 {
 252         struct stk8ba50_data *data;
 253
 254         data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
 255
 256         return stk8ba50_set_power(data, STK8BA50_MODE_SUSPEND);
 257 }
 258
 259 static int stk8ba50_resume(struct device *dev)
 260 {
 261         struct stk8ba50_data *data;
 262
 263         data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
 264
 265         return stk8ba50_set_power(data, STK8BA50_MODE_NORMAL);
 266 }
 267
 268 static SIMPLE_DEV_PM_OPS(stk8ba50_pm_ops, stk8ba50_suspend, stk8ba50_resume);
 269
 270 #define STK8BA50_PM_OPS (&stk8ba50_pm_ops)
 271 #else
 272 #define STK8BA50_PM_OPS NULL
 273 #endif
 274
 275 static const struct i2c_device_id stk8ba50_i2c_id[] = {
 276         {"stk8ba50", 0},
 277         {}
 278 };
 279
 280 static const struct acpi_device_id stk8ba50_acpi_id[] = {
 281         {"STK8BA50", 0},
 282         {}
 283 };
 284
 285 MODULE_DEVICE_TABLE(acpi, stk8ba50_acpi_id);
 286
 287 static struct i2c_driver stk8ba50_driver = {
 288         .driver = {
 289                 .name = "stk8ba50",
 290                 .pm = STK8BA50_PM_OPS,
 291                 .acpi_match_table = ACPI_PTR(stk8ba50_acpi_id),
 292         },
 293         .probe =            stk8ba50_probe,
 294         .remove =           stk8ba50_remove,
 295         .id_table =         stk8ba50_i2c_id,
 296 };
 297
 298 module_i2c_driver(stk8ba50_driver);
 299
 300 MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
 301 MODULE_DESCRIPTION("STK8BA50 3-Axis Accelerometer driver");
 302 MODULE_LICENSE("GPL v2");