drivers/iio/accel/mma7660.c

   1 /**
   2  * Freescale MMA7660FC 3-Axis Accelerometer
   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  * IIO driver for Freescale MMA7660FC; 7-bit I2C address: 0x4c.
  11  */
  12
  13 #include <linux/acpi.h>
  14 #include <linux/i2c.h>
  15 #include <linux/module.h>
  16 #include <linux/iio/iio.h>
  17 #include <linux/iio/sysfs.h>
  18
  19 #define MMA7660_DRIVER_NAME     "mma7660"
  20
  21 #define MMA7660_REG_XOUT        0x00
  22 #define MMA7660_REG_YOUT        0x01
  23 #define MMA7660_REG_ZOUT        0x02
  24 #define MMA7660_REG_OUT_BIT_ALERT       BIT(6)
  25
  26 #define MMA7660_REG_MODE        0x07
  27 #define MMA7660_REG_MODE_BIT_MODE       BIT(0)
  28 #define MMA7660_REG_MODE_BIT_TON        BIT(2)
  29
  30 #define MMA7660_I2C_READ_RETRIES        5
  31
  32 /*
  33  * The accelerometer has one measurement range:
  34  *
  35  * -1.5g - +1.5g (6-bit, signed)
  36  *
  37  * scale = (1.5 + 1.5) * 9.81 / (2^6 - 1)       = 0.467142857
  38  */
  39
  40 #define MMA7660_SCALE_AVAIL     "0.467142857"
  41
  42 static const int mma7660_nscale = 467142857;
  43
  44 #define MMA7660_CHANNEL(reg, axis) {    \
  45         .type = IIO_ACCEL,      \
  46         .address = reg, \
  47         .modified = 1,  \
  48         .channel2 = IIO_MOD_##axis,     \
  49         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
  50         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
  51 }
  52
  53 static const struct iio_chan_spec mma7660_channels[] = {
  54         MMA7660_CHANNEL(MMA7660_REG_XOUT, X),
  55         MMA7660_CHANNEL(MMA7660_REG_YOUT, Y),
  56         MMA7660_CHANNEL(MMA7660_REG_ZOUT, Z),
  57 };
  58
  59 enum mma7660_mode {
  60         MMA7660_MODE_STANDBY,
  61         MMA7660_MODE_ACTIVE
  62 };
  63
  64 struct mma7660_data {
  65         struct i2c_client *client;
  66         struct mutex lock;
  67         enum mma7660_mode mode;
  68 };
  69
  70 static IIO_CONST_ATTR(in_accel_scale_available, MMA7660_SCALE_AVAIL);
  71
  72 static struct attribute *mma7660_attributes[] = {
  73         &iio_const_attr_in_accel_scale_available.dev_attr.attr,
  74         NULL,
  75 };
  76
  77 static const struct attribute_group mma7660_attribute_group = {
  78         .attrs = mma7660_attributes
  79 };
  80
  81 static int mma7660_set_mode(struct mma7660_data *data,
  82                                 enum mma7660_mode mode)
  83 {
  84         int ret;
  85         struct i2c_client *client = data->client;
  86
  87         if (mode == data->mode)
  88                 return 0;
  89
  90         ret = i2c_smbus_read_byte_data(client, MMA7660_REG_MODE);
  91         if (ret < 0) {
  92                 dev_err(&client->dev, "failed to read sensor mode\n");
  93                 return ret;
  94         }
  95
  96         if (mode == MMA7660_MODE_ACTIVE) {
  97                 ret &= ~MMA7660_REG_MODE_BIT_TON;
  98                 ret |= MMA7660_REG_MODE_BIT_MODE;
  99         } else {
 100                 ret &= ~MMA7660_REG_MODE_BIT_TON;
 101                 ret &= ~MMA7660_REG_MODE_BIT_MODE;
 102         }
 103
 104         ret = i2c_smbus_write_byte_data(client, MMA7660_REG_MODE, ret);
 105         if (ret < 0) {
 106                 dev_err(&client->dev, "failed to change sensor mode\n");
 107                 return ret;
 108         }
 109
 110         data->mode = mode;
 111
 112         return ret;
 113 }
 114
 115 static int mma7660_read_accel(struct mma7660_data *data, u8 address)
 116 {
 117         int ret, retries = MMA7660_I2C_READ_RETRIES;
 118         struct i2c_client *client = data->client;
 119
 120         /*
 121          * Read data. If the Alert bit is set, the register was read at
 122          * the same time as the device was attempting to update the content.
 123          * The solution is to read the register again. Do this only
 124          * MMA7660_I2C_READ_RETRIES times to avoid spending too much time
 125          * in the kernel.
 126          */
 127         do {
 128                 ret = i2c_smbus_read_byte_data(client, address);
 129                 if (ret < 0) {
 130                         dev_err(&client->dev, "register read failed\n");
 131                         return ret;
 132                 }
 133         } while (retries-- > 0 && ret & MMA7660_REG_OUT_BIT_ALERT);
 134
 135         if (ret & MMA7660_REG_OUT_BIT_ALERT) {
 136                 dev_err(&client->dev, "all register read retries failed\n");
 137                 return -ETIMEDOUT;
 138         }
 139
 140         return ret;
 141 }
 142
 143 static int mma7660_read_raw(struct iio_dev *indio_dev,
 144                                 struct iio_chan_spec const *chan,
 145                                 int *val, int *val2, long mask)
 146 {
 147         struct mma7660_data *data = iio_priv(indio_dev);
 148         int ret;
 149
 150         switch (mask) {
 151         case IIO_CHAN_INFO_RAW:
 152                 mutex_lock(&data->lock);
 153                 ret = mma7660_read_accel(data, chan->address);
 154                 mutex_unlock(&data->lock);
 155                 if (ret < 0)
 156                         return ret;
 157                 *val = sign_extend32(ret, 5);
 158                 return IIO_VAL_INT;
 159         case IIO_CHAN_INFO_SCALE:
 160                 *val = 0;
 161                 *val2 = mma7660_nscale;
 162                 return IIO_VAL_INT_PLUS_NANO;
 163         default:
 164                 return -EINVAL;
 165         }
 166
 167         return -EINVAL;
 168 }
 169
 170 static const struct iio_info mma7660_info = {
 171         .driver_module  = THIS_MODULE,
 172         .read_raw               = mma7660_read_raw,
 173         .attrs                  = &mma7660_attribute_group,
 174 };
 175
 176 static int mma7660_probe(struct i2c_client *client,
 177                         const struct i2c_device_id *id)
 178 {
 179         int ret;
 180         struct iio_dev *indio_dev;
 181         struct mma7660_data *data;
 182
 183         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 184         if (!indio_dev) {
 185                 dev_err(&client->dev, "iio allocation failed!\n");
 186                 return -ENOMEM;
 187         }
 188
 189         data = iio_priv(indio_dev);
 190         data->client = client;
 191         i2c_set_clientdata(client, indio_dev);
 192         mutex_init(&data->lock);
 193         data->mode = MMA7660_MODE_STANDBY;
 194
 195         indio_dev->dev.parent = &client->dev;
 196         indio_dev->info = &mma7660_info;
 197         indio_dev->name = MMA7660_DRIVER_NAME;
 198         indio_dev->modes = INDIO_DIRECT_MODE;
 199         indio_dev->channels = mma7660_channels;
 200         indio_dev->num_channels = ARRAY_SIZE(mma7660_channels);
 201
 202         ret = mma7660_set_mode(data, MMA7660_MODE_ACTIVE);
 203         if (ret < 0)
 204                 return ret;
 205
 206         ret = iio_device_register(indio_dev);
 207         if (ret < 0) {
 208                 dev_err(&client->dev, "device_register failed\n");
 209                 mma7660_set_mode(data, MMA7660_MODE_STANDBY);
 210         }
 211
 212         return ret;
 213 }
 214
 215 static int mma7660_remove(struct i2c_client *client)
 216 {
 217         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 218
 219         iio_device_unregister(indio_dev);
 220
 221         return mma7660_set_mode(iio_priv(indio_dev), MMA7660_MODE_STANDBY);
 222 }
 223
 224 #ifdef CONFIG_PM_SLEEP
 225 static int mma7660_suspend(struct device *dev)
 226 {
 227         struct mma7660_data *data;
 228
 229         data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
 230
 231         return mma7660_set_mode(data, MMA7660_MODE_STANDBY);
 232 }
 233
 234 static int mma7660_resume(struct device *dev)
 235 {
 236         struct mma7660_data *data;
 237
 238         data = iio_priv(i2c_get_clientdata(to_i2c_client(dev)));
 239
 240         return mma7660_set_mode(data, MMA7660_MODE_ACTIVE);
 241 }
 242
 243 static SIMPLE_DEV_PM_OPS(mma7660_pm_ops, mma7660_suspend, mma7660_resume);
 244
 245 #define MMA7660_PM_OPS (&mma7660_pm_ops)
 246 #else
 247 #define MMA7660_PM_OPS NULL
 248 #endif
 249
 250 static const struct i2c_device_id mma7660_i2c_id[] = {
 251         {"mma7660", 0},
 252         {}
 253 };
 254 MODULE_DEVICE_TABLE(i2c, mma7660_i2c_id);
 255
 256 static const struct acpi_device_id mma7660_acpi_id[] = {
 257         {"MMA7660", 0},
 258         {}
 259 };
 260
 261 MODULE_DEVICE_TABLE(acpi, mma7660_acpi_id);
 262
 263 static struct i2c_driver mma7660_driver = {
 264         .driver = {
 265                 .name = "mma7660",
 266                 .pm = MMA7660_PM_OPS,
 267                 .acpi_match_table = ACPI_PTR(mma7660_acpi_id),
 268         },
 269         .probe          = mma7660_probe,
 270         .remove         = mma7660_remove,
 271         .id_table       = mma7660_i2c_id,
 272 };
 273
 274 module_i2c_driver(mma7660_driver);
 275
 276 MODULE_AUTHOR("Constantin Musca <constantin.musca@intel.com>");
 277 MODULE_DESCRIPTION("Freescale MMA7660FC 3-Axis Accelerometer driver");
 278 MODULE_LICENSE("GPL v2");