drivers/iio/accel/mxc6255.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * MXC6255 - MEMSIC orientation sensing accelerometer
   4  *
   5  * Copyright (c) 2015, Intel Corporation.
   6  *
   7  * IIO driver for MXC6255 (7-bit I2C slave address 0x15).
   8  */
   9
  10 #include <linux/module.h>
  11 #include <linux/i2c.h>
  12 #include <linux/init.h>
  13 #include <linux/iio/iio.h>
  14 #include <linux/delay.h>
  15 #include <linux/acpi.h>
  16 #include <linux/regmap.h>
  17 #include <linux/iio/sysfs.h>
  18
  19 #define MXC6255_DRV_NAME                "mxc6255"
  20 #define MXC6255_REGMAP_NAME             "mxc6255_regmap"
  21
  22 #define MXC6255_REG_XOUT                0x00
  23 #define MXC6255_REG_YOUT                0x01
  24 #define MXC6255_REG_CHIP_ID             0x08
  25
  26 #define MXC6255_CHIP_ID                 0x05
  27
  28 /*
  29  * MXC6255 has only one measurement range: +/- 2G.
  30  * The acceleration output is an 8-bit value.
  31  *
  32  * Scale is calculated as follows:
  33  * (2 + 2) * 9.80665 / (2^8 - 1) = 0.153829
  34  *
  35  * Scale value for +/- 2G measurement range
  36  */
  37 #define MXC6255_SCALE                   153829
  38
  39 enum mxc6255_axis {
  40         AXIS_X,
  41         AXIS_Y,
  42 };
  43
  44 struct mxc6255_data {
  45         struct i2c_client *client;
  46         struct regmap *regmap;
  47 };
  48
  49 static int mxc6255_read_raw(struct iio_dev *indio_dev,
  50                             struct iio_chan_spec const *chan,
  51                             int *val, int *val2, long mask)
  52 {
  53         struct mxc6255_data *data = iio_priv(indio_dev);
  54         unsigned int reg;
  55         int ret;
  56
  57         switch (mask) {
  58         case IIO_CHAN_INFO_RAW:
  59                 ret = regmap_read(data->regmap, chan->address, &reg);
  60                 if (ret < 0) {
  61                         dev_err(&data->client->dev,
  62                                 "Error reading reg %lu\n", chan->address);
  63                         return ret;
  64                 }
  65
  66                 *val = sign_extend32(reg, 7);
  67                 return IIO_VAL_INT;
  68         case IIO_CHAN_INFO_SCALE:
  69                 *val = 0;
  70                 *val2 = MXC6255_SCALE;
  71                 return IIO_VAL_INT_PLUS_MICRO;
  72         default:
  73                 return -EINVAL;
  74         }
  75 }
  76
  77 static const struct iio_info mxc6255_info = {
  78         .read_raw       = mxc6255_read_raw,
  79 };
  80
  81 #define MXC6255_CHANNEL(_axis, reg) {                           \
  82         .type = IIO_ACCEL,                                      \
  83         .modified = 1,                                          \
  84         .channel2 = IIO_MOD_##_axis,                            \
  85         .address = reg,                                         \
  86         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
  87         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
  88 }
  89
  90 static const struct iio_chan_spec mxc6255_channels[] = {
  91         MXC6255_CHANNEL(X, MXC6255_REG_XOUT),
  92         MXC6255_CHANNEL(Y, MXC6255_REG_YOUT),
  93 };
  94
  95 static bool mxc6255_is_readable_reg(struct device *dev, unsigned int reg)
  96 {
  97         switch (reg) {
  98         case MXC6255_REG_XOUT:
  99         case MXC6255_REG_YOUT:
 100         case MXC6255_REG_CHIP_ID:
 101                 return true;
 102         default:
 103                 return false;
 104         }
 105 }
 106
 107 static const struct regmap_config mxc6255_regmap_config = {
 108         .name = MXC6255_REGMAP_NAME,
 109
 110         .reg_bits = 8,
 111         .val_bits = 8,
 112
 113         .readable_reg = mxc6255_is_readable_reg,
 114 };
 115
 116 static int mxc6255_probe(struct i2c_client *client,
 117                          const struct i2c_device_id *id)
 118 {
 119         struct mxc6255_data *data;
 120         struct iio_dev *indio_dev;
 121         struct regmap *regmap;
 122         unsigned int chip_id;
 123         int ret;
 124
 125         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 126         if (!indio_dev)
 127                 return -ENOMEM;
 128
 129         regmap = devm_regmap_init_i2c(client, &mxc6255_regmap_config);
 130         if (IS_ERR(regmap)) {
 131                 dev_err(&client->dev, "Error initializing regmap\n");
 132                 return PTR_ERR(regmap);
 133         }
 134
 135         data = iio_priv(indio_dev);
 136         i2c_set_clientdata(client, indio_dev);
 137         data->client = client;
 138         data->regmap = regmap;
 139
 140         indio_dev->name = MXC6255_DRV_NAME;
 141         indio_dev->dev.parent = &client->dev;
 142         indio_dev->channels = mxc6255_channels;
 143         indio_dev->num_channels = ARRAY_SIZE(mxc6255_channels);
 144         indio_dev->modes = INDIO_DIRECT_MODE;
 145         indio_dev->info = &mxc6255_info;
 146
 147         ret = regmap_read(data->regmap, MXC6255_REG_CHIP_ID, &chip_id);
 148         if (ret < 0) {
 149                 dev_err(&client->dev, "Error reading chip id %d\n", ret);
 150                 return ret;
 151         }
 152
 153         if ((chip_id & 0x1f) != MXC6255_CHIP_ID) {
 154                 dev_err(&client->dev, "Invalid chip id %x\n", chip_id);
 155                 return -ENODEV;
 156         }
 157
 158         dev_dbg(&client->dev, "Chip id %x\n", chip_id);
 159
 160         ret = devm_iio_device_register(&client->dev, indio_dev);
 161         if (ret < 0) {
 162                 dev_err(&client->dev, "Could not register IIO device\n");
 163                 return ret;
 164         }
 165
 166         return 0;
 167 }
 168
 169 static const struct acpi_device_id mxc6255_acpi_match[] = {
 170         {"MXC6225",     0},
 171         {"MXC6255",     0},
 172         { }
 173 };
 174 MODULE_DEVICE_TABLE(acpi, mxc6255_acpi_match);
 175
 176 static const struct i2c_device_id mxc6255_id[] = {
 177         {"mxc6225",     0},
 178         {"mxc6255",     0},
 179         { }
 180 };
 181 MODULE_DEVICE_TABLE(i2c, mxc6255_id);
 182
 183 static struct i2c_driver mxc6255_driver = {
 184         .driver = {
 185                 .name = MXC6255_DRV_NAME,
 186                 .acpi_match_table = ACPI_PTR(mxc6255_acpi_match),
 187         },
 188         .probe          = mxc6255_probe,
 189         .id_table       = mxc6255_id,
 190 };
 191
 192 module_i2c_driver(mxc6255_driver);
 193
 194 MODULE_AUTHOR("Teodora Baluta <teodora.baluta@intel.com>");
 195 MODULE_DESCRIPTION("MEMSIC MXC6255 orientation sensing accelerometer driver");
 196 MODULE_LICENSE("GPL v2");