drivers/iio/accel/da280.c

   1 /**
   2  * IIO driver for the MiraMEMS DA280 3-axis accelerometer and
   3  * IIO driver for the MiraMEMS DA226 2-axis accelerometer
   4  *
   5  * Copyright (c) 2016 Hans de Goede <hdegoede@redhat.com>
   6  *
   7  * This program is free software; you can redistribute it and/or modify it
   8  * under the terms and conditions of the GNU General Public License,
   9  * version 2, as published by the Free Software Foundation.
  10  */
  11
  12 #include <linux/module.h>
  13 #include <linux/i2c.h>
  14 #include <linux/iio/iio.h>
  15 #include <linux/iio/sysfs.h>
  16 #include <linux/byteorder/generic.h>
  17
  18 #define DA280_REG_CHIP_ID               0x01
  19 #define DA280_REG_ACC_X_LSB             0x02
  20 #define DA280_REG_ACC_Y_LSB             0x04
  21 #define DA280_REG_ACC_Z_LSB             0x06
  22 #define DA280_REG_MODE_BW               0x11
  23
  24 #define DA280_CHIP_ID                   0x13
  25 #define DA280_MODE_ENABLE               0x1e
  26 #define DA280_MODE_DISABLE              0x9e
  27
  28 enum { da226, da280 };
  29
  30 /*
  31  * a value of + or -4096 corresponds to + or - 1G
  32  * scale = 9.81 / 4096 = 0.002395019
  33  */
  34
  35 static const int da280_nscale = 2395019;
  36
  37 #define DA280_CHANNEL(reg, axis) {      \
  38         .type = IIO_ACCEL,      \
  39         .address = reg, \
  40         .modified = 1,  \
  41         .channel2 = IIO_MOD_##axis,     \
  42         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),   \
  43         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
  44 }
  45
  46 static const struct iio_chan_spec da280_channels[] = {
  47         DA280_CHANNEL(DA280_REG_ACC_X_LSB, X),
  48         DA280_CHANNEL(DA280_REG_ACC_Y_LSB, Y),
  49         DA280_CHANNEL(DA280_REG_ACC_Z_LSB, Z),
  50 };
  51
  52 struct da280_data {
  53         struct i2c_client *client;
  54 };
  55
  56 static int da280_enable(struct i2c_client *client, bool enable)
  57 {
  58         u8 data = enable ? DA280_MODE_ENABLE : DA280_MODE_DISABLE;
  59
  60         return i2c_smbus_write_byte_data(client, DA280_REG_MODE_BW, data);
  61 }
  62
  63 static int da280_read_raw(struct iio_dev *indio_dev,
  64                                 struct iio_chan_spec const *chan,
  65                                 int *val, int *val2, long mask)
  66 {
  67         struct da280_data *data = iio_priv(indio_dev);
  68         int ret;
  69
  70         switch (mask) {
  71         case IIO_CHAN_INFO_RAW:
  72                 ret = i2c_smbus_read_word_data(data->client, chan->address);
  73                 if (ret < 0)
  74                         return ret;
  75                 /*
  76                  * Values are 14 bits, stored as 16 bits with the 2
  77                  * least significant bits always 0.
  78                  */
  79                 *val = (short)ret >> 2;
  80                 return IIO_VAL_INT;
  81         case IIO_CHAN_INFO_SCALE:
  82                 *val = 0;
  83                 *val2 = da280_nscale;
  84                 return IIO_VAL_INT_PLUS_NANO;
  85         default:
  86                 return -EINVAL;
  87         }
  88 }
  89
  90 static const struct iio_info da280_info = {
  91         .driver_module  = THIS_MODULE,
  92         .read_raw       = da280_read_raw,
  93 };
  94
  95 static int da280_probe(struct i2c_client *client,
  96                         const struct i2c_device_id *id)
  97 {
  98         int ret;
  99         struct iio_dev *indio_dev;
 100         struct da280_data *data;
 101
 102         ret = i2c_smbus_read_byte_data(client, DA280_REG_CHIP_ID);
 103         if (ret != DA280_CHIP_ID)
 104                 return (ret < 0) ? ret : -ENODEV;
 105
 106         indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
 107         if (!indio_dev)
 108                 return -ENOMEM;
 109
 110         data = iio_priv(indio_dev);
 111         data->client = client;
 112         i2c_set_clientdata(client, indio_dev);
 113
 114         indio_dev->dev.parent = &client->dev;
 115         indio_dev->info = &da280_info;
 116         indio_dev->modes = INDIO_DIRECT_MODE;
 117         indio_dev->channels = da280_channels;
 118         if (id->driver_data == da226) {
 119                 indio_dev->name = "da226";
 120                 indio_dev->num_channels = 2;
 121         } else {
 122                 indio_dev->name = "da280";
 123                 indio_dev->num_channels = 3;
 124         }
 125
 126         ret = da280_enable(client, true);
 127         if (ret < 0)
 128                 return ret;
 129
 130         ret = iio_device_register(indio_dev);
 131         if (ret < 0) {
 132                 dev_err(&client->dev, "device_register failed\n");
 133                 da280_enable(client, false);
 134         }
 135
 136         return ret;
 137 }
 138
 139 static int da280_remove(struct i2c_client *client)
 140 {
 141         struct iio_dev *indio_dev = i2c_get_clientdata(client);
 142
 143         iio_device_unregister(indio_dev);
 144
 145         return da280_enable(client, false);
 146 }
 147
 148 #ifdef CONFIG_PM_SLEEP
 149 static int da280_suspend(struct device *dev)
 150 {
 151         return da280_enable(to_i2c_client(dev), false);
 152 }
 153
 154 static int da280_resume(struct device *dev)
 155 {
 156         return da280_enable(to_i2c_client(dev), true);
 157 }
 158 #endif
 159
 160 static SIMPLE_DEV_PM_OPS(da280_pm_ops, da280_suspend, da280_resume);
 161
 162 static const struct i2c_device_id da280_i2c_id[] = {
 163         { "da226", da226 },
 164         { "da280", da280 },
 165         {}
 166 };
 167 MODULE_DEVICE_TABLE(i2c, da280_i2c_id);
 168
 169 static struct i2c_driver da280_driver = {
 170         .driver = {
 171                 .name = "da280",
 172                 .pm = &da280_pm_ops,
 173         },
 174         .probe          = da280_probe,
 175         .remove         = da280_remove,
 176         .id_table       = da280_i2c_id,
 177 };
 178
 179 module_i2c_driver(da280_driver);
 180
 181 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
 182 MODULE_DESCRIPTION("MiraMEMS DA280 3-Axis Accelerometer driver");
 183 MODULE_LICENSE("GPL v2");