drivers/iio/gyro/adis16130.c

   1 /*
   2  * ADIS16130 Digital Output, High Precision Angular Rate Sensor driver
   3  *
   4  * Copyright 2010 Analog Devices Inc.
   5  *
   6  * Licensed under the GPL-2 or later.
   7  */
   8
   9 #include <linux/mutex.h>
  10 #include <linux/kernel.h>
  11 #include <linux/spi/spi.h>
  12 #include <linux/module.h>
  13
  14 #include <linux/iio/iio.h>
  15
  16 #define ADIS16130_CON         0x0
  17 #define ADIS16130_CON_RD      (1 << 6)
  18 #define ADIS16130_IOP         0x1
  19
  20 /* 1 = data-ready signal low when unread data on all channels; */
  21 #define ADIS16130_IOP_ALL_RDY (1 << 3)
  22 #define ADIS16130_IOP_SYNC    (1 << 0) /* 1 = synchronization enabled */
  23 #define ADIS16130_RATEDATA    0x8 /* Gyroscope output, rate of rotation */
  24 #define ADIS16130_TEMPDATA    0xA /* Temperature output */
  25 #define ADIS16130_RATECS      0x28 /* Gyroscope channel setup */
  26 #define ADIS16130_RATECS_EN   (1 << 3) /* 1 = channel enable; */
  27 #define ADIS16130_TEMPCS      0x2A /* Temperature channel setup */
  28 #define ADIS16130_TEMPCS_EN   (1 << 3)
  29 #define ADIS16130_RATECONV    0x30
  30 #define ADIS16130_TEMPCONV    0x32
  31 #define ADIS16130_MODE        0x38
  32 #define ADIS16130_MODE_24BIT  (1 << 1) /* 1 = 24-bit resolution; */
  33
  34 /**
  35  * struct adis16130_state - device instance specific data
  36  * @us:                 actual spi_device to write data
  37  * @buf_lock:           mutex to protect tx and rx
  38  * @buf:                unified tx/rx buffer
  39  **/
  40 struct adis16130_state {
  41         struct spi_device               *us;
  42         struct mutex                    buf_lock;
  43         u8                              buf[4] ____cacheline_aligned;
  44 };
  45
  46 static int adis16130_spi_read(struct iio_dev *indio_dev, u8 reg_addr, u32 *val)
  47 {
  48         int ret;
  49         struct adis16130_state *st = iio_priv(indio_dev);
  50         struct spi_transfer xfer = {
  51                 .tx_buf = st->buf,
  52                 .rx_buf = st->buf,
  53                 .len = 4,
  54         };
  55
  56         mutex_lock(&st->buf_lock);
  57
  58         st->buf[0] = ADIS16130_CON_RD | reg_addr;
  59         st->buf[1] = st->buf[2] = st->buf[3] = 0;
  60
  61         ret = spi_sync_transfer(st->us, &xfer, 1);
  62         if (ret == 0)
  63                 *val = (st->buf[1] << 16) | (st->buf[2] << 8) | st->buf[3];
  64         mutex_unlock(&st->buf_lock);
  65
  66         return ret;
  67 }
  68
  69 static int adis16130_read_raw(struct iio_dev *indio_dev,
  70                               struct iio_chan_spec const *chan,
  71                               int *val, int *val2,
  72                               long mask)
  73 {
  74         int ret;
  75         u32 temp;
  76
  77         switch (mask) {
  78         case IIO_CHAN_INFO_RAW:
  79                 /* Take the iio_dev status lock */
  80                 mutex_lock(&indio_dev->mlock);
  81                 ret = adis16130_spi_read(indio_dev, chan->address, &temp);
  82                 mutex_unlock(&indio_dev->mlock);
  83                 if (ret)
  84                         return ret;
  85                 *val = temp;
  86                 return IIO_VAL_INT;
  87         case IIO_CHAN_INFO_SCALE:
  88                 switch (chan->type) {
  89                 case IIO_ANGL_VEL:
  90                         /* 0 degree = 838860, 250 degree = 14260608 */
  91                         *val = 250;
  92                         *val2 = 336440817; /* RAD_TO_DEGREE(14260608 - 8388608) */
  93                         return IIO_VAL_FRACTIONAL;
  94                 case IIO_TEMP:
  95                         /* 0C = 8036283, 105C = 9516048 */
  96                         *val = 105000;
  97                         *val2 = 9516048 - 8036283;
  98                         return IIO_VAL_FRACTIONAL;
  99                 default:
 100                         return -EINVAL;
 101                 }
 102         case IIO_CHAN_INFO_OFFSET:
 103                 switch (chan->type) {
 104                 case IIO_ANGL_VEL:
 105                         *val = -8388608;
 106                         return IIO_VAL_INT;
 107                 case IIO_TEMP:
 108                         *val = -8036283;
 109                         return IIO_VAL_INT;
 110                 default:
 111                         return -EINVAL;
 112                 }
 113         }
 114
 115         return -EINVAL;
 116 }
 117
 118 static const struct iio_chan_spec adis16130_channels[] = {
 119         {
 120                 .type = IIO_ANGL_VEL,
 121                 .modified = 1,
 122                 .channel2 = IIO_MOD_Z,
 123                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 124                         BIT(IIO_CHAN_INFO_SCALE) |
 125                         BIT(IIO_CHAN_INFO_OFFSET),
 126                 .address = ADIS16130_RATEDATA,
 127         }, {
 128                 .type = IIO_TEMP,
 129                 .indexed = 1,
 130                 .channel = 0,
 131                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 132                         BIT(IIO_CHAN_INFO_SCALE) |
 133                         BIT(IIO_CHAN_INFO_OFFSET),
 134                 .address = ADIS16130_TEMPDATA,
 135         }
 136 };
 137
 138 static const struct iio_info adis16130_info = {
 139         .read_raw = &adis16130_read_raw,
 140         .driver_module = THIS_MODULE,
 141 };
 142
 143 static int adis16130_probe(struct spi_device *spi)
 144 {
 145         struct adis16130_state *st;
 146         struct iio_dev *indio_dev;
 147
 148         /* setup the industrialio driver allocated elements */
 149         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 150         if (!indio_dev)
 151                 return -ENOMEM;
 152         st = iio_priv(indio_dev);
 153         /* this is only used for removal purposes */
 154         spi_set_drvdata(spi, indio_dev);
 155         st->us = spi;
 156         mutex_init(&st->buf_lock);
 157         indio_dev->name = spi->dev.driver->name;
 158         indio_dev->channels = adis16130_channels;
 159         indio_dev->num_channels = ARRAY_SIZE(adis16130_channels);
 160         indio_dev->dev.parent = &spi->dev;
 161         indio_dev->info = &adis16130_info;
 162         indio_dev->modes = INDIO_DIRECT_MODE;
 163
 164         return devm_iio_device_register(&spi->dev, indio_dev);
 165 }
 166
 167 static struct spi_driver adis16130_driver = {
 168         .driver = {
 169                 .name = "adis16130",
 170                 .owner = THIS_MODULE,
 171         },
 172         .probe = adis16130_probe,
 173 };
 174 module_spi_driver(adis16130_driver);
 175
 176 MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
 177 MODULE_DESCRIPTION("Analog Devices ADIS16130 High Precision Angular Rate");
 178 MODULE_LICENSE("GPL v2");
 179 MODULE_ALIAS("spi:adis16130");