drivers/staging/iio/gyro/adis16130_core.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/delay.h>
  10 #include <linux/mutex.h>
  11 #include <linux/device.h>
  12 #include <linux/kernel.h>
  13 #include <linux/spi/spi.h>
  14 #include <linux/slab.h>
  15 #include <linux/sysfs.h>
  16 #include <linux/list.h>
  17 #include <linux/module.h>
  18
  19 #include "../iio.h"
  20 #include "../sysfs.h"
  21
  22 #define ADIS16130_CON         0x0
  23 #define ADIS16130_CON_RD      (1 << 6)
  24 #define ADIS16130_IOP         0x1
  25
  26 /* 1 = data-ready signal low when unread data on all channels; */
  27 #define ADIS16130_IOP_ALL_RDY (1 << 3)
  28 #define ADIS16130_IOP_SYNC    (1 << 0) /* 1 = synchronization enabled */
  29 #define ADIS16130_RATEDATA    0x8 /* Gyroscope output, rate of rotation */
  30 #define ADIS16130_TEMPDATA    0xA /* Temperature output */
  31 #define ADIS16130_RATECS      0x28 /* Gyroscope channel setup */
  32 #define ADIS16130_RATECS_EN   (1 << 3) /* 1 = channel enable; */
  33 #define ADIS16130_TEMPCS      0x2A /* Temperature channel setup */
  34 #define ADIS16130_TEMPCS_EN   (1 << 3)
  35 #define ADIS16130_RATECONV    0x30
  36 #define ADIS16130_TEMPCONV    0x32
  37 #define ADIS16130_MODE        0x38
  38 #define ADIS16130_MODE_24BIT  (1 << 1) /* 1 = 24-bit resolution; */
  39
  40 /**
  41  * struct adis16130_state - device instance specific data
  42  * @us:                 actual spi_device to write data
  43  * @buf_lock:           mutex to protect tx and rx
  44  * @buf:                unified tx/rx buffer
  45  **/
  46 struct adis16130_state {
  47         struct spi_device               *us;
  48         struct mutex                    buf_lock;
  49         u8                              buf[4] ____cacheline_aligned;
  50 };
  51
  52 static int adis16130_spi_read(struct iio_dev *indio_dev, u8 reg_addr, u32 *val)
  53 {
  54         int ret;
  55         struct adis16130_state *st = iio_priv(indio_dev);
  56         struct spi_message msg;
  57         struct spi_transfer xfer = {
  58                 .tx_buf = st->buf,
  59                 .rx_buf = st->buf,
  60                 .len = 4,
  61         };
  62
  63         mutex_lock(&st->buf_lock);
  64
  65         st->buf[0] = ADIS16130_CON_RD | reg_addr;
  66         st->buf[1] = st->buf[2] = st->buf[3] = 0;
  67
  68         spi_message_init(&msg);
  69         spi_message_add_tail(&xfer, &msg);
  70         ret = spi_sync(st->us, &msg);
  71         ret = spi_read(st->us, st->buf, 4);
  72
  73         if (ret == 0)
  74                 *val = (st->buf[1] << 16) | (st->buf[2] << 8) | st->buf[3];
  75         mutex_unlock(&st->buf_lock);
  76
  77         return ret;
  78 }
  79
  80 static int adis16130_read_raw(struct iio_dev *indio_dev,
  81                               struct iio_chan_spec const *chan,
  82                               int *val, int *val2,
  83                               long mask)
  84 {
  85         int ret;
  86         u32 temp;
  87
  88         /* Take the iio_dev status lock */
  89         mutex_lock(&indio_dev->mlock);
  90         ret =  adis16130_spi_read(indio_dev, chan->address, &temp);
  91         mutex_unlock(&indio_dev->mlock);
  92         if (ret)
  93                 return ret;
  94         *val = temp;
  95         return IIO_VAL_INT;
  96 }
  97
  98 static const struct iio_chan_spec adis16130_channels[] = {
  99         {
 100                 .type = IIO_ANGL_VEL,
 101                 .modified = 1,
 102                 .channel2 = IIO_MOD_Z,
 103                 .address = ADIS16130_RATEDATA,
 104         }, {
 105                 .type = IIO_TEMP,
 106                 .indexed = 1,
 107                 .channel = 0,
 108                 .address = ADIS16130_TEMPDATA,
 109         }
 110 };
 111
 112 static const struct iio_info adis16130_info = {
 113         .read_raw = &adis16130_read_raw,
 114         .driver_module = THIS_MODULE,
 115 };
 116
 117 static int __devinit adis16130_probe(struct spi_device *spi)
 118 {
 119         int ret;
 120         struct adis16130_state *st;
 121         struct iio_dev *indio_dev;
 122
 123         /* setup the industrialio driver allocated elements */
 124         indio_dev = iio_allocate_device(sizeof(*st));
 125         if (indio_dev == NULL) {
 126                 ret = -ENOMEM;
 127                 goto error_ret;
 128         }
 129         st = iio_priv(indio_dev);
 130         /* this is only used for removal purposes */
 131         spi_set_drvdata(spi, indio_dev);
 132         st->us = spi;
 133         mutex_init(&st->buf_lock);
 134         indio_dev->name = spi->dev.driver->name;
 135         indio_dev->channels = adis16130_channels;
 136         indio_dev->num_channels = ARRAY_SIZE(adis16130_channels);
 137         indio_dev->dev.parent = &spi->dev;
 138         indio_dev->info = &adis16130_info;
 139         indio_dev->modes = INDIO_DIRECT_MODE;
 140
 141         ret = iio_device_register(indio_dev);
 142         if (ret)
 143                 goto error_free_dev;
 144
 145         return 0;
 146
 147 error_free_dev:
 148         iio_free_device(indio_dev);
 149
 150 error_ret:
 151         return ret;
 152 }
 153
 154 /* fixme, confirm ordering in this function */
 155 static int adis16130_remove(struct spi_device *spi)
 156 {
 157         iio_device_unregister(spi_get_drvdata(spi));
 158         iio_free_device(spi_get_drvdata(spi));
 159
 160         return 0;
 161 }
 162
 163 static struct spi_driver adis16130_driver = {
 164         .driver = {
 165                 .name = "adis16130",
 166                 .owner = THIS_MODULE,
 167         },
 168         .probe = adis16130_probe,
 169         .remove = __devexit_p(adis16130_remove),
 170 };
 171 module_spi_driver(adis16130_driver);
 172
 173 MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
 174 MODULE_DESCRIPTION("Analog Devices ADIS16130 High Precision Angular Rate");
 175 MODULE_LICENSE("GPL v2");
 176 MODULE_ALIAS("spi:adis16130");