drivers/iio/accel/kxsd9.c

   1 /*
   2  * kxsd9.c      simple support for the Kionix KXSD9 3D
   3  *              accelerometer.
   4  *
   5  * Copyright (c) 2008-2009 Jonathan Cameron <jic23@kernel.org>
   6  *
   7  * This program is free software; you can redistribute it and/or modify
   8  * it under the terms of the GNU General Public License version 2 as
   9  * published by the Free Software Foundation.
  10  *
  11  * The i2c interface is very similar, so shouldn't be a problem once
  12  * I have a suitable wire made up.
  13  *
  14  * TODO:        Support the motion detector
  15  *              Uses register address incrementing so could have a
  16  *              heavily optimized ring buffer access function.
  17  */
  18
  19 #include <linux/device.h>
  20 #include <linux/kernel.h>
  21 #include <linux/spi/spi.h>
  22 #include <linux/sysfs.h>
  23 #include <linux/slab.h>
  24 #include <linux/module.h>
  25
  26 #include <linux/iio/iio.h>
  27 #include <linux/iio/sysfs.h>
  28
  29 #define KXSD9_REG_X             0x00
  30 #define KXSD9_REG_Y             0x02
  31 #define KXSD9_REG_Z             0x04
  32 #define KXSD9_REG_AUX           0x06
  33 #define KXSD9_REG_RESET         0x0a
  34 #define KXSD9_REG_CTRL_C        0x0c
  35
  36 #define KXSD9_FS_MASK           0x03
  37
  38 #define KXSD9_REG_CTRL_B        0x0d
  39 #define KXSD9_REG_CTRL_A        0x0e
  40
  41 #define KXSD9_READ(a) (0x80 | (a))
  42 #define KXSD9_WRITE(a) (a)
  43
  44 #define KXSD9_STATE_RX_SIZE 2
  45 #define KXSD9_STATE_TX_SIZE 2
  46 /**
  47  * struct kxsd9_state - device related storage
  48  * @buf_lock:   protect the rx and tx buffers.
  49  * @us:         spi device
  50  * @rx:         single rx buffer storage
  51  * @tx:         single tx buffer storage
  52  **/
  53 struct kxsd9_state {
  54         struct mutex buf_lock;
  55         struct spi_device *us;
  56         u8 rx[KXSD9_STATE_RX_SIZE] ____cacheline_aligned;
  57         u8 tx[KXSD9_STATE_TX_SIZE];
  58 };
  59
  60 #define KXSD9_SCALE_2G "0.011978"
  61 #define KXSD9_SCALE_4G "0.023927"
  62 #define KXSD9_SCALE_6G "0.035934"
  63 #define KXSD9_SCALE_8G "0.047853"
  64
  65 /* reverse order */
  66 static const int kxsd9_micro_scales[4] = { 47853, 35934, 23927, 11978 };
  67
  68 static int kxsd9_write_scale(struct iio_dev *indio_dev, int micro)
  69 {
  70         int ret, i;
  71         struct kxsd9_state *st = iio_priv(indio_dev);
  72         bool foundit = false;
  73
  74         for (i = 0; i < 4; i++)
  75                 if (micro == kxsd9_micro_scales[i]) {
  76                         foundit = true;
  77                         break;
  78                 }
  79         if (!foundit)
  80                 return -EINVAL;
  81
  82         mutex_lock(&st->buf_lock);
  83         ret = spi_w8r8(st->us, KXSD9_READ(KXSD9_REG_CTRL_C));
  84         if (ret < 0)
  85                 goto error_ret;
  86         st->tx[0] = KXSD9_WRITE(KXSD9_REG_CTRL_C);
  87         st->tx[1] = (ret & ~KXSD9_FS_MASK) | i;
  88
  89         ret = spi_write(st->us, st->tx, 2);
  90 error_ret:
  91         mutex_unlock(&st->buf_lock);
  92         return ret;
  93 }
  94
  95 static int kxsd9_read(struct iio_dev *indio_dev, u8 address)
  96 {
  97         int ret;
  98         struct kxsd9_state *st = iio_priv(indio_dev);
  99         struct spi_transfer xfers[] = {
 100                 {
 101                         .bits_per_word = 8,
 102                         .len = 1,
 103                         .delay_usecs = 200,
 104                         .tx_buf = st->tx,
 105                 }, {
 106                         .bits_per_word = 8,
 107                         .len = 2,
 108                         .rx_buf = st->rx,
 109                 },
 110         };
 111
 112         mutex_lock(&st->buf_lock);
 113         st->tx[0] = KXSD9_READ(address);
 114         ret = spi_sync_transfer(st->us, xfers, ARRAY_SIZE(xfers));
 115         if (!ret)
 116                 ret = (((u16)(st->rx[0])) << 8) | (st->rx[1] & 0xF0);
 117         mutex_unlock(&st->buf_lock);
 118         return ret;
 119 }
 120
 121 static IIO_CONST_ATTR(accel_scale_available,
 122                 KXSD9_SCALE_2G " "
 123                 KXSD9_SCALE_4G " "
 124                 KXSD9_SCALE_6G " "
 125                 KXSD9_SCALE_8G);
 126
 127 static struct attribute *kxsd9_attributes[] = {
 128         &iio_const_attr_accel_scale_available.dev_attr.attr,
 129         NULL,
 130 };
 131
 132 static int kxsd9_write_raw(struct iio_dev *indio_dev,
 133                            struct iio_chan_spec const *chan,
 134                            int val,
 135                            int val2,
 136                            long mask)
 137 {
 138         int ret = -EINVAL;
 139
 140         if (mask == IIO_CHAN_INFO_SCALE) {
 141                 /* Check no integer component */
 142                 if (val)
 143                         return -EINVAL;
 144                 ret = kxsd9_write_scale(indio_dev, val2);
 145         }
 146
 147         return ret;
 148 }
 149
 150 static int kxsd9_read_raw(struct iio_dev *indio_dev,
 151                           struct iio_chan_spec const *chan,
 152                           int *val, int *val2, long mask)
 153 {
 154         int ret = -EINVAL;
 155         struct kxsd9_state *st = iio_priv(indio_dev);
 156
 157         switch (mask) {
 158         case IIO_CHAN_INFO_RAW:
 159                 ret = kxsd9_read(indio_dev, chan->address);
 160                 if (ret < 0)
 161                         goto error_ret;
 162                 *val = ret;
 163                 ret = IIO_VAL_INT;
 164                 break;
 165         case IIO_CHAN_INFO_SCALE:
 166                 ret = spi_w8r8(st->us, KXSD9_READ(KXSD9_REG_CTRL_C));
 167                 if (ret < 0)
 168                         goto error_ret;
 169                 *val2 = kxsd9_micro_scales[ret & KXSD9_FS_MASK];
 170                 ret = IIO_VAL_INT_PLUS_MICRO;
 171                 break;
 172         }
 173
 174 error_ret:
 175         return ret;
 176 };
 177 #define KXSD9_ACCEL_CHAN(axis)                                          \
 178         {                                                               \
 179                 .type = IIO_ACCEL,                                      \
 180                 .modified = 1,                                          \
 181                 .channel2 = IIO_MOD_##axis,                             \
 182                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
 183                 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
 184                 .address = KXSD9_REG_##axis,                            \
 185         }
 186
 187 static const struct iio_chan_spec kxsd9_channels[] = {
 188         KXSD9_ACCEL_CHAN(X), KXSD9_ACCEL_CHAN(Y), KXSD9_ACCEL_CHAN(Z),
 189         {
 190                 .type = IIO_VOLTAGE,
 191                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
 192                 .indexed = 1,
 193                 .address = KXSD9_REG_AUX,
 194         }
 195 };
 196
 197 static const struct attribute_group kxsd9_attribute_group = {
 198         .attrs = kxsd9_attributes,
 199 };
 200
 201 static int kxsd9_power_up(struct kxsd9_state *st)
 202 {
 203         int ret;
 204
 205         st->tx[0] = 0x0d;
 206         st->tx[1] = 0x40;
 207         ret = spi_write(st->us, st->tx, 2);
 208         if (ret)
 209                 return ret;
 210
 211         st->tx[0] = 0x0c;
 212         st->tx[1] = 0x9b;
 213         return spi_write(st->us, st->tx, 2);
 214 };
 215
 216 static const struct iio_info kxsd9_info = {
 217         .read_raw = &kxsd9_read_raw,
 218         .write_raw = &kxsd9_write_raw,
 219         .attrs = &kxsd9_attribute_group,
 220         .driver_module = THIS_MODULE,
 221 };
 222
 223 static int kxsd9_probe(struct spi_device *spi)
 224 {
 225         struct iio_dev *indio_dev;
 226         struct kxsd9_state *st;
 227
 228         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 229         if (!indio_dev)
 230                 return -ENOMEM;
 231
 232         st = iio_priv(indio_dev);
 233         spi_set_drvdata(spi, indio_dev);
 234
 235         st->us = spi;
 236         mutex_init(&st->buf_lock);
 237         indio_dev->channels = kxsd9_channels;
 238         indio_dev->num_channels = ARRAY_SIZE(kxsd9_channels);
 239         indio_dev->name = spi_get_device_id(spi)->name;
 240         indio_dev->dev.parent = &spi->dev;
 241         indio_dev->info = &kxsd9_info;
 242         indio_dev->modes = INDIO_DIRECT_MODE;
 243
 244         spi->mode = SPI_MODE_0;
 245         spi_setup(spi);
 246         kxsd9_power_up(st);
 247
 248         return iio_device_register(indio_dev);
 249 }
 250
 251 static int kxsd9_remove(struct spi_device *spi)
 252 {
 253         iio_device_unregister(spi_get_drvdata(spi));
 254
 255         return 0;
 256 }
 257
 258 static const struct spi_device_id kxsd9_id[] = {
 259         {"kxsd9", 0},
 260         { },
 261 };
 262 MODULE_DEVICE_TABLE(spi, kxsd9_id);
 263
 264 static struct spi_driver kxsd9_driver = {
 265         .driver = {
 266                 .name = "kxsd9",
 267         },
 268         .probe = kxsd9_probe,
 269         .remove = kxsd9_remove,
 270         .id_table = kxsd9_id,
 271 };
 272 module_spi_driver(kxsd9_driver);
 273
 274 MODULE_AUTHOR("Jonathan Cameron <jic23@kernel.org>");
 275 MODULE_DESCRIPTION("Kionix KXSD9 SPI driver");
 276 MODULE_LICENSE("GPL v2");