drivers/iio/accel/bma220_spi.c

   1 /**
   2  * BMA220 Digital triaxial acceleration sensor driver
   3  *
   4  * Copyright (c) 2016, Intel Corporation.
   5  *
   6  * This file is subject to the terms and conditions of version 2 of
   7  * the GNU General Public License. See the file COPYING in the main
   8  * directory of this archive for more details.
   9  */
  10
  11 #include <linux/acpi.h>
  12 #include <linux/kernel.h>
  13 #include <linux/module.h>
  14 #include <linux/iio/buffer.h>
  15 #include <linux/iio/iio.h>
  16 #include <linux/iio/sysfs.h>
  17 #include <linux/spi/spi.h>
  18 #include <linux/iio/trigger_consumer.h>
  19 #include <linux/iio/triggered_buffer.h>
  20
  21 #define BMA220_REG_ID                           0x00
  22 #define BMA220_REG_ACCEL_X                      0x02
  23 #define BMA220_REG_ACCEL_Y                      0x03
  24 #define BMA220_REG_ACCEL_Z                      0x04
  25 #define BMA220_REG_RANGE                        0x11
  26 #define BMA220_REG_SUSPEND                      0x18
  27
  28 #define BMA220_CHIP_ID                          0xDD
  29 #define BMA220_READ_MASK                        0x80
  30 #define BMA220_RANGE_MASK                       0x03
  31 #define BMA220_DATA_SHIFT                       2
  32 #define BMA220_SUSPEND_SLEEP                    0xFF
  33 #define BMA220_SUSPEND_WAKE                     0x00
  34
  35 #define BMA220_DEVICE_NAME                      "bma220"
  36 #define BMA220_SCALE_AVAILABLE                  "0.623 1.248 2.491 4.983"
  37
  38 #define BMA220_ACCEL_CHANNEL(index, reg, axis) {                        \
  39         .type = IIO_ACCEL,                                              \
  40         .address = reg,                                                 \
  41         .modified = 1,                                                  \
  42         .channel2 = IIO_MOD_##axis,                                     \
  43         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),                   \
  44         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),           \
  45         .scan_index = index,                                            \
  46         .scan_type = {                                                  \
  47                 .sign = 's',                                            \
  48                 .realbits = 6,                                          \
  49                 .storagebits = 8,                                       \
  50                 .shift = BMA220_DATA_SHIFT,                             \
  51                 .endianness = IIO_CPU,                                  \
  52         },                                                              \
  53 }
  54
  55 enum bma220_axis {
  56         AXIS_X,
  57         AXIS_Y,
  58         AXIS_Z,
  59 };
  60
  61 static IIO_CONST_ATTR(in_accel_scale_available, BMA220_SCALE_AVAILABLE);
  62
  63 static struct attribute *bma220_attributes[] = {
  64         &iio_const_attr_in_accel_scale_available.dev_attr.attr,
  65         NULL,
  66 };
  67
  68 static const struct attribute_group bma220_attribute_group = {
  69         .attrs = bma220_attributes,
  70 };
  71
  72 static const int bma220_scale_table[][4] = {
  73         {0, 623000}, {1, 248000}, {2, 491000}, {4, 983000}
  74 };
  75
  76 struct bma220_data {
  77         struct spi_device *spi_device;
  78         struct mutex lock;
  79         struct {
  80                 s8 chans[3];
  81                 /* Ensure timestamp is naturally aligned. */
  82                 s64 timestamp __aligned(8);
  83         } scan;
  84         u8 tx_buf[2] ____cacheline_aligned;
  85 };
  86
  87 static const struct iio_chan_spec bma220_channels[] = {
  88         BMA220_ACCEL_CHANNEL(0, BMA220_REG_ACCEL_X, X),
  89         BMA220_ACCEL_CHANNEL(1, BMA220_REG_ACCEL_Y, Y),
  90         BMA220_ACCEL_CHANNEL(2, BMA220_REG_ACCEL_Z, Z),
  91         IIO_CHAN_SOFT_TIMESTAMP(3),
  92 };
  93
  94 static inline int bma220_read_reg(struct spi_device *spi, u8 reg)
  95 {
  96         return spi_w8r8(spi, reg | BMA220_READ_MASK);
  97 }
  98
  99 static const unsigned long bma220_accel_scan_masks[] = {
 100         BIT(AXIS_X) | BIT(AXIS_Y) | BIT(AXIS_Z),
 101         0
 102 };
 103
 104 static irqreturn_t bma220_trigger_handler(int irq, void *p)
 105 {
 106         int ret;
 107         struct iio_poll_func *pf = p;
 108         struct iio_dev *indio_dev = pf->indio_dev;
 109         struct bma220_data *data = iio_priv(indio_dev);
 110         struct spi_device *spi = data->spi_device;
 111
 112         mutex_lock(&data->lock);
 113         data->tx_buf[0] = BMA220_REG_ACCEL_X | BMA220_READ_MASK;
 114         ret = spi_write_then_read(spi, data->tx_buf, 1, &data->scan.chans,
 115                                   ARRAY_SIZE(bma220_channels) - 1);
 116         if (ret < 0)
 117                 goto err;
 118
 119         iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
 120                                            pf->timestamp);
 121 err:
 122         mutex_unlock(&data->lock);
 123         iio_trigger_notify_done(indio_dev->trig);
 124
 125         return IRQ_HANDLED;
 126 }
 127
 128 static int bma220_read_raw(struct iio_dev *indio_dev,
 129                            struct iio_chan_spec const *chan,
 130                            int *val, int *val2, long mask)
 131 {
 132         int ret;
 133         u8 range_idx;
 134         struct bma220_data *data = iio_priv(indio_dev);
 135
 136         switch (mask) {
 137         case IIO_CHAN_INFO_RAW:
 138                 ret = bma220_read_reg(data->spi_device, chan->address);
 139                 if (ret < 0)
 140                         return -EINVAL;
 141                 *val = sign_extend32(ret >> BMA220_DATA_SHIFT, 5);
 142                 return IIO_VAL_INT;
 143         case IIO_CHAN_INFO_SCALE:
 144                 ret = bma220_read_reg(data->spi_device, BMA220_REG_RANGE);
 145                 if (ret < 0)
 146                         return ret;
 147                 range_idx = ret & BMA220_RANGE_MASK;
 148                 *val = bma220_scale_table[range_idx][0];
 149                 *val2 = bma220_scale_table[range_idx][1];
 150                 return IIO_VAL_INT_PLUS_MICRO;
 151         }
 152
 153         return -EINVAL;
 154 }
 155
 156 static int bma220_write_raw(struct iio_dev *indio_dev,
 157                             struct iio_chan_spec const *chan,
 158                             int val, int val2, long mask)
 159 {
 160         int i;
 161         int ret;
 162         int index = -1;
 163         struct bma220_data *data = iio_priv(indio_dev);
 164
 165         switch (mask) {
 166         case IIO_CHAN_INFO_SCALE:
 167                 for (i = 0; i < ARRAY_SIZE(bma220_scale_table); i++)
 168                         if (val == bma220_scale_table[i][0] &&
 169                             val2 == bma220_scale_table[i][1]) {
 170                                 index = i;
 171                                 break;
 172                         }
 173                 if (index < 0)
 174                         return -EINVAL;
 175
 176                 mutex_lock(&data->lock);
 177                 data->tx_buf[0] = BMA220_REG_RANGE;
 178                 data->tx_buf[1] = index;
 179                 ret = spi_write(data->spi_device, data->tx_buf,
 180                                 sizeof(data->tx_buf));
 181                 if (ret < 0)
 182                         dev_err(&data->spi_device->dev,
 183                                 "failed to set measurement range\n");
 184                 mutex_unlock(&data->lock);
 185
 186                 return 0;
 187         }
 188
 189         return -EINVAL;
 190 }
 191
 192 static const struct iio_info bma220_info = {
 193         .read_raw               = bma220_read_raw,
 194         .write_raw              = bma220_write_raw,
 195         .attrs                  = &bma220_attribute_group,
 196 };
 197
 198 static int bma220_init(struct spi_device *spi)
 199 {
 200         int ret;
 201
 202         ret = bma220_read_reg(spi, BMA220_REG_ID);
 203         if (ret != BMA220_CHIP_ID)
 204                 return -ENODEV;
 205
 206         /* Make sure the chip is powered on */
 207         ret = bma220_read_reg(spi, BMA220_REG_SUSPEND);
 208         if (ret < 0)
 209                 return ret;
 210         else if (ret == BMA220_SUSPEND_WAKE)
 211                 return bma220_read_reg(spi, BMA220_REG_SUSPEND);
 212
 213         return 0;
 214 }
 215
 216 static int bma220_deinit(struct spi_device *spi)
 217 {
 218         int ret;
 219
 220         /* Make sure the chip is powered off */
 221         ret = bma220_read_reg(spi, BMA220_REG_SUSPEND);
 222         if (ret < 0)
 223                 return ret;
 224         else if (ret == BMA220_SUSPEND_SLEEP)
 225                 return bma220_read_reg(spi, BMA220_REG_SUSPEND);
 226
 227         return 0;
 228 }
 229
 230 static int bma220_probe(struct spi_device *spi)
 231 {
 232         int ret;
 233         struct iio_dev *indio_dev;
 234         struct bma220_data *data;
 235
 236         indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*data));
 237         if (!indio_dev) {
 238                 dev_err(&spi->dev, "iio allocation failed!\n");
 239                 return -ENOMEM;
 240         }
 241
 242         data = iio_priv(indio_dev);
 243         data->spi_device = spi;
 244         spi_set_drvdata(spi, indio_dev);
 245         mutex_init(&data->lock);
 246
 247         indio_dev->dev.parent = &spi->dev;
 248         indio_dev->info = &bma220_info;
 249         indio_dev->name = BMA220_DEVICE_NAME;
 250         indio_dev->modes = INDIO_DIRECT_MODE;
 251         indio_dev->channels = bma220_channels;
 252         indio_dev->num_channels = ARRAY_SIZE(bma220_channels);
 253         indio_dev->available_scan_masks = bma220_accel_scan_masks;
 254
 255         ret = bma220_init(data->spi_device);
 256         if (ret < 0)
 257                 return ret;
 258
 259         ret = iio_triggered_buffer_setup(indio_dev, iio_pollfunc_store_time,
 260                                          bma220_trigger_handler, NULL);
 261         if (ret < 0) {
 262                 dev_err(&spi->dev, "iio triggered buffer setup failed\n");
 263                 goto err_suspend;
 264         }
 265
 266         ret = iio_device_register(indio_dev);
 267         if (ret < 0) {
 268                 dev_err(&spi->dev, "iio_device_register failed\n");
 269                 iio_triggered_buffer_cleanup(indio_dev);
 270                 goto err_suspend;
 271         }
 272
 273         return 0;
 274
 275 err_suspend:
 276         return bma220_deinit(spi);
 277 }
 278
 279 static int bma220_remove(struct spi_device *spi)
 280 {
 281         struct iio_dev *indio_dev = spi_get_drvdata(spi);
 282
 283         iio_device_unregister(indio_dev);
 284         iio_triggered_buffer_cleanup(indio_dev);
 285
 286         return bma220_deinit(spi);
 287 }
 288
 289 #ifdef CONFIG_PM_SLEEP
 290 static int bma220_suspend(struct device *dev)
 291 {
 292         struct bma220_data *data =
 293                         iio_priv(spi_get_drvdata(to_spi_device(dev)));
 294
 295         /* The chip can be suspended/woken up by a simple register read. */
 296         return bma220_read_reg(data->spi_device, BMA220_REG_SUSPEND);
 297 }
 298
 299 static int bma220_resume(struct device *dev)
 300 {
 301         struct bma220_data *data =
 302                         iio_priv(spi_get_drvdata(to_spi_device(dev)));
 303
 304         return bma220_read_reg(data->spi_device, BMA220_REG_SUSPEND);
 305 }
 306
 307 static SIMPLE_DEV_PM_OPS(bma220_pm_ops, bma220_suspend, bma220_resume);
 308
 309 #define BMA220_PM_OPS (&bma220_pm_ops)
 310 #else
 311 #define BMA220_PM_OPS NULL
 312 #endif
 313
 314 static const struct spi_device_id bma220_spi_id[] = {
 315         {"bma220", 0},
 316         {}
 317 };
 318
 319 static const struct acpi_device_id bma220_acpi_id[] = {
 320         {"BMA0220", 0},
 321         {}
 322 };
 323
 324 MODULE_DEVICE_TABLE(spi, bma220_spi_id);
 325
 326 static struct spi_driver bma220_driver = {
 327         .driver = {
 328                 .name = "bma220_spi",
 329                 .pm = BMA220_PM_OPS,
 330                 .acpi_match_table = ACPI_PTR(bma220_acpi_id),
 331         },
 332         .probe =            bma220_probe,
 333         .remove =           bma220_remove,
 334         .id_table =         bma220_spi_id,
 335 };
 336
 337 module_spi_driver(bma220_driver);
 338
 339 MODULE_AUTHOR("Tiberiu Breana <tiberiu.a.breana@intel.com>");
 340 MODULE_DESCRIPTION("BMA220 acceleration sensor driver");
 341 MODULE_LICENSE("GPL v2");