drivers/iio/accel/mma7455_core.c

   1 /*
   2  * IIO accel core driver for Freescale MMA7455L 3-axis 10-bit accelerometer
   3  * Copyright 2015 Joachim Eastwood <manabian@gmail.com>
   4  *
   5  * This program is free software; you can redistribute it and/or modify
   6  * it under the terms of the GNU General Public License version 2 as
   7  * published by the Free Software Foundation.
   8  *
   9  * UNSUPPORTED hardware features:
  10  *  - 8-bit mode with different scales
  11  *  - INT1/INT2 interrupts
  12  *  - Offset calibration
  13  *  - Events
  14  */
  15
  16 #include <linux/delay.h>
  17 #include <linux/iio/iio.h>
  18 #include <linux/iio/sysfs.h>
  19 #include <linux/iio/buffer.h>
  20 #include <linux/iio/trigger.h>
  21 #include <linux/iio/trigger_consumer.h>
  22 #include <linux/iio/triggered_buffer.h>
  23 #include <linux/module.h>
  24 #include <linux/regmap.h>
  25
  26 #include "mma7455.h"
  27
  28 #define MMA7455_REG_XOUTL               0x00
  29 #define MMA7455_REG_XOUTH               0x01
  30 #define MMA7455_REG_YOUTL               0x02
  31 #define MMA7455_REG_YOUTH               0x03
  32 #define MMA7455_REG_ZOUTL               0x04
  33 #define MMA7455_REG_ZOUTH               0x05
  34 #define MMA7455_REG_STATUS              0x09
  35 #define  MMA7455_STATUS_DRDY            BIT(0)
  36 #define MMA7455_REG_WHOAMI              0x0f
  37 #define  MMA7455_WHOAMI_ID              0x55
  38 #define MMA7455_REG_MCTL                0x16
  39 #define  MMA7455_MCTL_MODE_STANDBY      0x00
  40 #define  MMA7455_MCTL_MODE_MEASURE      0x01
  41 #define MMA7455_REG_CTL1                0x18
  42 #define  MMA7455_CTL1_DFBW_MASK         BIT(7)
  43 #define  MMA7455_CTL1_DFBW_125HZ        BIT(7)
  44 #define  MMA7455_CTL1_DFBW_62_5HZ       0
  45 #define MMA7455_REG_TW                  0x1e
  46
  47 /*
  48  * When MMA7455 is used in 10-bit it has a fullscale of -8g
  49  * corresponding to raw value -512. The userspace interface
  50  * uses m/s^2 and we declare micro units.
  51  * So scale factor is given by:
  52  *       g * 8 * 1e6 / 512 = 153228.90625, with g = 9.80665
  53  */
  54 #define MMA7455_10BIT_SCALE     153229
  55
  56 struct mma7455_data {
  57         struct regmap *regmap;
  58         struct device *dev;
  59 };
  60
  61 static int mma7455_drdy(struct mma7455_data *mma7455)
  62 {
  63         unsigned int reg;
  64         int tries = 3;
  65         int ret;
  66
  67         while (tries-- > 0) {
  68                 ret = regmap_read(mma7455->regmap, MMA7455_REG_STATUS, &reg);
  69                 if (ret)
  70                         return ret;
  71
  72                 if (reg & MMA7455_STATUS_DRDY)
  73                         return 0;
  74
  75                 msleep(20);
  76         }
  77
  78         dev_warn(mma7455->dev, "data not ready\n");
  79
  80         return -EIO;
  81 }
  82
  83 static irqreturn_t mma7455_trigger_handler(int irq, void *p)
  84 {
  85         struct iio_poll_func *pf = p;
  86         struct iio_dev *indio_dev = pf->indio_dev;
  87         struct mma7455_data *mma7455 = iio_priv(indio_dev);
  88         u8 buf[16]; /* 3 x 16-bit channels + padding + ts */
  89         int ret;
  90
  91         ret = mma7455_drdy(mma7455);
  92         if (ret)
  93                 goto done;
  94
  95         ret = regmap_bulk_read(mma7455->regmap, MMA7455_REG_XOUTL, buf,
  96                                sizeof(__le16) * 3);
  97         if (ret)
  98                 goto done;
  99
 100         iio_push_to_buffers_with_timestamp(indio_dev, buf, iio_get_time_ns());
 101
 102 done:
 103         iio_trigger_notify_done(indio_dev->trig);
 104
 105         return IRQ_HANDLED;
 106 }
 107
 108 static int mma7455_read_raw(struct iio_dev *indio_dev,
 109                             struct iio_chan_spec const *chan,
 110                             int *val, int *val2, long mask)
 111 {
 112         struct mma7455_data *mma7455 = iio_priv(indio_dev);
 113         unsigned int reg;
 114         __le16 data;
 115         int ret;
 116
 117         switch (mask) {
 118         case IIO_CHAN_INFO_RAW:
 119                 if (iio_buffer_enabled(indio_dev))
 120                         return -EBUSY;
 121
 122                 ret = mma7455_drdy(mma7455);
 123                 if (ret)
 124                         return ret;
 125
 126                 ret = regmap_bulk_read(mma7455->regmap, chan->address, &data,
 127                                        sizeof(data));
 128                 if (ret)
 129                         return ret;
 130
 131                 *val = sign_extend32(le16_to_cpu(data), 9);
 132
 133                 return IIO_VAL_INT;
 134
 135         case IIO_CHAN_INFO_SCALE:
 136                 *val = 0;
 137                 *val2 = MMA7455_10BIT_SCALE;
 138
 139                 return IIO_VAL_INT_PLUS_MICRO;
 140
 141         case IIO_CHAN_INFO_SAMP_FREQ:
 142                 ret = regmap_read(mma7455->regmap, MMA7455_REG_CTL1, &reg);
 143                 if (ret)
 144                         return ret;
 145
 146                 if (reg & MMA7455_CTL1_DFBW_MASK)
 147                         *val = 250;
 148                 else
 149                         *val = 125;
 150
 151                 return IIO_VAL_INT;
 152         }
 153
 154         return -EINVAL;
 155 }
 156
 157 static int mma7455_write_raw(struct iio_dev *indio_dev,
 158                              struct iio_chan_spec const *chan,
 159                              int val, int val2, long mask)
 160 {
 161         struct mma7455_data *mma7455 = iio_priv(indio_dev);
 162         int i;
 163
 164         switch (mask) {
 165         case IIO_CHAN_INFO_SAMP_FREQ:
 166                 if (val == 250 && val2 == 0)
 167                         i = MMA7455_CTL1_DFBW_125HZ;
 168                 else if (val == 125 && val2 == 0)
 169                         i = MMA7455_CTL1_DFBW_62_5HZ;
 170                 else
 171                         return -EINVAL;
 172
 173                 return regmap_update_bits(mma7455->regmap, MMA7455_REG_CTL1,
 174                                           MMA7455_CTL1_DFBW_MASK, i);
 175
 176         case IIO_CHAN_INFO_SCALE:
 177                 /* In 10-bit mode there is only one scale available */
 178                 if (val == 0 && val2 == MMA7455_10BIT_SCALE)
 179                         return 0;
 180                 break;
 181         }
 182
 183         return -EINVAL;
 184 }
 185
 186 static IIO_CONST_ATTR(sampling_frequency_available, "125 250");
 187
 188 static struct attribute *mma7455_attributes[] = {
 189         &iio_const_attr_sampling_frequency_available.dev_attr.attr,
 190         NULL
 191 };
 192
 193 static const struct attribute_group mma7455_group = {
 194         .attrs = mma7455_attributes,
 195 };
 196
 197 static const struct iio_info mma7455_info = {
 198         .attrs = &mma7455_group,
 199         .read_raw = mma7455_read_raw,
 200         .write_raw = mma7455_write_raw,
 201         .driver_module = THIS_MODULE,
 202 };
 203
 204 #define MMA7455_CHANNEL(axis, idx) { \
 205         .type = IIO_ACCEL, \
 206         .modified = 1, \
 207         .address = MMA7455_REG_##axis##OUTL,\
 208         .channel2 = IIO_MOD_##axis, \
 209         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
 210         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
 211                                     BIT(IIO_CHAN_INFO_SCALE), \
 212         .scan_index = idx, \
 213         .scan_type = { \
 214                 .sign = 's', \
 215                 .realbits = 10, \
 216                 .storagebits = 16, \
 217                 .endianness = IIO_LE, \
 218         }, \
 219 }
 220
 221 static const struct iio_chan_spec mma7455_channels[] = {
 222         MMA7455_CHANNEL(X, 0),
 223         MMA7455_CHANNEL(Y, 1),
 224         MMA7455_CHANNEL(Z, 2),
 225         IIO_CHAN_SOFT_TIMESTAMP(3),
 226 };
 227
 228 static const unsigned long mma7455_scan_masks[] = {0x7, 0};
 229
 230 const struct regmap_config mma7455_core_regmap = {
 231         .reg_bits = 8,
 232         .val_bits = 8,
 233         .max_register = MMA7455_REG_TW,
 234 };
 235 EXPORT_SYMBOL_GPL(mma7455_core_regmap);
 236
 237 int mma7455_core_probe(struct device *dev, struct regmap *regmap,
 238                        const char *name)
 239 {
 240         struct mma7455_data *mma7455;
 241         struct iio_dev *indio_dev;
 242         unsigned int reg;
 243         int ret;
 244
 245         ret = regmap_read(regmap, MMA7455_REG_WHOAMI, &reg);
 246         if (ret) {
 247                 dev_err(dev, "unable to read reg\n");
 248                 return ret;
 249         }
 250
 251         if (reg != MMA7455_WHOAMI_ID) {
 252                 dev_err(dev, "device id mismatch\n");
 253                 return -ENODEV;
 254         }
 255
 256         indio_dev = devm_iio_device_alloc(dev, sizeof(*mma7455));
 257         if (!indio_dev)
 258                 return -ENOMEM;
 259
 260         dev_set_drvdata(dev, indio_dev);
 261         mma7455 = iio_priv(indio_dev);
 262         mma7455->regmap = regmap;
 263         mma7455->dev = dev;
 264
 265         indio_dev->info = &mma7455_info;
 266         indio_dev->name = name;
 267         indio_dev->dev.parent = dev;
 268         indio_dev->modes = INDIO_DIRECT_MODE;
 269         indio_dev->channels = mma7455_channels;
 270         indio_dev->num_channels = ARRAY_SIZE(mma7455_channels);
 271         indio_dev->available_scan_masks = mma7455_scan_masks;
 272
 273         regmap_write(mma7455->regmap, MMA7455_REG_MCTL,
 274                      MMA7455_MCTL_MODE_MEASURE);
 275
 276         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 277                                          mma7455_trigger_handler, NULL);
 278         if (ret) {
 279                 dev_err(dev, "unable to setup triggered buffer\n");
 280                 return ret;
 281         }
 282
 283         ret = iio_device_register(indio_dev);
 284         if (ret) {
 285                 dev_err(dev, "unable to register device\n");
 286                 iio_triggered_buffer_cleanup(indio_dev);
 287                 return ret;
 288         }
 289
 290         return 0;
 291 }
 292 EXPORT_SYMBOL_GPL(mma7455_core_probe);
 293
 294 int mma7455_core_remove(struct device *dev)
 295 {
 296         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 297         struct mma7455_data *mma7455 = iio_priv(indio_dev);
 298
 299         iio_device_unregister(indio_dev);
 300         iio_triggered_buffer_cleanup(indio_dev);
 301
 302         regmap_write(mma7455->regmap, MMA7455_REG_MCTL,
 303                      MMA7455_MCTL_MODE_STANDBY);
 304
 305         return 0;
 306 }
 307 EXPORT_SYMBOL_GPL(mma7455_core_remove);
 308
 309 MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
 310 MODULE_DESCRIPTION("Freescale MMA7455L core accelerometer driver");
 311 MODULE_LICENSE("GPL v2");