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 };
  59
  60 static int mma7455_drdy(struct mma7455_data *mma7455)
  61 {
  62         struct device *dev = regmap_get_device(mma7455->regmap);
  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(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,
 101                                            iio_get_time_ns(indio_dev));
 102
 103 done:
 104         iio_trigger_notify_done(indio_dev->trig);
 105
 106         return IRQ_HANDLED;
 107 }
 108
 109 static int mma7455_read_raw(struct iio_dev *indio_dev,
 110                             struct iio_chan_spec const *chan,
 111                             int *val, int *val2, long mask)
 112 {
 113         struct mma7455_data *mma7455 = iio_priv(indio_dev);
 114         unsigned int reg;
 115         __le16 data;
 116         int ret;
 117
 118         switch (mask) {
 119         case IIO_CHAN_INFO_RAW:
 120                 if (iio_buffer_enabled(indio_dev))
 121                         return -EBUSY;
 122
 123                 ret = mma7455_drdy(mma7455);
 124                 if (ret)
 125                         return ret;
 126
 127                 ret = regmap_bulk_read(mma7455->regmap, chan->address, &data,
 128                                        sizeof(data));
 129                 if (ret)
 130                         return ret;
 131
 132                 *val = sign_extend32(le16_to_cpu(data), 9);
 133
 134                 return IIO_VAL_INT;
 135
 136         case IIO_CHAN_INFO_SCALE:
 137                 *val = 0;
 138                 *val2 = MMA7455_10BIT_SCALE;
 139
 140                 return IIO_VAL_INT_PLUS_MICRO;
 141
 142         case IIO_CHAN_INFO_SAMP_FREQ:
 143                 ret = regmap_read(mma7455->regmap, MMA7455_REG_CTL1, &reg);
 144                 if (ret)
 145                         return ret;
 146
 147                 if (reg & MMA7455_CTL1_DFBW_MASK)
 148                         *val = 250;
 149                 else
 150                         *val = 125;
 151
 152                 return IIO_VAL_INT;
 153         }
 154
 155         return -EINVAL;
 156 }
 157
 158 static int mma7455_write_raw(struct iio_dev *indio_dev,
 159                              struct iio_chan_spec const *chan,
 160                              int val, int val2, long mask)
 161 {
 162         struct mma7455_data *mma7455 = iio_priv(indio_dev);
 163         int i;
 164
 165         switch (mask) {
 166         case IIO_CHAN_INFO_SAMP_FREQ:
 167                 if (val == 250 && val2 == 0)
 168                         i = MMA7455_CTL1_DFBW_125HZ;
 169                 else if (val == 125 && val2 == 0)
 170                         i = MMA7455_CTL1_DFBW_62_5HZ;
 171                 else
 172                         return -EINVAL;
 173
 174                 return regmap_update_bits(mma7455->regmap, MMA7455_REG_CTL1,
 175                                           MMA7455_CTL1_DFBW_MASK, i);
 176
 177         case IIO_CHAN_INFO_SCALE:
 178                 /* In 10-bit mode there is only one scale available */
 179                 if (val == 0 && val2 == MMA7455_10BIT_SCALE)
 180                         return 0;
 181                 break;
 182         }
 183
 184         return -EINVAL;
 185 }
 186
 187 static IIO_CONST_ATTR(sampling_frequency_available, "125 250");
 188
 189 static struct attribute *mma7455_attributes[] = {
 190         &iio_const_attr_sampling_frequency_available.dev_attr.attr,
 191         NULL
 192 };
 193
 194 static const struct attribute_group mma7455_group = {
 195         .attrs = mma7455_attributes,
 196 };
 197
 198 static const struct iio_info mma7455_info = {
 199         .attrs = &mma7455_group,
 200         .read_raw = mma7455_read_raw,
 201         .write_raw = mma7455_write_raw,
 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
 264         indio_dev->info = &mma7455_info;
 265         indio_dev->name = name;
 266         indio_dev->dev.parent = dev;
 267         indio_dev->modes = INDIO_DIRECT_MODE;
 268         indio_dev->channels = mma7455_channels;
 269         indio_dev->num_channels = ARRAY_SIZE(mma7455_channels);
 270         indio_dev->available_scan_masks = mma7455_scan_masks;
 271
 272         regmap_write(mma7455->regmap, MMA7455_REG_MCTL,
 273                      MMA7455_MCTL_MODE_MEASURE);
 274
 275         ret = iio_triggered_buffer_setup(indio_dev, NULL,
 276                                          mma7455_trigger_handler, NULL);
 277         if (ret) {
 278                 dev_err(dev, "unable to setup triggered buffer\n");
 279                 return ret;
 280         }
 281
 282         ret = iio_device_register(indio_dev);
 283         if (ret) {
 284                 dev_err(dev, "unable to register device\n");
 285                 iio_triggered_buffer_cleanup(indio_dev);
 286                 return ret;
 287         }
 288
 289         return 0;
 290 }
 291 EXPORT_SYMBOL_GPL(mma7455_core_probe);
 292
 293 int mma7455_core_remove(struct device *dev)
 294 {
 295         struct iio_dev *indio_dev = dev_get_drvdata(dev);
 296         struct mma7455_data *mma7455 = iio_priv(indio_dev);
 297
 298         iio_device_unregister(indio_dev);
 299         iio_triggered_buffer_cleanup(indio_dev);
 300
 301         regmap_write(mma7455->regmap, MMA7455_REG_MCTL,
 302                      MMA7455_MCTL_MODE_STANDBY);
 303
 304         return 0;
 305 }
 306 EXPORT_SYMBOL_GPL(mma7455_core_remove);
 307
 308 MODULE_AUTHOR("Joachim Eastwood <manabian@gmail.com>");
 309 MODULE_DESCRIPTION("Freescale MMA7455L core accelerometer driver");
 310 MODULE_LICENSE("GPL v2");