drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * cros_ec_sensors - Driver for Chrome OS Embedded Controller sensors.
   4  *
   5  * Copyright (C) 2016 Google, Inc
   6  *
   7  * This driver uses the cros-ec interface to communicate with the Chrome OS
   8  * EC about sensors data. Data access is presented through iio sysfs.
   9  */
  10
  11 #include <linux/device.h>
  12 #include <linux/iio/buffer.h>
  13 #include <linux/iio/common/cros_ec_sensors_core.h>
  14 #include <linux/iio/iio.h>
  15 #include <linux/iio/kfifo_buf.h>
  16 #include <linux/iio/trigger_consumer.h>
  17 #include <linux/iio/triggered_buffer.h>
  18 #include <linux/kernel.h>
  19 #include <linux/module.h>
  20 #include <linux/platform_data/cros_ec_commands.h>
  21 #include <linux/platform_data/cros_ec_proto.h>
  22 #include <linux/platform_device.h>
  23 #include <linux/slab.h>
  24
  25 #define CROS_EC_SENSORS_MAX_CHANNELS 4
  26
  27 /* State data for ec_sensors iio driver. */
  28 struct cros_ec_sensors_state {
  29         /* Shared by all sensors */
  30         struct cros_ec_sensors_core_state core;
  31
  32         struct iio_chan_spec channels[CROS_EC_SENSORS_MAX_CHANNELS];
  33 };
  34
  35 static int cros_ec_sensors_read(struct iio_dev *indio_dev,
  36                           struct iio_chan_spec const *chan,
  37                           int *val, int *val2, long mask)
  38 {
  39         struct cros_ec_sensors_state *st = iio_priv(indio_dev);
  40         s16 data = 0;
  41         s64 val64;
  42         int i;
  43         int ret;
  44         int idx = chan->scan_index;
  45
  46         mutex_lock(&st->core.cmd_lock);
  47
  48         switch (mask) {
  49         case IIO_CHAN_INFO_RAW:
  50                 ret = st->core.read_ec_sensors_data(indio_dev, 1 << idx, &data);
  51                 if (ret < 0)
  52                         break;
  53                 ret = IIO_VAL_INT;
  54                 *val = data;
  55                 break;
  56         case IIO_CHAN_INFO_CALIBBIAS:
  57                 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_OFFSET;
  58                 st->core.param.sensor_offset.flags = 0;
  59
  60                 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
  61                 if (ret < 0)
  62                         break;
  63
  64                 /* Save values */
  65                 for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
  66                         st->core.calib[i].offset =
  67                                 st->core.resp->sensor_offset.offset[i];
  68                 ret = IIO_VAL_INT;
  69                 *val = st->core.calib[idx].offset;
  70                 break;
  71         case IIO_CHAN_INFO_CALIBSCALE:
  72                 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_SCALE;
  73                 st->core.param.sensor_offset.flags = 0;
  74
  75                 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
  76                 if (ret == -EPROTO || ret == -EOPNOTSUPP) {
  77                         /* Reading calibscale is not supported on older EC. */
  78                         *val = 1;
  79                         *val2 = 0;
  80                         ret = IIO_VAL_INT_PLUS_MICRO;
  81                         break;
  82                 } else if (ret) {
  83                         break;
  84                 }
  85
  86                 /* Save values */
  87                 for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
  88                         st->core.calib[i].scale =
  89                                 st->core.resp->sensor_scale.scale[i];
  90
  91                 *val = st->core.calib[idx].scale >> 15;
  92                 *val2 = ((st->core.calib[idx].scale & 0x7FFF) * 1000000LL) /
  93                         MOTION_SENSE_DEFAULT_SCALE;
  94                 ret = IIO_VAL_INT_PLUS_MICRO;
  95                 break;
  96         case IIO_CHAN_INFO_SCALE:
  97                 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
  98                 st->core.param.sensor_range.data = EC_MOTION_SENSE_NO_VALUE;
  99
 100                 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
 101                 if (ret < 0)
 102                         break;
 103
 104                 val64 = st->core.resp->sensor_range.ret;
 105                 switch (st->core.type) {
 106                 case MOTIONSENSE_TYPE_ACCEL:
 107                         /*
 108                          * EC returns data in g, iio exepects m/s^2.
 109                          * Do not use IIO_G_TO_M_S_2 to avoid precision loss.
 110                          */
 111                         *val = div_s64(val64 * 980665, 10);
 112                         *val2 = 10000 << (CROS_EC_SENSOR_BITS - 1);
 113                         ret = IIO_VAL_FRACTIONAL;
 114                         break;
 115                 case MOTIONSENSE_TYPE_GYRO:
 116                         /*
 117                          * EC returns data in dps, iio expects rad/s.
 118                          * Do not use IIO_DEGREE_TO_RAD to avoid precision
 119                          * loss. Round to the nearest integer.
 120                          */
 121                         *val = 0;
 122                         *val2 = div_s64(val64 * 3141592653ULL,
 123                                         180 << (CROS_EC_SENSOR_BITS - 1));
 124                         ret = IIO_VAL_INT_PLUS_NANO;
 125                         break;
 126                 case MOTIONSENSE_TYPE_MAG:
 127                         /*
 128                          * EC returns data in 16LSB / uT,
 129                          * iio expects Gauss
 130                          */
 131                         *val = val64;
 132                         *val2 = 100 << (CROS_EC_SENSOR_BITS - 1);
 133                         ret = IIO_VAL_FRACTIONAL;
 134                         break;
 135                 default:
 136                         ret = -EINVAL;
 137                 }
 138                 break;
 139         default:
 140                 ret = cros_ec_sensors_core_read(&st->core, chan, val, val2,
 141                                                 mask);
 142                 break;
 143         }
 144         mutex_unlock(&st->core.cmd_lock);
 145
 146         return ret;
 147 }
 148
 149 static int cros_ec_sensors_write(struct iio_dev *indio_dev,
 150                                struct iio_chan_spec const *chan,
 151                                int val, int val2, long mask)
 152 {
 153         struct cros_ec_sensors_state *st = iio_priv(indio_dev);
 154         int i;
 155         int ret;
 156         int idx = chan->scan_index;
 157
 158         mutex_lock(&st->core.cmd_lock);
 159
 160         switch (mask) {
 161         case IIO_CHAN_INFO_CALIBBIAS:
 162                 st->core.calib[idx].offset = val;
 163
 164                 /* Send to EC for each axis, even if not complete */
 165                 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_OFFSET;
 166                 st->core.param.sensor_offset.flags =
 167                         MOTION_SENSE_SET_OFFSET;
 168                 for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
 169                         st->core.param.sensor_offset.offset[i] =
 170                                 st->core.calib[i].offset;
 171                 st->core.param.sensor_offset.temp =
 172                         EC_MOTION_SENSE_INVALID_CALIB_TEMP;
 173
 174                 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
 175                 break;
 176         case IIO_CHAN_INFO_CALIBSCALE:
 177                 st->core.calib[idx].scale = val;
 178                 /* Send to EC for each axis, even if not complete */
 179
 180                 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_SCALE;
 181                 st->core.param.sensor_offset.flags =
 182                         MOTION_SENSE_SET_OFFSET;
 183                 for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
 184                         st->core.param.sensor_scale.scale[i] =
 185                                 st->core.calib[i].scale;
 186                 st->core.param.sensor_scale.temp =
 187                         EC_MOTION_SENSE_INVALID_CALIB_TEMP;
 188
 189                 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
 190                 break;
 191         case IIO_CHAN_INFO_SCALE:
 192                 if (st->core.type == MOTIONSENSE_TYPE_MAG) {
 193                         ret = -EINVAL;
 194                         break;
 195                 }
 196                 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
 197                 st->core.param.sensor_range.data = val;
 198
 199                 /* Always roundup, so caller gets at least what it asks for. */
 200                 st->core.param.sensor_range.roundup = 1;
 201
 202                 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
 203                 if (ret == 0) {
 204                         st->core.range_updated = true;
 205                         st->core.curr_range = val;
 206                 }
 207                 break;
 208         default:
 209                 ret = cros_ec_sensors_core_write(
 210                                 &st->core, chan, val, val2, mask);
 211                 break;
 212         }
 213
 214         mutex_unlock(&st->core.cmd_lock);
 215
 216         return ret;
 217 }
 218
 219 static const struct iio_info ec_sensors_info = {
 220         .read_raw = &cros_ec_sensors_read,
 221         .write_raw = &cros_ec_sensors_write,
 222         .read_avail = &cros_ec_sensors_core_read_avail,
 223 };
 224
 225 static int cros_ec_sensors_probe(struct platform_device *pdev)
 226 {
 227         struct device *dev = &pdev->dev;
 228         struct iio_dev *indio_dev;
 229         struct cros_ec_sensors_state *state;
 230         struct iio_chan_spec *channel;
 231         int ret, i;
 232
 233         indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*state));
 234         if (!indio_dev)
 235                 return -ENOMEM;
 236
 237         ret = cros_ec_sensors_core_init(pdev, indio_dev, true,
 238                                         cros_ec_sensors_capture,
 239                                         cros_ec_sensors_push_data);
 240         if (ret)
 241                 return ret;
 242
 243         indio_dev->info = &ec_sensors_info;
 244         state = iio_priv(indio_dev);
 245         for (channel = state->channels, i = CROS_EC_SENSOR_X;
 246              i < CROS_EC_SENSOR_MAX_AXIS; i++, channel++) {
 247                 /* Common part */
 248                 channel->info_mask_separate =
 249                         BIT(IIO_CHAN_INFO_RAW) |
 250                         BIT(IIO_CHAN_INFO_CALIBBIAS) |
 251                         BIT(IIO_CHAN_INFO_CALIBSCALE);
 252                 channel->info_mask_shared_by_all =
 253                         BIT(IIO_CHAN_INFO_SCALE) |
 254                         BIT(IIO_CHAN_INFO_SAMP_FREQ);
 255                 channel->info_mask_shared_by_all_available =
 256                         BIT(IIO_CHAN_INFO_SAMP_FREQ);
 257                 channel->scan_type.realbits = CROS_EC_SENSOR_BITS;
 258                 channel->scan_type.storagebits = CROS_EC_SENSOR_BITS;
 259                 channel->scan_index = i;
 260                 channel->ext_info = cros_ec_sensors_ext_info;
 261                 channel->modified = 1;
 262                 channel->channel2 = IIO_MOD_X + i;
 263                 channel->scan_type.sign = 's';
 264
 265                 /* Sensor specific */
 266                 switch (state->core.type) {
 267                 case MOTIONSENSE_TYPE_ACCEL:
 268                         channel->type = IIO_ACCEL;
 269                         break;
 270                 case MOTIONSENSE_TYPE_GYRO:
 271                         channel->type = IIO_ANGL_VEL;
 272                         break;
 273                 case MOTIONSENSE_TYPE_MAG:
 274                         channel->type = IIO_MAGN;
 275                         break;
 276                 default:
 277                         dev_err(&pdev->dev, "Unknown motion sensor\n");
 278                         return -EINVAL;
 279                 }
 280         }
 281
 282         /* Timestamp */
 283         channel->type = IIO_TIMESTAMP;
 284         channel->channel = -1;
 285         channel->scan_index = CROS_EC_SENSOR_MAX_AXIS;
 286         channel->scan_type.sign = 's';
 287         channel->scan_type.realbits = 64;
 288         channel->scan_type.storagebits = 64;
 289
 290         indio_dev->channels = state->channels;
 291         indio_dev->num_channels = CROS_EC_SENSORS_MAX_CHANNELS;
 292
 293         /* There is only enough room for accel and gyro in the io space */
 294         if ((state->core.ec->cmd_readmem != NULL) &&
 295             (state->core.type != MOTIONSENSE_TYPE_MAG))
 296                 state->core.read_ec_sensors_data = cros_ec_sensors_read_lpc;
 297         else
 298                 state->core.read_ec_sensors_data = cros_ec_sensors_read_cmd;
 299
 300         return devm_iio_device_register(dev, indio_dev);
 301 }
 302
 303 static const struct platform_device_id cros_ec_sensors_ids[] = {
 304         {
 305                 .name = "cros-ec-accel",
 306         },
 307         {
 308                 .name = "cros-ec-gyro",
 309         },
 310         {
 311                 .name = "cros-ec-mag",
 312         },
 313         { /* sentinel */ }
 314 };
 315 MODULE_DEVICE_TABLE(platform, cros_ec_sensors_ids);
 316
 317 static struct platform_driver cros_ec_sensors_platform_driver = {
 318         .driver = {
 319                 .name   = "cros-ec-sensors",
 320                 .pm     = &cros_ec_sensors_pm_ops,
 321         },
 322         .probe          = cros_ec_sensors_probe,
 323         .id_table       = cros_ec_sensors_ids,
 324 };
 325 module_platform_driver(cros_ec_sensors_platform_driver);
 326
 327 MODULE_DESCRIPTION("ChromeOS EC 3-axis sensors driver");
 328 MODULE_LICENSE("GPL v2");