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/mfd/cros_ec.h>
  20 #include <linux/mfd/cros_ec_commands.h>
  21 #include <linux/module.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] =
  67                                 st->core.resp->sensor_offset.offset[i];
  68                 ret = IIO_VAL_INT;
  69                 *val = st->core.calib[idx];
  70                 break;
  71         case IIO_CHAN_INFO_SCALE:
  72                 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
  73                 st->core.param.sensor_range.data = EC_MOTION_SENSE_NO_VALUE;
  74
  75                 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
  76                 if (ret < 0)
  77                         break;
  78
  79                 val64 = st->core.resp->sensor_range.ret;
  80                 switch (st->core.type) {
  81                 case MOTIONSENSE_TYPE_ACCEL:
  82                         /*
  83                          * EC returns data in g, iio exepects m/s^2.
  84                          * Do not use IIO_G_TO_M_S_2 to avoid precision loss.
  85                          */
  86                         *val = div_s64(val64 * 980665, 10);
  87                         *val2 = 10000 << (CROS_EC_SENSOR_BITS - 1);
  88                         ret = IIO_VAL_FRACTIONAL;
  89                         break;
  90                 case MOTIONSENSE_TYPE_GYRO:
  91                         /*
  92                          * EC returns data in dps, iio expects rad/s.
  93                          * Do not use IIO_DEGREE_TO_RAD to avoid precision
  94                          * loss. Round to the nearest integer.
  95                          */
  96                         *val = div_s64(val64 * 314159 + 9000000ULL, 1000);
  97                         *val2 = 18000 << (CROS_EC_SENSOR_BITS - 1);
  98                         ret = IIO_VAL_FRACTIONAL;
  99                         break;
 100                 case MOTIONSENSE_TYPE_MAG:
 101                         /*
 102                          * EC returns data in 16LSB / uT,
 103                          * iio expects Gauss
 104                          */
 105                         *val = val64;
 106                         *val2 = 100 << (CROS_EC_SENSOR_BITS - 1);
 107                         ret = IIO_VAL_FRACTIONAL;
 108                         break;
 109                 default:
 110                         ret = -EINVAL;
 111                 }
 112                 break;
 113         default:
 114                 ret = cros_ec_sensors_core_read(&st->core, chan, val, val2,
 115                                                 mask);
 116                 break;
 117         }
 118         mutex_unlock(&st->core.cmd_lock);
 119
 120         return ret;
 121 }
 122
 123 static int cros_ec_sensors_write(struct iio_dev *indio_dev,
 124                                struct iio_chan_spec const *chan,
 125                                int val, int val2, long mask)
 126 {
 127         struct cros_ec_sensors_state *st = iio_priv(indio_dev);
 128         int i;
 129         int ret;
 130         int idx = chan->scan_index;
 131
 132         mutex_lock(&st->core.cmd_lock);
 133
 134         switch (mask) {
 135         case IIO_CHAN_INFO_CALIBBIAS:
 136                 st->core.calib[idx] = val;
 137
 138                 /* Send to EC for each axis, even if not complete */
 139                 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_OFFSET;
 140                 st->core.param.sensor_offset.flags =
 141                         MOTION_SENSE_SET_OFFSET;
 142                 for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
 143                         st->core.param.sensor_offset.offset[i] =
 144                                 st->core.calib[i];
 145                 st->core.param.sensor_offset.temp =
 146                         EC_MOTION_SENSE_INVALID_CALIB_TEMP;
 147
 148                 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
 149                 break;
 150         case IIO_CHAN_INFO_SCALE:
 151                 if (st->core.type == MOTIONSENSE_TYPE_MAG) {
 152                         ret = -EINVAL;
 153                         break;
 154                 }
 155                 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
 156                 st->core.param.sensor_range.data = val;
 157
 158                 /* Always roundup, so caller gets at least what it asks for. */
 159                 st->core.param.sensor_range.roundup = 1;
 160
 161                 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
 162                 break;
 163         default:
 164                 ret = cros_ec_sensors_core_write(
 165                                 &st->core, chan, val, val2, mask);
 166                 break;
 167         }
 168
 169         mutex_unlock(&st->core.cmd_lock);
 170
 171         return ret;
 172 }
 173
 174 static const struct iio_info ec_sensors_info = {
 175         .read_raw = &cros_ec_sensors_read,
 176         .write_raw = &cros_ec_sensors_write,
 177 };
 178
 179 static int cros_ec_sensors_probe(struct platform_device *pdev)
 180 {
 181         struct device *dev = &pdev->dev;
 182         struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
 183         struct iio_dev *indio_dev;
 184         struct cros_ec_sensors_state *state;
 185         struct iio_chan_spec *channel;
 186         int ret, i;
 187
 188         if (!ec_dev || !ec_dev->ec_dev) {
 189                 dev_warn(&pdev->dev, "No CROS EC device found.\n");
 190                 return -EINVAL;
 191         }
 192
 193         indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*state));
 194         if (!indio_dev)
 195                 return -ENOMEM;
 196
 197         ret = cros_ec_sensors_core_init(pdev, indio_dev, true);
 198         if (ret)
 199                 return ret;
 200
 201         indio_dev->info = &ec_sensors_info;
 202         state = iio_priv(indio_dev);
 203         for (channel = state->channels, i = CROS_EC_SENSOR_X;
 204              i < CROS_EC_SENSOR_MAX_AXIS; i++, channel++) {
 205                 /* Common part */
 206                 channel->info_mask_separate =
 207                         BIT(IIO_CHAN_INFO_RAW) |
 208                         BIT(IIO_CHAN_INFO_CALIBBIAS);
 209                 channel->info_mask_shared_by_all =
 210                         BIT(IIO_CHAN_INFO_SCALE) |
 211                         BIT(IIO_CHAN_INFO_FREQUENCY) |
 212                         BIT(IIO_CHAN_INFO_SAMP_FREQ);
 213                 channel->scan_type.realbits = CROS_EC_SENSOR_BITS;
 214                 channel->scan_type.storagebits = CROS_EC_SENSOR_BITS;
 215                 channel->scan_index = i;
 216                 channel->ext_info = cros_ec_sensors_ext_info;
 217                 channel->modified = 1;
 218                 channel->channel2 = IIO_MOD_X + i;
 219                 channel->scan_type.sign = 's';
 220
 221                 /* Sensor specific */
 222                 switch (state->core.type) {
 223                 case MOTIONSENSE_TYPE_ACCEL:
 224                         channel->type = IIO_ACCEL;
 225                         break;
 226                 case MOTIONSENSE_TYPE_GYRO:
 227                         channel->type = IIO_ANGL_VEL;
 228                         break;
 229                 case MOTIONSENSE_TYPE_MAG:
 230                         channel->type = IIO_MAGN;
 231                         break;
 232                 default:
 233                         dev_err(&pdev->dev, "Unknown motion sensor\n");
 234                         return -EINVAL;
 235                 }
 236         }
 237
 238         /* Timestamp */
 239         channel->type = IIO_TIMESTAMP;
 240         channel->channel = -1;
 241         channel->scan_index = CROS_EC_SENSOR_MAX_AXIS;
 242         channel->scan_type.sign = 's';
 243         channel->scan_type.realbits = 64;
 244         channel->scan_type.storagebits = 64;
 245
 246         indio_dev->channels = state->channels;
 247         indio_dev->num_channels = CROS_EC_SENSORS_MAX_CHANNELS;
 248
 249         /* There is only enough room for accel and gyro in the io space */
 250         if ((state->core.ec->cmd_readmem != NULL) &&
 251             (state->core.type != MOTIONSENSE_TYPE_MAG))
 252                 state->core.read_ec_sensors_data = cros_ec_sensors_read_lpc;
 253         else
 254                 state->core.read_ec_sensors_data = cros_ec_sensors_read_cmd;
 255
 256         ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
 257                         cros_ec_sensors_capture, NULL);
 258         if (ret)
 259                 return ret;
 260
 261         return devm_iio_device_register(dev, indio_dev);
 262 }
 263
 264 static const struct platform_device_id cros_ec_sensors_ids[] = {
 265         {
 266                 .name = "cros-ec-accel",
 267         },
 268         {
 269                 .name = "cros-ec-gyro",
 270         },
 271         {
 272                 .name = "cros-ec-mag",
 273         },
 274         { /* sentinel */ }
 275 };
 276 MODULE_DEVICE_TABLE(platform, cros_ec_sensors_ids);
 277
 278 static struct platform_driver cros_ec_sensors_platform_driver = {
 279         .driver = {
 280                 .name   = "cros-ec-sensors",
 281                 .pm     = &cros_ec_sensors_pm_ops,
 282         },
 283         .probe          = cros_ec_sensors_probe,
 284         .id_table       = cros_ec_sensors_ids,
 285 };
 286 module_platform_driver(cros_ec_sensors_platform_driver);
 287
 288 MODULE_DESCRIPTION("ChromeOS EC 3-axis sensors driver");
 289 MODULE_LICENSE("GPL v2");