drivers/iio/pressure/cros_ec_baro.c

   1 /*
   2  * cros_ec_baro - Driver for barometer sensor behind CrosEC.
   3  *
   4  * Copyright (C) 2017 Google, Inc
   5  *
   6  * This software is licensed under the terms of the GNU General Public
   7  * License version 2, as published by the Free Software Foundation, and
   8  * may be copied, distributed, and modified under those terms.
   9  *
  10  * This program is distributed in the hope that it will be useful,
  11  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  12  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  13  * GNU General Public License for more details.
  14  */
  15
  16 #include <linux/delay.h>
  17 #include <linux/device.h>
  18 #include <linux/iio/buffer.h>
  19 #include <linux/iio/common/cros_ec_sensors_core.h>
  20 #include <linux/iio/iio.h>
  21 #include <linux/iio/kfifo_buf.h>
  22 #include <linux/iio/trigger.h>
  23 #include <linux/iio/triggered_buffer.h>
  24 #include <linux/iio/trigger_consumer.h>
  25 #include <linux/kernel.h>
  26 #include <linux/mfd/cros_ec.h>
  27 #include <linux/mfd/cros_ec_commands.h>
  28 #include <linux/module.h>
  29 #include <linux/slab.h>
  30 #include <linux/platform_device.h>
  31
  32 /*
  33  * One channel for pressure, the other for timestamp.
  34  */
  35 #define CROS_EC_BARO_MAX_CHANNELS (1 + 1)
  36
  37 /* State data for ec_sensors iio driver. */
  38 struct cros_ec_baro_state {
  39         /* Shared by all sensors */
  40         struct cros_ec_sensors_core_state core;
  41
  42         struct iio_chan_spec channels[CROS_EC_BARO_MAX_CHANNELS];
  43 };
  44
  45 static int cros_ec_baro_read(struct iio_dev *indio_dev,
  46                              struct iio_chan_spec const *chan,
  47                              int *val, int *val2, long mask)
  48 {
  49         struct cros_ec_baro_state *st = iio_priv(indio_dev);
  50         u16 data = 0;
  51         int ret = IIO_VAL_INT;
  52         int idx = chan->scan_index;
  53
  54         mutex_lock(&st->core.cmd_lock);
  55
  56         switch (mask) {
  57         case IIO_CHAN_INFO_RAW:
  58                 if (cros_ec_sensors_read_cmd(indio_dev, 1 << idx,
  59                                              (s16 *)&data) < 0)
  60                         ret = -EIO;
  61                 *val = data;
  62                 break;
  63         case IIO_CHAN_INFO_SCALE:
  64                 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
  65                 st->core.param.sensor_range.data = EC_MOTION_SENSE_NO_VALUE;
  66
  67                 if (cros_ec_motion_send_host_cmd(&st->core, 0)) {
  68                         ret = -EIO;
  69                         break;
  70                 }
  71                 *val = st->core.resp->sensor_range.ret;
  72
  73                 /* scale * in_pressure_raw --> kPa */
  74                 *val2 = 10 << CROS_EC_SENSOR_BITS;
  75                 ret = IIO_VAL_FRACTIONAL;
  76                 break;
  77         default:
  78                 ret = cros_ec_sensors_core_read(&st->core, chan, val, val2,
  79                                                 mask);
  80                 break;
  81         }
  82
  83         mutex_unlock(&st->core.cmd_lock);
  84
  85         return ret;
  86 }
  87
  88 static int cros_ec_baro_write(struct iio_dev *indio_dev,
  89                               struct iio_chan_spec const *chan,
  90                               int val, int val2, long mask)
  91 {
  92         struct cros_ec_baro_state *st = iio_priv(indio_dev);
  93         int ret = 0;
  94
  95         mutex_lock(&st->core.cmd_lock);
  96
  97         switch (mask) {
  98         case IIO_CHAN_INFO_SCALE:
  99                 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
 100                 st->core.param.sensor_range.data = val;
 101
 102                 /* Always roundup, so caller gets at least what it asks for. */
 103                 st->core.param.sensor_range.roundup = 1;
 104
 105                 if (cros_ec_motion_send_host_cmd(&st->core, 0))
 106                         ret = -EIO;
 107                 break;
 108         default:
 109                 ret = cros_ec_sensors_core_write(&st->core, chan, val, val2,
 110                                                  mask);
 111                 break;
 112         }
 113
 114         mutex_unlock(&st->core.cmd_lock);
 115
 116         return ret;
 117 }
 118
 119 static const struct iio_info cros_ec_baro_info = {
 120         .read_raw = &cros_ec_baro_read,
 121         .write_raw = &cros_ec_baro_write,
 122 };
 123
 124 static int cros_ec_baro_probe(struct platform_device *pdev)
 125 {
 126         struct device *dev = &pdev->dev;
 127         struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
 128         struct iio_dev *indio_dev;
 129         struct cros_ec_baro_state *state;
 130         struct iio_chan_spec *channel;
 131         int ret;
 132
 133         if (!ec_dev || !ec_dev->ec_dev) {
 134                 dev_warn(dev, "No CROS EC device found.\n");
 135                 return -EINVAL;
 136         }
 137
 138         indio_dev = devm_iio_device_alloc(dev, sizeof(*state));
 139         if (!indio_dev)
 140                 return -ENOMEM;
 141
 142         ret = cros_ec_sensors_core_init(pdev, indio_dev, true);
 143         if (ret)
 144                 return ret;
 145
 146         indio_dev->info = &cros_ec_baro_info;
 147         state = iio_priv(indio_dev);
 148         state->core.type = state->core.resp->info.type;
 149         state->core.loc = state->core.resp->info.location;
 150         channel = state->channels;
 151         /* Common part */
 152         channel->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
 153         channel->info_mask_shared_by_all =
 154                 BIT(IIO_CHAN_INFO_SCALE) |
 155                 BIT(IIO_CHAN_INFO_SAMP_FREQ) |
 156                 BIT(IIO_CHAN_INFO_FREQUENCY);
 157         channel->scan_type.realbits = CROS_EC_SENSOR_BITS;
 158         channel->scan_type.storagebits = CROS_EC_SENSOR_BITS;
 159         channel->scan_type.shift = 0;
 160         channel->scan_index = 0;
 161         channel->ext_info = cros_ec_sensors_ext_info;
 162         channel->scan_type.sign = 'u';
 163
 164         state->core.calib[0] = 0;
 165
 166         /* Sensor specific */
 167         switch (state->core.type) {
 168         case MOTIONSENSE_TYPE_BARO:
 169                 channel->type = IIO_PRESSURE;
 170                 break;
 171         default:
 172                 dev_warn(dev, "Unknown motion sensor\n");
 173                 return -EINVAL;
 174         }
 175
 176         /* Timestamp */
 177         channel++;
 178         channel->type = IIO_TIMESTAMP;
 179         channel->channel = -1;
 180         channel->scan_index = 1;
 181         channel->scan_type.sign = 's';
 182         channel->scan_type.realbits = 64;
 183         channel->scan_type.storagebits = 64;
 184
 185         indio_dev->channels = state->channels;
 186         indio_dev->num_channels = CROS_EC_BARO_MAX_CHANNELS;
 187
 188         state->core.read_ec_sensors_data = cros_ec_sensors_read_cmd;
 189
 190         ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
 191                                               cros_ec_sensors_capture, NULL);
 192         if (ret)
 193                 return ret;
 194
 195         return devm_iio_device_register(dev, indio_dev);
 196 }
 197
 198 static const struct platform_device_id cros_ec_baro_ids[] = {
 199         {
 200                 .name = "cros-ec-baro",
 201         },
 202         { /* sentinel */ }
 203 };
 204 MODULE_DEVICE_TABLE(platform, cros_ec_baro_ids);
 205
 206 static struct platform_driver cros_ec_baro_platform_driver = {
 207         .driver = {
 208                 .name   = "cros-ec-baro",
 209         },
 210         .probe          = cros_ec_baro_probe,
 211         .id_table       = cros_ec_baro_ids,
 212 };
 213 module_platform_driver(cros_ec_baro_platform_driver);
 214
 215 MODULE_DESCRIPTION("ChromeOS EC barometer sensor driver");
 216 MODULE_LICENSE("GPL v2");