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/iio.h>
  20 #include <linux/iio/kfifo_buf.h>
  21 #include <linux/iio/trigger.h>
  22 #include <linux/iio/triggered_buffer.h>
  23 #include <linux/iio/trigger_consumer.h>
  24 #include <linux/kernel.h>
  25 #include <linux/mfd/cros_ec.h>
  26 #include <linux/mfd/cros_ec_commands.h>
  27 #include <linux/module.h>
  28 #include <linux/slab.h>
  29 #include <linux/platform_device.h>
  30
  31 #include "../common/cros_ec_sensors/cros_ec_sensors_core.h"
  32
  33 /*
  34  * One channel for pressure, the other for timestamp.
  35  */
  36 #define CROS_EC_BARO_MAX_CHANNELS (1 + 1)
  37
  38 /* State data for ec_sensors iio driver. */
  39 struct cros_ec_baro_state {
  40         /* Shared by all sensors */
  41         struct cros_ec_sensors_core_state core;
  42
  43         struct iio_chan_spec channels[CROS_EC_BARO_MAX_CHANNELS];
  44 };
  45
  46 static int cros_ec_baro_read(struct iio_dev *indio_dev,
  47                              struct iio_chan_spec const *chan,
  48                              int *val, int *val2, long mask)
  49 {
  50         struct cros_ec_baro_state *st = iio_priv(indio_dev);
  51         u16 data = 0;
  52         int ret = IIO_VAL_INT;
  53         int idx = chan->scan_index;
  54
  55         mutex_lock(&st->core.cmd_lock);
  56
  57         switch (mask) {
  58         case IIO_CHAN_INFO_RAW:
  59                 if (cros_ec_sensors_read_cmd(indio_dev, 1 << idx,
  60                                              (s16 *)&data) < 0)
  61                         ret = -EIO;
  62                 *val = data;
  63                 break;
  64         case IIO_CHAN_INFO_SCALE:
  65                 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
  66                 st->core.param.sensor_range.data = EC_MOTION_SENSE_NO_VALUE;
  67
  68                 if (cros_ec_motion_send_host_cmd(&st->core, 0)) {
  69                         ret = -EIO;
  70                         break;
  71                 }
  72                 *val = st->core.resp->sensor_range.ret;
  73
  74                 /* scale * in_pressure_raw --> kPa */
  75                 *val2 = 10 << CROS_EC_SENSOR_BITS;
  76                 ret = IIO_VAL_FRACTIONAL;
  77                 break;
  78         default:
  79                 ret = cros_ec_sensors_core_read(&st->core, chan, val, val2,
  80                                                 mask);
  81                 break;
  82         }
  83
  84         mutex_unlock(&st->core.cmd_lock);
  85
  86         return ret;
  87 }
  88
  89 static int cros_ec_baro_write(struct iio_dev *indio_dev,
  90                               struct iio_chan_spec const *chan,
  91                               int val, int val2, long mask)
  92 {
  93         struct cros_ec_baro_state *st = iio_priv(indio_dev);
  94         int ret = 0;
  95
  96         mutex_lock(&st->core.cmd_lock);
  97
  98         switch (mask) {
  99         case IIO_CHAN_INFO_SCALE:
 100                 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
 101                 st->core.param.sensor_range.data = val;
 102
 103                 /* Always roundup, so caller gets at least what it asks for. */
 104                 st->core.param.sensor_range.roundup = 1;
 105
 106                 if (cros_ec_motion_send_host_cmd(&st->core, 0))
 107                         ret = -EIO;
 108                 break;
 109         default:
 110                 ret = cros_ec_sensors_core_write(&st->core, chan, val, val2,
 111                                                  mask);
 112                 break;
 113         }
 114
 115         mutex_unlock(&st->core.cmd_lock);
 116
 117         return ret;
 118 }
 119
 120 static const struct iio_info cros_ec_baro_info = {
 121         .read_raw = &cros_ec_baro_read,
 122         .write_raw = &cros_ec_baro_write,
 123 };
 124
 125 static int cros_ec_baro_probe(struct platform_device *pdev)
 126 {
 127         struct device *dev = &pdev->dev;
 128         struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
 129         struct iio_dev *indio_dev;
 130         struct cros_ec_baro_state *state;
 131         struct iio_chan_spec *channel;
 132         int ret;
 133
 134         if (!ec_dev || !ec_dev->ec_dev) {
 135                 dev_warn(dev, "No CROS EC device found.\n");
 136                 return -EINVAL;
 137         }
 138
 139         indio_dev = devm_iio_device_alloc(dev, sizeof(*state));
 140         if (!indio_dev)
 141                 return -ENOMEM;
 142
 143         ret = cros_ec_sensors_core_init(pdev, indio_dev, true);
 144         if (ret)
 145                 return ret;
 146
 147         indio_dev->info = &cros_ec_baro_info;
 148         state = iio_priv(indio_dev);
 149         state->core.type = state->core.resp->info.type;
 150         state->core.loc = state->core.resp->info.location;
 151         channel = state->channels;
 152         /* Common part */
 153         channel->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
 154         channel->info_mask_shared_by_all =
 155                 BIT(IIO_CHAN_INFO_SCALE) |
 156                 BIT(IIO_CHAN_INFO_SAMP_FREQ) |
 157                 BIT(IIO_CHAN_INFO_FREQUENCY);
 158         channel->scan_type.realbits = CROS_EC_SENSOR_BITS;
 159         channel->scan_type.storagebits = CROS_EC_SENSOR_BITS;
 160         channel->scan_type.shift = 0;
 161         channel->scan_index = 0;
 162         channel->ext_info = cros_ec_sensors_ext_info;
 163         channel->scan_type.sign = 'u';
 164
 165         state->core.calib[0] = 0;
 166
 167         /* Sensor specific */
 168         switch (state->core.type) {
 169         case MOTIONSENSE_TYPE_BARO:
 170                 channel->type = IIO_PRESSURE;
 171                 break;
 172         default:
 173                 dev_warn(dev, "Unknown motion sensor\n");
 174                 return -EINVAL;
 175         }
 176
 177         /* Timestamp */
 178         channel++;
 179         channel->type = IIO_TIMESTAMP;
 180         channel->channel = -1;
 181         channel->scan_index = 1;
 182         channel->scan_type.sign = 's';
 183         channel->scan_type.realbits = 64;
 184         channel->scan_type.storagebits = 64;
 185
 186         indio_dev->channels = state->channels;
 187         indio_dev->num_channels = CROS_EC_BARO_MAX_CHANNELS;
 188
 189         state->core.read_ec_sensors_data = cros_ec_sensors_read_cmd;
 190
 191         ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
 192                                               cros_ec_sensors_capture, NULL);
 193         if (ret)
 194                 return ret;
 195
 196         return devm_iio_device_register(dev, indio_dev);
 197 }
 198
 199 static const struct platform_device_id cros_ec_baro_ids[] = {
 200         {
 201                 .name = "cros-ec-baro",
 202         },
 203         { /* sentinel */ }
 204 };
 205 MODULE_DEVICE_TABLE(platform, cros_ec_baro_ids);
 206
 207 static struct platform_driver cros_ec_baro_platform_driver = {
 208         .driver = {
 209                 .name   = "cros-ec-baro",
 210         },
 211         .probe          = cros_ec_baro_probe,
 212         .id_table       = cros_ec_baro_ids,
 213 };
 214 module_platform_driver(cros_ec_baro_platform_driver);
 215
 216 MODULE_DESCRIPTION("ChromeOS EC barometer sensor driver");
 217 MODULE_LICENSE("GPL v2");