drivers/iio/pressure/cros_ec_baro.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * cros_ec_baro - Driver for barometer sensor behind CrosEC.
   4  *
   5  * Copyright (C) 2017 Google, Inc
   6  */
   7
   8 #include <linux/device.h>
   9 #include <linux/iio/buffer.h>
  10 #include <linux/iio/common/cros_ec_sensors_core.h>
  11 #include <linux/iio/iio.h>
  12 #include <linux/iio/kfifo_buf.h>
  13 #include <linux/iio/trigger.h>
  14 #include <linux/iio/triggered_buffer.h>
  15 #include <linux/iio/trigger_consumer.h>
  16 #include <linux/kernel.h>
  17 #include <linux/mfd/cros_ec.h>
  18 #include <linux/mfd/cros_ec_commands.h>
  19 #include <linux/module.h>
  20 #include <linux/slab.h>
  21 #include <linux/platform_device.h>
  22
  23 /*
  24  * One channel for pressure, the other for timestamp.
  25  */
  26 #define CROS_EC_BARO_MAX_CHANNELS (1 + 1)
  27
  28 /* State data for ec_sensors iio driver. */
  29 struct cros_ec_baro_state {
  30         /* Shared by all sensors */
  31         struct cros_ec_sensors_core_state core;
  32
  33         struct iio_chan_spec channels[CROS_EC_BARO_MAX_CHANNELS];
  34 };
  35
  36 static int cros_ec_baro_read(struct iio_dev *indio_dev,
  37                              struct iio_chan_spec const *chan,
  38                              int *val, int *val2, long mask)
  39 {
  40         struct cros_ec_baro_state *st = iio_priv(indio_dev);
  41         u16 data = 0;
  42         int ret = IIO_VAL_INT;
  43         int idx = chan->scan_index;
  44
  45         mutex_lock(&st->core.cmd_lock);
  46
  47         switch (mask) {
  48         case IIO_CHAN_INFO_RAW:
  49                 if (cros_ec_sensors_read_cmd(indio_dev, 1 << idx,
  50                                              (s16 *)&data) < 0)
  51                         ret = -EIO;
  52                 *val = data;
  53                 break;
  54         case IIO_CHAN_INFO_SCALE:
  55                 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
  56                 st->core.param.sensor_range.data = EC_MOTION_SENSE_NO_VALUE;
  57
  58                 if (cros_ec_motion_send_host_cmd(&st->core, 0)) {
  59                         ret = -EIO;
  60                         break;
  61                 }
  62                 *val = st->core.resp->sensor_range.ret;
  63
  64                 /* scale * in_pressure_raw --> kPa */
  65                 *val2 = 10 << CROS_EC_SENSOR_BITS;
  66                 ret = IIO_VAL_FRACTIONAL;
  67                 break;
  68         default:
  69                 ret = cros_ec_sensors_core_read(&st->core, chan, val, val2,
  70                                                 mask);
  71                 break;
  72         }
  73
  74         mutex_unlock(&st->core.cmd_lock);
  75
  76         return ret;
  77 }
  78
  79 static int cros_ec_baro_write(struct iio_dev *indio_dev,
  80                               struct iio_chan_spec const *chan,
  81                               int val, int val2, long mask)
  82 {
  83         struct cros_ec_baro_state *st = iio_priv(indio_dev);
  84         int ret = 0;
  85
  86         mutex_lock(&st->core.cmd_lock);
  87
  88         switch (mask) {
  89         case IIO_CHAN_INFO_SCALE:
  90                 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
  91                 st->core.param.sensor_range.data = val;
  92
  93                 /* Always roundup, so caller gets at least what it asks for. */
  94                 st->core.param.sensor_range.roundup = 1;
  95
  96                 if (cros_ec_motion_send_host_cmd(&st->core, 0))
  97                         ret = -EIO;
  98                 break;
  99         default:
 100                 ret = cros_ec_sensors_core_write(&st->core, chan, val, val2,
 101                                                  mask);
 102                 break;
 103         }
 104
 105         mutex_unlock(&st->core.cmd_lock);
 106
 107         return ret;
 108 }
 109
 110 static const struct iio_info cros_ec_baro_info = {
 111         .read_raw = &cros_ec_baro_read,
 112         .write_raw = &cros_ec_baro_write,
 113 };
 114
 115 static int cros_ec_baro_probe(struct platform_device *pdev)
 116 {
 117         struct device *dev = &pdev->dev;
 118         struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
 119         struct iio_dev *indio_dev;
 120         struct cros_ec_baro_state *state;
 121         struct iio_chan_spec *channel;
 122         int ret;
 123
 124         if (!ec_dev || !ec_dev->ec_dev) {
 125                 dev_warn(dev, "No CROS EC device found.\n");
 126                 return -EINVAL;
 127         }
 128
 129         indio_dev = devm_iio_device_alloc(dev, sizeof(*state));
 130         if (!indio_dev)
 131                 return -ENOMEM;
 132
 133         ret = cros_ec_sensors_core_init(pdev, indio_dev, true);
 134         if (ret)
 135                 return ret;
 136
 137         indio_dev->info = &cros_ec_baro_info;
 138         state = iio_priv(indio_dev);
 139         state->core.type = state->core.resp->info.type;
 140         state->core.loc = state->core.resp->info.location;
 141         channel = state->channels;
 142         /* Common part */
 143         channel->info_mask_separate = BIT(IIO_CHAN_INFO_RAW);
 144         channel->info_mask_shared_by_all =
 145                 BIT(IIO_CHAN_INFO_SCALE) |
 146                 BIT(IIO_CHAN_INFO_SAMP_FREQ) |
 147                 BIT(IIO_CHAN_INFO_FREQUENCY);
 148         channel->scan_type.realbits = CROS_EC_SENSOR_BITS;
 149         channel->scan_type.storagebits = CROS_EC_SENSOR_BITS;
 150         channel->scan_type.shift = 0;
 151         channel->scan_index = 0;
 152         channel->ext_info = cros_ec_sensors_ext_info;
 153         channel->scan_type.sign = 'u';
 154
 155         state->core.calib[0] = 0;
 156
 157         /* Sensor specific */
 158         switch (state->core.type) {
 159         case MOTIONSENSE_TYPE_BARO:
 160                 channel->type = IIO_PRESSURE;
 161                 break;
 162         default:
 163                 dev_warn(dev, "Unknown motion sensor\n");
 164                 return -EINVAL;
 165         }
 166
 167         /* Timestamp */
 168         channel++;
 169         channel->type = IIO_TIMESTAMP;
 170         channel->channel = -1;
 171         channel->scan_index = 1;
 172         channel->scan_type.sign = 's';
 173         channel->scan_type.realbits = 64;
 174         channel->scan_type.storagebits = 64;
 175
 176         indio_dev->channels = state->channels;
 177         indio_dev->num_channels = CROS_EC_BARO_MAX_CHANNELS;
 178
 179         state->core.read_ec_sensors_data = cros_ec_sensors_read_cmd;
 180
 181         ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
 182                                               cros_ec_sensors_capture, NULL);
 183         if (ret)
 184                 return ret;
 185
 186         return devm_iio_device_register(dev, indio_dev);
 187 }
 188
 189 static const struct platform_device_id cros_ec_baro_ids[] = {
 190         {
 191                 .name = "cros-ec-baro",
 192         },
 193         { /* sentinel */ }
 194 };
 195 MODULE_DEVICE_TABLE(platform, cros_ec_baro_ids);
 196
 197 static struct platform_driver cros_ec_baro_platform_driver = {
 198         .driver = {
 199                 .name   = "cros-ec-baro",
 200         },
 201         .probe          = cros_ec_baro_probe,
 202         .id_table       = cros_ec_baro_ids,
 203 };
 204 module_platform_driver(cros_ec_baro_platform_driver);
 205
 206 MODULE_DESCRIPTION("ChromeOS EC barometer sensor driver");
 207 MODULE_LICENSE("GPL v2");