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