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