2 * cros_ec_sensors - Driver for Chrome OS Embedded Controller sensors.
4 * Copyright (C) 2016 Google, Inc
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.
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.
15 * This driver uses the cros-ec interface to communicate with the Chrome OS
16 * EC about sensors data. Data access is presented through iio sysfs.
19 #include <linux/delay.h>
20 #include <linux/device.h>
21 #include <linux/iio/buffer.h>
22 #include <linux/iio/common/cros_ec_sensors_core.h>
23 #include <linux/iio/iio.h>
24 #include <linux/iio/kfifo_buf.h>
25 #include <linux/iio/trigger_consumer.h>
26 #include <linux/iio/triggered_buffer.h>
27 #include <linux/kernel.h>
28 #include <linux/mfd/cros_ec.h>
29 #include <linux/mfd/cros_ec_commands.h>
30 #include <linux/module.h>
31 #include <linux/platform_device.h>
32 #include <linux/slab.h>
33 #include <linux/sysfs.h>
35 #define CROS_EC_SENSORS_MAX_CHANNELS 4
37 /* State data for ec_sensors iio driver. */
38 struct cros_ec_sensors_state {
39 /* Shared by all sensors */
40 struct cros_ec_sensors_core_state core;
42 struct iio_chan_spec channels[CROS_EC_SENSORS_MAX_CHANNELS];
45 static int cros_ec_sensors_read(struct iio_dev *indio_dev,
46 struct iio_chan_spec const *chan,
47 int *val, int *val2, long mask)
49 struct cros_ec_sensors_state *st = iio_priv(indio_dev);
54 int idx = chan->scan_index;
56 mutex_lock(&st->core.cmd_lock);
59 case IIO_CHAN_INFO_RAW:
60 ret = st->core.read_ec_sensors_data(indio_dev, 1 << idx, &data);
66 case IIO_CHAN_INFO_CALIBBIAS:
67 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_OFFSET;
68 st->core.param.sensor_offset.flags = 0;
70 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
75 for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
77 st->core.resp->sensor_offset.offset[i];
79 *val = st->core.calib[idx];
81 case IIO_CHAN_INFO_SCALE:
82 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
83 st->core.param.sensor_range.data = EC_MOTION_SENSE_NO_VALUE;
85 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
89 val64 = st->core.resp->sensor_range.ret;
90 switch (st->core.type) {
91 case MOTIONSENSE_TYPE_ACCEL:
93 * EC returns data in g, iio exepects m/s^2.
94 * Do not use IIO_G_TO_M_S_2 to avoid precision loss.
96 *val = div_s64(val64 * 980665, 10);
97 *val2 = 10000 << (CROS_EC_SENSOR_BITS - 1);
98 ret = IIO_VAL_FRACTIONAL;
100 case MOTIONSENSE_TYPE_GYRO:
102 * EC returns data in dps, iio expects rad/s.
103 * Do not use IIO_DEGREE_TO_RAD to avoid precision
104 * loss. Round to the nearest integer.
107 *val2 = div_s64(val64 * 3141592653ULL,
108 180 << (CROS_EC_SENSOR_BITS - 1));
109 ret = IIO_VAL_INT_PLUS_NANO;
111 case MOTIONSENSE_TYPE_MAG:
113 * EC returns data in 16LSB / uT,
117 *val2 = 100 << (CROS_EC_SENSOR_BITS - 1);
118 ret = IIO_VAL_FRACTIONAL;
125 ret = cros_ec_sensors_core_read(&st->core, chan, val, val2,
129 mutex_unlock(&st->core.cmd_lock);
134 static int cros_ec_sensors_write(struct iio_dev *indio_dev,
135 struct iio_chan_spec const *chan,
136 int val, int val2, long mask)
138 struct cros_ec_sensors_state *st = iio_priv(indio_dev);
141 int idx = chan->scan_index;
143 mutex_lock(&st->core.cmd_lock);
146 case IIO_CHAN_INFO_CALIBBIAS:
147 st->core.calib[idx] = val;
149 /* Send to EC for each axis, even if not complete */
150 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_OFFSET;
151 st->core.param.sensor_offset.flags =
152 MOTION_SENSE_SET_OFFSET;
153 for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
154 st->core.param.sensor_offset.offset[i] =
156 st->core.param.sensor_offset.temp =
157 EC_MOTION_SENSE_INVALID_CALIB_TEMP;
159 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
161 case IIO_CHAN_INFO_SCALE:
162 if (st->core.type == MOTIONSENSE_TYPE_MAG) {
166 st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
167 st->core.param.sensor_range.data = val;
169 /* Always roundup, so caller gets at least what it asks for. */
170 st->core.param.sensor_range.roundup = 1;
172 ret = cros_ec_motion_send_host_cmd(&st->core, 0);
175 ret = cros_ec_sensors_core_write(
176 &st->core, chan, val, val2, mask);
180 mutex_unlock(&st->core.cmd_lock);
185 static const struct iio_info ec_sensors_info = {
186 .read_raw = &cros_ec_sensors_read,
187 .write_raw = &cros_ec_sensors_write,
190 static int cros_ec_sensors_probe(struct platform_device *pdev)
192 struct device *dev = &pdev->dev;
193 struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
194 struct iio_dev *indio_dev;
195 struct cros_ec_sensors_state *state;
196 struct iio_chan_spec *channel;
199 if (!ec_dev || !ec_dev->ec_dev) {
200 dev_warn(&pdev->dev, "No CROS EC device found.\n");
204 indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*state));
208 ret = cros_ec_sensors_core_init(pdev, indio_dev, true);
212 indio_dev->info = &ec_sensors_info;
213 state = iio_priv(indio_dev);
214 for (channel = state->channels, i = CROS_EC_SENSOR_X;
215 i < CROS_EC_SENSOR_MAX_AXIS; i++, channel++) {
217 channel->info_mask_separate =
218 BIT(IIO_CHAN_INFO_RAW) |
219 BIT(IIO_CHAN_INFO_CALIBBIAS);
220 channel->info_mask_shared_by_all =
221 BIT(IIO_CHAN_INFO_SCALE) |
222 BIT(IIO_CHAN_INFO_FREQUENCY) |
223 BIT(IIO_CHAN_INFO_SAMP_FREQ);
224 channel->scan_type.realbits = CROS_EC_SENSOR_BITS;
225 channel->scan_type.storagebits = CROS_EC_SENSOR_BITS;
226 channel->scan_index = i;
227 channel->ext_info = cros_ec_sensors_ext_info;
228 channel->modified = 1;
229 channel->channel2 = IIO_MOD_X + i;
230 channel->scan_type.sign = 's';
232 /* Sensor specific */
233 switch (state->core.type) {
234 case MOTIONSENSE_TYPE_ACCEL:
235 channel->type = IIO_ACCEL;
237 case MOTIONSENSE_TYPE_GYRO:
238 channel->type = IIO_ANGL_VEL;
240 case MOTIONSENSE_TYPE_MAG:
241 channel->type = IIO_MAGN;
244 dev_err(&pdev->dev, "Unknown motion sensor\n");
250 channel->type = IIO_TIMESTAMP;
251 channel->channel = -1;
252 channel->scan_index = CROS_EC_SENSOR_MAX_AXIS;
253 channel->scan_type.sign = 's';
254 channel->scan_type.realbits = 64;
255 channel->scan_type.storagebits = 64;
257 indio_dev->channels = state->channels;
258 indio_dev->num_channels = CROS_EC_SENSORS_MAX_CHANNELS;
260 /* There is only enough room for accel and gyro in the io space */
261 if ((state->core.ec->cmd_readmem != NULL) &&
262 (state->core.type != MOTIONSENSE_TYPE_MAG))
263 state->core.read_ec_sensors_data = cros_ec_sensors_read_lpc;
265 state->core.read_ec_sensors_data = cros_ec_sensors_read_cmd;
267 ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
268 cros_ec_sensors_capture, NULL);
272 return devm_iio_device_register(dev, indio_dev);
275 static const struct platform_device_id cros_ec_sensors_ids[] = {
277 .name = "cros-ec-accel",
280 .name = "cros-ec-gyro",
283 .name = "cros-ec-mag",
287 MODULE_DEVICE_TABLE(platform, cros_ec_sensors_ids);
289 static struct platform_driver cros_ec_sensors_platform_driver = {
291 .name = "cros-ec-sensors",
292 .pm = &cros_ec_sensors_pm_ops,
294 .probe = cros_ec_sensors_probe,
295 .id_table = cros_ec_sensors_ids,
297 module_platform_driver(cros_ec_sensors_platform_driver);
299 MODULE_DESCRIPTION("ChromeOS EC 3-axis sensors driver");
300 MODULE_LICENSE("GPL v2");