iio: cros_ec_sensors: add ChromeOS EC Contiguous Sensors driver

Handle 3d contiguous sensors like Accelerometers, Gyroscope and
Magnetometer that are presented by the ChromeOS EC Sensor hub.

Signed-off-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
This commit is contained in:
Enric Balletbo i Serra 2016-08-01 11:54:36 +02:00 committed by Jonathan Cameron
parent 974e6f02e2
commit c14dca07a3
3 changed files with 332 additions and 0 deletions

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@ -12,3 +12,12 @@ config IIO_CROS_EC_SENSORS_CORE
drivers.
Define common attributes and sysfs interrupt handler.
config IIO_CROS_EC_SENSORS
tristate "ChromeOS EC Contiguous Sensors"
select IIO_CROS_EC_SENSORS_CORE
select MFD_CROSS_EC
help
Module to handle 3d contiguous sensors like
Accelerometers, Gyroscope and Magnetometer that are
presented by the ChromeOS EC Sensor hub.
Creates an IIO device for each functions.

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@ -3,3 +3,4 @@
#
obj-$(CONFIG_IIO_CROS_EC_SENSORS_CORE) += cros_ec_sensors_core.o
obj-$(CONFIG_IIO_CROS_EC_SENSORS) += cros_ec_sensors.o

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@ -0,0 +1,322 @@
/*
* cros_ec_sensors - Driver for Chrome OS Embedded Controller sensors.
*
* Copyright (C) 2016 Google, Inc
*
* This software is licensed under the terms of the GNU General Public
* License version 2, as published by the Free Software Foundation, and
* may be copied, distributed, and modified under those terms.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* This driver uses the cros-ec interface to communicate with the Chrome OS
* EC about sensors data. Data access is presented through iio sysfs.
*/
#include <linux/delay.h>
#include <linux/device.h>
#include <linux/iio/buffer.h>
#include <linux/iio/iio.h>
#include <linux/iio/kfifo_buf.h>
#include <linux/iio/trigger_consumer.h>
#include <linux/iio/triggered_buffer.h>
#include <linux/kernel.h>
#include <linux/mfd/cros_ec.h>
#include <linux/mfd/cros_ec_commands.h>
#include <linux/module.h>
#include <linux/platform_device.h>
#include <linux/slab.h>
#include <linux/sysfs.h>
#include "cros_ec_sensors_core.h"
#define CROS_EC_SENSORS_MAX_CHANNELS 4
/* State data for ec_sensors iio driver. */
struct cros_ec_sensors_state {
/* Shared by all sensors */
struct cros_ec_sensors_core_state core;
struct iio_chan_spec channels[CROS_EC_SENSORS_MAX_CHANNELS];
};
static int cros_ec_sensors_read(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int *val, int *val2, long mask)
{
struct cros_ec_sensors_state *st = iio_priv(indio_dev);
s16 data = 0;
s64 val64;
int i;
int ret = IIO_VAL_INT;
int idx = chan->scan_index;
mutex_lock(&st->core.cmd_lock);
switch (mask) {
case IIO_CHAN_INFO_RAW:
ret = st->core.read_ec_sensors_data(indio_dev, 1 << idx, &data);
if (ret < 0)
break;
*val = data;
break;
case IIO_CHAN_INFO_CALIBBIAS:
st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_OFFSET;
st->core.param.sensor_offset.flags = 0;
ret = cros_ec_motion_send_host_cmd(&st->core, 0);
if (ret < 0)
break;
/* Save values */
for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
st->core.calib[i] =
st->core.resp->sensor_offset.offset[i];
*val = st->core.calib[idx];
break;
case IIO_CHAN_INFO_SCALE:
st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
st->core.param.sensor_range.data = EC_MOTION_SENSE_NO_VALUE;
ret = cros_ec_motion_send_host_cmd(&st->core, 0);
if (ret < 0)
break;
val64 = st->core.resp->sensor_range.ret;
switch (st->core.type) {
case MOTIONSENSE_TYPE_ACCEL:
/*
* EC returns data in g, iio exepects m/s^2.
* Do not use IIO_G_TO_M_S_2 to avoid precision loss.
*/
*val = div_s64(val64 * 980665, 10);
*val2 = 10000 << (CROS_EC_SENSOR_BITS - 1);
ret = IIO_VAL_FRACTIONAL;
break;
case MOTIONSENSE_TYPE_GYRO:
/*
* EC returns data in dps, iio expects rad/s.
* Do not use IIO_DEGREE_TO_RAD to avoid precision
* loss. Round to the nearest integer.
*/
*val = div_s64(val64 * 314159 + 9000000ULL, 1000);
*val2 = 18000 << (CROS_EC_SENSOR_BITS - 1);
ret = IIO_VAL_FRACTIONAL;
break;
case MOTIONSENSE_TYPE_MAG:
/*
* EC returns data in 16LSB / uT,
* iio expects Gauss
*/
*val = val64;
*val2 = 100 << (CROS_EC_SENSOR_BITS - 1);
ret = IIO_VAL_FRACTIONAL;
break;
default:
ret = -EINVAL;
}
break;
default:
ret = cros_ec_sensors_core_read(&st->core, chan, val, val2,
mask);
break;
}
mutex_unlock(&st->core.cmd_lock);
return ret;
}
static int cros_ec_sensors_write(struct iio_dev *indio_dev,
struct iio_chan_spec const *chan,
int val, int val2, long mask)
{
struct cros_ec_sensors_state *st = iio_priv(indio_dev);
int i;
int ret = 0;
int idx = chan->scan_index;
mutex_lock(&st->core.cmd_lock);
switch (mask) {
case IIO_CHAN_INFO_CALIBBIAS:
st->core.calib[idx] = val;
/* Send to EC for each axis, even if not complete */
st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_OFFSET;
st->core.param.sensor_offset.flags =
MOTION_SENSE_SET_OFFSET;
for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
st->core.param.sensor_offset.offset[i] =
st->core.calib[i];
st->core.param.sensor_offset.temp =
EC_MOTION_SENSE_INVALID_CALIB_TEMP;
ret = cros_ec_motion_send_host_cmd(&st->core, 0);
break;
case IIO_CHAN_INFO_SCALE:
if (st->core.type == MOTIONSENSE_TYPE_MAG) {
ret = -EINVAL;
break;
}
st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
st->core.param.sensor_range.data = val;
/* Always roundup, so caller gets at least what it asks for. */
st->core.param.sensor_range.roundup = 1;
ret = cros_ec_motion_send_host_cmd(&st->core, 0);
break;
default:
ret = cros_ec_sensors_core_write(
&st->core, chan, val, val2, mask);
break;
}
mutex_unlock(&st->core.cmd_lock);
return ret;
}
static const struct iio_info ec_sensors_info = {
.read_raw = &cros_ec_sensors_read,
.write_raw = &cros_ec_sensors_write,
.driver_module = THIS_MODULE,
};
static int cros_ec_sensors_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct cros_ec_dev *ec_dev = dev_get_drvdata(dev->parent);
struct cros_ec_device *ec_device;
struct iio_dev *indio_dev;
struct cros_ec_sensors_state *state;
struct iio_chan_spec *channel;
int ret, i;
if (!ec_dev || !ec_dev->ec_dev) {
dev_warn(&pdev->dev, "No CROS EC device found.\n");
return -EINVAL;
}
ec_device = ec_dev->ec_dev;
indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*state));
if (!indio_dev)
return -ENOMEM;
ret = cros_ec_sensors_core_init(pdev, indio_dev, true);
if (ret)
return ret;
indio_dev->info = &ec_sensors_info;
state = iio_priv(indio_dev);
for (channel = state->channels, i = CROS_EC_SENSOR_X;
i < CROS_EC_SENSOR_MAX_AXIS; i++, channel++) {
/* Common part */
channel->info_mask_separate =
BIT(IIO_CHAN_INFO_RAW) |
BIT(IIO_CHAN_INFO_CALIBBIAS);
channel->info_mask_shared_by_all =
BIT(IIO_CHAN_INFO_SCALE) |
BIT(IIO_CHAN_INFO_FREQUENCY) |
BIT(IIO_CHAN_INFO_SAMP_FREQ);
channel->scan_type.realbits = CROS_EC_SENSOR_BITS;
channel->scan_type.storagebits = CROS_EC_SENSOR_BITS;
channel->scan_index = i;
channel->ext_info = cros_ec_sensors_ext_info;
channel->modified = 1;
channel->channel2 = IIO_MOD_X + i;
channel->scan_type.sign = 's';
/* Sensor specific */
switch (state->core.type) {
case MOTIONSENSE_TYPE_ACCEL:
channel->type = IIO_ACCEL;
break;
case MOTIONSENSE_TYPE_GYRO:
channel->type = IIO_ANGL_VEL;
break;
case MOTIONSENSE_TYPE_MAG:
channel->type = IIO_MAGN;
break;
default:
dev_err(&pdev->dev, "Unknown motion sensor\n");
return -EINVAL;
}
}
/* Timestamp */
channel->type = IIO_TIMESTAMP;
channel->channel = -1;
channel->scan_index = CROS_EC_SENSOR_MAX_AXIS;
channel->scan_type.sign = 's';
channel->scan_type.realbits = 64;
channel->scan_type.storagebits = 64;
indio_dev->channels = state->channels;
indio_dev->num_channels = CROS_EC_SENSORS_MAX_CHANNELS;
/* There is only enough room for accel and gyro in the io space */
if ((state->core.ec->cmd_readmem != NULL) &&
(state->core.type != MOTIONSENSE_TYPE_MAG))
state->core.read_ec_sensors_data = cros_ec_sensors_read_lpc;
else
state->core.read_ec_sensors_data = cros_ec_sensors_read_cmd;
ret = iio_triggered_buffer_setup(indio_dev, NULL,
cros_ec_sensors_capture, NULL);
if (ret)
return ret;
ret = iio_device_register(indio_dev);
if (ret)
goto error_uninit_buffer;
return 0;
error_uninit_buffer:
iio_triggered_buffer_cleanup(indio_dev);
return ret;
}
static int cros_ec_sensors_remove(struct platform_device *pdev)
{
struct iio_dev *indio_dev = platform_get_drvdata(pdev);
iio_device_unregister(indio_dev);
iio_triggered_buffer_cleanup(indio_dev);
return 0;
}
static const struct platform_device_id cros_ec_sensors_ids[] = {
{
.name = "cros-ec-accel",
},
{
.name = "cros-ec-gyro",
},
{
.name = "cros-ec-mag",
},
{ /* sentinel */ }
};
MODULE_DEVICE_TABLE(platform, cros_ec_sensors_ids);
static struct platform_driver cros_ec_sensors_platform_driver = {
.driver = {
.name = "cros-ec-sensors",
},
.probe = cros_ec_sensors_probe,
.remove = cros_ec_sensors_remove,
.id_table = cros_ec_sensors_ids,
};
module_platform_driver(cros_ec_sensors_platform_driver);
MODULE_DESCRIPTION("ChromeOS EC 3-axis sensors driver");
MODULE_LICENSE("GPL v2");