Re: [PATCH v4 2/4] iio: cros_ec_sensors: add ChromeOS EC Contiguous Sensors driver

[Jonathan Cameron]

On 15/08/16 16:28, Jonathan Cameron wrote:
> On 01/08/16 10:54, Enric Balletbo i Serra wrote:
>> Handle 3d contiguous sensors like Accelerometers, Gyroscope and
>> Magnetometer that are presented by the ChromeOS EC Sensor hub.
>>
>> Signed-off-by: Guenter Roeck <groeck@xxxxxxxxxxxx>
>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
> Reviewed-by: Jonathan Cameron <jic23@xxxxxxxxxx>
> 
> Again, fine if this goes via mfd.
A bit of white space fun that I cleaned up in the previous patch
made this interesting to apply but think I got it right
(there was an extra blank line at the end of the Kconfig)

Thanks,

Jonathan
> 
> Thanks,
> 
> Jonathan
>> ---
>>
>> Changes since v3:
>>   - Remove some useless initialitzations as always overwritten.
>>   - Convert calib structure to a simple array.
>> Changes since v2:
>>   - Fix some typos
>>   - Skip filling by zero structure parameters that already zero'd.
>>   - Order includes alphabetically.
>>   - Propagate error codes.
>> Changes since v1:
>>   - Fixup multiline comments.
>>   - Fix some spelling mistakes.
>>   - Blank line before return statements.
>>   - Add CROS_EC_SENSORS_ prefix.
>>
>>  drivers/iio/common/cros_ec_sensors/Kconfig         |   8 +
>>  drivers/iio/common/cros_ec_sensors/Makefile        |   1 +
>>  .../iio/common/cros_ec_sensors/cros_ec_sensors.c   | 322 +++++++++++++++++++++
>>  3 files changed, 331 insertions(+)
>>  create mode 100644 drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c
>>
>> diff --git a/drivers/iio/common/cros_ec_sensors/Kconfig b/drivers/iio/common/cros_ec_sensors/Kconfig
>> index 24743be..980bea2 100644
>> --- a/drivers/iio/common/cros_ec_sensors/Kconfig
>> +++ b/drivers/iio/common/cros_ec_sensors/Kconfig
>> @@ -12,3 +12,11 @@ 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
>> +	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.
>> diff --git a/drivers/iio/common/cros_ec_sensors/Makefile b/drivers/iio/common/cros_ec_sensors/Makefile
>> index 95b6901..ec716ff 100644
>> --- a/drivers/iio/common/cros_ec_sensors/Makefile
>> +++ b/drivers/iio/common/cros_ec_sensors/Makefile
>> @@ -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
>> diff --git a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c
>> new file mode 100644
>> index 0000000..48edeba
>> --- /dev/null
>> +++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c
>> @@ -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");
>>
> 
> --
> To unsubscribe from this list: send the line "unsubscribe linux-iio" in
> the body of a message to majordomo@xxxxxxxxxxxxxxx
> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>