Re: [PATCH v4 1/4] iio: cros_ec_sensors_core: Add common functions for the ChromeOS EC Sensor Hub.

[Jonathan Cameron]

On 15/08/16 16:28, Jonathan Cameron wrote:
> On 01/08/16 10:54, Enric Balletbo i Serra wrote:
>> Add the core functions to be able to support the sensors attached behind
>> the ChromeOS Embedded Controller and used by other IIO cros-ec sensor
>> drivers.
>>
>> The cros_ec_sensor_core driver matches with current driver in ChromeOS
>> 4.4 tree, so it includes all the fixes at the moment. The support for
>> this driver was made by Gwendal Grignou. The original patch and all the
>> fixes has been squashed and rebased on top of mainline.
>>
>> Signed-off-by: Gwendal Grignou <gwendal@xxxxxxxxxxxx>
>> Signed-off-by: Guenter Roeck <groeck@xxxxxxxxxxxx>
>> [eballetbo: split, squash and rebase on top of mainline the patches
>> found in ChromeOS tree]
>> Signed-off-by: Enric Balletbo i Serra <enric.balletbo@xxxxxxxxxxxxx>
> Reviewed-by: Jonathan Cameron <jic23@xxxxxxxxxx>
Applied to a new branch in IIO for the purpose.
ib-iio-mfd-4.9

Not entirely sure which route I'll take to unwinding this to upstream
so it may go through a merge into iio.git or a separate pull request.

Will figure that out later!

Thanks,

Jonathan
> 
> Thanks,
> 
> Jonathan
>> ---
>>
>> Changes since v3:
>>   - Convert structure to a simple array
>>   - Remove PM declarations
>>   - Remove unnecessary initializations
>>   - cros_ec_sensors_cmd_read_u16: Conversion should only be done if ret >= 0
>>   - Remove unnecessary else
>>
>> Changes since v2:
>>   - Rebased and fix build error.
>>   - Include a list of possible values in the description of location attr.
>>   - Fix some typos.
>>   - Remove id sysfs entry.
>>
>> Changes since v1:
>>   - Check kernel-doc documentation.
>>   - Bring this in as an when you need it in the rest of the series.
>>   - Fix some spelling mistakes.
>>   - Include ABI documentation.
>>   - Be more careful with buffer sizes (sprintf -> snprintf)
>>   - Add cros_ec_sensors prefix to all function.
>>   - Check return values on some functions.
>>
>>  Documentation/ABI/testing/sysfs-bus-iio-cros-ec    |  18 +
>>  drivers/iio/common/Kconfig                         |   1 +
>>  drivers/iio/common/Makefile                        |   1 +
>>  drivers/iio/common/cros_ec_sensors/Kconfig         |  14 +
>>  drivers/iio/common/cros_ec_sensors/Makefile        |   5 +
>>  .../common/cros_ec_sensors/cros_ec_sensors_core.c  | 450 +++++++++++++++++++++
>>  .../common/cros_ec_sensors/cros_ec_sensors_core.h  | 175 ++++++++
>>  include/linux/mfd/cros_ec.h                        |   9 +
>>  include/linux/mfd/cros_ec_commands.h               |  99 ++++-
>>  9 files changed, 767 insertions(+), 5 deletions(-)
>>  create mode 100644 Documentation/ABI/testing/sysfs-bus-iio-cros-ec
>>  create mode 100644 drivers/iio/common/cros_ec_sensors/Kconfig
>>  create mode 100644 drivers/iio/common/cros_ec_sensors/Makefile
>>  create mode 100644 drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
>>  create mode 100644 drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.h
>>
>> diff --git a/Documentation/ABI/testing/sysfs-bus-iio-cros-ec b/Documentation/ABI/testing/sysfs-bus-iio-cros-ec
>> new file mode 100644
>> index 0000000..297b972
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/sysfs-bus-iio-cros-ec
>> @@ -0,0 +1,18 @@
>> +What:		/sys/bus/iio/devices/iio:deviceX/calibrate
>> +Date:		July 2015
>> +KernelVersion:	4.7
>> +Contact:	linux-iio@xxxxxxxxxxxxxxx
>> +Description:
>> +		Writing '1' will perform a FOC (Fast Online Calibration). The
>> +                corresponding calibration offsets can be read from *_calibbias
>> +                entries.
>> +
>> +What:		/sys/bus/iio/devices/iio:deviceX/location
>> +Date:		July 2015
>> +KernelVersion:	4.7
>> +Contact:	linux-iio@xxxxxxxxxxxxxxx
>> +Description:
>> +		This attribute returns a string with the physical location where
>> +                the motion sensor is placed. For example, in a laptop a motion
>> +                sensor can be located on the base or on the lid. Current valid
>> +		values are 'base' and 'lid'.
>> diff --git a/drivers/iio/common/Kconfig b/drivers/iio/common/Kconfig
>> index 26a6026..e108996 100644
>> --- a/drivers/iio/common/Kconfig
>> +++ b/drivers/iio/common/Kconfig
>> @@ -2,6 +2,7 @@
>>  # IIO common modules
>>  #
>>  
>> +source "drivers/iio/common/cros_ec_sensors/Kconfig"
>>  source "drivers/iio/common/hid-sensors/Kconfig"
>>  source "drivers/iio/common/ms_sensors/Kconfig"
>>  source "drivers/iio/common/ssp_sensors/Kconfig"
>> diff --git a/drivers/iio/common/Makefile b/drivers/iio/common/Makefile
>> index 585da6a..6fa760e 100644
>> --- a/drivers/iio/common/Makefile
>> +++ b/drivers/iio/common/Makefile
>> @@ -7,6 +7,7 @@
>>  #
>>  
>>  # When adding new entries keep the list in alphabetical order
>> +obj-y += cros_ec_sensors/
>>  obj-y += hid-sensors/
>>  obj-y += ms_sensors/
>>  obj-y += ssp_sensors/
>> diff --git a/drivers/iio/common/cros_ec_sensors/Kconfig b/drivers/iio/common/cros_ec_sensors/Kconfig
>> new file mode 100644
>> index 0000000..24743be
>> --- /dev/null
>> +++ b/drivers/iio/common/cros_ec_sensors/Kconfig
>> @@ -0,0 +1,14 @@
>> +#
>> +# Chrome OS Embedded Controller managed sensors library
>> +#
>> +config IIO_CROS_EC_SENSORS_CORE
>> +	tristate "ChromeOS EC Sensors Core"
>> +	depends on SYSFS && MFD_CROS_EC
>> +	select IIO_BUFFER
>> +	select IIO_TRIGGERED_BUFFER
>> +	help
>> +	  Base module for the ChromeOS EC Sensors module.
>> +	  Contains core functions used by other IIO CrosEC sensor
>> +	  drivers.
>> +	  Define common attributes and sysfs interrupt handler.
>> +
>> diff --git a/drivers/iio/common/cros_ec_sensors/Makefile b/drivers/iio/common/cros_ec_sensors/Makefile
>> new file mode 100644
>> index 0000000..95b6901
>> --- /dev/null
>> +++ b/drivers/iio/common/cros_ec_sensors/Makefile
>> @@ -0,0 +1,5 @@
>> +#
>> +# Makefile for sensors seen through the ChromeOS EC sensor hub.
>> +#
>> +
>> +obj-$(CONFIG_IIO_CROS_EC_SENSORS_CORE) += cros_ec_sensors_core.o
>> diff --git a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
>> new file mode 100644
>> index 0000000..a3be799
>> --- /dev/null
>> +++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
>> @@ -0,0 +1,450 @@
>> +/*
>> + * cros_ec_sensors_core - Common function for Chrome OS EC sensor driver.
>> + *
>> + * 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.
>> + */
>> +
>> +#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/kernel.h>
>> +#include <linux/mfd/cros_ec.h>
>> +#include <linux/mfd/cros_ec_commands.h>
>> +#include <linux/module.h>
>> +#include <linux/slab.h>
>> +#include <linux/sysfs.h>
>> +#include <linux/platform_device.h>
>> +
>> +#include "cros_ec_sensors_core.h"
>> +
>> +static char *cros_ec_loc[] = {
>> +	[MOTIONSENSE_LOC_BASE] = "base",
>> +	[MOTIONSENSE_LOC_LID] = "lid",
>> +	[MOTIONSENSE_LOC_MAX] = "unknown",
>> +};
>> +
>> +int cros_ec_sensors_core_init(struct platform_device *pdev,
>> +			      struct iio_dev *indio_dev,
>> +			      bool physical_device)
>> +{
>> +	struct device *dev = &pdev->dev;
>> +	struct cros_ec_sensors_core_state *state = iio_priv(indio_dev);
>> +	struct cros_ec_dev *ec = dev_get_drvdata(pdev->dev.parent);
>> +	struct cros_ec_sensor_platform *sensor_platform = dev_get_platdata(dev);
>> +
>> +	platform_set_drvdata(pdev, indio_dev);
>> +
>> +	state->ec = ec->ec_dev;
>> +	state->msg = devm_kzalloc(&pdev->dev,
>> +				max((u16)sizeof(struct ec_params_motion_sense),
>> +				state->ec->max_response), GFP_KERNEL);
>> +	if (!state->msg)
>> +		return -ENOMEM;
>> +
>> +	state->resp = (struct ec_response_motion_sense *)state->msg->data;
>> +
>> +	mutex_init(&state->cmd_lock);
>> +
>> +	/* Set up the host command structure. */
>> +	state->msg->version = 2;
>> +	state->msg->command = EC_CMD_MOTION_SENSE_CMD + ec->cmd_offset;
>> +	state->msg->outsize = sizeof(struct ec_params_motion_sense);
>> +
>> +	indio_dev->dev.parent = &pdev->dev;
>> +	indio_dev->name = pdev->name;
>> +
>> +	if (physical_device) {
>> +		indio_dev->modes = INDIO_DIRECT_MODE;
>> +
>> +		state->param.cmd = MOTIONSENSE_CMD_INFO;
>> +		state->param.info.sensor_num = sensor_platform->sensor_num;
>> +		if (cros_ec_motion_send_host_cmd(state, 0)) {
>> +			dev_warn(dev, "Can not access sensor info\n");
>> +			return -EIO;
>> +		}
>> +		state->type = state->resp->info.type;
>> +		state->loc = state->resp->info.location;
>> +	}
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(cros_ec_sensors_core_init);
>> +
>> +int cros_ec_motion_send_host_cmd(struct cros_ec_sensors_core_state *state,
>> +				 u16 opt_length)
>> +{
>> +	int ret;
>> +
>> +	if (opt_length)
>> +		state->msg->insize = min(opt_length, state->ec->max_response);
>> +	else
>> +		state->msg->insize = state->ec->max_response;
>> +
>> +	memcpy(state->msg->data, &state->param, sizeof(state->param));
>> +
>> +	ret = cros_ec_cmd_xfer_status(state->ec, state->msg);
>> +	if (ret < 0)
>> +		return -EIO;
>> +
>> +	if (ret &&
>> +	    state->resp != (struct ec_response_motion_sense *)state->msg->data)
>> +		memcpy(state->resp, state->msg->data, ret);
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(cros_ec_motion_send_host_cmd);
>> +
>> +static ssize_t cros_ec_sensors_calibrate(struct iio_dev *indio_dev,
>> +		uintptr_t private, const struct iio_chan_spec *chan,
>> +		const char *buf, size_t len)
>> +{
>> +	struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
>> +	int ret, i;
>> +	bool calibrate;
>> +
>> +	ret = strtobool(buf, &calibrate);
>> +	if (ret < 0)
>> +		return ret;
>> +	if (!calibrate)
>> +		return -EINVAL;
>> +
>> +	mutex_lock(&st->cmd_lock);
>> +	st->param.cmd = MOTIONSENSE_CMD_PERFORM_CALIB;
>> +	ret = cros_ec_motion_send_host_cmd(st, 0);
>> +	if (ret != 0) {
>> +		dev_warn(&indio_dev->dev, "Unable to calibrate sensor\n");
>> +	} else {
>> +		/* Save values */
>> +		for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
>> +			st->calib[i] = st->resp->perform_calib.offset[i];
>> +	}
>> +	mutex_unlock(&st->cmd_lock);
>> +
>> +	return ret ? ret : len;
>> +}
>> +
>> +static ssize_t cros_ec_sensors_loc(struct iio_dev *indio_dev,
>> +		uintptr_t private, const struct iio_chan_spec *chan,
>> +		char *buf)
>> +{
>> +	struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
>> +
>> +	return snprintf(buf, PAGE_SIZE, "%s\n", cros_ec_loc[st->loc]);
>> +}
>> +
>> +const struct iio_chan_spec_ext_info cros_ec_sensors_ext_info[] = {
>> +	{
>> +		.name = "calibrate",
>> +		.shared = IIO_SHARED_BY_ALL,
>> +		.write = cros_ec_sensors_calibrate
>> +	},
>> +	{
>> +		.name = "location",
>> +		.shared = IIO_SHARED_BY_ALL,
>> +		.read = cros_ec_sensors_loc
>> +	},
>> +	{ },
>> +};
>> +EXPORT_SYMBOL_GPL(cros_ec_sensors_ext_info);
>> +
>> +/**
>> + * cros_ec_sensors_idx_to_reg - convert index into offset in shared memory
>> + * @st:		pointer to state information for device
>> + * @idx:	sensor index (should be element of enum sensor_index)
>> + *
>> + * Return:	address to read at
>> + */
>> +static unsigned int cros_ec_sensors_idx_to_reg(
>> +					struct cros_ec_sensors_core_state *st,
>> +					unsigned int idx)
>> +{
>> +	/*
>> +	 * When using LPC interface, only space for 2 Accel and one Gyro.
>> +	 * First halfword of MOTIONSENSE_TYPE_ACCEL is used by angle.
>> +	 */
>> +	if (st->type == MOTIONSENSE_TYPE_ACCEL)
>> +		return EC_MEMMAP_ACC_DATA + sizeof(u16) *
>> +			(1 + idx + st->param.info.sensor_num *
>> +			 CROS_EC_SENSOR_MAX_AXIS);
>> +
>> +	return EC_MEMMAP_GYRO_DATA + sizeof(u16) * idx;
>> +}
>> +
>> +static int cros_ec_sensors_cmd_read_u8(struct cros_ec_device *ec,
>> +				       unsigned int offset, u8 *dest)
>> +{
>> +	return ec->cmd_readmem(ec, offset, 1, dest);
>> +}
>> +
>> +static int cros_ec_sensors_cmd_read_u16(struct cros_ec_device *ec,
>> +					 unsigned int offset, u16 *dest)
>> +{
>> +	__le16 tmp;
>> +	int ret = ec->cmd_readmem(ec, offset, 2, &tmp);
>> +
>> +	if (ret >= 0)
>> +		*dest = le16_to_cpu(tmp);
>> +
>> +	return ret;
>> +}
>> +
>> +/**
>> + * cros_ec_sensors_read_until_not_busy() - read until is not busy
>> + *
>> + * @st:	pointer to state information for device
>> + *
>> + * Read from EC status byte until it reads not busy.
>> + * Return: 8-bit status if ok, -errno on failure.
>> + */
>> +static int cros_ec_sensors_read_until_not_busy(
>> +					struct cros_ec_sensors_core_state *st)
>> +{
>> +	struct cros_ec_device *ec = st->ec;
>> +	u8 status;
>> +	int ret, attempts = 0;
>> +
>> +	ret = cros_ec_sensors_cmd_read_u8(ec, EC_MEMMAP_ACC_STATUS, &status);
>> +	if (ret < 0)
>> +		return ret;
>> +
>> +	while (status & EC_MEMMAP_ACC_STATUS_BUSY_BIT) {
>> +		/* Give up after enough attempts, return error. */
>> +		if (attempts++ >= 50)
>> +			return -EIO;
>> +
>> +		/* Small delay every so often. */
>> +		if (attempts % 5 == 0)
>> +			msleep(25);
>> +
>> +		ret = cros_ec_sensors_cmd_read_u8(ec, EC_MEMMAP_ACC_STATUS,
>> +						  &status);
>> +		if (ret < 0)
>> +			return ret;
>> +	}
>> +
>> +	return status;
>> +}
>> +
>> +/**
>> + * read_ec_sensors_data_unsafe() - read acceleration data from EC shared memory
>> + * @indio_dev:	pointer to IIO device
>> + * @scan_mask:	bitmap of the sensor indices to scan
>> + * @data:	location to store data
>> + *
>> + * This is the unsafe function for reading the EC data. It does not guarantee
>> + * that the EC will not modify the data as it is being read in.
>> + *
>> + * Return: 0 on success, -errno on failure.
>> + */
>> +static int cros_ec_sensors_read_data_unsafe(struct iio_dev *indio_dev,
>> +			 unsigned long scan_mask, s16 *data)
>> +{
>> +	struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
>> +	struct cros_ec_device *ec = st->ec;
>> +	unsigned int i;
>> +	int ret;
>> +
>> +	/* Read all sensors enabled in scan_mask. Each value is 2 bytes. */
>> +	for_each_set_bit(i, &scan_mask, indio_dev->masklength) {
>> +		ret = cros_ec_sensors_cmd_read_u16(ec,
>> +					     cros_ec_sensors_idx_to_reg(st, i),
>> +					     data);
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		data++;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +int cros_ec_sensors_read_lpc(struct iio_dev *indio_dev,
>> +			     unsigned long scan_mask, s16 *data)
>> +{
>> +	struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
>> +	struct cros_ec_device *ec = st->ec;
>> +	u8 samp_id = 0xff, status = 0;
>> +	int ret, attempts = 0;
>> +
>> +	/*
>> +	 * Continually read all data from EC until the status byte after
>> +	 * all reads reflects that the EC is not busy and the sample id
>> +	 * matches the sample id from before all reads. This guarantees
>> +	 * that data read in was not modified by the EC while reading.
>> +	 */
>> +	while ((status & (EC_MEMMAP_ACC_STATUS_BUSY_BIT |
>> +			  EC_MEMMAP_ACC_STATUS_SAMPLE_ID_MASK)) != samp_id) {
>> +		/* If we have tried to read too many times, return error. */
>> +		if (attempts++ >= 5)
>> +			return -EIO;
>> +
>> +		/* Read status byte until EC is not busy. */
>> +		status = cros_ec_sensors_read_until_not_busy(st);
>> +		if (status < 0)
>> +			return status;
>> +
>> +		/*
>> +		 * Store the current sample id so that we can compare to the
>> +		 * sample id after reading the data.
>> +		 */
>> +		samp_id = status & EC_MEMMAP_ACC_STATUS_SAMPLE_ID_MASK;
>> +
>> +		/* Read all EC data, format it, and store it into data. */
>> +		ret = cros_ec_sensors_read_data_unsafe(indio_dev, scan_mask,
>> +						       data);
>> +		if (ret < 0)
>> +			return ret;
>> +
>> +		/* Read status byte. */
>> +		ret = cros_ec_sensors_cmd_read_u8(ec, EC_MEMMAP_ACC_STATUS,
>> +						  &status);
>> +		if (ret < 0)
>> +			return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(cros_ec_sensors_read_lpc);
>> +
>> +int cros_ec_sensors_read_cmd(struct iio_dev *indio_dev,
>> +			     unsigned long scan_mask, s16 *data)
>> +{
>> +	struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
>> +	int ret;
>> +	unsigned int i;
>> +
>> +	/* Read all sensor data through a command. */
>> +	st->param.cmd = MOTIONSENSE_CMD_DATA;
>> +	ret = cros_ec_motion_send_host_cmd(st, sizeof(st->resp->data));
>> +	if (ret != 0) {
>> +		dev_warn(&indio_dev->dev, "Unable to read sensor data\n");
>> +		return ret;
>> +	}
>> +
>> +	for_each_set_bit(i, &scan_mask, indio_dev->masklength) {
>> +		*data = st->resp->data.data[i];
>> +		data++;
>> +	}
>> +
>> +	return 0;
>> +}
>> +EXPORT_SYMBOL_GPL(cros_ec_sensors_read_cmd);
>> +
>> +irqreturn_t cros_ec_sensors_capture(int irq, void *p)
>> +{
>> +	struct iio_poll_func *pf = p;
>> +	struct iio_dev *indio_dev = pf->indio_dev;
>> +	struct cros_ec_sensors_core_state *st = iio_priv(indio_dev);
>> +	int ret;
>> +
>> +	mutex_lock(&st->cmd_lock);
>> +
>> +	/* Clear capture data. */
>> +	memset(st->samples, 0, indio_dev->scan_bytes);
>> +
>> +	/* Read data based on which channels are enabled in scan mask. */
>> +	ret = st->read_ec_sensors_data(indio_dev,
>> +				       *(indio_dev->active_scan_mask),
>> +				       (s16 *)st->samples);
>> +	if (ret < 0)
>> +		goto done;
>> +
>> +	iio_push_to_buffers_with_timestamp(indio_dev, st->samples,
>> +					   iio_get_time_ns(indio_dev));
>> +
>> +done:
>> +	/*
>> +	 * Tell the core we are done with this trigger and ready for the
>> +	 * next one.
>> +	 */
>> +	iio_trigger_notify_done(indio_dev->trig);
>> +
>> +	mutex_unlock(&st->cmd_lock);
>> +
>> +	return IRQ_HANDLED;
>> +}
>> +EXPORT_SYMBOL_GPL(cros_ec_sensors_capture);
>> +
>> +int cros_ec_sensors_core_read(struct cros_ec_sensors_core_state *st,
>> +			  struct iio_chan_spec const *chan,
>> +			  int *val, int *val2, long mask)
>> +{
>> +	int ret = IIO_VAL_INT;
>> +
>> +	switch (mask) {
>> +	case IIO_CHAN_INFO_SAMP_FREQ:
>> +		st->param.cmd = MOTIONSENSE_CMD_EC_RATE;
>> +		st->param.ec_rate.data =
>> +			EC_MOTION_SENSE_NO_VALUE;
>> +
>> +		if (cros_ec_motion_send_host_cmd(st, 0))
>> +			ret = -EIO;
>> +		else
>> +			*val = st->resp->ec_rate.ret;
>> +		break;
>> +	case IIO_CHAN_INFO_FREQUENCY:
>> +		st->param.cmd = MOTIONSENSE_CMD_SENSOR_ODR;
>> +		st->param.sensor_odr.data =
>> +			EC_MOTION_SENSE_NO_VALUE;
>> +
>> +		if (cros_ec_motion_send_host_cmd(st, 0))
>> +			ret = -EIO;
>> +		else
>> +			*val = st->resp->sensor_odr.ret;
>> +		break;
>> +	default:
>> +		break;
>> +	}
>> +
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(cros_ec_sensors_core_read);
>> +
>> +int cros_ec_sensors_core_write(struct cros_ec_sensors_core_state *st,
>> +			       struct iio_chan_spec const *chan,
>> +			       int val, int val2, long mask)
>> +{
>> +	int ret = 0;
>> +
>> +	switch (mask) {
>> +	case IIO_CHAN_INFO_FREQUENCY:
>> +		st->param.cmd = MOTIONSENSE_CMD_SENSOR_ODR;
>> +		st->param.sensor_odr.data = val;
>> +
>> +		/* Always roundup, so caller gets at least what it asks for. */
>> +		st->param.sensor_odr.roundup = 1;
>> +
>> +		if (cros_ec_motion_send_host_cmd(st, 0))
>> +			ret = -EIO;
>> +		break;
>> +	case IIO_CHAN_INFO_SAMP_FREQ:
>> +		st->param.cmd = MOTIONSENSE_CMD_EC_RATE;
>> +		st->param.ec_rate.data = val;
>> +
>> +		if (cros_ec_motion_send_host_cmd(st, 0))
>> +			ret = -EIO;
>> +		else
>> +			st->curr_sampl_freq = val;
>> +		break;
>> +	default:
>> +		ret = -EINVAL;
>> +		break;
>> +	}
>> +	return ret;
>> +}
>> +EXPORT_SYMBOL_GPL(cros_ec_sensors_core_write);
>> +
>> +MODULE_DESCRIPTION("ChromeOS EC sensor hub core functions");
>> +MODULE_LICENSE("GPL v2");
>> diff --git a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.h b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.h
>> new file mode 100644
>> index 0000000..8bc2ca3
>> --- /dev/null
>> +++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.h
>> @@ -0,0 +1,175 @@
>> +/*
>> + * ChromeOS EC sensor hub
>> + *
>> + * 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.
>> + */
>> +
>> +#ifndef __CROS_EC_SENSORS_CORE_H
>> +#define __CROS_EC_SENSORS_CORE_H
>> +
>> +#include <linux/irqreturn.h>
>> +
>> +enum {
>> +	CROS_EC_SENSOR_X,
>> +	CROS_EC_SENSOR_Y,
>> +	CROS_EC_SENSOR_Z,
>> +	CROS_EC_SENSOR_MAX_AXIS,
>> +};
>> +
>> +/* EC returns sensor values using signed 16 bit registers */
>> +#define CROS_EC_SENSOR_BITS 16
>> +
>> +/*
>> + * 4 16 bit channels are allowed.
>> + * Good enough for current sensors, they use up to 3 16 bit vectors.
>> + */
>> +#define CROS_EC_SAMPLE_SIZE  (sizeof(s64) * 2)
>> +
>> +/* Minimum sampling period to use when device is suspending */
>> +#define CROS_EC_MIN_SUSPEND_SAMPLING_FREQUENCY 1000  /* 1 second */
>> +
>> +/**
>> + * struct cros_ec_sensors_core_state - state data for EC sensors IIO driver
>> + * @ec:				cros EC device structure
>> + * @cmd_lock:			lock used to prevent simultaneous access to the
>> + *				commands.
>> + * @msg:			cros EC command structure
>> + * @param:			motion sensor parameters structure
>> + * @resp:			motion sensor response structure
>> + * @type:			type of motion sensor
>> + * @loc:			location where the motion sensor is placed
>> + * @calib:			calibration parameters. Note that trigger
>> + *				captured data will always provide the calibrated
>> + *				data
>> + * @samples:			static array to hold data from a single capture.
>> + *				For each channel we need 2 bytes, except for
>> + *				the timestamp. The timestamp is always last and
>> + *				is always 8-byte aligned.
>> + * @read_ec_sensors_data:	function used for accessing sensors values
>> + * @cuur_sampl_freq:		current sampling period
>> + */
>> +struct cros_ec_sensors_core_state {
>> +	struct cros_ec_device *ec;
>> +	struct mutex cmd_lock;
>> +
>> +	struct cros_ec_command *msg;
>> +	struct ec_params_motion_sense param;
>> +	struct ec_response_motion_sense *resp;
>> +
>> +	enum motionsensor_type type;
>> +	enum motionsensor_location loc;
>> +
>> +	s16 calib[CROS_EC_SENSOR_MAX_AXIS];
>> +
>> +	u8 samples[CROS_EC_SAMPLE_SIZE];
>> +
>> +	int (*read_ec_sensors_data)(struct iio_dev *indio_dev,
>> +				    unsigned long scan_mask, s16 *data);
>> +
>> +	int curr_sampl_freq;
>> +};
>> +
>> +/**
>> + * cros_ec_sensors_read_lpc() - retrieve data from EC shared memory
>> + * @indio_dev:	pointer to IIO device
>> + * @scan_mask:	bitmap of the sensor indices to scan
>> + * @data:	location to store data
>> + *
>> + * This is the safe function for reading the EC data. It guarantees that the
>> + * data sampled was not modified by the EC while being read.
>> + *
>> + * Return: 0 on success, -errno on failure.
>> + */
>> +int cros_ec_sensors_read_lpc(struct iio_dev *indio_dev, unsigned long scan_mask,
>> +			     s16 *data);
>> +
>> +/**
>> + * cros_ec_sensors_read_cmd() - retrieve data using the EC command protocol
>> + * @indio_dev:	pointer to IIO device
>> + * @scan_mask:	bitmap of the sensor indices to scan
>> + * @data:	location to store data
>> + *
>> + * Return: 0 on success, -errno on failure.
>> + */
>> +int cros_ec_sensors_read_cmd(struct iio_dev *indio_dev, unsigned long scan_mask,
>> +			     s16 *data);
>> +
>> +/**
>> + * cros_ec_sensors_core_init() - basic initialization of the core structure
>> + * @pdev:		platform device created for the sensors
>> + * @indio_dev:		iio device structure of the device
>> + * @physical_device:	true if the device refers to a physical device
>> + *
>> + * Return: 0 on success, -errno on failure.
>> + */
>> +int cros_ec_sensors_core_init(struct platform_device *pdev,
>> +			      struct iio_dev *indio_dev, bool physical_device);
>> +
>> +/**
>> + * cros_ec_sensors_capture() - the trigger handler function
>> + * @irq:	the interrupt number.
>> + * @p:		a pointer to the poll function.
>> + *
>> + * On a trigger event occurring, if the pollfunc is attached then this
>> + * handler is called as a threaded interrupt (and hence may sleep). It
>> + * is responsible for grabbing data from the device and pushing it into
>> + * the associated buffer.
>> + *
>> + * Return: IRQ_HANDLED
>> + */
>> +irqreturn_t cros_ec_sensors_capture(int irq, void *p);
>> +
>> +/**
>> + * cros_ec_motion_send_host_cmd() - send motion sense host command
>> + * @st:		pointer to state information for device
>> + * @opt_length:	optional length to reduce the response size, useful on the data
>> + *		path. Otherwise, the maximal allowed response size is used
>> + *
>> + * When called, the sub-command is assumed to be set in param->cmd.
>> + *
>> + * Return: 0 on success, -errno on failure.
>> + */
>> +int cros_ec_motion_send_host_cmd(struct cros_ec_sensors_core_state *st,
>> +				 u16 opt_length);
>> +
>> +/**
>> + * cros_ec_sensors_core_read() - function to request a value from the sensor
>> + * @st:		pointer to state information for device
>> + * @chan:	channel specification structure table
>> + * @val:	will contain one element making up the returned value
>> + * @val2:	will contain another element making up the returned value
>> + * @mask:	specifies which values to be requested
>> + *
>> + * Return:	the type of value returned by the device
>> + */
>> +int cros_ec_sensors_core_read(struct cros_ec_sensors_core_state *st,
>> +			      struct iio_chan_spec const *chan,
>> +			      int *val, int *val2, long mask);
>> +
>> +/**
>> + * cros_ec_sensors_core_write() - function to write a value to the sensor
>> + * @st:		pointer to state information for device
>> + * @chan:	channel specification structure table
>> + * @val:	first part of value to write
>> + * @val2:	second part of value to write
>> + * @mask:	specifies which values to write
>> + *
>> + * Return:	the type of value returned by the device
>> + */
>> +int cros_ec_sensors_core_write(struct cros_ec_sensors_core_state *st,
>> +			       struct iio_chan_spec const *chan,
>> +			       int val, int val2, long mask);
>> +
>> +/* List of extended channel specification for all sensors */
>> +extern const struct iio_chan_spec_ext_info cros_ec_sensors_ext_info[];
>> +
>> +#endif  /* __CROS_EC_SENSORS_CORE_H */
>> diff --git a/include/linux/mfd/cros_ec.h b/include/linux/mfd/cros_ec.h
>> index d6539c1..7769ea6 100644
>> --- a/include/linux/mfd/cros_ec.h
>> +++ b/include/linux/mfd/cros_ec.h
>> @@ -151,6 +151,15 @@ struct cros_ec_device {
>>  	int event_size;
>>  };
>>  
>> +/**
>> + * struct cros_ec_sensor_platform - ChromeOS EC sensor platform information
>> + *
>> + * @sensor_num: Id of the sensor, as reported by the EC.
>> + */
>> +struct cros_ec_sensor_platform {
>> +	u8 sensor_num;
>> +};
>> +
>>  /* struct cros_ec_platform - ChromeOS EC platform information
>>   *
>>   * @ec_name: name of EC device (e.g. 'cros-ec', 'cros-pd', ...)
>> diff --git a/include/linux/mfd/cros_ec_commands.h b/include/linux/mfd/cros_ec_commands.h
>> index 76728ff..8826e0f 100644
>> --- a/include/linux/mfd/cros_ec_commands.h
>> +++ b/include/linux/mfd/cros_ec_commands.h
>> @@ -1315,6 +1315,24 @@ enum motionsense_command {
>>  	 */
>>  	MOTIONSENSE_CMD_KB_WAKE_ANGLE = 5,
>>  
>> +	/*
>> +	 * Returns a single sensor data.
>> +	 */
>> +	MOTIONSENSE_CMD_DATA = 6,
>> +
>> +	/*
>> +	 * Perform low level calibration.. On sensors that support it, ask to
>> +	 * do offset calibration.
>> +	 */
>> +	MOTIONSENSE_CMD_PERFORM_CALIB = 10,
>> +
>> +	/*
>> +	 * Sensor Offset command is a setter/getter command for the offset used
>> +	 * for calibration. The offsets can be calculated by the host, or via
>> +	 * PERFORM_CALIB command.
>> +	 */
>> +	MOTIONSENSE_CMD_SENSOR_OFFSET = 11,
>> +
>>  	/* Number of motionsense sub-commands. */
>>  	MOTIONSENSE_NUM_CMDS
>>  };
>> @@ -1335,12 +1353,18 @@ enum motionsensor_id {
>>  enum motionsensor_type {
>>  	MOTIONSENSE_TYPE_ACCEL = 0,
>>  	MOTIONSENSE_TYPE_GYRO = 1,
>> +	MOTIONSENSE_TYPE_MAG = 2,
>> +	MOTIONSENSE_TYPE_PROX = 3,
>> +	MOTIONSENSE_TYPE_LIGHT = 4,
>> +	MOTIONSENSE_TYPE_ACTIVITY = 5,
>> +	MOTIONSENSE_TYPE_MAX
>>  };
>>  
>>  /* List of motion sensor locations. */
>>  enum motionsensor_location {
>>  	MOTIONSENSE_LOC_BASE = 0,
>>  	MOTIONSENSE_LOC_LID = 1,
>> +	MOTIONSENSE_LOC_MAX,
>>  };
>>  
>>  /* List of motion sensor chips. */
>> @@ -1361,6 +1385,31 @@ enum motionsensor_chip {
>>   */
>>  #define EC_MOTION_SENSE_NO_VALUE -1
>>  
>> +#define EC_MOTION_SENSE_INVALID_CALIB_TEMP 0x8000
>> +
>> +/* Set Calibration information */
>> +#define MOTION_SENSE_SET_OFFSET	1
>> +
>> +struct ec_response_motion_sensor_data {
>> +	/* Flags for each sensor. */
>> +	uint8_t flags;
>> +	/* Sensor number the data comes from */
>> +	uint8_t sensor_num;
>> +	/* Each sensor is up to 3-axis. */
>> +	union {
>> +		int16_t             data[3];
>> +		struct {
>> +			uint16_t    rsvd;
>> +			uint32_t    timestamp;
>> +		} __packed;
>> +		struct {
>> +			uint8_t     activity; /* motionsensor_activity */
>> +			uint8_t     state;
>> +			int16_t     add_info[2];
>> +		};
>> +	};
>> +} __packed;
>> +
>>  struct ec_params_motion_sense {
>>  	uint8_t cmd;
>>  	union {
>> @@ -1378,9 +1427,37 @@ struct ec_params_motion_sense {
>>  			int16_t data;
>>  		} ec_rate, kb_wake_angle;
>>  
>> +		/* Used for MOTIONSENSE_CMD_SENSOR_OFFSET */
>> +		struct {
>> +			uint8_t sensor_num;
>> +
>> +			/*
>> +			 * bit 0: If set (MOTION_SENSE_SET_OFFSET), set
>> +			 * the calibration information in the EC.
>> +			 * If unset, just retrieve calibration information.
>> +			 */
>> +			uint16_t flags;
>> +
>> +			/*
>> +			 * Temperature at calibration, in units of 0.01 C
>> +			 * 0x8000: invalid / unknown.
>> +			 * 0x0: 0C
>> +			 * 0x7fff: +327.67C
>> +			 */
>> +			int16_t temp;
>> +
>> +			/*
>> +			 * Offset for calibration.
>> +			 * Unit:
>> +			 * Accelerometer: 1/1024 g
>> +			 * Gyro:          1/1024 deg/s
>> +			 * Compass:       1/16 uT
>> +			 */
>> +			int16_t offset[3];
>> +		} __packed sensor_offset;
>> +
>>  		/* Used for MOTIONSENSE_CMD_INFO. */
>>  		struct {
>> -			/* Should be element of enum motionsensor_id. */
>>  			uint8_t sensor_num;
>>  		} info;
>>  
>> @@ -1410,11 +1487,14 @@ struct ec_response_motion_sense {
>>  			/* Flags representing the motion sensor module. */
>>  			uint8_t module_flags;
>>  
>> -			/* Flags for each sensor in enum motionsensor_id. */
>> -			uint8_t sensor_flags[EC_MOTION_SENSOR_COUNT];
>> +			/* Number of sensors managed directly by the EC. */
>> +			uint8_t sensor_count;
>>  
>> -			/* Array of all sensor data. Each sensor is 3-axis. */
>> -			int16_t data[3*EC_MOTION_SENSOR_COUNT];
>> +			/*
>> +			 * Sensor data is truncated if response_max is too small
>> +			 * for holding all the data.
>> +			 */
>> +			struct ec_response_motion_sensor_data sensor[0];
>>  		} dump;
>>  
>>  		/* Used for MOTIONSENSE_CMD_INFO. */
>> @@ -1429,6 +1509,9 @@ struct ec_response_motion_sense {
>>  			uint8_t chip;
>>  		} info;
>>  
>> +		/* Used for MOTIONSENSE_CMD_DATA */
>> +		struct ec_response_motion_sensor_data data;
>> +
>>  		/*
>>  		 * Used for MOTIONSENSE_CMD_EC_RATE, MOTIONSENSE_CMD_SENSOR_ODR,
>>  		 * MOTIONSENSE_CMD_SENSOR_RANGE, and
>> @@ -1438,6 +1521,12 @@ struct ec_response_motion_sense {
>>  			/* Current value of the parameter queried. */
>>  			int32_t ret;
>>  		} ec_rate, sensor_odr, sensor_range, kb_wake_angle;
>> +
>> +		/* Used for MOTIONSENSE_CMD_SENSOR_OFFSET */
>> +		struct {
>> +			int16_t temp;
>> +			int16_t offset[3];
>> +		} sensor_offset, perform_calib;
>>  	};
>>  } __packed;
>>  
>>
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