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

From: Jonathan Cameron
Date: Mon Aug 15 2016 - 11:28:55 EST

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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.

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");
>

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