Re: [PATCH v2 2/4] iio: cros_ec_sensors: add ChromeOS EC Contiguous Sensors driver

From: Enric Balletbo Serra
Date: Thu Jul 28 2016 - 08:50:31 EST

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Hi Guenter,

Thanks for the review, some answers below, just preparing next version
that I'll send asap.

2016-07-25 19:25 GMT+02:00 Guenter Roeck <groeck@xxxxxxxxxx>:
> On Wed, Jul 20, 2016 at 2:22 AM, Enric Balletbo i Serra
> <enric.balletbo@xxxxxxxxxxxxx> 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>
>> ---
>>
>> 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 | 327 +++++++++++++++++++++
>> 3 files changed, 336 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..b363321
>> --- /dev/null
>> +++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors.c
>> @@ -0,0 +1,327 @@
>> +/*
>> + * 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/slab.h>
>> +#include <linux/sysfs.h>
>> +#include <linux/platform_device.h>
>> +
>
> Nit: Every include file but the last one is in alphabetic order.
>
>> +#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:
>> + if (st->core.read_ec_sensors_data(indio_dev,
>> + 1 << idx, &data) < 0)
>> + ret = -EIO;
>
> break for consistency ?

Yes

> Also, any reason for not returning the error from the called function
> (here and for
> the return value from cros_ec_motion_send_host_cmd) ?
>

Right, there is no reason, I'll propagate the returned error.

>> + *val = data;
>> + break;
>> + case IIO_CHAN_INFO_CALIBBIAS:
>> + st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_OFFSET;
>> + st->core.param.sensor_offset.flags = 0;
>> +
>> + if (cros_ec_motion_send_host_cmd(&st->core, 0) < 0) {
>> + ret = -EIO;
>> + break;
>> + }
>> +
>> + /* Save values */
>> + for (i = CROS_EC_SENSOR_X; i < CROS_EC_SENSOR_MAX_AXIS; i++)
>> + st->core.calib[i].offset =
>> + st->core.resp->sensor_offset.offset[i];
>> +
>> + *val = st->core.calib[idx].offset;
>> + 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;
>> +
>> + if (cros_ec_motion_send_host_cmd(&st->core, 0) < 0) {
>> + ret = -EIO;
>> + 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 date 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 date 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].offset = 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].offset;
>> + st->core.param.sensor_offset.temp =
>> + EC_MOTION_SENSE_INVALID_CALIB_TEMP;
>> +
>> + if (cros_ec_motion_send_host_cmd(&st->core, 0) < 0)
>> + ret = -EIO;
>> + 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;
>> +
>> + if (cros_ec_motion_send_host_cmd(&st->core, 0) < 0)
>> + ret = -EIO;
>> + 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_type.shift = 0;
>> + 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';
>> +
>> + state->core.calib[i].offset = 0;
>> +
>> + /* 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_warn(&pdev->dev, "unknown\n");
>
> This nevertheless results in increasing the channel pointer.
> Is this on purpose (resulting in type == 0) ?
>

No, I'd fail if we found a sensor that is not handled by the driver.

> Also, the error message seems to be pretty useless. Unknown what ?
>

Modified to be more clear in next version.

>> + }
>> + }
>> +
>> + /* 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 = 4;
>> +
>
> CROS_EC_SENSORS_MAX_CHANNELS, or the number of identified 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");
>> --
>> 2.1.0
>>

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Previous message: Josh Poimboeuf: "Re: warning: calling â__builtin_return_addressâ with a nonzero argument is unsafe"
In reply to: Guenter Roeck: "Re: [PATCH v2 2/4] iio: cros_ec_sensors: add ChromeOS EC Contiguous Sensors driver"
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