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

Enric Balletbo i Serra
2016-08-01T09:55:13Z

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>
---

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");
--
2.1.0