iio: cros_ec_light_prox: add ChromeOS EC Light and Proximity Sensors

Handle Light and Proximity sensors presented by the ChromeOS EC Sensor hub.
Creates an IIO device for each functions.
Signed-off-by: Gwendal Grignou <gwendal@chromium.org>
Signed-off-by: Guenter Roeck <groeck@chromium.org>
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/light/Kconfig

@@ -136,6 +136,16 @@ config CM36651
 	 To compile this driver as a module, choose M here:
 	 the module will be called cm36651.
 
+config IIO_CROS_EC_LIGHT_PROX
+	tristate "ChromeOS EC Light and Proximity Sensors"
+	depends on IIO_CROS_EC_SENSORS_CORE
+	help
+	  Say Y here if you use the light and proximity sensors
+	  presented by the ChromeOS EC Sensor hub.
+
+	  To compile this driver as a module, choose M here:
+	  the module will be called cros_ec_light_prox.
+
 config GP2AP020A00F
 	tristate "Sharp GP2AP020A00F Proximity/ALS sensor"
 	depends on I2C

drivers/iio/light/Makefile

@@ -15,6 +15,7 @@ obj-$(CONFIG_CM3232)		+= cm3232.o
 obj-$(CONFIG_CM3323)		+= cm3323.o
 obj-$(CONFIG_CM3605)		+= cm3605.o
 obj-$(CONFIG_CM36651)		+= cm36651.o
+obj-$(CONFIG_IIO_CROS_EC_LIGHT_PROX) += cros_ec_light_prox.o
 obj-$(CONFIG_GP2AP020A00F)	+= gp2ap020a00f.o
 obj-$(CONFIG_HID_SENSOR_ALS)	+= hid-sensor-als.o
 obj-$(CONFIG_HID_SENSOR_PROX)	+= hid-sensor-prox.o

drivers/iio/light/cros_ec_light_prox.c

+/*
+ * cros_ec_light_prox - Driver for light and prox sensors behing CrosEC.
+ *
+ * Copyright (C) 2017 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.h>
+#include <linux/iio/triggered_buffer.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/platform_device.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+
+#include "../common/cros_ec_sensors/cros_ec_sensors_core.h"
+
+/*
+ * We only represent one entry for light or proximity. EC is merging different
+ * light sensors to return the what the eye would see. For proximity, we
+ * currently support only one light source.
+ */
+#define CROS_EC_LIGHT_PROX_MAX_CHANNELS (1 + 1)
+
+/* State data for ec_sensors iio driver. */
+struct cros_ec_light_prox_state {
+	/* Shared by all sensors */
+	struct cros_ec_sensors_core_state core;
+
+	struct iio_chan_spec channels[CROS_EC_LIGHT_PROX_MAX_CHANNELS];
+};
+
+static int cros_ec_light_prox_read(struct iio_dev *indio_dev,
+				   struct iio_chan_spec const *chan,
+				   int *val, int *val2, long mask)
+{
+	struct cros_ec_light_prox_state *st = iio_priv(indio_dev);
+	u16 data = 0;
+	s64 val64;
+	int ret = IIO_VAL_INT;
+	int idx = chan->scan_index;
+
+	mutex_lock(&st->core.cmd_lock);
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (chan->type == IIO_PROXIMITY) {
+			if (cros_ec_sensors_read_cmd(indio_dev, 1 << idx,
+						     (s16 *)&data) < 0) {
+				ret = -EIO;
+				break;
+			}
+			*val = data;
+		} else {
+			ret = -EINVAL;
+		}
+		break;
+	case IIO_CHAN_INFO_PROCESSED:
+		if (chan->type == IIO_LIGHT) {
+			if (cros_ec_sensors_read_cmd(indio_dev, 1 << idx,
+						     (s16 *)&data) < 0) {
+				ret = -EIO;
+				break;
+			}
+			/*
+			 * The data coming from the light sensor is
+			 * pre-processed and represents the ambient light
+			 * illuminance reading expressed in lux.
+			 */
+			*val = data;
+			ret = IIO_VAL_INT;
+		} else {
+			ret = -EINVAL;
+		}
+		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)) {
+			ret = -EIO;
+			break;
+		}
+
+		/* Save values */
+		st->core.calib[0] = st->core.resp->sensor_offset.offset[0];
+
+		*val = st->core.calib[idx];
+		break;
+	case IIO_CHAN_INFO_CALIBSCALE:
+		/*
+		 * RANGE is used for calibration
+		 * scale is a number x.y, where x is coded on 16 bits,
+		 * y coded on 16 bits, between 0 and 9999.
+		 */
+		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)) {
+			ret = -EIO;
+			break;
+		}
+
+		val64 = st->core.resp->sensor_range.ret;
+		*val = val64 >> 16;
+		*val2 = (val64 & 0xffff) * 100;
+		ret = IIO_VAL_INT_PLUS_MICRO;
+		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_light_prox_write(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       int val, int val2, long mask)
+{
+	struct cros_ec_light_prox_state *st = iio_priv(indio_dev);
+	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;
+		st->core.param.sensor_offset.offset[0] = st->core.calib[0];
+		st->core.param.sensor_offset.temp =
+					EC_MOTION_SENSE_INVALID_CALIB_TEMP;
+		if (cros_ec_motion_send_host_cmd(&st->core, 0))
+			ret = -EIO;
+		break;
+	case IIO_CHAN_INFO_CALIBSCALE:
+		st->core.param.cmd = MOTIONSENSE_CMD_SENSOR_RANGE;
+		st->core.param.sensor_range.data = (val << 16) | (val2 / 100);
+		if (cros_ec_motion_send_host_cmd(&st->core, 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 cros_ec_light_prox_info = {
+	.read_raw = &cros_ec_light_prox_read,
+	.write_raw = &cros_ec_light_prox_write,
+	.driver_module = THIS_MODULE,
+};
+
+static int cros_ec_light_prox_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_light_prox_state *state;
+	struct iio_chan_spec *channel;
+	int ret;
+
+	if (!ec_dev || !ec_dev->ec_dev) {
+		dev_warn(dev, "No CROS EC device found.\n");
+		return -EINVAL;
+	}
+	ec_device = ec_dev->ec_dev;
+
+	indio_dev = devm_iio_device_alloc(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 = &cros_ec_light_prox_info;
+	state = iio_priv(indio_dev);
+	state->core.type = state->core.resp->info.type;
+	state->core.loc = state->core.resp->info.location;
+	channel = state->channels;
+
+	/* Common part */
+	channel->info_mask_shared_by_all =
+		BIT(IIO_CHAN_INFO_SAMP_FREQ) |
+		BIT(IIO_CHAN_INFO_FREQUENCY);
+	channel->scan_type.realbits = CROS_EC_SENSOR_BITS;
+	channel->scan_type.storagebits = CROS_EC_SENSOR_BITS;
+	channel->scan_type.shift = 0;
+	channel->scan_index = 0;
+	channel->ext_info = cros_ec_sensors_ext_info;
+	channel->scan_type.sign = 'u';
+
+	state->core.calib[0] = 0;
+
+	/* Sensor specific */
+	switch (state->core.type) {
+	case MOTIONSENSE_TYPE_LIGHT:
+		channel->type = IIO_LIGHT;
+		channel->info_mask_separate =
+			BIT(IIO_CHAN_INFO_PROCESSED) |
+			BIT(IIO_CHAN_INFO_CALIBBIAS) |
+			BIT(IIO_CHAN_INFO_CALIBSCALE);
+		break;
+	case MOTIONSENSE_TYPE_PROX:
+		channel->type = IIO_PROXIMITY;
+		channel->info_mask_separate =
+			BIT(IIO_CHAN_INFO_RAW) |
+			BIT(IIO_CHAN_INFO_CALIBBIAS) |
+			BIT(IIO_CHAN_INFO_CALIBSCALE);
+		break;
+	default:
+		dev_warn(dev, "Unknown motion sensor\n");
+		return -EINVAL;
+	}
+
+	/* Timestamp */
+	channel++;
+	channel->type = IIO_TIMESTAMP;
+	channel->channel = -1;
+	channel->scan_index = 1;
+	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_LIGHT_PROX_MAX_CHANNELS;
+
+	state->core.read_ec_sensors_data = cros_ec_sensors_read_cmd;
+
+	ret = devm_iio_triggered_buffer_setup(dev, indio_dev, NULL,
+					      cros_ec_sensors_capture, NULL);
+	if (ret)
+		return ret;
+
+	return devm_iio_device_register(dev, indio_dev);
+}
+
+static const struct platform_device_id cros_ec_light_prox_ids[] = {
+	{
+		.name = "cros-ec-prox",
+	},
+	{
+		.name = "cros-ec-light",
+	},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(platform, cros_ec_light_prox_ids);
+
+static struct platform_driver cros_ec_light_prox_platform_driver = {
+	.driver = {
+		.name	= "cros-ec-light-prox",
+	},
+	.probe		= cros_ec_light_prox_probe,
+	.id_table	= cros_ec_light_prox_ids,
+};
+module_platform_driver(cros_ec_light_prox_platform_driver);
+
+MODULE_DESCRIPTION("ChromeOS EC light/proximity sensors driver");
+MODULE_LICENSE("GPL v2");