[PATCH 3/3] iio: cros_ec_activity: add ChromeOS EC Activity Sensors

[Thierry Escande]

From: Gwendal Grignou <gwendal@xxxxxxxxxxxx>

This patch adds a driver for handling activity/gesture recognition
coming from the EC. Only significant motion is currently supported. It
is an incomplete driver: activity can be set, but ring buffer must be
used to receive interruption.

Signed-off-by: Gwendal Grignou <gwendal@xxxxxxxxxxxx>
Signed-off-by: Thierry Escande <thierry.escande@xxxxxxxxxxxxx>
---
 drivers/iio/common/cros_ec_sensors/Kconfig         |  10 +
 drivers/iio/common/cros_ec_sensors/Makefile        |   1 +
 .../iio/common/cros_ec_sensors/cros_ec_activity.c  | 300 +++++++++++++++++++++
 .../common/cros_ec_sensors/cros_ec_sensors_core.c  |  24 ++
 .../common/cros_ec_sensors/cros_ec_sensors_core.h  |   1 +
 5 files changed, 336 insertions(+)
 create mode 100644 drivers/iio/common/cros_ec_sensors/cros_ec_activity.c

diff --git a/drivers/iio/common/cros_ec_sensors/Kconfig b/drivers/iio/common/cros_ec_sensors/Kconfig
index 3349c9d..0a64928 100644
--- a/drivers/iio/common/cros_ec_sensors/Kconfig
+++ b/drivers/iio/common/cros_ec_sensors/Kconfig
@@ -21,3 +21,13 @@ config IIO_CROS_EC_SENSORS
 	  Accelerometers, Gyroscope and Magnetometer that are
 	  presented by the ChromeOS EC Sensor hub.
 	  Creates an IIO device for each functions.
+
+config IIO_CROS_EC_ACTIVITY
+	tristate "ChromeOS EC Activity Sensors"
+	select IIO_CROS_EC_SENSORS_CORE
+	help
+	  Module to handle activity events detections presented by the ChromeOS
+	  EC Sensor hub.
+	  Activities can be simple (low/no motion) or more complex (riding train).
+	  They are being reported by physical devices or the EC itself.
+	  Creates an IIO device to manage all activities.
diff --git a/drivers/iio/common/cros_ec_sensors/Makefile b/drivers/iio/common/cros_ec_sensors/Makefile
index ec716ff..a4a2d6c 100644
--- a/drivers/iio/common/cros_ec_sensors/Makefile
+++ b/drivers/iio/common/cros_ec_sensors/Makefile
@@ -4,3 +4,4 @@
 
 obj-$(CONFIG_IIO_CROS_EC_SENSORS_CORE) += cros_ec_sensors_core.o
 obj-$(CONFIG_IIO_CROS_EC_SENSORS) += cros_ec_sensors.o
+obj-$(CONFIG_IIO_CROS_EC_ACTIVITY) += cros_ec_activity.o
diff --git a/drivers/iio/common/cros_ec_sensors/cros_ec_activity.c b/drivers/iio/common/cros_ec_sensors/cros_ec_activity.c
new file mode 100644
index 0000000..f14c3d3
--- /dev/null
+++ b/drivers/iio/common/cros_ec_sensors/cros_ec_activity.c
@@ -0,0 +1,300 @@
+/*
+ * cros_ec_sensors_activity - Driver for activities/gesture recognition.
+ *
+ * Copyright (C) 2015 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 accelerometer data. Accelerometer access is presented through
+ * iio sysfs.
+ */
+
+#include <linux/delay.h>
+#include <linux/device.h>
+#include <linux/iio/iio.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/platform_device.h>
+
+#include "cros_ec_sensors_core.h"
+
+#define DRV_NAME "cros-ec-activity"
+
+/* st 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;
+	unsigned int nb_activities;
+};
+
+static const struct iio_event_spec cros_ec_activity_single_shot[] = {
+	{
+		.type = IIO_EV_TYPE_CHANGE,
+		/* significant motion trigger when we get out of still. */
+		.dir = IIO_EV_DIR_FALLING,
+		.mask_separate = BIT(IIO_EV_INFO_ENABLE),
+	 },
+};
+
+static int ec_sensors_read(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val, int *val2, long mask)
+{
+	dev_warn(&indio_dev->dev, "%s: Not Expected: %d\n", __func__,
+		 chan->channel2);
+
+	return -EPERM;
+}
+
+static int ec_sensors_write(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan,
+			    int val, int val2, long mask)
+{
+	dev_warn(&indio_dev->dev, "%s: Not Expected: %d\n", __func__,
+		 chan->channel2);
+
+	return -EPERM;
+}
+
+static int cros_ec_read_event_config(struct iio_dev *indio_dev,
+				     const struct iio_chan_spec *chan,
+				     enum iio_event_type type,
+				     enum iio_event_direction dir)
+{
+	struct cros_ec_sensors_state *st = iio_priv(indio_dev);
+	int ret;
+
+	if (chan->type != IIO_ACTIVITY)
+		return -EINVAL;
+
+	mutex_lock(&st->core.cmd_lock);
+
+	st->core.param.cmd = MOTIONSENSE_CMD_LIST_ACTIVITIES;
+
+	if (cros_ec_motion_send_host_cmd(&st->core, 0) != EC_RES_SUCCESS) {
+		ret = -EIO;
+		goto exit;
+	}
+
+	switch (chan->channel2) {
+	case IIO_MOD_STILL:
+		ret = !!(st->core.resp->list_activities.enabled &
+			 (1 << MOTIONSENSE_ACTIVITY_SIG_MOTION));
+		break;
+	case IIO_MOD_DOUBLE_TAP:
+		ret = !!(st->core.resp->list_activities.enabled &
+			 (1 << MOTIONSENSE_ACTIVITY_DOUBLE_TAP));
+		break;
+	default:
+		dev_warn(&indio_dev->dev, "Unknown activity: %d\n",
+			 chan->channel2);
+		ret = -EINVAL;
+	}
+
+exit:
+	mutex_unlock(&st->core.cmd_lock);
+
+	return ret;
+}
+
+static int cros_ec_write_event_config(struct iio_dev *indio_dev,
+				      const struct iio_chan_spec *chan,
+				      enum iio_event_type type,
+				      enum iio_event_direction dir, int state)
+{
+	struct cros_ec_sensors_state *st = iio_priv(indio_dev);
+	int ret;
+
+	if (chan->type != IIO_ACTIVITY)
+		return -EINVAL;
+
+	mutex_lock(&st->core.cmd_lock);
+	st->core.param.cmd = MOTIONSENSE_CMD_SET_ACTIVITY;
+
+	switch (chan->channel2) {
+	case IIO_MOD_STILL:
+		st->core.param.set_activity.activity =
+			MOTIONSENSE_ACTIVITY_SIG_MOTION;
+		break;
+	case IIO_MOD_DOUBLE_TAP:
+		st->core.param.set_activity.activity =
+			MOTIONSENSE_ACTIVITY_DOUBLE_TAP;
+		break;
+	default:
+		dev_warn(&indio_dev->dev, "Unknown activity: %d\n",
+			 chan->channel2);
+	}
+
+	st->core.param.set_activity.enable = state;
+
+	ret = cros_ec_motion_send_host_cmd(&st->core, 0);
+
+	mutex_unlock(&st->core.cmd_lock);
+
+	return ret;
+}
+
+/* Not implemented */
+static int cros_ec_read_event_value(struct iio_dev *indio_dev,
+				    const struct iio_chan_spec *chan,
+				    enum iio_event_type type,
+				    enum iio_event_direction dir,
+				    enum iio_event_info info,
+				    int *val, int *val2)
+{
+	dev_warn(&indio_dev->dev, "%s: Not Expected: %d\n", __func__,
+		 chan->channel2);
+
+	return -EPERM;
+}
+
+static int cros_ec_write_event_value(struct iio_dev *indio_dev,
+				     const struct iio_chan_spec *chan,
+				     enum iio_event_type type,
+				     enum iio_event_direction dir,
+				     enum iio_event_info info,
+				     int val, int val2)
+{
+	dev_warn(&indio_dev->dev, "%s: Not Expected: %d\n", __func__,
+		 chan->channel2);
+
+	return -EPERM;
+}
+
+static const struct iio_info ec_sensors_info = {
+	.read_raw = &ec_sensors_read,
+	.write_raw = &ec_sensors_write,
+	.read_event_config = cros_ec_read_event_config,
+	.write_event_config = cros_ec_write_event_config,
+	.read_event_value = cros_ec_read_event_value,
+	.write_event_value = cros_ec_write_event_value,
+};
+
+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 *st;
+	struct iio_chan_spec *channel;
+	unsigned long activities;
+	int i, index, ret, nb_activities;
+
+	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(*st));
+	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;
+	st = iio_priv(indio_dev);
+	st->core.type = st->core.resp->info.type;
+	st->core.loc = st->core.resp->info.location;
+
+	/* List all available activities */
+	st->core.param.cmd = MOTIONSENSE_CMD_LIST_ACTIVITIES;
+	ret = cros_ec_motion_send_host_cmd(&st->core, 0);
+	if (ret)
+		return ret;
+
+	activities = st->core.resp->list_activities.enabled |
+		     st->core.resp->list_activities.disabled;
+	nb_activities = hweight_long(activities) + 1;
+
+	if (!activities)
+		return -ENODEV;
+
+	/* Allocate a channel per activity and one for timestamp */
+	st->channels = devm_kcalloc(&pdev->dev, nb_activities,
+				    sizeof(*st->channels), GFP_KERNEL);
+	if (!st->channels)
+		return -ENOMEM;
+
+	channel = &st->channels[0];
+	index = 0;
+	for_each_set_bit(i, &activities, BITS_PER_LONG) {
+		channel->scan_index = index;
+
+		/* List all available activities */
+		channel->type = IIO_ACTIVITY;
+		channel->modified = 1;
+		channel->event_spec = cros_ec_activity_single_shot;
+		channel->num_event_specs =
+				ARRAY_SIZE(cros_ec_activity_single_shot);
+		switch (i) {
+		case MOTIONSENSE_ACTIVITY_SIG_MOTION:
+			channel->channel2 = IIO_MOD_STILL;
+			break;
+		case MOTIONSENSE_ACTIVITY_DOUBLE_TAP:
+			channel->channel2 = IIO_MOD_DOUBLE_TAP;
+			break;
+		default:
+			dev_warn(&pdev->dev, "Unknown activity: %d\n", i);
+			continue;
+		}
+		channel->ext_info = cros_ec_sensors_limited_info;
+		channel++;
+		index++;
+	}
+
+	/* Timestamp */
+	channel->scan_index = index;
+	channel->type = IIO_TIMESTAMP;
+	channel->channel = -1;
+	channel->scan_type.sign = 's';
+	channel->scan_type.realbits = 64;
+	channel->scan_type.storagebits = 64;
+
+	indio_dev->channels = st->channels;
+	indio_dev->num_channels = index + 1;
+
+	st->core.read_ec_sensors_data = cros_ec_sensors_read_cmd;
+
+	/* Driver is incomplete: by itself, no way to get event directly */
+	return iio_device_register(indio_dev);
+}
+
+static int cros_ec_sensors_remove(struct platform_device *pdev)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+
+	iio_device_unregister(indio_dev);
+
+	return 0;
+}
+
+static struct platform_driver cros_ec_sensors_platform_driver = {
+	.driver = {
+		.name	= DRV_NAME,
+	},
+	.probe		= cros_ec_sensors_probe,
+	.remove		= cros_ec_sensors_remove,
+};
+module_platform_driver(cros_ec_sensors_platform_driver);
+
+MODULE_DESCRIPTION("ChromeOS EC activity sensors driver");
+MODULE_ALIAS("platform:" DRV_NAME);
+MODULE_LICENSE("GPL v2");
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
index a3be799..6010718 100644
--- a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
+++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.c
@@ -135,6 +135,15 @@ static ssize_t cros_ec_sensors_calibrate(struct iio_dev *indio_dev,
 	return ret ? ret : len;
 }
 
+static ssize_t cros_ec_sensors_id(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, "%d\n", st->param.info.sensor_num);
+}
+
 static ssize_t cros_ec_sensors_loc(struct iio_dev *indio_dev,
 		uintptr_t private, const struct iio_chan_spec *chan,
 		char *buf)
@@ -159,6 +168,21 @@ const struct iio_chan_spec_ext_info cros_ec_sensors_ext_info[] = {
 };
 EXPORT_SYMBOL_GPL(cros_ec_sensors_ext_info);
 
+const struct iio_chan_spec_ext_info cros_ec_sensors_limited_info[] = {
+	{
+		.name = "id",
+		.shared = IIO_SHARED_BY_ALL,
+		.read = cros_ec_sensors_id
+	},
+	{
+		.name = "location",
+		.shared = IIO_SHARED_BY_ALL,
+		.read = cros_ec_sensors_loc
+	},
+	{ },
+};
+EXPORT_SYMBOL_GPL(cros_ec_sensors_limited_info);
+
 /**
  * cros_ec_sensors_idx_to_reg - convert index into offset in shared memory
  * @st:		pointer to state information for device
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
index 8bc2ca3..b785f2b 100644
--- a/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.h
+++ b/drivers/iio/common/cros_ec_sensors/cros_ec_sensors_core.h
@@ -171,5 +171,6 @@ int cros_ec_sensors_core_write(struct cros_ec_sensors_core_state *st,
 
 /* List of extended channel specification for all sensors */
 extern const struct iio_chan_spec_ext_info cros_ec_sensors_ext_info[];
+extern const struct iio_chan_spec_ext_info cros_ec_sensors_limited_info[];
 
 #endif  /* __CROS_EC_SENSORS_CORE_H */
-- 
2.7.4