iio: hid-sensors: Added device rotation support

Added usage id processing for device rotation. This uses IIO
interfaces for triggered buffer to present data to user
mode.This uses HID sensor framework for registering callback
events from the sensor hub.
Data is exported to user space in the form of quaternion rotation
format.

Signed-off-by: Srinivas Pandruvada <[e-mail]>
Signed-off-by: Jonathan Cameron <[e-mail]>

drivers/iio/orientation/Kconfig

···
 	  Say yes here to build support for the HID SENSOR
 	  Inclinometer 3D.
 
+config HID_SENSOR_DEVICE_ROTATION
+	depends on HID_SENSOR_HUB
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	select HID_SENSOR_IIO_COMMON
+	select HID_SENSOR_IIO_TRIGGER
+	tristate "HID Device Rotation"
+	help
+	  Say yes here to build support for the HID SENSOR
+	  device rotation. The output of a device rotation sensor
+	  is presented using quaternion format.
+
 endmenu

drivers/iio/orientation/Makefile

···
 
 # When adding new entries keep the list in alphabetical order
 obj-$(CONFIG_HID_SENSOR_INCLINOMETER_3D) += hid-sensor-incl-3d.o
+obj-$(CONFIG_HID_SENSOR_DEVICE_ROTATION) += hid-sensor-rotation.o

drivers/iio/orientation/hid-sensor-rotation.c

···
+/*
+ * HID Sensors Driver
+ * Copyright (c) 2014, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope 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/device.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/slab.h>
+#include <linux/hid-sensor-hub.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/trigger_consumer.h>
+#include <linux/iio/triggered_buffer.h>
+#include "../common/hid-sensors/hid-sensor-trigger.h"
+
+struct dev_rot_state {
+	struct hid_sensor_hub_callbacks callbacks;
+	struct hid_sensor_common common_attributes;
+	struct hid_sensor_hub_attribute_info quaternion;
+	u32 sampled_vals[4];
+};
+
+/* Channel definitions */
+static const struct iio_chan_spec dev_rot_channels[] = {
+	{
+		.type = IIO_ROT,
+		.modified = 1,
+		.channel2 = IIO_MOD_QUATERNION,
+		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+		.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ) |
+					BIT(IIO_CHAN_INFO_HYSTERESIS)
+	}
+};
+
+/* Adjust channel real bits based on report descriptor */
+static void dev_rot_adjust_channel_bit_mask(struct iio_chan_spec *chan,
+						int size)
+{
+	chan->scan_type.sign = 's';
+	/* Real storage bits will change based on the report desc. */
+	chan->scan_type.realbits = size * 8;
+	/* Maximum size of a sample to capture is u32 */
+	chan->scan_type.storagebits = sizeof(u32) * 8;
+	chan->scan_type.repeat = 4;
+}
+
+/* Channel read_raw handler */
+static int dev_rot_read_raw(struct iio_dev *indio_dev,
+				struct iio_chan_spec const *chan,
+				int size, int *vals, int *val_len,
+				long mask)
+{
+	struct dev_rot_state *rot_state = iio_priv(indio_dev);
+	int ret_type;
+	int i;
+
+	vals[0] = 0;
+	vals[1] = 0;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		if (size >= 4) {
+			for (i = 0; i < 4; ++i)
+				vals[i] = rot_state->sampled_vals[i];
+			ret_type = IIO_VAL_INT_MULTIPLE;
+			*val_len =  4;
+		} else
+			ret_type = -EINVAL;
+		break;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		ret_type = hid_sensor_read_samp_freq_value(
+			&rot_state->common_attributes, &vals[0], &vals[1]);
+		break;
+	case IIO_CHAN_INFO_HYSTERESIS:
+		ret_type = hid_sensor_read_raw_hyst_value(
+			&rot_state->common_attributes, &vals[0], &vals[1]);
+		break;
+	default:
+		ret_type = -EINVAL;
+		break;
+	}
+
+	return ret_type;
+}
+
+/* Channel write_raw handler */
+static int dev_rot_write_raw(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       int val,
+			       int val2,
+			       long mask)
+{
+	struct dev_rot_state *rot_state = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		ret = hid_sensor_write_samp_freq_value(
+				&rot_state->common_attributes, val, val2);
+		break;
+	case IIO_CHAN_INFO_HYSTERESIS:
+		ret = hid_sensor_write_raw_hyst_value(
+				&rot_state->common_attributes, val, val2);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+static const struct iio_info dev_rot_info = {
+	.driver_module = THIS_MODULE,
+	.read_raw_multi = &dev_rot_read_raw,
+	.write_raw = &dev_rot_write_raw,
+};
+
+/* Function to push data to buffer */
+static void hid_sensor_push_data(struct iio_dev *indio_dev, u8 *data, int len)
+{
+	dev_dbg(&indio_dev->dev, "hid_sensor_push_data >>\n");
+	iio_push_to_buffers(indio_dev, (u8 *)data);
+	dev_dbg(&indio_dev->dev, "hid_sensor_push_data <<\n");
+
+}
+
+/* Callback handler to send event after all samples are received and captured */
+static int dev_rot_proc_event(struct hid_sensor_hub_device *hsdev,
+				unsigned usage_id,
+				void *priv)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(priv);
+	struct dev_rot_state *rot_state = iio_priv(indio_dev);
+
+	dev_dbg(&indio_dev->dev, "dev_rot_proc_event [%d]\n",
+				rot_state->common_attributes.data_ready);
+
+	if (rot_state->common_attributes.data_ready)
+		hid_sensor_push_data(indio_dev,
+				(u8 *)rot_state->sampled_vals,
+				sizeof(rot_state->sampled_vals));
+
+	return 0;
+}
+
+/* Capture samples in local storage */
+static int dev_rot_capture_sample(struct hid_sensor_hub_device *hsdev,
+				unsigned usage_id,
+				size_t raw_len, char *raw_data,
+				void *priv)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(priv);
+	struct dev_rot_state *rot_state = iio_priv(indio_dev);
+
+	if (usage_id == HID_USAGE_SENSOR_ORIENT_QUATERNION) {
+		memcpy(rot_state->sampled_vals, raw_data,
+					sizeof(rot_state->sampled_vals));
+		dev_dbg(&indio_dev->dev, "Recd Quat len:%zu::%zu\n", raw_len,
+					sizeof(rot_state->sampled_vals));
+	}
+
+	return 0;
+}
+
+/* Parse report which is specific to an usage id*/
+static int dev_rot_parse_report(struct platform_device *pdev,
+				struct hid_sensor_hub_device *hsdev,
+				struct iio_chan_spec *channels,
+				unsigned usage_id,
+				struct dev_rot_state *st)
+{
+	int ret;
+
+	ret = sensor_hub_input_get_attribute_info(hsdev,
+				HID_INPUT_REPORT,
+				usage_id,
+				HID_USAGE_SENSOR_ORIENT_QUATERNION,
+				&st->quaternion);
+	if (ret)
+		return ret;
+
+	dev_rot_adjust_channel_bit_mask(&channels[0],
+		st->quaternion.size / 4);
+
+	dev_dbg(&pdev->dev, "dev_rot %x:%x\n", st->quaternion.index,
+		st->quaternion.report_id);
+
+	dev_dbg(&pdev->dev, "dev_rot: attrib size %d\n",
+				st->quaternion.size);
+
+	/* Set Sensitivity field ids, when there is no individual modifier */
+	if (st->common_attributes.sensitivity.index < 0) {
+		sensor_hub_input_get_attribute_info(hsdev,
+			HID_FEATURE_REPORT, usage_id,
+			HID_USAGE_SENSOR_DATA_MOD_CHANGE_SENSITIVITY_ABS |
+			HID_USAGE_SENSOR_DATA_ORIENTATION,
+			&st->common_attributes.sensitivity);
+		dev_dbg(&pdev->dev, "Sensitivity index:report %d:%d\n",
+			st->common_attributes.sensitivity.index,
+			st->common_attributes.sensitivity.report_id);
+	}
+
+	return 0;
+}
+
+/* Function to initialize the processing for usage id */
+static int hid_dev_rot_probe(struct platform_device *pdev)
+{
+	int ret;
+	static char *name = "dev_rotation";
+	struct iio_dev *indio_dev;
+	struct dev_rot_state *rot_state;
+	struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
+	struct iio_chan_spec *channels;
+
+	indio_dev = devm_iio_device_alloc(&pdev->dev,
+					  sizeof(struct dev_rot_state));
+	if (indio_dev == NULL)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, indio_dev);
+
+	rot_state = iio_priv(indio_dev);
+	rot_state->common_attributes.hsdev = hsdev;
+	rot_state->common_attributes.pdev = pdev;
+
+	ret = hid_sensor_parse_common_attributes(hsdev,
+				HID_USAGE_SENSOR_DEVICE_ORIENTATION,
+				&rot_state->common_attributes);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to setup common attributes\n");
+		return ret;
+	}
+
+	channels = devm_kmemdup(&pdev->dev, dev_rot_channels,
+					sizeof(dev_rot_channels), GFP_KERNEL);
+	if (!channels) {
+		dev_err(&pdev->dev, "failed to duplicate channels\n");
+		return -ENOMEM;
+	}
+
+	ret = dev_rot_parse_report(pdev, hsdev, channels,
+			HID_USAGE_SENSOR_DEVICE_ORIENTATION, rot_state);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to setup attributes\n");
+		return ret;
+	}
+
+	indio_dev->channels = channels;
+	indio_dev->num_channels = ARRAY_SIZE(dev_rot_channels);
+	indio_dev->dev.parent = &pdev->dev;
+	indio_dev->info = &dev_rot_info;
+	indio_dev->name = name;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = iio_triggered_buffer_setup(indio_dev, &iio_pollfunc_store_time,
+		NULL, NULL);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to initialize trigger buffer\n");
+		return ret;
+	}
+	rot_state->common_attributes.data_ready = false;
+	ret = hid_sensor_setup_trigger(indio_dev, name,
+					&rot_state->common_attributes);
+	if (ret) {
+		dev_err(&pdev->dev, "trigger setup failed\n");
+		goto error_unreg_buffer_funcs;
+	}
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "device register failed\n");
+		goto error_remove_trigger;
+	}
+
+	rot_state->callbacks.send_event = dev_rot_proc_event;
+	rot_state->callbacks.capture_sample = dev_rot_capture_sample;
+	rot_state->callbacks.pdev = pdev;
+	ret = sensor_hub_register_callback(hsdev,
+					HID_USAGE_SENSOR_DEVICE_ORIENTATION,
+					&rot_state->callbacks);
+	if (ret) {
+		dev_err(&pdev->dev, "callback reg failed\n");
+		goto error_iio_unreg;
+	}
+
+	return 0;
+
+error_iio_unreg:
+	iio_device_unregister(indio_dev);
+error_remove_trigger:
+	hid_sensor_remove_trigger(&rot_state->common_attributes);
+error_unreg_buffer_funcs:
+	iio_triggered_buffer_cleanup(indio_dev);
+	return ret;
+}
+
+/* Function to deinitialize the processing for usage id */
+static int hid_dev_rot_remove(struct platform_device *pdev)
+{
+	struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
+	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+	struct dev_rot_state *rot_state = iio_priv(indio_dev);
+
+	sensor_hub_remove_callback(hsdev, HID_USAGE_SENSOR_DEVICE_ORIENTATION);
+	iio_device_unregister(indio_dev);
+	hid_sensor_remove_trigger(&rot_state->common_attributes);
+	iio_triggered_buffer_cleanup(indio_dev);
+
+	return 0;
+}
+
+static struct platform_device_id hid_dev_rot_ids[] = {
+	{
+		/* Format: HID-SENSOR-usage_id_in_hex_lowercase */
+		.name = "HID-SENSOR-20008a",
+	},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(platform, hid_dev_rot_ids);
+
+static struct platform_driver hid_dev_rot_platform_driver = {
+	.id_table = hid_dev_rot_ids,
+	.driver = {
+		.name	= KBUILD_MODNAME,
+		.owner	= THIS_MODULE,
+	},
+	.probe		= hid_dev_rot_probe,
+	.remove		= hid_dev_rot_remove,
+};
+module_platform_driver(hid_dev_rot_platform_driver);
+
+MODULE_DESCRIPTION("HID Sensor Device Rotation");
+MODULE_AUTHOR("Srinivas Pandruvada <[e-mail]>");
+MODULE_LICENSE("GPL");

include/linux/hid-sensor-ids.h

···
 #define HID_USAGE_SENSOR_ORIENT_TILT_Y				0x200480
 #define HID_USAGE_SENSOR_ORIENT_TILT_Z				0x200481
 
+#define HID_USAGE_SENSOR_DEVICE_ORIENTATION			0x20008A
 #define HID_USAGE_SENSOR_ORIENT_ROTATION_MATRIX			0x200482
 #define HID_USAGE_SENSOR_ORIENT_QUATERNION			0x200483
 #define HID_USAGE_SENSOR_ORIENT_MAGN_FLUX			0x200484