[PATCH v3 2/3] iio: hid-sensors: Add hinge sensor driver

[Ye Xiang]

The Hinge sensor is a common custom sensor on laptops. It calculates
the angle between the lid (screen) and the base (keyboard). In addition,
it also exposes screen and the keyboard angles with respect to the
ground. Applications can easily get laptop's status in space through
this sensor, in order to display appropriate user interface.

Signed-off-by: Ye Xiang <xiang.ye@xxxxxxxxx>
---
 .../hid-sensors/hid-sensor-attributes.c       |   2 +
 drivers/iio/position/Kconfig                  |  16 +
 drivers/iio/position/Makefile                 |   1 +
 .../position/hid-sensor-custom-intel-hinge.c  | 393 ++++++++++++++++++
 4 files changed, 412 insertions(+)
 create mode 100644 drivers/iio/position/hid-sensor-custom-intel-hinge.c

diff --git a/drivers/iio/common/hid-sensors/hid-sensor-attributes.c b/drivers/iio/common/hid-sensors/hid-sensor-attributes.c
index 442ff787f7af..5b822a4298a0 100644
--- a/drivers/iio/common/hid-sensors/hid-sensor-attributes.c
+++ b/drivers/iio/common/hid-sensors/hid-sensor-attributes.c
@@ -71,6 +71,8 @@ static struct {
 	{HID_USAGE_SENSOR_TEMPERATURE, HID_USAGE_SENSOR_UNITS_DEGREES, 1000, 0},
 
 	{HID_USAGE_SENSOR_HUMIDITY, 0, 1000, 0},
+	{HID_USAGE_SENSOR_HINGE, 0, 0, 17453293},
+	{HID_USAGE_SENSOR_HINGE, HID_USAGE_SENSOR_UNITS_DEGREES, 0, 17453293},
 };
 
 static void simple_div(int dividend, int divisor, int *whole,
diff --git a/drivers/iio/position/Kconfig b/drivers/iio/position/Kconfig
index eda67f008c5b..1576a6380b53 100644
--- a/drivers/iio/position/Kconfig
+++ b/drivers/iio/position/Kconfig
@@ -16,4 +16,20 @@ config IQS624_POS
 	  To compile this driver as a module, choose M here: the module
 	  will be called iqs624-pos.
 
+config HID_SENSOR_CUSTOM_INTEL_HINGE
+	depends on HID_SENSOR_HUB
+	select IIO_BUFFER
+	select IIO_TRIGGERED_BUFFER
+	select HID_SENSOR_IIO_COMMON
+	select HID_SENSOR_IIO_TRIGGER
+	tristate "HID Hinge"
+	help
+	  This sensor present three angles, hinge angel, screen angles
+	  and keyboard angle respect to horizon (ground).
+	  Say yes here to build support for the HID custom
+	  intel hinge sensor.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called hid-sensor-custom-hinge.
+
 endmenu
diff --git a/drivers/iio/position/Makefile b/drivers/iio/position/Makefile
index 3cbe7a734352..d70902f2979d 100644
--- a/drivers/iio/position/Makefile
+++ b/drivers/iio/position/Makefile
@@ -4,4 +4,5 @@
 
 # When adding new entries keep the list in alphabetical order
 
+obj-$(CONFIG_HID_SENSOR_CUSTOM_INTEL_HINGE) += hid-sensor-custom-intel-hinge.o
 obj-$(CONFIG_IQS624_POS)	+= iqs624-pos.o
diff --git a/drivers/iio/position/hid-sensor-custom-intel-hinge.c b/drivers/iio/position/hid-sensor-custom-intel-hinge.c
new file mode 100644
index 000000000000..7145e96ef6e0
--- /dev/null
+++ b/drivers/iio/position/hid-sensor-custom-intel-hinge.c
@@ -0,0 +1,393 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * HID Sensors Driver
+ * Copyright (c) 2020, Intel Corporation.
+ */
+#include <linux/hid-sensor-hub.h>
+#include <linux/iio/buffer.h>
+#include <linux/iio/iio.h>
+#include <linux/platform_device.h>
+
+#include "../common/hid-sensors/hid-sensor-trigger.h"
+
+enum hinge_channel {
+	CHANNEL_SCAN_INDEX_HINGE_ANGLE,
+	CHANNEL_SCAN_INDEX_SCREEN_ANGLE,
+	CHANNEL_SCAN_INDEX_KEYBOARD_ANGLE,
+	CHANNEL_SCAN_INDEX_MAX,
+};
+
+#define CHANNEL_SCAN_INDEX_TIMESTAMP CHANNEL_SCAN_INDEX_MAX
+
+static const u32 hinge_addresses[CHANNEL_SCAN_INDEX_MAX] = {
+	HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE(1),
+	HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE(2),
+	HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE(3)
+};
+
+struct hinge_state {
+	struct iio_dev *indio_dev;
+	struct hid_sensor_hub_attribute_info hinge[CHANNEL_SCAN_INDEX_MAX];
+	struct hid_sensor_hub_callbacks callbacks;
+	struct hid_sensor_common common_attributes;
+	const char *labels[CHANNEL_SCAN_INDEX_MAX];
+	struct {
+		u32 hinge_val[3];
+		u64 timestamp __aligned(8);
+	} scan;
+
+	int scale_pre_decml;
+	int scale_post_decml;
+	int scale_precision;
+	int value_offset;
+	u64 timestamp;
+};
+
+/* Channel definitions */
+static const struct iio_chan_spec hinge_channels[] = {
+	{ .type = IIO_ANGL,
+	  .indexed = 1,
+	  .channel = 0,
+	  .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+	  .info_mask_shared_by_type =
+		  BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_SCALE) |
+		  BIT(IIO_CHAN_INFO_SAMP_FREQ) | BIT(IIO_CHAN_INFO_HYSTERESIS),
+
+	  .scan_index = CHANNEL_SCAN_INDEX_HINGE_ANGLE },
+	{ .type = IIO_ANGL,
+	  .indexed = 1,
+	  .channel = 1,
+	  .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+	  .info_mask_shared_by_type =
+		  BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_SCALE) |
+		  BIT(IIO_CHAN_INFO_SAMP_FREQ) | BIT(IIO_CHAN_INFO_HYSTERESIS),
+	  .scan_index = CHANNEL_SCAN_INDEX_SCREEN_ANGLE },
+	{ .type = IIO_ANGL,
+	  .indexed = 1,
+	  .channel = 2,
+	  .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
+	  .info_mask_shared_by_type =
+		  BIT(IIO_CHAN_INFO_OFFSET) | BIT(IIO_CHAN_INFO_SCALE) |
+		  BIT(IIO_CHAN_INFO_SAMP_FREQ) | BIT(IIO_CHAN_INFO_HYSTERESIS),
+	  .scan_index = CHANNEL_SCAN_INDEX_KEYBOARD_ANGLE },
+
+	IIO_CHAN_SOFT_TIMESTAMP(CHANNEL_SCAN_INDEX_TIMESTAMP)
+};
+
+/* Adjust channel real bits based on report descriptor */
+static void hinge_adjust_channel_bit_mask(struct iio_chan_spec *channels,
+					  int channel, int size)
+{
+	channels[channel].scan_type.sign = 's';
+	/* Real storage bits will change based on the report desc. */
+	channels[channel].scan_type.realbits = size * 8;
+	/* Maximum size of a sample to capture is u32 */
+	channels[channel].scan_type.storagebits = sizeof(u32) * 8;
+}
+
+/* Channel read_raw handler */
+static int hinge_read_raw(struct iio_dev *indio_dev,
+			  struct iio_chan_spec const *chan, int *val, int *val2,
+			  long mask)
+{
+	struct hinge_state *st = iio_priv(indio_dev);
+	struct hid_sensor_hub_device *hsdev;
+	int report_id = -1;
+	int ret_type;
+	s32 min;
+
+	hsdev = st->common_attributes.hsdev;
+
+	*val = 0;
+	*val2 = 0;
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		hid_sensor_power_state(&st->common_attributes, true);
+		report_id = st->hinge[chan->scan_index].report_id;
+		min = st->hinge[chan->scan_index].logical_minimum;
+		if (report_id < 0) {
+			*val = 0;
+			hid_sensor_power_state(&st->common_attributes, false);
+			return -EINVAL;
+		}
+
+		*val = sensor_hub_input_attr_get_raw_value(
+			st->common_attributes.hsdev, hsdev->usage,
+			hinge_addresses[chan->scan_index], report_id,
+			SENSOR_HUB_SYNC, min < 0);
+
+		hid_sensor_power_state(&st->common_attributes, false);
+		ret_type = IIO_VAL_INT;
+		break;
+	case IIO_CHAN_INFO_SCALE:
+		*val = st->scale_pre_decml;
+		*val2 = st->scale_post_decml;
+		ret_type = st->scale_precision;
+		break;
+	case IIO_CHAN_INFO_OFFSET:
+		*val = st->value_offset;
+		ret_type = IIO_VAL_INT;
+		break;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		ret_type = hid_sensor_read_samp_freq_value(
+			&st->common_attributes, val, val2);
+		break;
+	case IIO_CHAN_INFO_HYSTERESIS:
+		ret_type = hid_sensor_read_raw_hyst_value(
+			&st->common_attributes, val, val2);
+		break;
+	default:
+		ret_type = -EINVAL;
+		break;
+	}
+
+	return ret_type;
+}
+
+/* Channel write_raw handler */
+static int hinge_write_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan, int val, int val2,
+			   long mask)
+{
+	struct hinge_state *st = iio_priv(indio_dev);
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		ret = hid_sensor_write_samp_freq_value(&st->common_attributes,
+						       val, val2);
+		break;
+	case IIO_CHAN_INFO_HYSTERESIS:
+		ret = hid_sensor_write_raw_hyst_value(&st->common_attributes,
+						      val, val2);
+
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+static int hinge_read_label(struct iio_dev *indio_dev,
+			    struct iio_chan_spec const *chan, char *label)
+{
+	struct hinge_state *st = iio_priv(indio_dev);
+
+	return sprintf(label, "%s\n", st->labels[chan->channel]);
+}
+
+static const struct iio_info hinge_info = {
+	.read_raw = hinge_read_raw,
+	.write_raw = hinge_write_raw,
+	.read_label = hinge_read_label,
+};
+
+/*
+ * Callback handler to send event after all samples are received
+ * and captured.
+ */
+static int hinge_proc_event(struct hid_sensor_hub_device *hsdev,
+			    unsigned int usage_id, void *priv)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(priv);
+	struct hinge_state *st = iio_priv(indio_dev);
+
+	dev_dbg(&indio_dev->dev, "%s timestamp:%llu scan_bytes:%d\n", __func__,
+		st->timestamp, indio_dev->scan_bytes);
+
+	if (atomic_read(&st->common_attributes.data_ready)) {
+		if (!st->timestamp)
+			st->timestamp = iio_get_time_ns(indio_dev);
+
+		iio_push_to_buffers_with_timestamp(indio_dev, &st->scan,
+						   st->timestamp);
+
+		st->timestamp = 0;
+	}
+	return 0;
+}
+
+/* Capture samples in local storage */
+static int hinge_capture_sample(struct hid_sensor_hub_device *hsdev,
+				unsigned int usage_id, size_t raw_len,
+				char *raw_data, void *priv)
+{
+	struct iio_dev *indio_dev = platform_get_drvdata(priv);
+	struct hinge_state *st = iio_priv(indio_dev);
+	int offset;
+
+	switch (usage_id) {
+	case HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE(1):
+	case HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE(2):
+	case HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE(3):
+		offset = usage_id - HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE(1);
+		st->scan.hinge_val[offset] = *(u32 *)raw_data;
+		return 0;
+	case HID_USAGE_SENSOR_TIME_TIMESTAMP:
+		st->timestamp = hid_sensor_convert_timestamp(
+			&st->common_attributes, *(int64_t *)raw_data);
+		return 0;
+	default:
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+/* Parse report which is specific to an usage id */
+static int hinge_parse_report(struct platform_device *pdev,
+			      struct hid_sensor_hub_device *hsdev,
+			      struct iio_chan_spec *channels,
+			      unsigned int usage_id, struct hinge_state *st)
+{
+	int ret;
+	int i;
+
+	for (i = 0; i < CHANNEL_SCAN_INDEX_MAX; ++i) {
+		ret = sensor_hub_input_get_attribute_info(
+			hsdev, HID_INPUT_REPORT, usage_id, hinge_addresses[i],
+			&st->hinge[i]);
+		if (ret < 0)
+			return ret;
+
+		hinge_adjust_channel_bit_mask(channels, i, st->hinge[i].size);
+	}
+
+	st->scale_precision = hid_sensor_format_scale(
+		HID_USAGE_SENSOR_HINGE,
+		&st->hinge[CHANNEL_SCAN_INDEX_HINGE_ANGLE],
+		&st->scale_pre_decml, &st->scale_post_decml);
+
+	/* 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_FIELD_CUSTOM_VALUE(1),
+			&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 ret;
+}
+
+/* Function to initialize the processing for usage id */
+static int hid_hinge_probe(struct platform_device *pdev)
+{
+	struct hinge_state *st;
+	struct iio_dev *indio_dev;
+	struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
+	int ret;
+
+	indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*st));
+	if (indio_dev == NULL)
+		return -ENOMEM;
+
+	platform_set_drvdata(pdev, indio_dev);
+
+	st = iio_priv(indio_dev);
+	st->common_attributes.hsdev = hsdev;
+	st->common_attributes.pdev = pdev;
+	st->indio_dev = indio_dev;
+	st->labels[0] = "hinge";
+	st->labels[1] = "screen";
+	st->labels[2] = "keyboard";
+
+	ret = hid_sensor_parse_common_attributes(hsdev, hsdev->usage,
+						 &st->common_attributes);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to setup common attributes\n");
+		return ret;
+	}
+
+	indio_dev->num_channels = ARRAY_SIZE(hinge_channels);
+	indio_dev->channels =
+		kmemdup(hinge_channels, sizeof(hinge_channels), GFP_KERNEL);
+
+	ret = hinge_parse_report(pdev, hsdev,
+				 (struct iio_chan_spec *)indio_dev->channels,
+				 hsdev->usage, st);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to setup attributes\n");
+		goto error_out;
+	}
+
+	indio_dev->dev.parent = &pdev->dev;
+	indio_dev->info = &hinge_info;
+	indio_dev->name = "hinge";
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	atomic_set(&st->common_attributes.data_ready, 0);
+	ret = hid_sensor_setup_trigger(indio_dev, indio_dev->name,
+				       &st->common_attributes);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "trigger setup failed\n");
+		goto error_out;
+	}
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "device register failed\n");
+		goto error_remove_trigger;
+	}
+
+	st->callbacks.send_event = hinge_proc_event;
+	st->callbacks.capture_sample = hinge_capture_sample;
+	st->callbacks.pdev = pdev;
+	ret = sensor_hub_register_callback(hsdev, hsdev->usage, &st->callbacks);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "callback reg failed\n");
+		goto error_iio_unreg;
+	}
+	return ret;
+
+error_iio_unreg:
+	iio_device_unregister(indio_dev);
+error_remove_trigger:
+	hid_sensor_remove_trigger(indio_dev, &st->common_attributes);
+error_out:
+	kfree(indio_dev->channels);
+	return ret;
+}
+
+/* Function to deinitialize the processing for usage id */
+static int hid_hinge_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 hinge_state *st = iio_priv(indio_dev);
+
+	sensor_hub_remove_callback(hsdev, hsdev->usage);
+	iio_device_unregister(indio_dev);
+	hid_sensor_remove_trigger(indio_dev, &st->common_attributes);
+	kfree(indio_dev->channels);
+
+	return 0;
+}
+
+static const struct platform_device_id hid_hinge_ids[] = {
+	{
+		/* Format: HID-SENSOR-INT-usage_id_in_hex_lowercase */
+		.name = "HID-SENSOR-INT-020b",
+	},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(platform, hid_hinge_ids);
+
+static struct platform_driver hid_hinge_platform_driver = {
+	.id_table = hid_hinge_ids,
+	.driver = {
+		.name	= KBUILD_MODNAME,
+		.pm	= &hid_sensor_pm_ops,
+	},
+	.probe		= hid_hinge_probe,
+	.remove		= hid_hinge_remove,
+};
+module_platform_driver(hid_hinge_platform_driver);
+
+MODULE_DESCRIPTION("HID Sensor Hinge");
+MODULE_AUTHOR("Ye Xiang <xiang.ye@xxxxxxxxx>");
+MODULE_LICENSE("GPL");
-- 
2.17.1