[PATCH 4/4] 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 angels 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                 |   3 +
 .../iio/position/hid-sensor-custom-hinge.c    | 412 ++++++++++++++++++
 4 files changed, 433 insertions(+)
 create mode 100644 drivers/iio/position/hid-sensor-custom-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..0346f6f2b422 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_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 SENSOR CUSTOM
+	  HINGE.
+
+	  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..7a6225977a01 100644
--- a/drivers/iio/position/Makefile
+++ b/drivers/iio/position/Makefile
@@ -5,3 +5,6 @@
 # When adding new entries keep the list in alphabetical order
 
 obj-$(CONFIG_IQS624_POS)	+= iqs624-pos.o
+
+obj-$(CONFIG_HID_SENSOR_CUSTOM_HINGE) += hid-sensor-custom-hinge.o
+ccflags-y	+= -I$(srctree)/drivers/iio/common/hid-sensors
diff --git a/drivers/iio/position/hid-sensor-custom-hinge.c b/drivers/iio/position/hid-sensor-custom-hinge.c
new file mode 100644
index 000000000000..a91b333f36fa
--- /dev/null
+++ b/drivers/iio/position/hid-sensor-custom-hinge.c
@@ -0,0 +1,412 @@
+// 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 "hid-sensor-trigger.h"
+
+/* Channel definitions */
+static const struct iio_chan_spec hinge_channels[] = {
+	{ .type = IIO_ANGL,
+	  .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_type.realbits = 16,
+	  .scan_type.storagebits = 32,
+	  .scan_type.sign = 's',
+	  .scan_index = 0 },
+
+	IIO_CHAN_SOFT_TIMESTAMP(1)
+};
+
+struct hinge_state {
+	struct iio_dev *indio_dev;
+	struct hid_sensor_hub_attribute_info hinge;
+	/* Reserve for 1 channel + pading + timestamp */
+	u32 hinge_val[1 + 3];
+	int scale_pre_decml;
+	int scale_post_decml;
+	int scale_precision;
+	int value_offset;
+	int64_t timestamp;
+	u32 hinge_address;
+};
+
+#define IIO_DEV_NUM 3
+
+struct hinge_group {
+	struct hinge_state *hg_states[IIO_DEV_NUM];
+	struct hid_sensor_hub_callbacks callbacks;
+	struct hid_sensor_common common_attributes;
+};
+
+static struct hinge_group *hg_group;
+
+/* 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 *hg_state = iio_priv(indio_dev);
+	struct hid_sensor_hub_device *hsdev;
+	int report_id = -1;
+	int ret_type;
+	s32 min;
+
+	hsdev = hg_group->common_attributes.hsdev;
+
+	*val = 0;
+	*val2 = 0;
+	switch (mask) {
+	case IIO_CHAN_INFO_RAW:
+		hid_sensor_power_state(&hg_group->common_attributes, true);
+		report_id = hg_state->hinge.report_id;
+		min = hg_state->hinge.logical_minimum;
+		if (report_id < 0) {
+			*val = 0;
+			hid_sensor_power_state(&hg_group->common_attributes,
+					       false);
+			return -EINVAL;
+		}
+
+		*val = sensor_hub_input_attr_get_raw_value(
+			hg_group->common_attributes.hsdev, hsdev->usage,
+			hg_state->hinge_address, report_id, SENSOR_HUB_SYNC,
+			min < 0);
+
+		hid_sensor_power_state(&hg_group->common_attributes, false);
+		ret_type = IIO_VAL_INT;
+		break;
+	case IIO_CHAN_INFO_SCALE:
+		*val = hg_state->scale_pre_decml;
+		*val2 = hg_state->scale_post_decml;
+		ret_type = hg_state->scale_precision;
+		break;
+	case IIO_CHAN_INFO_OFFSET:
+		*val = hg_state->value_offset;
+		ret_type = IIO_VAL_INT;
+		break;
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		ret_type = hid_sensor_read_samp_freq_value(
+			&hg_group->common_attributes, val, val2);
+		break;
+	case IIO_CHAN_INFO_HYSTERESIS:
+		ret_type = hid_sensor_read_raw_hyst_value(
+			&hg_group->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)
+{
+	int ret;
+
+	switch (mask) {
+	case IIO_CHAN_INFO_SAMP_FREQ:
+		ret = hid_sensor_write_samp_freq_value(
+			&hg_group->common_attributes, val, val2);
+		break;
+	case IIO_CHAN_INFO_HYSTERESIS:
+		ret = hid_sensor_write_raw_hyst_value(
+			&hg_group->common_attributes, val, val2);
+
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+static const struct iio_info hinge_info = {
+	.read_raw = &hinge_read_raw,
+	.write_raw = &hinge_write_raw,
+};
+
+/*
+ * Function to push data to buffer;
+ * wrapper added for symmetry with other hid-sensor drivers
+ */
+static void hid_sensor_push_data(struct iio_dev *indio_dev, void *data, int len,
+				 int64_t timestamp)
+{
+	iio_push_to_buffers_with_timestamp(indio_dev, data, timestamp);
+}
+
+/*
+ * 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)
+{
+	int i;
+
+	for (i = 0; i < IIO_DEV_NUM; ++i) {
+		struct hinge_state *hg_state;
+		struct iio_dev *indio_dev;
+
+		hg_state = hg_group->hg_states[i];
+		indio_dev = hg_state->indio_dev;
+
+		dev_dbg(&indio_dev->dev, "%s timestamp:%llu scan_bytes:%d\n",
+			__func__, hg_state->timestamp, indio_dev->scan_bytes);
+
+		if (!hg_state->timestamp)
+			hg_state->timestamp = iio_get_time_ns(indio_dev);
+
+		hid_sensor_push_data(indio_dev, hg_state->hinge_val,
+				     sizeof(hg_state->hinge_val),
+				     hg_state->timestamp);
+
+		hg_state->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 hinge_state *hg_state;
+	int offset;
+	int ret = -EINVAL;
+	int i;
+
+	if (usage_id == HID_USAGE_SENSOR_TIME_TIMESTAMP) {
+		for (i = 0; i < IIO_DEV_NUM; i++)
+			hg_group->hg_states[i]->timestamp =
+				hid_sensor_convert_timestamp(
+					&hg_group->common_attributes,
+					*(int64_t *)raw_data);
+		return 0;
+	}
+
+	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;
+		hg_state = hg_group->hg_states[offset];
+		hg_state->hinge_val[0] = *(u32 *)raw_data;
+		ret = 0;
+		break;
+	default:
+		break;
+	}
+
+	return ret;
+}
+
+/* Parse report which is specific to an usage id */
+static int hinge_parse_report(struct platform_device *pdev,
+			      struct hid_sensor_hub_device *hsdev,
+			      unsigned int usage_id, unsigned int attr_usage_id,
+			      struct hinge_state *st)
+{
+	int ret;
+
+	ret = sensor_hub_input_get_attribute_info(
+		hsdev, HID_INPUT_REPORT, usage_id, attr_usage_id, &st->hinge);
+	if (ret < 0)
+		return ret;
+
+	st->hinge_address = attr_usage_id;
+	st->scale_precision =
+		hid_sensor_format_scale(HID_USAGE_SENSOR_HINGE, &st->hinge,
+					&st->scale_pre_decml,
+					&st->scale_post_decml);
+
+	/* Set Sensitivity field ids, when there is no individual modifier */
+	if (hg_group->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,
+			&hg_group->common_attributes.sensitivity);
+		dev_dbg(&pdev->dev, "Sensitivity index:report %d:%d\n",
+			hg_group->common_attributes.sensitivity.index,
+			hg_group->common_attributes.sensitivity.report_id);
+	}
+
+	return ret;
+}
+
+/* Function to initialize the processing for usage id */
+static int hinge_add_iio_device(struct platform_device *pdev, int index,
+				const char *name, struct hinge_state **st)
+{
+	struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
+	struct hinge_state *hg_state;
+	struct iio_dev *indio_dev;
+	int ret;
+
+	indio_dev =
+		devm_iio_device_alloc(&pdev->dev, sizeof(struct hinge_state));
+	if (indio_dev == NULL)
+		return -ENOMEM;
+
+	hg_state = iio_priv(indio_dev);
+	hg_state->indio_dev = indio_dev;
+
+	indio_dev->num_channels = ARRAY_SIZE(hinge_channels);
+	indio_dev->channels =
+		kmemdup(hinge_channels, sizeof(hinge_channels), GFP_KERNEL);
+	if (!indio_dev->channels)
+		return -ENOMEM;
+
+	ret = hinge_parse_report(
+		pdev, hsdev, hsdev->usage,
+		HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_1 + index, hg_state);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to setup attributes\n");
+		goto error_free_dev_mem;
+	}
+
+	indio_dev->dev.parent = &pdev->dev;
+	indio_dev->info = &hinge_info;
+	indio_dev->name = name;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = hid_sensor_setup_trigger(indio_dev, name,
+				       &hg_group->common_attributes);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "trigger setup failed\n");
+		goto error_free_dev_mem;
+	}
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(&pdev->dev, "device register failed\n");
+		goto error_remove_trigger;
+	}
+
+	*st = hg_state;
+
+	return ret;
+
+error_remove_trigger:
+	hid_sensor_remove_trigger(indio_dev, &hg_group->common_attributes);
+error_free_dev_mem:
+	kfree(indio_dev->channels);
+	return ret;
+}
+
+/* Function to deinitialize the processing for usage id */
+static int hinge_remove_iio_device(struct platform_device *pdev, int index)
+{
+	struct hinge_state *hg_state = hg_group->hg_states[index];
+	struct iio_dev *indio_dev = hg_state->indio_dev;
+
+	iio_device_unregister(indio_dev);
+	hid_sensor_remove_trigger(indio_dev, &hg_group->common_attributes);
+	kfree(indio_dev->channels);
+
+	return 0;
+}
+
+static int hid_hinge_probe(struct platform_device *pdev)
+{
+	struct hinge_state *hg_state;
+	struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
+	static const char *const names[] = { "hinge", "screen", "keyboard" };
+	int ret;
+	int i;
+
+	hg_group = devm_kzalloc(&pdev->dev, sizeof(struct hinge_group),
+				GFP_KERNEL);
+	if (!hg_group)
+		return -ENOMEM;
+
+	hg_group->common_attributes.hsdev = hsdev;
+	hg_group->common_attributes.pdev = pdev;
+
+	ret = hid_sensor_parse_common_attributes(hsdev, hsdev->usage,
+						 &hg_group->common_attributes);
+	if (ret) {
+		dev_err(&pdev->dev, "failed to setup common attributes\n");
+		return ret;
+	}
+
+	atomic_set(&hg_group->common_attributes.data_ready, 0);
+	for (i = 0; i < IIO_DEV_NUM; i++) {
+		ret = hinge_add_iio_device(pdev, i, names[i], &hg_state);
+		if (ret)
+			goto err_probe;
+
+		hg_group->hg_states[i] = hg_state;
+	}
+
+	/* use the first iio device to do the PM */
+	platform_set_drvdata(pdev, hg_group->hg_states[0]->indio_dev);
+
+	hg_group->callbacks.send_event = hinge_proc_event;
+	hg_group->callbacks.capture_sample = hinge_capture_sample;
+	hg_group->callbacks.pdev = pdev;
+	ret = sensor_hub_register_callback(hsdev, hsdev->usage,
+					   &hg_group->callbacks);
+	if (ret < 0)
+		dev_err(&pdev->dev, "callback reg failed\n");
+
+	return ret;
+
+err_probe:
+	for (i--; i >= 0; i--)
+		hinge_remove_iio_device(pdev, i);
+
+	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;
+	int i;
+
+	sensor_hub_remove_callback(hsdev, hsdev->usage);
+
+	for (i = 0; i < IIO_DEV_NUM; i++)
+		hinge_remove_iio_device(pdev, i);
+
+	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 Custom Hinge");
+MODULE_AUTHOR("Ye Xiang <xiang.ye@xxxxxxxxx>");
+MODULE_LICENSE("GPL");
-- 
2.17.1