add custom hinge sensor support

add custom hinge sensor support

[Ye Xiang]

Here three separate iio devices are presented which presents angle for
hinge, keyboard and screen.

This driver works on devices with Intel integrated sensor hub, where
hinge sensor is presented using a custom sensor usage id.

Here the angle is presented in degrees, which is converted to radians.

Changes since v2:
  - use 1 iio device instead of 3 for hinge sensor.
  - use indexed channel instead of modified channel and added channel
    labels.
  - remove 2,3 patch in last version, add a document patch to describe the
    hinge channels.
  - hid-sensor-custom: use meaningful return value in 
    get_known_custom_sensor_index and checked in call side.
  - hid-sensor-ids.h: use HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE(x) to 
    define custom sensor value.

Changes since v1:
  - fixed errors reported by lkp

Ye Xiang (3):
  HID: hid-sensor-custom: Add custom sensor iio support
  iio: hid-sensors: Add hinge sensor driver
  iio:Documentation: Add documentation for hinge sensor channels

 Documentation/ABI/testing/sysfs-bus-iio       |  17 +
 drivers/hid/hid-sensor-custom.c               | 181 ++++++++
 .../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 ++++++++++++++++++
 include/linux/hid-sensor-ids.h                |  14 +
 7 files changed, 624 insertions(+)
 create mode 100644 drivers/iio/position/hid-sensor-custom-intel-hinge.c

-- 
2.17.1

[PATCH v3 1/3] HID: hid-sensor-custom: Add custom sensor iio support

[Ye Xiang]

Currently custom sensors properties are not decoded and it is up to
user space to interpret.

Some manufacturers already standardized the meaning of some custom sensors.
They can be presented as a proper IIO sensor. We can identify these sensors
based on manufacturer and serial number property in the report.

This change is identifying hinge sensor when the manufacturer is "INTEL".
This creates a platform device so that a sensor driver can be loaded to
process these sensors.

Signed-off-by: Ye Xiang <xiang.ye@intel.com>
---
 drivers/hid/hid-sensor-custom.c | 181 ++++++++++++++++++++++++++++++++
 include/linux/hid-sensor-ids.h  |  14 +++
 2 files changed, 195 insertions(+)

diff --git a/drivers/hid/hid-sensor-custom.c b/drivers/hid/hid-sensor-custom.c
index 4d25577a8573..b8e59021c6a8 100644
--- a/drivers/hid/hid-sensor-custom.c
+++ b/drivers/hid/hid-sensor-custom.c
@@ -4,6 +4,7 @@
  * Copyright (c) 2015, Intel Corporation.
  */
 
+#include <linux/ctype.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
 #include <linux/init.h>
@@ -21,6 +22,7 @@
 #define HID_CUSTOM_TOTAL_ATTRS		(HID_CUSTOM_MAX_CORE_ATTRS + 1)
 #define HID_CUSTOM_FIFO_SIZE		4096
 #define HID_CUSTOM_MAX_FEATURE_BYTES	64
+#define HID_SENSOR_USAGE_LENGTH (4 + 1)
 
 struct hid_sensor_custom_field {
 	int report_id;
@@ -50,6 +52,8 @@ struct hid_sensor_custom {
 	struct kfifo data_fifo;
 	unsigned long misc_opened;
 	wait_queue_head_t wait;
+	struct platform_device *custom_pdev;
+	bool custom_pdev_exposed;
 };
 
 /* Header for each sample to user space via dev interface */
@@ -746,11 +750,164 @@ static void hid_sensor_custom_dev_if_remove(struct hid_sensor_custom
 
 }
 
+/*
+ * use sensors luid which is defined in FW, such as ISH,
+ * to identify sensor.
+ */
+static const char *const known_sensor_luid[] = { "020B000000000000" };
+
+static int get_luid_table_index(unsigned char *usage_str)
+{
+	int i;
+
+	for (i = 0; i < ARRAY_SIZE(known_sensor_luid); i++) {
+		if (!strncmp(usage_str, known_sensor_luid[i],
+			     strlen(known_sensor_luid[i])))
+			return i;
+	}
+
+	return -1;
+}
+
+static int get_known_custom_sensor_index(struct hid_sensor_hub_device *hsdev)
+{
+	struct hid_sensor_hub_attribute_info sensor_manufacturer = { 0 };
+	struct hid_sensor_hub_attribute_info sensor_luid_info = { 0 };
+	int report_size;
+	int ret;
+	u16 *w_buf;
+	char *buf;
+	int w_buf_len = sizeof(u16) * HID_CUSTOM_MAX_FEATURE_BYTES;
+	int buf_len = sizeof(char) * HID_CUSTOM_MAX_FEATURE_BYTES;
+	int i;
+	int index;
+
+	w_buf = kzalloc(w_buf_len, GFP_KERNEL);
+	if (!w_buf) {
+		ret = -ENOMEM;
+		goto error_out2;
+	}
+
+	buf = kzalloc(buf_len, GFP_KERNEL);
+	if (!buf) {
+		ret = -ENOMEM;
+		goto error_out1;
+	}
+	/* get manufacturer info */
+	ret = sensor_hub_input_get_attribute_info(
+		hsdev, HID_FEATURE_REPORT, hsdev->usage,
+		HID_USAGE_SENSOR_PROP_MANUFACTURER, &sensor_manufacturer);
+	if (ret < 0) {
+		ret = -ENODEV;
+		goto error_out;
+	}
+
+	report_size =
+		sensor_hub_get_feature(hsdev, sensor_manufacturer.report_id,
+				       sensor_manufacturer.index, w_buf_len,
+				       w_buf);
+	if (report_size <= 0) {
+		hid_err(hsdev->hdev,
+			"Failed to get sensor manufacturer info %d\n",
+			report_size);
+		ret = -ENODEV;
+		goto error_out;
+	}
+
+	/* convert from wide char to char */
+	for (i = 0; i < buf_len - 1 && w_buf[i]; i++)
+		buf[i] = (char)w_buf[i];
+
+	/* ensure it's ISH sensor */
+	if (strncmp(buf, "INTEL", strlen("INTEL"))) {
+		ret = -ENODEV;
+		goto error_out;
+	}
+
+	memset(w_buf, 0, w_buf_len);
+	memset(buf, 0, buf_len);
+
+	/* get real usage id */
+	ret = sensor_hub_input_get_attribute_info(
+		hsdev, HID_FEATURE_REPORT, hsdev->usage,
+		HID_USAGE_SENSOR_PROP_SERIAL_NUM, &sensor_luid_info);
+	if (ret < 0) {
+		ret = -ENODEV;
+		goto error_out;
+	}
+
+	report_size = sensor_hub_get_feature(hsdev, sensor_luid_info.report_id,
+					     sensor_luid_info.index, w_buf_len,
+					     w_buf);
+	if (report_size <= 0) {
+		hid_err(hsdev->hdev, "Failed to get real usage info %d\n",
+			report_size);
+		ret = -ENODEV;
+		goto error_out;
+	}
+
+	/* convert from wide char to char */
+	for (i = 0; i < buf_len - 1 && w_buf[i]; i++)
+		buf[i] = (char)w_buf[i];
+
+	if (strlen(buf) != strlen(known_sensor_luid[0]) + 5) {
+		hid_err(hsdev->hdev,
+			"%s luid length not match %zu != (%zu + 5)\n", __func__,
+			strlen(buf), strlen(known_sensor_luid[0]));
+		ret = -ENODEV;
+		goto error_out;
+	}
+
+	/* get table index with luid (not matching 'LUID: ' in luid) */
+	index = get_luid_table_index(&buf[5]);
+	if (index >= 0)
+		ret = index;
+	else
+		ret = -ENODEV;
+
+error_out:
+	kfree(buf);
+error_out1:
+	kfree(w_buf);
+error_out2:
+	return ret;
+}
+
+static struct platform_device *
+hid_sensor_register_platform_device(struct platform_device *pdev,
+				    struct hid_sensor_hub_device *hsdev,
+				    int index)
+{
+	char real_usage[HID_SENSOR_USAGE_LENGTH] = { 0 };
+	struct platform_device *custom_pdev;
+	const char *dev_name;
+	char *c;
+
+	/* copy real usage id */
+	memcpy(real_usage, known_sensor_luid[index], 4);
+
+	/* usage id are all lowcase */
+	for (c = real_usage; *c != '\0'; c++)
+		*c = tolower(*c);
+
+	/* HID-SENSOR-INT-REAL_USAGE_ID */
+	dev_name = kasprintf(GFP_KERNEL, "HID-SENSOR-INT-%s", real_usage);
+	if (!dev_name)
+		return NULL;
+
+	custom_pdev = platform_device_register_data(pdev->dev.parent, dev_name,
+						    PLATFORM_DEVID_NONE, hsdev,
+						    sizeof(*hsdev));
+	kfree(dev_name);
+	return custom_pdev;
+}
+
 static int hid_sensor_custom_probe(struct platform_device *pdev)
 {
 	struct hid_sensor_custom *sensor_inst;
 	struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
 	int ret;
+	int index;
 
 	sensor_inst = devm_kzalloc(&pdev->dev, sizeof(*sensor_inst),
 				   GFP_KERNEL);
@@ -764,6 +921,25 @@ static int hid_sensor_custom_probe(struct platform_device *pdev)
 	sensor_inst->pdev = pdev;
 	mutex_init(&sensor_inst->mutex);
 	platform_set_drvdata(pdev, sensor_inst);
+
+	index = get_known_custom_sensor_index(hsdev);
+	if (index >= 0 && index < ARRAY_SIZE(known_sensor_luid)) {
+		sensor_inst->custom_pdev =
+			hid_sensor_register_platform_device(pdev, hsdev, index);
+
+		ret = PTR_ERR_OR_ZERO(sensor_inst->custom_pdev);
+		if (ret) {
+			dev_err(&pdev->dev,
+				"register_platform_device failed\n");
+			return ret;
+		}
+
+		sensor_inst->custom_pdev_exposed = true;
+		return 0;
+	} else if (index < 0 && index != -ENODEV) {
+		return index;
+	}
+
 	ret = sensor_hub_register_callback(hsdev, hsdev->usage,
 					   &sensor_inst->callbacks);
 	if (ret < 0) {
@@ -802,6 +978,11 @@ static int hid_sensor_custom_remove(struct platform_device *pdev)
 	struct hid_sensor_custom *sensor_inst = platform_get_drvdata(pdev);
 	struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
 
+	if (sensor_inst->custom_pdev_exposed) {
+		platform_device_unregister(sensor_inst->custom_pdev);
+		return 0;
+	}
+
 	hid_sensor_custom_dev_if_remove(sensor_inst);
 	hid_sensor_custom_remove_attributes(sensor_inst);
 	sysfs_remove_group(&sensor_inst->pdev->dev.kobj,
diff --git a/include/linux/hid-sensor-ids.h b/include/linux/hid-sensor-ids.h
index 530c09f3e64a..ac631159403a 100644
--- a/include/linux/hid-sensor-ids.h
+++ b/include/linux/hid-sensor-ids.h
@@ -128,6 +128,10 @@
 #define HID_USAGE_SENSOR_UNITS_DEGREES_PER_SECOND		0x15
 
 /* Common selectors */
+#define HID_USAGE_SENSOR_PROP_DESC				0x200300
+#define HID_USAGE_SENSOR_PROP_FRIENDLY_NAME			0x200301
+#define HID_USAGE_SENSOR_PROP_SERIAL_NUM			0x200307
+#define HID_USAGE_SENSOR_PROP_MANUFACTURER			0x200305
 #define HID_USAGE_SENSOR_PROP_REPORT_INTERVAL			0x20030E
 #define HID_USAGE_SENSOR_PROP_SENSITIVITY_ABS			0x20030F
 #define HID_USAGE_SENSOR_PROP_SENSITIVITY_RANGE_PCT		0x200310
@@ -159,4 +163,14 @@
 #define HID_USAGE_SENSOR_PROP_REPORTING_STATE_NO_EVENTS_ENUM	0x200840
 #define HID_USAGE_SENSOR_PROP_REPORTING_STATE_ALL_EVENTS_ENUM	0x200841
 
+/* Custom Sensor (2000e1) */
+#define HID_USAGE_SENSOR_HINGE				        0x20020B
+#define HID_USAGE_SENSOR_DATA_FIELD_LOCATION			0x200400
+#define HID_USAGE_SENSOR_DATA_FIELE_TIME_SINCE_SYS_BOOT		0x20052B
+#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_USAGE		0x200541
+#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_BASE           0x200543
+/* Custom Sensor data 28=>x>=0 */
+#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE(x)                            \
+	(HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_BASE + (x))
+
 #endif
-- 
2.17.1

[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@intel.com>
---
 .../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@intel.com>");
+MODULE_LICENSE("GPL");
-- 
2.17.1

[PATCH v3 3/3] iio:Documentation: Add documentation for hinge sensor channels

[Ye Xiang]

Add channel description for hinge sensor, including channel label
attribute and raw data description.

Signed-off-by: Ye Xiang <xiang.ye@intel.com>
---
 Documentation/ABI/testing/sysfs-bus-iio | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
index df42bed09f25..82303b1bdff0 100644
--- a/Documentation/ABI/testing/sysfs-bus-iio
+++ b/Documentation/ABI/testing/sysfs-bus-iio
@@ -1802,3 +1802,20 @@ Contact:	linux-iio@vger.kernel.org
 Description:
 		Unscaled light intensity according to CIE 1931/DIN 5033 color space.
 		Units after application of scale are nano nanowatts per square meter.
+
+What:		/sys/bus/iio/devices/iio:deviceX/in_anglY_raw
+KernelVersion:	5.12
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Angle of rotation for channel Y. Units after application of scale
+		and offset are radians.
+
+What:		/sys/bus/iio/devices/iio:deviceX/in_anglY_label
+KernelVersion:	5.12
+Contact:	linux-iio@vger.kernel.org
+Description:
+		Optional symbolic label for channel Y.
+		For Intel hid hinge sensor, the label values are:
+		hinge, keyboard, screen. It means the three channels
+		each correspond respectively to hinge angle, keyboard angle,
+		and screen angle.
-- 
2.17.1

Re: [PATCH v3 3/3] iio:Documentation: Add documentation for hinge sensor channels

[Srinivas Pandruvada]

On Thu, 2020-12-03 at 11:53 +0800, Ye Xiang wrote:
> Add channel description for hinge sensor, including channel label
> attribute and raw data description.
> 
> Signed-off-by: Ye Xiang <xiang.ye@intel.com>
> ---
>  Documentation/ABI/testing/sysfs-bus-iio | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio
> b/Documentation/ABI/testing/sysfs-bus-iio
> index df42bed09f25..82303b1bdff0 100644
> --- a/Documentation/ABI/testing/sysfs-bus-iio
> +++ b/Documentation/ABI/testing/sysfs-bus-iio
> @@ -1802,3 +1802,20 @@ Contact:	linux-iio@vger.kernel.org
>  Description:
>  		Unscaled light intensity according to CIE 1931/DIN 5033
> color space.
>  		Units after application of scale are nano nanowatts per
> square meter.
> +
> +What:		/sys/bus/iio/devices/iio:deviceX/in_anglY_raw
Channel "Y" doesn't sound to be a variable. Why not just say "*"

Thanks,
Srinivas

> +KernelVersion:	5.12
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Angle of rotation for channel Y. Units after
> application of scale
> +		and offset are radians.
> +
> +What:		/sys/bus/iio/devices/iio:deviceX/in_anglY_label
> +KernelVersion:	5.12
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Optional symbolic label for channel Y.
> +		For Intel hid hinge sensor, the label values are:
> +		hinge, keyboard, screen. It means the three channels
> +		each correspond respectively to hinge angle, keyboard
> angle,
> +		and screen angle.

Re: add custom hinge sensor support

[Srinivas Pandruvada]

On Thu, 2020-12-03 at 11:53 +0800, Ye Xiang wrote:
> Here three separate iio devices are presented which presents angle
> for
> hinge, keyboard and screen.
You are presenting one IIO device now with three channels.

> 
> This driver works on devices with Intel integrated sensor hub, where
> hinge sensor is presented using a custom sensor usage id.
> 
> Here the angle is presented in degrees, which is converted to
> radians.
> 
> Changes since v2:
>   - use 1 iio device instead of 3 for hinge sensor.
>   - use indexed channel instead of modified channel and added channel
>     labels.
>   - remove 2,3 patch in last version, add a document patch to
> describe the
>     hinge channels.
>   - hid-sensor-custom: use meaningful return value in 
>     get_known_custom_sensor_index and checked in call side.
>   - hid-sensor-ids.h: use HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE(x)
> to 
>     define custom sensor value.
> 
> Changes since v1:
>   - fixed errors reported by lkp
> 
> Ye Xiang (3):
>   HID: hid-sensor-custom: Add custom sensor iio support
>   iio: hid-sensors: Add hinge sensor driver
>   iio:Documentation: Add documentation for hinge sensor channels
> 
>  Documentation/ABI/testing/sysfs-bus-iio       |  17 +
>  drivers/hid/hid-sensor-custom.c               | 181 ++++++++
>  .../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
> ++++++++++++++++++
>  include/linux/hid-sensor-ids.h                |  14 +
>  7 files changed, 624 insertions(+)
>  create mode 100644 drivers/iio/position/hid-sensor-custom-intel-
> hinge.c
> 

Re: [PATCH v3 3/3] iio:Documentation: Add documentation for hinge sensor channels

[Jonathan Cameron]

On Fri, 04 Dec 2020 03:40:15 -0800
Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com> wrote:

> On Thu, 2020-12-03 at 11:53 +0800, Ye Xiang wrote:
> > Add channel description for hinge sensor, including channel label
> > attribute and raw data description.
> > 
> > Signed-off-by: Ye Xiang <xiang.ye@intel.com>
> > ---
> >  Documentation/ABI/testing/sysfs-bus-iio | 17 +++++++++++++++++
> >  1 file changed, 17 insertions(+)
> > 
> > diff --git a/Documentation/ABI/testing/sysfs-bus-iio
> > b/Documentation/ABI/testing/sysfs-bus-iio
> > index df42bed09f25..82303b1bdff0 100644
> > --- a/Documentation/ABI/testing/sysfs-bus-iio
> > +++ b/Documentation/ABI/testing/sysfs-bus-iio
> > @@ -1802,3 +1802,20 @@ Contact:	linux-iio@vger.kernel.org
> >  Description:
> >  		Unscaled light intensity according to CIE 1931/DIN 5033
> > color space.
> >  		Units after application of scale are nano nanowatts per
> > square meter.
> > +
> > +What:		/sys/bus/iio/devices/iio:deviceX/in_anglY_raw  
> Channel "Y" doesn't sound to be a variable. Why not just say "*"

Long term convention.  More generally you need a way to refer to the
individual wild cards. Sometimes there are more than the two we have
here.

Not entirely sure where the convention comes from but it is used
throughout this file and I doubt I invented it.

Jonathan


> 
> Thanks,
> Srinivas
> 
> > +KernelVersion:	5.12
> > +Contact:	linux-iio@vger.kernel.org
> > +Description:
> > +		Angle of rotation for channel Y. Units after
> > application of scale
> > +		and offset are radians.
> > +
> > +What:		/sys/bus/iio/devices/iio:deviceX/in_anglY_label
> > +KernelVersion:	5.12
> > +Contact:	linux-iio@vger.kernel.org
> > +Description:
> > +		Optional symbolic label for channel Y.
> > +		For Intel hid hinge sensor, the label values are:
> > +		hinge, keyboard, screen. It means the three channels
> > +		each correspond respectively to hinge angle, keyboard
> > angle,
> > +		and screen angle.  
> 

Re: [PATCH v3 1/3] HID: hid-sensor-custom: Add custom sensor iio support

[Jonathan Cameron]

On Thu,  3 Dec 2020 11:53:50 +0800
Ye Xiang <xiang.ye@intel.com> wrote:

> Currently custom sensors properties are not decoded and it is up to
> user space to interpret.
> 
> Some manufacturers already standardized the meaning of some custom sensors.
> They can be presented as a proper IIO sensor. We can identify these sensors
> based on manufacturer and serial number property in the report.
> 
> This change is identifying hinge sensor when the manufacturer is "INTEL".
> This creates a platform device so that a sensor driver can be loaded to
> process these sensors.
> 
> Signed-off-by: Ye Xiang <xiang.ye@intel.com>
Hi,

A few little comments inline.

Others are much more familiar with this code than I am though so I'm sure
they will give a more in depth review!

> ---
>  drivers/hid/hid-sensor-custom.c | 181 ++++++++++++++++++++++++++++++++
>  include/linux/hid-sensor-ids.h  |  14 +++
>  2 files changed, 195 insertions(+)
> 
> diff --git a/drivers/hid/hid-sensor-custom.c b/drivers/hid/hid-sensor-custom.c
> index 4d25577a8573..b8e59021c6a8 100644
> --- a/drivers/hid/hid-sensor-custom.c
> +++ b/drivers/hid/hid-sensor-custom.c
> @@ -4,6 +4,7 @@
>   * Copyright (c) 2015, Intel Corporation.
>   */
>  
> +#include <linux/ctype.h>
>  #include <linux/kernel.h>
>  #include <linux/module.h>
>  #include <linux/init.h>
> @@ -21,6 +22,7 @@
>  #define HID_CUSTOM_TOTAL_ATTRS		(HID_CUSTOM_MAX_CORE_ATTRS + 1)
>  #define HID_CUSTOM_FIFO_SIZE		4096
>  #define HID_CUSTOM_MAX_FEATURE_BYTES	64
> +#define HID_SENSOR_USAGE_LENGTH (4 + 1)
>  
>  struct hid_sensor_custom_field {
>  	int report_id;
> @@ -50,6 +52,8 @@ struct hid_sensor_custom {
>  	struct kfifo data_fifo;
>  	unsigned long misc_opened;
>  	wait_queue_head_t wait;
> +	struct platform_device *custom_pdev;
> +	bool custom_pdev_exposed;

Note on this below.  I'm not sure the boolean brings us any advantages.

>  };
>  
>  /* Header for each sample to user space via dev interface */
> @@ -746,11 +750,164 @@ static void hid_sensor_custom_dev_if_remove(struct hid_sensor_custom
>  
>  }
>  
> +/*
> + * use sensors luid which is defined in FW, such as ISH,
> + * to identify sensor.
Perhaps rephrase as

luid defined in FW (e.g. ISH).  May be used to identify sensor.
 
> + */
> +static const char *const known_sensor_luid[] = { "020B000000000000" };
> +
> +static int get_luid_table_index(unsigned char *usage_str)
> +{
> +	int i;
> +
> +	for (i = 0; i < ARRAY_SIZE(known_sensor_luid); i++) {
> +		if (!strncmp(usage_str, known_sensor_luid[i],
> +			     strlen(known_sensor_luid[i])))
> +			return i;
> +	}
> +
> +	return -1;
> +}
> +
> +static int get_known_custom_sensor_index(struct hid_sensor_hub_device *hsdev)
> +{
> +	struct hid_sensor_hub_attribute_info sensor_manufacturer = { 0 };
> +	struct hid_sensor_hub_attribute_info sensor_luid_info = { 0 };
> +	int report_size;
> +	int ret;
> +	u16 *w_buf;
> +	char *buf;
> +	int w_buf_len = sizeof(u16) * HID_CUSTOM_MAX_FEATURE_BYTES;
> +	int buf_len = sizeof(char) * HID_CUSTOM_MAX_FEATURE_BYTES;
> +	int i;
> +	int index;
> +
> +	w_buf = kzalloc(w_buf_len, GFP_KERNEL);
> +	if (!w_buf) {
> +		ret = -ENOMEM;
> +		goto error_out2;
> +	}
> +
> +	buf = kzalloc(buf_len, GFP_KERNEL);
> +	if (!buf) {
> +		ret = -ENOMEM;
> +		goto error_out1;
> +	}
> +	/* get manufacturer info */
> +	ret = sensor_hub_input_get_attribute_info(
> +		hsdev, HID_FEATURE_REPORT, hsdev->usage,
> +		HID_USAGE_SENSOR_PROP_MANUFACTURER, &sensor_manufacturer);
> +	if (ret < 0) {
> +		ret = -ENODEV;
> +		goto error_out;
> +	}
> +
> +	report_size =
> +		sensor_hub_get_feature(hsdev, sensor_manufacturer.report_id,
> +				       sensor_manufacturer.index, w_buf_len,
> +				       w_buf);
> +	if (report_size <= 0) {
> +		hid_err(hsdev->hdev,
> +			"Failed to get sensor manufacturer info %d\n",
> +			report_size);
> +		ret = -ENODEV;
> +		goto error_out;
> +	}
> +
> +	/* convert from wide char to char */
> +	for (i = 0; i < buf_len - 1 && w_buf[i]; i++)
> +		buf[i] = (char)w_buf[i];
> +
> +	/* ensure it's ISH sensor */
> +	if (strncmp(buf, "INTEL", strlen("INTEL"))) {
> +		ret = -ENODEV;
> +		goto error_out;
> +	}
> +
> +	memset(w_buf, 0, w_buf_len);
> +	memset(buf, 0, buf_len);
> +
> +	/* get real usage id */
> +	ret = sensor_hub_input_get_attribute_info(
> +		hsdev, HID_FEATURE_REPORT, hsdev->usage,
> +		HID_USAGE_SENSOR_PROP_SERIAL_NUM, &sensor_luid_info);
> +	if (ret < 0) {
> +		ret = -ENODEV;
> +		goto error_out;
> +	}
> +
> +	report_size = sensor_hub_get_feature(hsdev, sensor_luid_info.report_id,
> +					     sensor_luid_info.index, w_buf_len,
> +					     w_buf);
> +	if (report_size <= 0) {
> +		hid_err(hsdev->hdev, "Failed to get real usage info %d\n",
> +			report_size);
> +		ret = -ENODEV;
> +		goto error_out;
> +	}
> +
> +	/* convert from wide char to char */
> +	for (i = 0; i < buf_len - 1 && w_buf[i]; i++)
> +		buf[i] = (char)w_buf[i];
> +
> +	if (strlen(buf) != strlen(known_sensor_luid[0]) + 5) {
> +		hid_err(hsdev->hdev,
> +			"%s luid length not match %zu != (%zu + 5)\n", __func__,
> +			strlen(buf), strlen(known_sensor_luid[0]));
> +		ret = -ENODEV;
> +		goto error_out;
> +	}
> +
> +	/* get table index with luid (not matching 'LUID: ' in luid) */
> +	index = get_luid_table_index(&buf[5]);
> +	if (index >= 0)
> +		ret = index;
> +	else
> +		ret = -ENODEV;
> +
> +error_out:
> +	kfree(buf);
> +error_out1:
> +	kfree(w_buf);
> +error_out2:
> +	return ret;
> +}
> +
> +static struct platform_device *
> +hid_sensor_register_platform_device(struct platform_device *pdev,
> +				    struct hid_sensor_hub_device *hsdev,
> +				    int index)
> +{
> +	char real_usage[HID_SENSOR_USAGE_LENGTH] = { 0 };
> +	struct platform_device *custom_pdev;
> +	const char *dev_name;
> +	char *c;
> +
> +	/* copy real usage id */
> +	memcpy(real_usage, known_sensor_luid[index], 4);
> +
> +	/* usage id are all lowcase */
> +	for (c = real_usage; *c != '\0'; c++)
> +		*c = tolower(*c);
> +
> +	/* HID-SENSOR-INT-REAL_USAGE_ID */
> +	dev_name = kasprintf(GFP_KERNEL, "HID-SENSOR-INT-%s", real_usage);
> +	if (!dev_name)
> +		return NULL;
> +
> +	custom_pdev = platform_device_register_data(pdev->dev.parent, dev_name,
> +						    PLATFORM_DEVID_NONE, hsdev,
> +						    sizeof(*hsdev));
> +	kfree(dev_name);
> +	return custom_pdev;
> +}
> +
>  static int hid_sensor_custom_probe(struct platform_device *pdev)
>  {
>  	struct hid_sensor_custom *sensor_inst;
>  	struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
>  	int ret;
> +	int index;
>  
>  	sensor_inst = devm_kzalloc(&pdev->dev, sizeof(*sensor_inst),
>  				   GFP_KERNEL);
> @@ -764,6 +921,25 @@ static int hid_sensor_custom_probe(struct platform_device *pdev)
>  	sensor_inst->pdev = pdev;
>  	mutex_init(&sensor_inst->mutex);
>  	platform_set_drvdata(pdev, sensor_inst);
> +
> +	index = get_known_custom_sensor_index(hsdev);
> +	if (index >= 0 && index < ARRAY_SIZE(known_sensor_luid)) {
> +		sensor_inst->custom_pdev =
> +			hid_sensor_register_platform_device(pdev, hsdev, index);
> +
> +		ret = PTR_ERR_OR_ZERO(sensor_inst->custom_pdev);
> +		if (ret) {
> +			dev_err(&pdev->dev,
> +				"register_platform_device failed\n");
> +			return ret;
> +		}
> +
> +		sensor_inst->custom_pdev_exposed = true;

Do we need an additional boolean or can we just use the existence of
custom_pdev?

> +		return 0;
> +	} else if (index < 0 && index != -ENODEV) {
> +		return index;
> +	}
> +
>  	ret = sensor_hub_register_callback(hsdev, hsdev->usage,
>  					   &sensor_inst->callbacks);
>  	if (ret < 0) {
> @@ -802,6 +978,11 @@ static int hid_sensor_custom_remove(struct platform_device *pdev)
>  	struct hid_sensor_custom *sensor_inst = platform_get_drvdata(pdev);
>  	struct hid_sensor_hub_device *hsdev = pdev->dev.platform_data;
>  
> +	if (sensor_inst->custom_pdev_exposed) {
> +		platform_device_unregister(sensor_inst->custom_pdev);
> +		return 0;
> +	}
> +
>  	hid_sensor_custom_dev_if_remove(sensor_inst);
>  	hid_sensor_custom_remove_attributes(sensor_inst);
>  	sysfs_remove_group(&sensor_inst->pdev->dev.kobj,
> diff --git a/include/linux/hid-sensor-ids.h b/include/linux/hid-sensor-ids.h
> index 530c09f3e64a..ac631159403a 100644
> --- a/include/linux/hid-sensor-ids.h
> +++ b/include/linux/hid-sensor-ids.h
> @@ -128,6 +128,10 @@
>  #define HID_USAGE_SENSOR_UNITS_DEGREES_PER_SECOND		0x15
>  
>  /* Common selectors */
> +#define HID_USAGE_SENSOR_PROP_DESC				0x200300
> +#define HID_USAGE_SENSOR_PROP_FRIENDLY_NAME			0x200301
> +#define HID_USAGE_SENSOR_PROP_SERIAL_NUM			0x200307
> +#define HID_USAGE_SENSOR_PROP_MANUFACTURER			0x200305
>  #define HID_USAGE_SENSOR_PROP_REPORT_INTERVAL			0x20030E
>  #define HID_USAGE_SENSOR_PROP_SENSITIVITY_ABS			0x20030F
>  #define HID_USAGE_SENSOR_PROP_SENSITIVITY_RANGE_PCT		0x200310
> @@ -159,4 +163,14 @@
>  #define HID_USAGE_SENSOR_PROP_REPORTING_STATE_NO_EVENTS_ENUM	0x200840
>  #define HID_USAGE_SENSOR_PROP_REPORTING_STATE_ALL_EVENTS_ENUM	0x200841
>  
> +/* Custom Sensor (2000e1) */
> +#define HID_USAGE_SENSOR_HINGE				        0x20020B
> +#define HID_USAGE_SENSOR_DATA_FIELD_LOCATION			0x200400
> +#define HID_USAGE_SENSOR_DATA_FIELE_TIME_SINCE_SYS_BOOT		0x20052B
> +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_USAGE		0x200541
> +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_BASE           0x200543
> +/* Custom Sensor data 28=>x>=0 */
> +#define HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE(x)                            \
> +	(HID_USAGE_SENSOR_DATA_FIELD_CUSTOM_VALUE_BASE + (x))
> +
>  #endif

Re: [PATCH v3 3/3] iio:Documentation: Add documentation for hinge sensor channels

[Jonathan Cameron]

On Thu,  3 Dec 2020 11:53:52 +0800
Ye Xiang <xiang.ye@intel.com> wrote:

> Add channel description for hinge sensor, including channel label
> attribute and raw data description.
> 
> Signed-off-by: Ye Xiang <xiang.ye@intel.com>
> ---
>  Documentation/ABI/testing/sysfs-bus-iio | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
> index df42bed09f25..82303b1bdff0 100644
> --- a/Documentation/ABI/testing/sysfs-bus-iio
> +++ b/Documentation/ABI/testing/sysfs-bus-iio
> @@ -1802,3 +1802,20 @@ Contact:	linux-iio@vger.kernel.org
>  Description:
>  		Unscaled light intensity according to CIE 1931/DIN 5033 color space.
>  		Units after application of scale are nano nanowatts per square meter.
> +
> +What:		/sys/bus/iio/devices/iio:deviceX/in_anglY_raw
> +KernelVersion:	5.12
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Angle of rotation for channel Y. Units after application of scale
> +		and offset are radians.

This entry is already mostly in the doc around line 200, just without the index.
Please just add the What: line to that block to reduce repetition.
If you want to add... "Where present, Y indexes the channel." or something like
that feel free.


> +
> +What:		/sys/bus/iio/devices/iio:deviceX/in_anglY_label
> +KernelVersion:	5.12
> +Contact:	linux-iio@vger.kernel.org
> +Description:
> +		Optional symbolic label for channel Y.
> +		For Intel hid hinge sensor, the label values are:
> +		hinge, keyboard, screen. It means the three channels
> +		each correspond respectively to hinge angle, keyboard angle,
> +		and screen angle.

Makes sense to keep this block separate given the additional info provided.
Alternative would be to add it to the one with in_voltageY_label which would
be odd given what follows!

Thanks,

Jonathan

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

[Jonathan Cameron]

On Thu,  3 Dec 2020 11:53:51 +0800
Ye Xiang <xiang.ye@intel.com> wrote:

> 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@intel.com>

A few new comments inline.  This is coming together nicely now.

No great rush btw as IIO is effectively closed for this cycle
(merge window opens in about a week and everything needs some time
in linux-next).

We should be good to line this up early in the next cycle.

Thanks,

Jonathan

> ---
>  .../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,
Probably better to indent this a bit more (and don't worry too much about line length
	{
		.indexed = 1,
...

	}, {
	}
> +	  .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;
Why are we 'adjusting' this or the sign marker above?  They appear
to be fixed. From this code I'd expect this function to only be
changing realbits.  The rest should be in the channel array template
you have above.

> +}
> +
> +/* 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;

Is there a path in which this is used where it isn't set before use?

> +	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;

If you return an error code the *val won't be used for anything so no
need to clear it.

Likewise, if you set type to IIO_VAL_INT, *val2 is not used by the core
so no need to ensure that is 0 either.

> +			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;

Use returns in the switch statement.  Shorter more readable code.
(slightly!)

> +}
> +
> +/* 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;

Might as well use direct returns in the switch statement. Saves a
few lines of code and isn't any harder to read.
> +}
> +
> +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);

This feels like left over debug that won't make a huge amount of
sense in a production driver. I'd drop it.

> +
> +	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;

Can't get here that I can see so drop this final return.

> +}
> +
> +/* 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);
Superficially doesn't seem to be anything to do with a bit_mask?  Perhaps rename.
> +	}
> +
> +	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";

As these are const, you should be fine I think to put them in a
static const array and just assign a pointer here.

> +
> +	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);

devm_kmemdup - see below.

> +
> +	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;

With devm_kmemdup will be able to return directly here.

> +	}
> +
> +	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;

return directly with change as suggested above.

> +	}
> +
> +	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);
As mentioned below, use devm_kmemdup
> +	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);

As this is last, we could have ended up with the same order using
a devm_kmemdup for indio_dev->channels and had same result
with slightly simpler error handling etc.

> +
> +	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@intel.com>");
> +MODULE_LICENSE("GPL");

Re: [PATCH v3 3/3] iio:Documentation: Add documentation for hinge sensor channels

[Ye, Xiang]

Hi Jonathan

Thanks for review and comments.

On Sat, Dec 05, 2020 at 04:05:40PM +0000, Jonathan Cameron wrote:
> On Thu,  3 Dec 2020 11:53:52 +0800
> Ye Xiang <xiang.ye@intel.com> wrote:
> 
> > Add channel description for hinge sensor, including channel label
> > attribute and raw data description.
> > 
> > Signed-off-by: Ye Xiang <xiang.ye@intel.com>
> > ---
> >  Documentation/ABI/testing/sysfs-bus-iio | 17 +++++++++++++++++
> >  1 file changed, 17 insertions(+)
> > 
> > diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
> > index df42bed09f25..82303b1bdff0 100644
> > --- a/Documentation/ABI/testing/sysfs-bus-iio
> > +++ b/Documentation/ABI/testing/sysfs-bus-iio
> > @@ -1802,3 +1802,20 @@ Contact:	linux-iio@vger.kernel.org
> >  Description:
> >  		Unscaled light intensity according to CIE 1931/DIN 5033 color space.
> >  		Units after application of scale are nano nanowatts per square meter.
> > +
> > +What:		/sys/bus/iio/devices/iio:deviceX/in_anglY_raw
> > +KernelVersion:	5.12
> > +Contact:	linux-iio@vger.kernel.org
> > +Description:
> > +		Angle of rotation for channel Y. Units after application of scale
> > +		and offset are radians.
> 
> This entry is already mostly in the doc around line 200, just without the index.
> Please just add the What: line to that block to reduce repetition.
> If you want to add... "Where present, Y indexes the channel." or something like
> that feel free.
When adding in_anglY_raw to in_angl_raw block, Should I update the KernelVersion form
4.17 to 5.12? Like blow:

What:		/sys/bus/iio/devices/iio:deviceX/in_angl_raw
What:		/sys/bus/iio/devices/iio:deviceX/in_anglY_raw
KernelVersion:	5.12
Contact:	linux-iio@vger.kernel.org
Description:
		Angle of rotation. Units after application of scale and offset
		are radians. Where present, Y indexes the channel.

> 
> 
> > +
> > +What:		/sys/bus/iio/devices/iio:deviceX/in_anglY_label
> > +KernelVersion:	5.12
> > +Contact:	linux-iio@vger.kernel.org
> > +Description:
> > +		Optional symbolic label for channel Y.
> > +		For Intel hid hinge sensor, the label values are:
> > +		hinge, keyboard, screen. It means the three channels
> > +		each correspond respectively to hinge angle, keyboard angle,
> > +		and screen angle.
> 
> Makes sense to keep this block separate given the additional info provided.
> Alternative would be to add it to the one with in_voltageY_label which would
> be odd given what follows!
Ok, Then I will keep the in_anglY_label block here. BTW, I didnot see in_voltageY_label
in sysfs-bus-iio in current kernel master branch.

> 
> Thanks,
> 
> Jonathan
> 
Thanks
Ye, Xiang
> 

Re: [PATCH v3 3/3] iio:Documentation: Add documentation for hinge sensor channels

[Jonathan Cameron]

On Mon, 7 Dec 2020 17:18:18 +0800
"Ye, Xiang" <xiang.ye@intel.com> wrote:

> Hi Jonathan
> 
> Thanks for review and comments.
> 
> On Sat, Dec 05, 2020 at 04:05:40PM +0000, Jonathan Cameron wrote:
> > On Thu,  3 Dec 2020 11:53:52 +0800
> > Ye Xiang <xiang.ye@intel.com> wrote:
> >   
> > > Add channel description for hinge sensor, including channel label
> > > attribute and raw data description.
> > > 
> > > Signed-off-by: Ye Xiang <xiang.ye@intel.com>
> > > ---
> > >  Documentation/ABI/testing/sysfs-bus-iio | 17 +++++++++++++++++
> > >  1 file changed, 17 insertions(+)
> > > 
> > > diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
> > > index df42bed09f25..82303b1bdff0 100644
> > > --- a/Documentation/ABI/testing/sysfs-bus-iio
> > > +++ b/Documentation/ABI/testing/sysfs-bus-iio
> > > @@ -1802,3 +1802,20 @@ Contact:	linux-iio@vger.kernel.org
> > >  Description:
> > >  		Unscaled light intensity according to CIE 1931/DIN 5033 color space.
> > >  		Units after application of scale are nano nanowatts per square meter.
> > > +
> > > +What:		/sys/bus/iio/devices/iio:deviceX/in_anglY_raw
> > > +KernelVersion:	5.12
> > > +Contact:	linux-iio@vger.kernel.org
> > > +Description:
> > > +		Angle of rotation for channel Y. Units after application of scale
> > > +		and offset are radians.  
> > 
> > This entry is already mostly in the doc around line 200, just without the index.
> > Please just add the What: line to that block to reduce repetition.
> > If you want to add... "Where present, Y indexes the channel." or something like
> > that feel free.  
> When adding in_anglY_raw to in_angl_raw block, Should I update the KernelVersion form
> 4.17 to 5.12? Like blow:
> 
> What:		/sys/bus/iio/devices/iio:deviceX/in_angl_raw
> What:		/sys/bus/iio/devices/iio:deviceX/in_anglY_raw
> KernelVersion:	5.12
> Contact:	linux-iio@vger.kernel.org
> Description:
> 		Angle of rotation. Units after application of scale and offset
> 		are radians. Where present, Y indexes the channel.

No. This is an unfortunate limitation of these files unless we keep duplicating
nearly identical text.

I'm not that worried about documenting an optional bit of ABI as apparently
being in an earlier kernel than it actually was.  That way any userspace
will work.  The other way around is more likely to cause problems.

> 
> > 
> >   
> > > +
> > > +What:		/sys/bus/iio/devices/iio:deviceX/in_anglY_label
> > > +KernelVersion:	5.12
> > > +Contact:	linux-iio@vger.kernel.org
> > > +Description:
> > > +		Optional symbolic label for channel Y.
> > > +		For Intel hid hinge sensor, the label values are:
> > > +		hinge, keyboard, screen. It means the three channels
> > > +		each correspond respectively to hinge angle, keyboard angle,
> > > +		and screen angle.  
> > 
> > Makes sense to keep this block separate given the additional info provided.
> > Alternative would be to add it to the one with in_voltageY_label which would
> > be odd given what follows!  
> Ok, Then I will keep the in_anglY_label block here. BTW, I didnot see in_voltageY_label
> in sysfs-bus-iio in current kernel master branch.
It was part of the series that added the support for per channel labels to the core.
3079188f821c ("iio:Documentation: Add documentation for label channel attribute")
so will only going into current master in the merge window that will open shortly.

Thanks,

Jonathan

> 
> > 
> > Thanks,
> > 
> > Jonathan
> >   
> Thanks
> Ye, Xiang
> >   

Re: [PATCH v3 3/3] iio:Documentation: Add documentation for hinge sensor channels

[Ye, Xiang]

On Sun, Dec 13, 2020 at 02:15:45PM +0000, Jonathan Cameron wrote:
> On Mon, 7 Dec 2020 17:18:18 +0800
> "Ye, Xiang" <xiang.ye@intel.com> wrote:
> 
> > Hi Jonathan
> > 
> > Thanks for review and comments.
> > 
> > On Sat, Dec 05, 2020 at 04:05:40PM +0000, Jonathan Cameron wrote:
> > > On Thu,  3 Dec 2020 11:53:52 +0800
> > > Ye Xiang <xiang.ye@intel.com> wrote:
> > >   
> > > > Add channel description for hinge sensor, including channel label
> > > > attribute and raw data description.
> > > > 
> > > > Signed-off-by: Ye Xiang <xiang.ye@intel.com>
> > > > ---
> > > >  Documentation/ABI/testing/sysfs-bus-iio | 17 +++++++++++++++++
> > > >  1 file changed, 17 insertions(+)
> > > > 
> > > > diff --git a/Documentation/ABI/testing/sysfs-bus-iio b/Documentation/ABI/testing/sysfs-bus-iio
> > > > index df42bed09f25..82303b1bdff0 100644
> > > > --- a/Documentation/ABI/testing/sysfs-bus-iio
> > > > +++ b/Documentation/ABI/testing/sysfs-bus-iio
> > > > @@ -1802,3 +1802,20 @@ Contact:	linux-iio@vger.kernel.org
> > > >  Description:
> > > >  		Unscaled light intensity according to CIE 1931/DIN 5033 color space.
> > > >  		Units after application of scale are nano nanowatts per square meter.
> > > > +
> > > > +What:		/sys/bus/iio/devices/iio:deviceX/in_anglY_raw
> > > > +KernelVersion:	5.12
> > > > +Contact:	linux-iio@vger.kernel.org
> > > > +Description:
> > > > +		Angle of rotation for channel Y. Units after application of scale
> > > > +		and offset are radians.  
> > > 
> > > This entry is already mostly in the doc around line 200, just without the index.
> > > Please just add the What: line to that block to reduce repetition.
> > > If you want to add... "Where present, Y indexes the channel." or something like
> > > that feel free.  
> > When adding in_anglY_raw to in_angl_raw block, Should I update the KernelVersion form
> > 4.17 to 5.12? Like blow:
> > 
> > What:		/sys/bus/iio/devices/iio:deviceX/in_angl_raw
> > What:		/sys/bus/iio/devices/iio:deviceX/in_anglY_raw
> > KernelVersion:	5.12
> > Contact:	linux-iio@vger.kernel.org
> > Description:
> > 		Angle of rotation. Units after application of scale and offset
> > 		are radians. Where present, Y indexes the channel.
> 
> No. This is an unfortunate limitation of these files unless we keep duplicating
> nearly identical text.
> 
> I'm not that worried about documenting an optional bit of ABI as apparently
> being in an earlier kernel than it actually was.  That way any userspace
> will work.  The other way around is more likely to cause problems.
Got it, then I will keep KernelVersion 4.17. will send the next version out
for review soon. Thanks again for the review.
> 
> > 
> > > 
> > >   
> > > > +
> > > > +What:		/sys/bus/iio/devices/iio:deviceX/in_anglY_label
> > > > +KernelVersion:	5.12
> > > > +Contact:	linux-iio@vger.kernel.org
> > > > +Description:
> > > > +		Optional symbolic label for channel Y.
> > > > +		For Intel hid hinge sensor, the label values are:
> > > > +		hinge, keyboard, screen. It means the three channels
> > > > +		each correspond respectively to hinge angle, keyboard angle,
> > > > +		and screen angle.  
> > > 
> > > Makes sense to keep this block separate given the additional info provided.
> > > Alternative would be to add it to the one with in_voltageY_label which would
> > > be odd given what follows!  
> > Ok, Then I will keep the in_anglY_label block here. BTW, I didnot see in_voltageY_label
> > in sysfs-bus-iio in current kernel master branch.
> It was part of the series that added the support for per channel labels to the core.
> 3079188f821c ("iio:Documentation: Add documentation for label channel attribute")
> so will only going into current master in the merge window that will open shortly.
got it.
> 

Thanks
Ye, Xiang