[PATCH v4 0/2] HID: HID Sensor: Custom and Generic sensor support

[PATCH v4 0/2] HID: HID Sensor: Custom and Generic sensor support

[Srinivas Pandruvada]

v4
- Fix sysfs_attr_init arguments. Again sorry for the mistake
- Fix attribute value size for multi byte feature report

v3
- Added name attribute
Although documentation patch is acked by Jonathan for previous
version, I didn't use this as the name attribute is added.

v2
- Addressed review comments from Jonathan
- Added poll capability on misc device
- Added time stamp to the report id

v1
- Two trailing white spaces in the document
- Error in getting attribute value found by
saurabh rawat <saurabh.rawat@st.com>

v0
Base version
Srinivas Pandruvada (2):
  HID: HID Sensor: Custom and Generic sensor support
  HID: HID Sensor: Update document for custom sensor

 Documentation/hid/hid-sensor.txt |  84 ++++
 drivers/hid/Kconfig              |  15 +
 drivers/hid/Makefile             |   1 +
 drivers/hid/hid-sensor-custom.c  | 849 +++++++++++++++++++++++++++++++++++++++
 4 files changed, 949 insertions(+)
 create mode 100644 drivers/hid/hid-sensor-custom.c

-- 
2.1.0

[PATCH v4 1/2] HID: HID Sensor: Custom and Generic sensor support

[Srinivas Pandruvada]

HID Sensor Spec defines two usage ids for custom sensors
HID_USAGE_SENSOR_TYPE_OTHER_CUSTOM (0x09, 0xE1)
HID_USAGE_SENSOR_TYPE_OTHER_GENERIC(0x09, 0xE2)
In addition the standard also defines usage ids for custom fields.
The purpose of these sensors is to extend the functionality or provide a
way to obfuscate the data being communicated by a sensor. Without knowing the
mapping between the data and its encapsulated form, it is difficult for
an driver to determine what data is being communicated by the sensor.
This allows some differentiating use cases, where vendor can provide applications.
Since these can't be represented by standard sensor interfaces like IIO,
we present these as fields with
- type (input/output)
- units
- min/max
- get/set value
In addition an dev interface to transfer report events. Details about this
interface is described in /Documentation/hid/hid-sensor.txt.
Manufacturers should not use these ids for any standard sensors, otherwise
the the product/vendor id can be added to black list.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
---
 drivers/hid/Kconfig             |  15 +
 drivers/hid/Makefile            |   1 +
 drivers/hid/hid-sensor-custom.c | 849 ++++++++++++++++++++++++++++++++++++++++
 3 files changed, 865 insertions(+)
 create mode 100644 drivers/hid/hid-sensor-custom.c

diff --git a/drivers/hid/Kconfig b/drivers/hid/Kconfig
index 152b006..7de0e9e 100644
--- a/drivers/hid/Kconfig
+++ b/drivers/hid/Kconfig
@@ -885,6 +885,21 @@ config HID_SENSOR_HUB
 	  for events and handle data streams. Each sensor driver can format
 	  data and present to user mode using input or IIO interface.
 
+config HID_SENSOR_CUSTOM_SENSOR
+	tristate "HID Sensors hub custom sensor support"
+	depends on HID_SENSOR_HUB
+	default n
+	---help---
+	  HID Sensor hub specification allows definition of some custom and
+	  generic sensors. Unlike other HID sensors, they can't be exported
+	  via Linux IIO because of custom fields. This is up to the manufacturer
+	  to decide how to interpret these special sensor ids and process in
+	  the user space. Currently some manufacturers are using these ids for
+	  sensor calibration and debugging other sensors. Manufacturers
+	  should't use these special custom sensor ids to export any of the
+	  standard sensors.
+	  Select this config option for custom/generic sensor support.
+
 endmenu
 
 endif # HID
diff --git a/drivers/hid/Makefile b/drivers/hid/Makefile
index 6f19958..c90ce7b 100644
--- a/drivers/hid/Makefile
+++ b/drivers/hid/Makefile
@@ -101,6 +101,7 @@ obj-$(CONFIG_HID_WACOM)		+= wacom.o
 obj-$(CONFIG_HID_WALTOP)	+= hid-waltop.o
 obj-$(CONFIG_HID_WIIMOTE)	+= hid-wiimote.o
 obj-$(CONFIG_HID_SENSOR_HUB)	+= hid-sensor-hub.o
+obj-$(CONFIG_HID_SENSOR_CUSTOM_SENSOR)	+= hid-sensor-custom.o
 
 obj-$(CONFIG_USB_HID)		+= usbhid/
 obj-$(CONFIG_USB_MOUSE)		+= usbhid/
diff --git a/drivers/hid/hid-sensor-custom.c b/drivers/hid/hid-sensor-custom.c
new file mode 100644
index 0000000..5614fee
--- /dev/null
+++ b/drivers/hid/hid-sensor-custom.c
@@ -0,0 +1,849 @@
+/*
+ * hid-sensor-custom.c
+ * Copyright (c) 2015, Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/miscdevice.h>
+#include <linux/kfifo.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
+#include <linux/poll.h>
+#include <linux/bsearch.h>
+#include <linux/platform_device.h>
+#include <linux/hid-sensor-hub.h>
+
+#define HID_CUSTOM_NAME_LENGTH		64
+#define HID_CUSTOM_MAX_CORE_ATTRS	10
+#define HID_CUSTOM_TOTAL_ATTRS		(HID_CUSTOM_MAX_CORE_ATTRS + 1)
+#define HID_CUSTOM_FIFO_SIZE		4096
+#define HID_CUSTOM_MAX_FEATURE_BYTES	64
+
+struct hid_sensor_custom_field {
+	int report_id;
+	char group_name[HID_CUSTOM_NAME_LENGTH];
+	struct hid_sensor_hub_attribute_info attribute;
+	struct device_attribute sd_attrs[HID_CUSTOM_MAX_CORE_ATTRS];
+	char attr_name[HID_CUSTOM_TOTAL_ATTRS][HID_CUSTOM_NAME_LENGTH];
+	struct attribute *attrs[HID_CUSTOM_TOTAL_ATTRS];
+	struct attribute_group hid_custom_attribute_group;
+};
+
+struct hid_sensor_custom {
+	struct mutex mutex;
+	struct platform_device *pdev;
+	struct hid_sensor_hub_device *hsdev;
+	struct hid_sensor_hub_callbacks callbacks;
+	int sensor_field_count;
+	struct hid_sensor_custom_field *fields;
+	int input_field_count;
+	int input_report_size;
+	int input_report_recd_size;
+	bool input_skip_sample;
+	bool enable;
+	struct hid_sensor_custom_field *power_state;
+	struct hid_sensor_custom_field *report_state;
+	struct miscdevice custom_dev;
+	struct kfifo data_fifo;
+	unsigned long misc_opened;
+	wait_queue_head_t wait;
+};
+
+/* Header for each sample to user space via dev interface */
+struct hid_sensor_sample {
+	u32 usage_id;
+	u64 timestamp;
+	u32 raw_len;
+} __packed;
+
+static struct attribute hid_custom_attrs[] = {
+	{.name = "name", .mode = S_IRUGO},
+	{.name = "units", .mode = S_IRUGO},
+	{.name = "unit-expo", .mode = S_IRUGO},
+	{.name = "minimum", .mode = S_IRUGO},
+	{.name = "maximum", .mode = S_IRUGO},
+	{.name = "size", .mode = S_IRUGO},
+	{.name = "value", .mode = S_IWUSR | S_IRUGO},
+	{.name = NULL}
+};
+
+static const struct hid_custom_usage_desc {
+	int usage_id;
+	char *desc;
+} hid_custom_usage_desc_table[] = {
+	{0x200201,	"event-sensor-state"},
+	{0x200202,	"event-sensor-event"},
+	{0x200301,	"property-friendly-name"},
+	{0x200302,	"property-persistent-unique-id"},
+	{0x200303,	"property-sensor-status"},
+	{0x200304,	"property-min-report-interval"},
+	{0x200305,	"property-sensor-manufacturer"},
+	{0x200306,	"property-sensor-model"},
+	{0x200307,	"property-sensor-serial-number"},
+	{0x200308,	"property-sensor-description"},
+	{0x200309,	"property-sensor-connection-type"},
+	{0x20030A,	"property-sensor-device-path"},
+	{0x20030B,	"property-hardware-revision"},
+	{0x20030C,	"property-firmware-version"},
+	{0x20030D,	"property-release-date"},
+	{0x20030E,	"property-report-interval"},
+	{0x20030F,	"property-change-sensitivity-absolute"},
+	{0x200310,	"property-change-sensitivity-percent-range"},
+	{0x200311,	"property-change-sensitivity-percent-relative"},
+	{0x200312,	"property-accuracy"},
+	{0x200313,	"property-resolution"},
+	{0x200314,	"property-maximum"},
+	{0x200315,	"property-minimum"},
+	{0x200316,	"property-reporting-state"},
+	{0x200317,	"property-sampling-rate"},
+	{0x200318,	"property-response-curve"},
+	{0x200319,	"property-power-state"},
+	{0x200540,	"data-field-custom"},
+	{0x200541,	"data-field-custom-usage"},
+	{0x200542,	"data-field-custom-boolean-array"},
+	{0x200543,	"data-field-custom-value"},
+	{0x200544,	"data-field-custom-value_1"},
+	{0x200545,	"data-field-custom-value_2"},
+	{0x200546,	"data-field-custom-value_3"},
+	{0x200547,	"data-field-custom-value_4"},
+	{0x200548,	"data-field-custom-value_5"},
+	{0x200549,	"data-field-custom-value_6"},
+	{0x20054A,	"data-field-custom-value_7"},
+	{0x20054B,	"data-field-custom-value_8"},
+	{0x20054C,	"data-field-custom-value_9"},
+	{0x20054D,	"data-field-custom-value_10"},
+	{0x20054E,	"data-field-custom-value_11"},
+	{0x20054F,	"data-field-custom-value_12"},
+	{0x200550,	"data-field-custom-value_13"},
+	{0x200551,	"data-field-custom-value_14"},
+	{0x200552,	"data-field-custom-value_15"},
+	{0x200553,	"data-field-custom-value_16"},
+	{0x200554,	"data-field-custom-value_17"},
+	{0x200555,	"data-field-custom-value_18"},
+	{0x200556,	"data-field-custom-value_19"},
+	{0x200557,	"data-field-custom-value_20"},
+	{0x200558,	"data-field-custom-value_21"},
+	{0x200559,	"data-field-custom-value_22"},
+	{0x20055A,	"data-field-custom-value_23"},
+	{0x20055B,	"data-field-custom-value_24"},
+	{0x20055C,	"data-field-custom-value_25"},
+	{0x20055D,	"data-field-custom-value_26"},
+	{0x20055E,	"data-field-custom-value_27"},
+	{0x20055F,	"data-field-custom-value_28"},
+};
+
+static int usage_id_cmp(const void *p1, const void *p2)
+{
+	if (*(int *)p1 < *(int *)p2)
+		return -1;
+
+	if (*(int *)p1 > *(int *)p2)
+		return 1;
+
+	return 0;
+}
+
+static ssize_t enable_sensor_show(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct hid_sensor_custom *sensor_inst = platform_get_drvdata(pdev);
+
+	return sprintf(buf, "%d\n", sensor_inst->enable);
+}
+
+static int set_power_report_state(struct hid_sensor_custom *sensor_inst,
+				  bool state)
+{
+	int power_val = -1;
+	int report_val = -1;
+	u32 power_state_usage_id;
+	u32 report_state_usage_id;
+	int ret;
+
+	/*
+	 * It is possible that the power/report state ids are not present.
+	 * In this case this function will return success. But if the
+	 * ids are present, then it will return error if set fails.
+	 */
+	if (state) {
+		power_state_usage_id =
+			HID_USAGE_SENSOR_PROP_POWER_STATE_D0_FULL_POWER_ENUM;
+		report_state_usage_id =
+			HID_USAGE_SENSOR_PROP_REPORTING_STATE_ALL_EVENTS_ENUM;
+	} else {
+		power_state_usage_id =
+			HID_USAGE_SENSOR_PROP_POWER_STATE_D4_POWER_OFF_ENUM;
+		report_state_usage_id =
+			HID_USAGE_SENSOR_PROP_REPORTING_STATE_NO_EVENTS_ENUM;
+	}
+
+	if (sensor_inst->power_state)
+		power_val = hid_sensor_get_usage_index(sensor_inst->hsdev,
+				sensor_inst->power_state->attribute.report_id,
+				sensor_inst->power_state->attribute.index,
+				power_state_usage_id);
+	if (sensor_inst->report_state)
+		report_val = hid_sensor_get_usage_index(sensor_inst->hsdev,
+				sensor_inst->report_state->attribute.report_id,
+				sensor_inst->report_state->attribute.index,
+				report_state_usage_id);
+
+	if (power_val >= 0) {
+		power_val +=
+			sensor_inst->power_state->attribute.logical_minimum;
+		ret = sensor_hub_set_feature(sensor_inst->hsdev,
+				sensor_inst->power_state->attribute.report_id,
+				sensor_inst->power_state->attribute.index,
+				sizeof(power_val),
+				&power_val);
+		if (ret) {
+			hid_err(sensor_inst->hsdev->hdev,
+				"Set power state failed\n");
+			return ret;
+		}
+	}
+
+	if (report_val >= 0) {
+		report_val +=
+			sensor_inst->report_state->attribute.logical_minimum;
+		ret = sensor_hub_set_feature(sensor_inst->hsdev,
+				sensor_inst->report_state->attribute.report_id,
+				sensor_inst->report_state->attribute.index,
+				sizeof(report_val),
+				&report_val);
+		if (ret) {
+			hid_err(sensor_inst->hsdev->hdev,
+				"Set report state failed\n");
+			return ret;
+		}
+	}
+
+	return 0;
+}
+
+static ssize_t enable_sensor_store(struct device *dev,
+				   struct device_attribute *attr,
+				   const char *buf, size_t count)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct hid_sensor_custom *sensor_inst = platform_get_drvdata(pdev);
+	int value;
+	int ret = -EINVAL;
+
+	if (kstrtoint(buf, 0, &value) != 0)
+		return -EINVAL;
+
+	mutex_lock(&sensor_inst->mutex);
+	if (value && !sensor_inst->enable) {
+		ret = sensor_hub_device_open(sensor_inst->hsdev);
+		if (ret)
+			goto unlock_state;
+
+		ret = set_power_report_state(sensor_inst, true);
+		if (ret) {
+			sensor_hub_device_close(sensor_inst->hsdev);
+			goto unlock_state;
+		}
+		sensor_inst->enable = true;
+	} else if (!value && sensor_inst->enable) {
+		ret = set_power_report_state(sensor_inst, false);
+		sensor_hub_device_close(sensor_inst->hsdev);
+		sensor_inst->enable = false;
+	}
+unlock_state:
+	mutex_unlock(&sensor_inst->mutex);
+	if (ret < 0)
+		return ret;
+
+	return count;
+}
+static DEVICE_ATTR_RW(enable_sensor);
+
+static struct attribute *enable_sensor_attrs[] = {
+	&dev_attr_enable_sensor.attr,
+	NULL,
+};
+
+static struct attribute_group enable_sensor_attr_group = {
+	.attrs = enable_sensor_attrs,
+};
+
+static ssize_t show_value(struct device *dev, struct device_attribute *attr,
+			  char *buf)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct hid_sensor_custom *sensor_inst = platform_get_drvdata(pdev);
+	struct hid_sensor_hub_attribute_info *attribute;
+	int index, usage, field_index;
+	char name[HID_CUSTOM_NAME_LENGTH];
+	bool feature = false;
+	bool input = false;
+	int value = 0;
+
+	if (sscanf(attr->attr.name, "feature-%d-%x-%s", &index, &usage,
+		   name) == 3) {
+		feature = true;
+		field_index = index + sensor_inst->input_field_count;
+	} else if (sscanf(attr->attr.name, "input-%d-%x-%s", &index, &usage,
+		   name) == 3) {
+		input = true;
+		field_index = index;
+	} else
+		return -EINVAL;
+
+	if (!strncmp(name, "value", strlen("value"))) {
+		u32 report_id;
+		int ret;
+
+		attribute = &sensor_inst->fields[field_index].attribute;
+		report_id = attribute->report_id;
+		if (feature) {
+			u8 values[HID_CUSTOM_MAX_FEATURE_BYTES];
+			int len = 0;
+			u64 value = 0;
+			int i = 0;
+
+			ret = sensor_hub_get_feature(sensor_inst->hsdev,
+						     report_id,
+						     index,
+						     sizeof(values), values);
+			if (ret < 0)
+				return ret;
+
+			while (i < ret) {
+				if (i + attribute->size > ret) {
+					len += snprintf(&buf[len],
+							PAGE_SIZE - len,
+							"%d ", values[i]);
+					break;
+				}
+				switch (attribute->size) {
+				case 2:
+					value = (u64) *(u16 *)&values[i];
+					i += attribute->size;
+					break;
+				case 4:
+					value = (u64) *(u32 *)&values[i];
+					i += attribute->size;
+					break;
+				case 8:
+					value = *(u64 *)&values[i];
+					i += attribute->size;
+					break;
+				default:
+					value = (u64) values[i];
+					++i;
+					break;
+				}
+				len += snprintf(&buf[len], PAGE_SIZE - len,
+						"%lld ", value);
+			}
+			len += snprintf(&buf[len], PAGE_SIZE - len, "\n");
+
+			return len;
+		} else if (input)
+			value = sensor_hub_input_attr_get_raw_value(
+						sensor_inst->hsdev,
+						sensor_inst->hsdev->usage,
+						usage, report_id,
+						SENSOR_HUB_SYNC);
+	} else if (!strncmp(name, "units", strlen("units")))
+		value = sensor_inst->fields[field_index].attribute.units;
+	else if (!strncmp(name, "unit-expo", strlen("unit-expo")))
+		value = sensor_inst->fields[field_index].attribute.unit_expo;
+	else if (!strncmp(name, "size", strlen("size")))
+		value = sensor_inst->fields[field_index].attribute.size;
+	else if (!strncmp(name, "minimum", strlen("minimum")))
+		value = sensor_inst->fields[field_index].attribute.
+							logical_minimum;
+	else if (!strncmp(name, "maximum", strlen("maximum")))
+		value = sensor_inst->fields[field_index].attribute.
+							logical_maximum;
+	else if (!strncmp(name, "name", strlen("name"))) {
+		struct hid_custom_usage_desc *usage_desc;
+
+		usage_desc = bsearch(&usage, hid_custom_usage_desc_table,
+				     ARRAY_SIZE(hid_custom_usage_desc_table),
+				     sizeof(struct hid_custom_usage_desc),
+				     usage_id_cmp);
+		if (usage_desc)
+			return snprintf(buf, PAGE_SIZE, "%s\n",
+					usage_desc->desc);
+		else
+			return sprintf(buf, "not-specified\n");
+	 } else
+		return -EINVAL;
+
+	return sprintf(buf, "%d\n", value);
+}
+
+static ssize_t store_value(struct device *dev, struct device_attribute *attr,
+			   const char *buf, size_t count)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct hid_sensor_custom *sensor_inst = platform_get_drvdata(pdev);
+	int index, field_index, usage;
+	char name[HID_CUSTOM_NAME_LENGTH];
+	int value;
+
+	if (sscanf(attr->attr.name, "feature-%d-%x-%s", &index, &usage,
+		   name) == 3) {
+		field_index = index + sensor_inst->input_field_count;
+	} else
+		return -EINVAL;
+
+	if (!strncmp(name, "value", strlen("value"))) {
+		u32 report_id;
+		int ret;
+
+		if (kstrtoint(buf, 0, &value) != 0)
+			return -EINVAL;
+
+		report_id = sensor_inst->fields[field_index].attribute.
+								report_id;
+		ret = sensor_hub_set_feature(sensor_inst->hsdev, report_id,
+					     index, sizeof(value), &value);
+	} else
+		return -EINVAL;
+
+	return count;
+}
+
+static int hid_sensor_capture_sample(struct hid_sensor_hub_device *hsdev,
+				  unsigned usage_id, size_t raw_len,
+				  char *raw_data, void *priv)
+{
+	struct hid_sensor_custom *sensor_inst = platform_get_drvdata(priv);
+	struct hid_sensor_sample header;
+
+	/* If any error occurs in a sample, rest of the fields are ignored */
+	if (sensor_inst->input_skip_sample) {
+		hid_err(sensor_inst->hsdev->hdev, "Skipped remaining data\n");
+		return 0;
+	}
+
+	hid_dbg(sensor_inst->hsdev->hdev, "%s received %d of %d\n", __func__,
+		(int) (sensor_inst->input_report_recd_size + raw_len),
+		sensor_inst->input_report_size);
+
+	if (!test_bit(0, &sensor_inst->misc_opened))
+		return 0;
+
+	if (!sensor_inst->input_report_recd_size) {
+		int required_size = sizeof(struct hid_sensor_sample) +
+						sensor_inst->input_report_size;
+		header.usage_id = hsdev->usage;
+		header.raw_len = sensor_inst->input_report_size;
+		header.timestamp = ktime_get_real_ns();
+		if (kfifo_avail(&sensor_inst->data_fifo) >= required_size) {
+			kfifo_in(&sensor_inst->data_fifo,
+				 (unsigned char *)&header,
+				 sizeof(header));
+		} else
+			sensor_inst->input_skip_sample = true;
+	}
+	if (kfifo_avail(&sensor_inst->data_fifo) >= raw_len)
+		kfifo_in(&sensor_inst->data_fifo, (unsigned char *)raw_data,
+			 raw_len);
+
+	sensor_inst->input_report_recd_size += raw_len;
+
+	return 0;
+}
+
+static int hid_sensor_send_event(struct hid_sensor_hub_device *hsdev,
+				 unsigned usage_id, void *priv)
+{
+	struct hid_sensor_custom *sensor_inst = platform_get_drvdata(priv);
+
+	if (!test_bit(0, &sensor_inst->misc_opened))
+		return 0;
+
+	sensor_inst->input_report_recd_size = 0;
+	sensor_inst->input_skip_sample = false;
+
+	wake_up(&sensor_inst->wait);
+
+	return 0;
+}
+
+static int hid_sensor_custom_add_field(struct hid_sensor_custom *sensor_inst,
+				       int index, int report_type,
+				       struct hid_report *report,
+				       struct hid_field *field)
+{
+	struct hid_sensor_custom_field *sensor_field;
+	void *fields;
+
+	fields = krealloc(sensor_inst->fields,
+			  (sensor_inst->sensor_field_count + 1) *
+			   sizeof(struct hid_sensor_custom_field), GFP_KERNEL);
+	if (!fields) {
+		kfree(sensor_inst->fields);
+		return -ENOMEM;
+	}
+	sensor_inst->fields = fields;
+	sensor_field = &sensor_inst->fields[sensor_inst->sensor_field_count];
+	sensor_field->attribute.usage_id = sensor_inst->hsdev->usage;
+	if (field->logical)
+		sensor_field->attribute.attrib_id = field->logical;
+	else
+		sensor_field->attribute.attrib_id = field->usage[0].hid;
+
+	sensor_field->attribute.index = index;
+	sensor_field->attribute.report_id = report->id;
+	sensor_field->attribute.units = field->unit;
+	sensor_field->attribute.unit_expo = field->unit_exponent;
+	sensor_field->attribute.size = (field->report_size / 8);
+	sensor_field->attribute.logical_minimum = field->logical_minimum;
+	sensor_field->attribute.logical_maximum = field->logical_maximum;
+
+	if (report_type == HID_FEATURE_REPORT)
+		snprintf(sensor_field->group_name,
+			 sizeof(sensor_field->group_name), "feature-%x-%x",
+			 sensor_field->attribute.index,
+			 sensor_field->attribute.attrib_id);
+	else if (report_type == HID_INPUT_REPORT) {
+		snprintf(sensor_field->group_name,
+			 sizeof(sensor_field->group_name),
+			 "input-%x-%x", sensor_field->attribute.index,
+			 sensor_field->attribute.attrib_id);
+		sensor_inst->input_field_count++;
+		sensor_inst->input_report_size += (field->report_size *
+						   field->report_count) / 8;
+	}
+
+	memset(&sensor_field->hid_custom_attribute_group, 0,
+	       sizeof(struct attribute_group));
+	sensor_inst->sensor_field_count++;
+
+	return 0;
+}
+
+static int hid_sensor_custom_add_fields(struct hid_sensor_custom *sensor_inst,
+					struct hid_report_enum *report_enum,
+					int report_type)
+{
+	int i;
+	int ret;
+	struct hid_report *report;
+	struct hid_field *field;
+	struct hid_sensor_hub_device *hsdev = sensor_inst->hsdev;
+
+	list_for_each_entry(report, &report_enum->report_list, list) {
+		for (i = 0; i < report->maxfield; ++i) {
+			field = report->field[i];
+			if (field->maxusage &&
+			    ((field->usage[0].collection_index >=
+			      hsdev->start_collection_index) &&
+			      (field->usage[0].collection_index <
+			       hsdev->end_collection_index))) {
+
+				ret = hid_sensor_custom_add_field(sensor_inst,
+								  i,
+								  report_type,
+								  report,
+								  field);
+				if (ret)
+					return ret;
+
+			}
+		}
+	}
+
+	return 0;
+}
+
+static int hid_sensor_custom_add_attributes(struct hid_sensor_custom
+								*sensor_inst)
+{
+	struct hid_sensor_hub_device *hsdev = sensor_inst->hsdev;
+	struct hid_device *hdev = hsdev->hdev;
+	int ret = -1;
+	int i, j;
+
+	for (j = 0; j < HID_REPORT_TYPES; ++j) {
+		if (j == HID_OUTPUT_REPORT)
+			continue;
+
+		ret = hid_sensor_custom_add_fields(sensor_inst,
+						   &hdev->report_enum[j], j);
+		if (ret)
+			return ret;
+
+	}
+
+	/* Create sysfs attributes */
+	for (i = 0; i < sensor_inst->sensor_field_count; ++i) {
+		j = 0;
+		while (j < HID_CUSTOM_TOTAL_ATTRS &&
+		       hid_custom_attrs[j].name) {
+			struct device_attribute *device_attr;
+
+			device_attr = &sensor_inst->fields[i].sd_attrs[j];
+
+			snprintf((char *)&sensor_inst->fields[i].attr_name[j],
+				 HID_CUSTOM_NAME_LENGTH, "%s-%s",
+				 sensor_inst->fields[i].group_name,
+				 hid_custom_attrs[j].name);
+			sysfs_attr_init(&device_attr->attr);
+			device_attr->attr.name =
+				(char *)&sensor_inst->fields[i].attr_name[j];
+			device_attr->attr.mode = hid_custom_attrs[j].mode;
+			device_attr->show = show_value;
+			if (hid_custom_attrs[j].mode & S_IWUSR)
+				device_attr->store = store_value;
+			sensor_inst->fields[i].attrs[j] = &device_attr->attr;
+			++j;
+		}
+		sensor_inst->fields[i].attrs[j] = NULL;
+		sensor_inst->fields[i].hid_custom_attribute_group.attrs =
+						sensor_inst->fields[i].attrs;
+		sensor_inst->fields[i].hid_custom_attribute_group.name =
+					sensor_inst->fields[i].group_name;
+		ret = sysfs_create_group(&sensor_inst->pdev->dev.kobj,
+					 &sensor_inst->fields[i].
+					 hid_custom_attribute_group);
+		if (ret)
+			break;
+
+		/* For power or report field store indexes */
+		if (sensor_inst->fields[i].attribute.attrib_id ==
+					HID_USAGE_SENSOR_PROY_POWER_STATE)
+			sensor_inst->power_state = &sensor_inst->fields[i];
+		else if (sensor_inst->fields[i].attribute.attrib_id ==
+					HID_USAGE_SENSOR_PROP_REPORT_STATE)
+			sensor_inst->report_state = &sensor_inst->fields[i];
+	}
+
+	return ret;
+}
+
+static void hid_sensor_custom_remove_attributes(struct hid_sensor_custom *
+								sensor_inst)
+{
+	int i;
+
+	for (i = 0; i < sensor_inst->sensor_field_count; ++i)
+		sysfs_remove_group(&sensor_inst->pdev->dev.kobj,
+				   &sensor_inst->fields[i].
+				   hid_custom_attribute_group);
+
+	kfree(sensor_inst->fields);
+}
+
+static ssize_t hid_sensor_custom_read(struct file *file, char __user *buf,
+				      size_t count, loff_t *f_ps)
+{
+	struct hid_sensor_custom *sensor_inst;
+	unsigned int copied;
+	int ret;
+
+	sensor_inst = container_of(file->private_data,
+				   struct hid_sensor_custom, custom_dev);
+
+	if (count < sizeof(struct hid_sensor_sample))
+		return -EINVAL;
+
+	do {
+		if (kfifo_is_empty(&sensor_inst->data_fifo)) {
+			if (file->f_flags & O_NONBLOCK)
+				return -EAGAIN;
+
+			ret = wait_event_interruptible(sensor_inst->wait,
+				!kfifo_is_empty(&sensor_inst->data_fifo));
+			if (ret)
+				return ret;
+		}
+		ret = kfifo_to_user(&sensor_inst->data_fifo, buf, count,
+				    &copied);
+		if (ret)
+			return ret;
+
+	} while (copied == 0);
+
+	return copied;
+}
+
+static int hid_sensor_custom_release(struct inode *inode, struct file *file)
+{
+	struct hid_sensor_custom *sensor_inst;
+
+	sensor_inst = container_of(file->private_data,
+				   struct hid_sensor_custom, custom_dev);
+
+	clear_bit(0, &sensor_inst->misc_opened);
+
+	return 0;
+}
+
+static int hid_sensor_custom_open(struct inode *inode, struct file *file)
+{
+	struct hid_sensor_custom *sensor_inst;
+
+	sensor_inst = container_of(file->private_data,
+				   struct hid_sensor_custom, custom_dev);
+	/* We essentially have single reader and writer */
+	if (test_and_set_bit(0, &sensor_inst->misc_opened))
+		return -EBUSY;
+
+	return nonseekable_open(inode, file);
+}
+
+static unsigned int hid_sensor_custom_poll(struct file *file,
+					   struct poll_table_struct *wait)
+{
+	struct hid_sensor_custom *sensor_inst;
+	unsigned int mask = 0;
+
+	sensor_inst = container_of(file->private_data,
+				   struct hid_sensor_custom, custom_dev);
+
+	poll_wait(file, &sensor_inst->wait, wait);
+
+	if (!kfifo_is_empty(&sensor_inst->data_fifo))
+		mask = POLLIN | POLLRDNORM;
+
+	return mask;
+}
+
+static const struct file_operations hid_sensor_custom_fops = {
+	.open =  hid_sensor_custom_open,
+	.read =  hid_sensor_custom_read,
+	.release = hid_sensor_custom_release,
+	.poll = hid_sensor_custom_poll,
+	.llseek = noop_llseek,
+};
+
+static int hid_sensor_custom_dev_if_add(struct hid_sensor_custom *sensor_inst)
+{
+	int ret;
+
+	ret = kfifo_alloc(&sensor_inst->data_fifo, HID_CUSTOM_FIFO_SIZE,
+			  GFP_KERNEL);
+	if (ret)
+		return ret;
+
+	init_waitqueue_head(&sensor_inst->wait);
+
+	sensor_inst->custom_dev.minor = MISC_DYNAMIC_MINOR;
+	sensor_inst->custom_dev.name = dev_name(&sensor_inst->pdev->dev);
+	sensor_inst->custom_dev.fops = &hid_sensor_custom_fops,
+	ret = misc_register(&sensor_inst->custom_dev);
+	if (ret) {
+		kfifo_free(&sensor_inst->data_fifo);
+		return ret;
+	}
+	return 0;
+}
+
+static void hid_sensor_custom_dev_if_remove(struct hid_sensor_custom
+								*sensor_inst)
+{
+	wake_up(&sensor_inst->wait);
+	misc_deregister(&sensor_inst->custom_dev);
+	kfifo_free(&sensor_inst->data_fifo);
+
+}
+
+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;
+
+	sensor_inst = devm_kzalloc(&pdev->dev, sizeof(*sensor_inst),
+				   GFP_KERNEL);
+	if (!sensor_inst)
+		return -ENOMEM;
+
+	sensor_inst->callbacks.capture_sample = hid_sensor_capture_sample;
+	sensor_inst->callbacks.send_event = hid_sensor_send_event;
+	sensor_inst->callbacks.pdev = pdev;
+	sensor_inst->hsdev = hsdev;
+	sensor_inst->pdev = pdev;
+	mutex_init(&sensor_inst->mutex);
+	platform_set_drvdata(pdev, sensor_inst);
+	ret = sensor_hub_register_callback(hsdev, hsdev->usage,
+					   &sensor_inst->callbacks);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "callback reg failed\n");
+		return ret;
+	}
+
+	ret = sysfs_create_group(&sensor_inst->pdev->dev.kobj,
+				 &enable_sensor_attr_group);
+	if (ret)
+		goto err_remove_callback;
+
+	ret = hid_sensor_custom_add_attributes(sensor_inst);
+	if (ret)
+		goto err_remove_group;
+
+	ret = hid_sensor_custom_dev_if_add(sensor_inst);
+	if (ret)
+		goto err_remove_attributes;
+
+	return 0;
+
+err_remove_attributes:
+	hid_sensor_custom_remove_attributes(sensor_inst);
+err_remove_group:
+	sysfs_remove_group(&sensor_inst->pdev->dev.kobj,
+			   &enable_sensor_attr_group);
+err_remove_callback:
+	sensor_hub_remove_callback(hsdev, hsdev->usage);
+
+	return ret;
+}
+
+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;
+
+	hid_sensor_custom_dev_if_remove(sensor_inst);
+	hid_sensor_custom_remove_attributes(sensor_inst);
+	sysfs_remove_group(&sensor_inst->pdev->dev.kobj,
+			   &enable_sensor_attr_group);
+	sensor_hub_remove_callback(hsdev, hsdev->usage);
+
+	return 0;
+}
+
+static struct platform_device_id hid_sensor_custom_ids[] = {
+	{
+		.name = "HID-SENSOR-2000e1",
+	},
+	{
+		.name = "HID-SENSOR-2000e2",
+	},
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(platform, hid_sensor_custom_ids);
+
+static struct platform_driver hid_sensor_custom_platform_driver = {
+	.id_table = hid_sensor_custom_ids,
+	.driver = {
+		.name	= KBUILD_MODNAME,
+	},
+	.probe		= hid_sensor_custom_probe,
+	.remove		= hid_sensor_custom_remove,
+};
+module_platform_driver(hid_sensor_custom_platform_driver);
+
+MODULE_DESCRIPTION("HID Sensor Custom and Generic sensor Driver");
+MODULE_AUTHOR("Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>");
+MODULE_LICENSE("GPL");
-- 
2.1.0

[PATCH v4 2/2] HID: HID Sensor: Update document for custom sensor

[Srinivas Pandruvada]

[-- Warning: decoded text below may be mangled, UTF-8 assumed --]
[-- Attachment #1: Type: text/plain; charset=a, Size: 4541 bytes --]

Added custom sensor documentation

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Acked-by: Jonathan Cameron <jic23@kernel.org>
---
 Documentation/hid/hid-sensor.txt | 84 ++++++++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)

diff --git a/Documentation/hid/hid-sensor.txt b/Documentation/hid/hid-sensor.txt
index 948b098..073052f 100644
--- a/Documentation/hid/hid-sensor.txt
+++ b/Documentation/hid/hid-sensor.txt
@@ -138,3 +138,87 @@ accelerometer wants to poll X axis value, then it can call this function with
 the usage id of X axis. HID sensors can provide events, so this is not necessary
 to poll for any field. If there is some new sample, the core driver will call
 registered callback function to process the sample.
+
+
+----------
+
+HID Custom and generic Sensors
+
+HID Sensor specification defines two special sensor usage types. Since they
+don't represent a standard sensor, it is not possible to define using Linux IIO
+type interfaces.
+The purpose of these sensors is to extend the functionality or provide a
+way to obfuscate the data being communicated by a sensor. Without knowing the
+mapping between the data and its encapsulated form, it is difficult for
+an application/driver to determine what data is being communicated by the sensor.
+This allows some differentiating use cases, where vendor can provide applications.
+Some common use cases are debug other sensors or to provide some events like
+keyboard attached/detached or lid open/close.
+
+To allow application to utilize these sensors, here they are exported uses sysfs
+attribute groups, attributes and misc device interface.
+
+An example of this representation on sysfs:
+/sys/devices/pci0000:00/INT33C2:00/i2c-0/i2c-INT33D1:00/0018:8086:09FA.0001/HID-SENSOR-2000e1.6.auto$ tree -R
+.
+├── enable_sensor
+├── feature-0-200316
+│   ├── feature-0-200316-maximum
+│   ├── feature-0-200316-minimum
+│   ├── feature-0-200316-name
+│   ├── feature-0-200316-size
+│   ├── feature-0-200316-unit-expo
+│   ├── feature-0-200316-units
+│   └── feature-0-200316-value
+├── feature-1-200201
+│   ├── feature-1-200201-maximum
+│   ├── feature-1-200201-minimum
+│   ├── feature-1-200201-name
+│   ├── feature-1-200201-size
+│   ├── feature-1-200201-unit-expo
+│   ├── feature-1-200201-units
+│   └── feature-1-200201-value
+├── input-0-200201
+│   ├── input-0-200201-maximum
+│   ├── input-0-200201-minimum
+│   ├── input-0-200201-name
+│   ├── input-0-200201-size
+│   ├── input-0-200201-unit-expo
+│   ├── input-0-200201-units
+│   └── input-0-200201-value
+├── input-1-200202
+│   ├── input-1-200202-maximum
+│   ├── input-1-200202-minimum
+│   ├── input-1-200202-name
+│   ├── input-1-200202-size
+│   ├── input-1-200202-unit-expo
+│   ├── input-1-200202-units
+│   └── input-1-200202-value
+
+Here there is a custom sensors with four fields, two feature and two inputs.
+Each field is represented by a set of attributes. All fields except the "value"
+are read only. The value field is a RW field.
+Example
+/sys/bus/platform/devices/HID-SENSOR-2000e1.6.auto/feature-0-200316$ grep -r . *
+feature-0-200316-maximum:6
+feature-0-200316-minimum:0
+feature-0-200316-name:property-reporting-state
+feature-0-200316-size:1
+feature-0-200316-unit-expo:0
+feature-0-200316-units:25
+feature-0-200316-value:1
+
+How to enable such sensor?
+By default sensor can be power gated. To enable sysfs attribute "enable" can be
+used.
+$ echo 1 > enable_sensor
+
+Once enabled and powered on, sensor can report value using HID reports.
+These reports are pushed using misc device interface in a FIFO order.
+/dev$ tree | grep HID-SENSOR-2000e1.6.auto
+│   ├── 10:53 -> ../HID-SENSOR-2000e1.6.auto
+├── HID-SENSOR-2000e1.6.auto
+
+Each reports can be of variable length preceded by a header. This header
+consist of a 32 bit usage id, 64 bit time stamp and 32 bit length field of raw
+data.
-- 
2.1.0

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Re: [PATCH v4 0/2] HID: HID Sensor: Custom and Generic sensor support

[Jiri Kosina]

On Fri, 10 Apr 2015, Srinivas Pandruvada wrote:

> v4
> - Fix sysfs_attr_init arguments. Again sorry for the mistake
> - Fix attribute value size for multi byte feature report

I have now applied v4 to for-4.1/sensor-hub. I have retained Jonathan's 
Reviewed-by, given the very limited amount of changes Srinivas did 
compared to v3. Please let me know if you have objections to that.

Thanks,

-- 
Jiri Kosina
SUSE Labs