[PATCH 1/2] HID: sensor-hub: Add sensor_hub_input_attr_read_values() for multi-byte reads

[Zhang Lixu <lixu.zhang@intel.com>]

From: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>

sensor_hub_input_attr_get_raw_value() is limited to returning a single
32-bit value, which is insufficient for sensors that report data larger
than 32 bits, such as a quaternion with four s16 elements.

Add sensor_hub_input_attr_read_values() that accepts a caller-provided
buffer and accumulates incoming data until the buffer is full. The two
paths are distinguished in sensor_hub_raw_event() by pending.max_raw_size
being non-zero, preserving backward compatibility.

Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Co-developed-by: Zhang Lixu <lixu.zhang@intel.com>
Signed-off-by: Zhang Lixu <lixu.zhang@intel.com>
---
 drivers/hid/hid-sensor-hub.c   | 77 +++++++++++++++++++++++++++++++---
 include/linux/hid-sensor-hub.h | 25 +++++++++++
 2 files changed, 96 insertions(+), 6 deletions(-)

diff --git a/drivers/hid/hid-sensor-hub.c b/drivers/hid/hid-sensor-hub.c
index 90666ff629def..34f710c465b80 100644
--- a/drivers/hid/hid-sensor-hub.c
+++ b/drivers/hid/hid-sensor-hub.c
@@ -286,6 +286,54 @@ int sensor_hub_get_feature(struct hid_sensor_hub_device *hsdev, u32 report_id,
 }
 EXPORT_SYMBOL_GPL(sensor_hub_get_feature);
 
+int sensor_hub_input_attr_read_values(struct hid_sensor_hub_device *hsdev,
+				      u32 usage_id, u32 attr_usage_id,
+				      u32 report_id,
+				      enum sensor_hub_read_flags flag,
+				      u32 buffer_size, u8 *buffer)
+{
+	struct sensor_hub_data *data = hid_get_drvdata(hsdev->hdev);
+	struct hid_report *report;
+	unsigned long flags;
+	long cycles;
+	int ret;
+
+	report = sensor_hub_report(report_id, hsdev->hdev, HID_INPUT_REPORT);
+	if (!report)
+		return -EINVAL;
+
+	mutex_lock(hsdev->mutex_ptr);
+	if (flag == SENSOR_HUB_SYNC) {
+		memset(&hsdev->pending, 0, sizeof(hsdev->pending));
+		init_completion(&hsdev->pending.ready);
+		hsdev->pending.usage_id = usage_id;
+		hsdev->pending.attr_usage_id = attr_usage_id;
+		hsdev->pending.max_raw_size = buffer_size;
+		hsdev->pending.raw_data = buffer;
+
+		spin_lock_irqsave(&data->lock, flags);
+		hsdev->pending.status = true;
+		spin_unlock_irqrestore(&data->lock, flags);
+	}
+	mutex_lock(&data->mutex);
+	hid_hw_request(hsdev->hdev, report, HID_REQ_GET_REPORT);
+	mutex_unlock(&data->mutex);
+	ret = 0;
+	if (flag == SENSOR_HUB_SYNC) {
+		cycles = wait_for_completion_interruptible_timeout(&hsdev->pending.ready,
+								   HZ * 5);
+		if (cycles == 0)
+			ret = -ETIMEDOUT;
+		else if (cycles < 0)
+			ret = cycles;
+
+		hsdev->pending.status = false;
+	}
+	mutex_unlock(hsdev->mutex_ptr);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(sensor_hub_input_attr_read_values);
 
 int sensor_hub_input_attr_get_raw_value(struct hid_sensor_hub_device *hsdev,
 					u32 usage_id,
@@ -478,6 +526,8 @@ static int sensor_hub_raw_event(struct hid_device *hdev,
 	struct hid_collection *collection = NULL;
 	void *priv = NULL;
 	struct hid_sensor_hub_device *hsdev = NULL;
+	u32 copy_size;
+	u32 avail;
 
 	hid_dbg(hdev, "sensor_hub_raw_event report id:0x%x size:%d type:%d\n",
 			 report->id, size, report->type);
@@ -518,12 +568,27 @@ static int sensor_hub_raw_event(struct hid_device *hdev,
 					      hsdev->pending.attr_usage_id ==
 					      report->field[i]->logical)) {
 			hid_dbg(hdev, "data was pending ...\n");
-			hsdev->pending.raw_data = kmemdup(ptr, sz, GFP_ATOMIC);
-			if (hsdev->pending.raw_data)
-				hsdev->pending.raw_size = sz;
-			else
-				hsdev->pending.raw_size = 0;
-			complete(&hsdev->pending.ready);
+			if (hsdev->pending.max_raw_size) {
+				if (hsdev->pending.index < hsdev->pending.max_raw_size) {
+					avail = hsdev->pending.max_raw_size - hsdev->pending.index;
+					copy_size = clamp(sz, 0U, avail);
+
+					memcpy(hsdev->pending.raw_data + hsdev->pending.index,
+					       ptr, copy_size);
+					hsdev->pending.index += copy_size;
+					if (hsdev->pending.index >= hsdev->pending.max_raw_size) {
+						hsdev->pending.raw_size = hsdev->pending.index;
+						complete(&hsdev->pending.ready);
+					}
+				}
+			} else {
+				hsdev->pending.raw_data = kmemdup(ptr, sz, GFP_ATOMIC);
+				if (hsdev->pending.raw_data)
+					hsdev->pending.raw_size = sz;
+				else
+					hsdev->pending.raw_size = 0;
+				complete(&hsdev->pending.ready);
+			}
 		}
 		if (callback->capture_sample) {
 			if (report->field[i]->logical)
diff --git a/include/linux/hid-sensor-hub.h b/include/linux/hid-sensor-hub.h
index e710565531085..ab5cc8db3fbb3 100644
--- a/include/linux/hid-sensor-hub.h
+++ b/include/linux/hid-sensor-hub.h
@@ -43,6 +43,8 @@ struct hid_sensor_hub_attribute_info {
  * @attr_usage_id:	Usage Id of a field, e.g. X-axis for a gyro.
  * @raw_size:		Response size for a read request.
  * @raw_data:		Place holder for received response.
+ * @index:		Current write index into raw_data for multi-byte reads.
+ * @max_raw_size:	Total buffer size for multi-byte reads; 0 for single-value reads.
  */
 struct sensor_hub_pending {
 	bool status;
@@ -51,6 +53,8 @@ struct sensor_hub_pending {
 	u32 attr_usage_id;
 	int raw_size;
 	u8  *raw_data;
+	u32 index;
+	u32 max_raw_size;
 };
 
 /**
@@ -183,6 +187,27 @@ int sensor_hub_input_attr_get_raw_value(struct hid_sensor_hub_device *hsdev,
 					bool is_signed
 );
 
+/**
+ * sensor_hub_input_attr_read_values() - Synchronous multi-byte read request
+ * @hsdev:		Hub device instance.
+ * @usage_id:		Attribute usage id of parent physical device as per spec
+ * @attr_usage_id:	Attribute usage id as per spec
+ * @report_id:		Report id to look for
+ * @flag:		Synchronous or asynchronous read
+ * @buffer_size:	Size of the buffer in bytes
+ * @buffer:		Buffer to store the read data
+ *
+ * Issues a synchronous or asynchronous read request for an input attribute,
+ * accumulating data into the provided buffer until it is full.
+ * Return: 0 on success, -ETIMEDOUT if the device did not respond, or a
+ * negative error code.
+ */
+int sensor_hub_input_attr_read_values(struct hid_sensor_hub_device *hsdev,
+				      u32 usage_id, u32 attr_usage_id,
+				      u32 report_id,
+				      enum sensor_hub_read_flags flag,
+				      u32 buffer_size, u8 *buffer);
+
 /**
 * sensor_hub_set_feature() - Feature set request
 * @hsdev:	Hub device instance.
-- 
2.43.0