Re: [PATCH 1/9] HID: hid-sensor-hub: Extend API for async reads

[Jonathan Cameron <jic23@kernel.org>]

On 07/01/15 18:47, Srinivas Pandruvada wrote:
> Add additional flag to read in async mode. In this mode the caller
> need to register for events and match attribute usage id for result.
An example of this being used would make ti easier to see how it is meant
to work...
> 
> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
> ---
>  drivers/hid/hid-sensor-hub.c   | 15 ++++++++++++++-
>  include/linux/hid-sensor-hub.h | 19 +++++++++++++------
>  2 files changed, 27 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/hid/hid-sensor-hub.c b/drivers/hid/hid-sensor-hub.c
> index 8bed109..7403b25 100644
> --- a/drivers/hid/hid-sensor-hub.c
> +++ b/drivers/hid/hid-sensor-hub.c
> @@ -275,13 +275,26 @@ EXPORT_SYMBOL_GPL(sensor_hub_get_feature);
>  
>  int sensor_hub_input_attr_get_raw_value(struct hid_sensor_hub_device *hsdev,
>  					u32 usage_id,
> -					u32 attr_usage_id, u32 report_id)
> +					u32 attr_usage_id, u32 report_id,
> +					enum sensor_hub_read_flags flag)
>  {
>  	struct sensor_hub_data *data = hid_get_drvdata(hsdev->hdev);
>  	unsigned long flags;
>  	struct hid_report *report;
>  	int ret_val = 0;
>  
> +	if (flag == SENSOR_HUB_ASYNC) {
> +		report = sensor_hub_report(report_id, hsdev->hdev,
> +					   HID_INPUT_REPORT);
> +		if (!report)
> +			return -EINVAL;
> +
> +		mutex_lock(&data->mutex);
> +		hid_hw_request(hsdev->hdev, report, HID_REQ_GET_REPORT);
> +		mutex_unlock(&data->mutex);
> +		return 0;
> +	}
> +
>  	mutex_lock(&hsdev->mutex);
>  	memset(&hsdev->pending, 0, sizeof(hsdev->pending));
>  	init_completion(&hsdev->pending.ready);
> diff --git a/include/linux/hid-sensor-hub.h b/include/linux/hid-sensor-hub.h
> index a51c768..d48e91f 100644
> --- a/include/linux/hid-sensor-hub.h
> +++ b/include/linux/hid-sensor-hub.h
> @@ -171,20 +171,27 @@ int sensor_hub_input_get_attribute_info(struct hid_sensor_hub_device *hsdev,
>  			struct hid_sensor_hub_attribute_info *info);
>  
>  /**
> -* sensor_hub_input_attr_get_raw_value() - Synchronous read request
> +* sensor_hub_input_attr_get_raw_value() - Attribute 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:	Synchronour or asynchronous read
>  *
> -* Issues a synchronous read request for an input attribute. Returns
> -* data upto 32 bits. Since client can get events, so this call should
> -* not be used for data paths, this will impact performance.
> +* Issues a synchronous or asynchronous read request for an input attribute.
> +* Returns data upto 32 bits.
>  */
>  
> +enum sensor_hub_read_flags {
> +	SENSOR_HUB_SYNC,
> +	SENSOR_HUB_ASYNC,
> +};
> +
>  int sensor_hub_input_attr_get_raw_value(struct hid_sensor_hub_device *hsdev,
> -			u32 usage_id,
> -			u32 attr_usage_id, u32 report_id);
> +					u32 usage_id,
> +					u32 attr_usage_id, u32 report_id,
> +					enum sensor_hub_read_flags flag
> +);
>  /**
>  * sensor_hub_set_feature() - Feature set request
>  * @hsdev:	Hub device instance.
>