Re: [PATCH 1/3] HID: Delay opening HID device

[Srinivas Pandruvada <srinivas.pandruvada-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>]

On 09/15/2013 03:15 AM, Jonathan Cameron wrote:
> On 09/10/13 21:03, Srinivas Pandruvada wrote:
>> Don't call hid_open_device till there is actually an user. This saves
>> power by not opening underlying transport for HID. Also close device
>> if there are no active mfd client using HID sensor hub.
>>
>> Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>
> Buglet inline.
>> ---
>>   drivers/hid/hid-sensor-hub.c   | 45 ++++++++++++++++++++++++++++++++----------
>>   include/linux/hid-sensor-hub.h | 18 +++++++++++++++++
>>   2 files changed, 53 insertions(+), 10 deletions(-)
>>
>> diff --git a/drivers/hid/hid-sensor-hub.c b/drivers/hid/hid-sensor-hub.c
>> index 10e1581..8effdee 100644
>> --- a/drivers/hid/hid-sensor-hub.c
>> +++ b/drivers/hid/hid-sensor-hub.c
>> @@ -465,6 +465,39 @@ static int sensor_hub_raw_event(struct hid_device *hdev,
>>   	return 1;
>>   }
>>   
>> +int sensor_hub_device_open(struct hid_sensor_hub_device *hsdev)
>> +{
>> +	int ret;
>> +	struct sensor_hub_data *data =  hid_get_drvdata(hsdev->hdev);
>> +
>> +	mutex_lock(&data->mutex);
>> +	if (!hsdev->ref_cnt) {
>> +		ret = hid_hw_open(hsdev->hdev);
>> +		if (ret) {
>> +			hid_err(hsdev->hdev, "failed to open hid device\n");
>> +			mutex_unlock(&data->mutex);
>> +			return ret;
>> +		}
>> +	}
>> +	hsdev->ref_cnt++;
>> +	mutex_unlock(&data->mutex);
>> +
>> +	return ret;
> Not initialized.
Good catch.
>> +}
>> +EXPORT_SYMBOL_GPL(sensor_hub_device_open);
>> +
>> +void sensor_hub_device_close(struct hid_sensor_hub_device *hsdev)
>> +{
>> +	struct sensor_hub_data *data =  hid_get_drvdata(hsdev->hdev);
>> +
>> +	mutex_lock(&data->mutex);
>> +	hsdev->ref_cnt--;
>> +	if (!hsdev->ref_cnt)
>> +		hid_hw_close(hsdev->hdev);
>> +	mutex_unlock(&data->mutex);
>> +}
>> +EXPORT_SYMBOL_GPL(sensor_hub_device_close);
>> +
>>   static int sensor_hub_probe(struct hid_device *hdev,
>>   				const struct hid_device_id *id)
>>   {
>> @@ -506,12 +539,6 @@ static int sensor_hub_probe(struct hid_device *hdev,
>>   		hid_err(hdev, "hw start failed\n");
>>   		return ret;
>>   	}
>> -	ret = hid_hw_open(hdev);
>> -	if (ret) {
>> -		hid_err(hdev, "failed to open input interrupt pipe\n");
>> -		goto err_stop_hw;
>> -	}
>> -
>>   	INIT_LIST_HEAD(&sd->dyn_callback_list);
>>   	sd->hid_sensor_client_cnt = 0;
>>   	report_enum = &hdev->report_enum[HID_INPUT_REPORT];
>> @@ -520,7 +547,7 @@ static int sensor_hub_probe(struct hid_device *hdev,
>>   	if (dev_cnt > HID_MAX_PHY_DEVICES) {
>>   		hid_err(hdev, "Invalid Physical device count\n");
>>   		ret = -EINVAL;
>> -		goto err_close;
>> +		goto err_stop_hw;
>>   	}
>>   	sd->hid_sensor_hub_client_devs = kzalloc(dev_cnt *
>>   						sizeof(struct mfd_cell),
>> @@ -528,7 +555,7 @@ static int sensor_hub_probe(struct hid_device *hdev,
>>   	if (sd->hid_sensor_hub_client_devs == NULL) {
>>   		hid_err(hdev, "Failed to allocate memory for mfd cells\n");
>>   			ret = -ENOMEM;
>> -			goto err_close;
>> +			goto err_stop_hw;
>>   	}
>>   	list_for_each_entry(report, &report_enum->report_list, list) {
>>   		hid_dbg(hdev, "Report id:%x\n", report->id);
>> @@ -565,8 +592,6 @@ err_free_names:
>>   	for (i = 0; i < sd->hid_sensor_client_cnt ; ++i)
>>   		kfree(sd->hid_sensor_hub_client_devs[i].name);
>>   	kfree(sd->hid_sensor_hub_client_devs);
>> -err_close:
>> -	hid_hw_close(hdev);
>>   err_stop_hw:
>>   	hid_hw_stop(hdev);
>>   
>> diff --git a/include/linux/hid-sensor-hub.h b/include/linux/hid-sensor-hub.h
>> index 32ba451..a265af2 100644
>> --- a/include/linux/hid-sensor-hub.h
>> +++ b/include/linux/hid-sensor-hub.h
>> @@ -47,11 +47,13 @@ struct hid_sensor_hub_attribute_info {
>>    * @hdev:		Stores the hid instance.
>>    * @vendor_id:		Vendor id of hub device.
>>    * @product_id:		Product id of hub device.
>> + * @ref_cnt:		Number of MFD clients have opened this device
>>    */
>>   struct hid_sensor_hub_device {
>>   	struct hid_device *hdev;
>>   	u32 vendor_id;
>>   	u32 product_id;
>> +	int ref_cnt;
>>   };
>>   
>>   /**
>> @@ -74,6 +76,22 @@ struct hid_sensor_hub_callbacks {
>>   			 void *priv);
>>   };
>>   
>> +/**
>> +* sensor_hub_device_open() - Open hub device
>> +* @hsdev:	Hub device instance.
>> +*
>> +* Used to open hid device for sensor hub.
>> +*/
>> +int sensor_hub_device_open(struct hid_sensor_hub_device *hsdev);
>> +
>> +/**
>> +* sensor_hub_device_clode() - Close hub device
>> +* @hsdev:	Hub device instance.
>> +*
>> +* Used to clode hid device for sensor hub.
>> +*/
>> +void sensor_hub_device_close(struct hid_sensor_hub_device *hsdev);
>> +
>>   /* Registration functions */
>>   
>>   /**
>>
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Thanks,
Srinivas