diff mbox series

[v13,2/6] media: change au0828 to use Media Device Allocator API

Message ID 05ec250a56d9eaa868e7c8cf6376d6f8e29bb102.1553814518.git.shuah@kernel.org (mailing list archive)
State New, archived
Headers show
Series Media Device Allocator API | expand

Commit Message

Shuah March 29, 2019, 12:04 a.m. UTC 
Media Device Allocator API to allows multiple drivers share a media device.
This API solves a very common use-case for media devices where one physical
device (an USB stick) provides both audio and video. When such media device
exposes a standard USB Audio class, a proprietary Video class, two or more
independent drivers will share a single physical USB bridge. In such cases,
it is necessary to coordinate access to the shared resource.

Using this API, drivers can allocate a media device with the shared struct
device as the key. Once the media device is allocated by a driver, other
drivers can get a reference to it. The media device is released when all
the references are released.

Change au0828 to use Media Device Allocator API to allocate media device
with the parent usb struct device as the key, so it can be shared with the
snd_usb_audio driver.

Signed-off-by: Shuah Khan <shuah@kernel.org>
---
 drivers/media/usb/au0828/Kconfig       |  2 ++
 drivers/media/usb/au0828/au0828-core.c | 13 +++++--------
 drivers/media/usb/au0828/au0828.h      |  1 +
 3 files changed, 8 insertions(+), 8 deletions(-)

Comments

Hans Verkuil March 29, 2019, 8:27 a.m. UTC | #1 
On 3/29/19 1:04 AM, Shuah Khan wrote:
> Media Device Allocator API to allows multiple drivers share a media device.
> This API solves a very common use-case for media devices where one physical
> device (an USB stick) provides both audio and video. When such media device
> exposes a standard USB Audio class, a proprietary Video class, two or more
> independent drivers will share a single physical USB bridge. In such cases,
> it is necessary to coordinate access to the shared resource.
> 
> Using this API, drivers can allocate a media device with the shared struct
> device as the key. Once the media device is allocated by a driver, other
> drivers can get a reference to it. The media device is released when all
> the references are released.
> 
> Change au0828 to use Media Device Allocator API to allocate media device
> with the parent usb struct device as the key, so it can be shared with the
> snd_usb_audio driver.
> 
> Signed-off-by: Shuah Khan <shuah@kernel.org>
> ---
>  drivers/media/usb/au0828/Kconfig       |  2 ++
>  drivers/media/usb/au0828/au0828-core.c | 13 +++++--------
>  drivers/media/usb/au0828/au0828.h      |  1 +
>  3 files changed, 8 insertions(+), 8 deletions(-)
> 
> diff --git a/drivers/media/usb/au0828/Kconfig b/drivers/media/usb/au0828/Kconfig
> index 65fc067eb864..98de6e24329e 100644
> --- a/drivers/media/usb/au0828/Kconfig
> +++ b/drivers/media/usb/au0828/Kconfig
> @@ -2,6 +2,8 @@
>  config VIDEO_AU0828
>  	tristate "Auvitek AU0828 support"
>  	depends on I2C && INPUT && DVB_CORE && USB && VIDEO_V4L2
> +	select MEDIA_CONTROLLER
> +	select MEDIA_CONTROLLER_DVB

Is it required to select MEDIA_CONTROLLER_DVB? Does something fail to work
if this is unset?

Regards,

	Hans

>  	select I2C_ALGOBIT
>  	select VIDEO_TVEEPROM
>  	select VIDEOBUF2_VMALLOC if VIDEO_V4L2
> diff --git a/drivers/media/usb/au0828/au0828-core.c b/drivers/media/usb/au0828/au0828-core.c
> index 3f8c92a70116..4f8ba6f64d3c 100644
> --- a/drivers/media/usb/au0828/au0828-core.c
> +++ b/drivers/media/usb/au0828/au0828-core.c
> @@ -155,9 +155,7 @@ static void au0828_unregister_media_device(struct au0828_dev *dev)
>  	dev->media_dev->disable_source = NULL;
>  	mutex_unlock(&mdev->graph_mutex);
>  
> -	media_device_unregister(dev->media_dev);
> -	media_device_cleanup(dev->media_dev);
> -	kfree(dev->media_dev);
> +	media_device_delete(dev->media_dev, KBUILD_MODNAME, THIS_MODULE);
>  	dev->media_dev = NULL;
>  #endif
>  }
> @@ -210,14 +208,10 @@ static int au0828_media_device_init(struct au0828_dev *dev,
>  #ifdef CONFIG_MEDIA_CONTROLLER
>  	struct media_device *mdev;
>  
> -	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
> +	mdev = media_device_usb_allocate(udev, KBUILD_MODNAME, THIS_MODULE);
>  	if (!mdev)
>  		return -ENOMEM;
>  
> -	/* check if media device is already initialized */
> -	if (!mdev->dev)
> -		media_device_usb_init(mdev, udev, udev->product);
> -
>  	dev->media_dev = mdev;
>  #endif
>  	return 0;
> @@ -480,6 +474,9 @@ static int au0828_media_device_register(struct au0828_dev *dev,
>  		/* register media device */
>  		ret = media_device_register(dev->media_dev);
>  		if (ret) {
> +			media_device_delete(dev->media_dev, KBUILD_MODNAME,
> +					    THIS_MODULE);
> +			dev->media_dev = NULL;
>  			dev_err(&udev->dev,
>  				"Media Device Register Error: %d\n", ret);
>  			return ret;
> diff --git a/drivers/media/usb/au0828/au0828.h b/drivers/media/usb/au0828/au0828.h
> index 425c35d16057..57b00de8d3f2 100644
> --- a/drivers/media/usb/au0828/au0828.h
> +++ b/drivers/media/usb/au0828/au0828.h
> @@ -31,6 +31,7 @@
>  #include <media/v4l2-ctrls.h>
>  #include <media/v4l2-fh.h>
>  #include <media/media-device.h>
> +#include <media/media-dev-allocator.h>
>  
>  /* DVB */
>  #include <media/demux.h>
>
Shuah March 29, 2019, 2:14 p.m. UTC | #2 
On 3/29/19 2:27 AM, Hans Verkuil wrote:
> On 3/29/19 1:04 AM, Shuah Khan wrote:
>> Media Device Allocator API to allows multiple drivers share a media device.
>> This API solves a very common use-case for media devices where one physical
>> device (an USB stick) provides both audio and video. When such media device
>> exposes a standard USB Audio class, a proprietary Video class, two or more
>> independent drivers will share a single physical USB bridge. In such cases,
>> it is necessary to coordinate access to the shared resource.
>>
>> Using this API, drivers can allocate a media device with the shared struct
>> device as the key. Once the media device is allocated by a driver, other
>> drivers can get a reference to it. The media device is released when all
>> the references are released.
>>
>> Change au0828 to use Media Device Allocator API to allocate media device
>> with the parent usb struct device as the key, so it can be shared with the
>> snd_usb_audio driver.
>>
>> Signed-off-by: Shuah Khan <shuah@kernel.org>
>> ---
>>   drivers/media/usb/au0828/Kconfig       |  2 ++
>>   drivers/media/usb/au0828/au0828-core.c | 13 +++++--------
>>   drivers/media/usb/au0828/au0828.h      |  1 +
>>   3 files changed, 8 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/media/usb/au0828/Kconfig b/drivers/media/usb/au0828/Kconfig
>> index 65fc067eb864..98de6e24329e 100644
>> --- a/drivers/media/usb/au0828/Kconfig
>> +++ b/drivers/media/usb/au0828/Kconfig
>> @@ -2,6 +2,8 @@
>>   config VIDEO_AU0828
>>   	tristate "Auvitek AU0828 support"
>>   	depends on I2C && INPUT && DVB_CORE && USB && VIDEO_V4L2
>> +	select MEDIA_CONTROLLER
>> +	select MEDIA_CONTROLLER_DVB
> 
> Is it required to select MEDIA_CONTROLLER_DVB? Does something fail to work
> if this is unset?
> 

Need this enabled for dvb driver to use media controller. api.

e.g dvb_register_media_device() does all its media controller code
when MEDIA_CONTROLLER_DVB is enabled.

See drivers/media/dvb-core/dvbdev.c

The config still says experimental:

config MEDIA_CONTROLLER_DVB
         bool "Enable Media controller for DVB (EXPERIMENTAL)"
         depends on MEDIA_CONTROLLER && DVB_CORE
         ---help---
           Enable the media controller API support for DVB.

           This is currently experimental.

Is that still accurate? Should be updated?

thanks,
-- Shuah
diff mbox series

Patch

diff --git a/drivers/media/usb/au0828/Kconfig b/drivers/media/usb/au0828/Kconfig
index 65fc067eb864..98de6e24329e 100644
--- a/drivers/media/usb/au0828/Kconfig
+++ b/drivers/media/usb/au0828/Kconfig
@@ -2,6 +2,8 @@ 
 config VIDEO_AU0828
 	tristate "Auvitek AU0828 support"
 	depends on I2C && INPUT && DVB_CORE && USB && VIDEO_V4L2
+	select MEDIA_CONTROLLER
+	select MEDIA_CONTROLLER_DVB
 	select I2C_ALGOBIT
 	select VIDEO_TVEEPROM
 	select VIDEOBUF2_VMALLOC if VIDEO_V4L2
diff --git a/drivers/media/usb/au0828/au0828-core.c b/drivers/media/usb/au0828/au0828-core.c
index 3f8c92a70116..4f8ba6f64d3c 100644
--- a/drivers/media/usb/au0828/au0828-core.c
+++ b/drivers/media/usb/au0828/au0828-core.c
@@ -155,9 +155,7 @@  static void au0828_unregister_media_device(struct au0828_dev *dev)
 	dev->media_dev->disable_source = NULL;
 	mutex_unlock(&mdev->graph_mutex);
 
-	media_device_unregister(dev->media_dev);
-	media_device_cleanup(dev->media_dev);
-	kfree(dev->media_dev);
+	media_device_delete(dev->media_dev, KBUILD_MODNAME, THIS_MODULE);
 	dev->media_dev = NULL;
 #endif
 }
@@ -210,14 +208,10 @@  static int au0828_media_device_init(struct au0828_dev *dev,
 #ifdef CONFIG_MEDIA_CONTROLLER
 	struct media_device *mdev;
 
-	mdev = kzalloc(sizeof(*mdev), GFP_KERNEL);
+	mdev = media_device_usb_allocate(udev, KBUILD_MODNAME, THIS_MODULE);
 	if (!mdev)
 		return -ENOMEM;
 
-	/* check if media device is already initialized */
-	if (!mdev->dev)
-		media_device_usb_init(mdev, udev, udev->product);
-
 	dev->media_dev = mdev;
 #endif
 	return 0;
@@ -480,6 +474,9 @@  static int au0828_media_device_register(struct au0828_dev *dev,
 		/* register media device */
 		ret = media_device_register(dev->media_dev);
 		if (ret) {
+			media_device_delete(dev->media_dev, KBUILD_MODNAME,
+					    THIS_MODULE);
+			dev->media_dev = NULL;
 			dev_err(&udev->dev,
 				"Media Device Register Error: %d\n", ret);
 			return ret;
diff --git a/drivers/media/usb/au0828/au0828.h b/drivers/media/usb/au0828/au0828.h
index 425c35d16057..57b00de8d3f2 100644
--- a/drivers/media/usb/au0828/au0828.h
+++ b/drivers/media/usb/au0828/au0828.h
@@ -31,6 +31,7 @@ 
 #include <media/v4l2-ctrls.h>
 #include <media/v4l2-fh.h>
 #include <media/media-device.h>
+#include <media/media-dev-allocator.h>
 
 /* DVB */
 #include <media/demux.h>