On 11/03/2015 09:23 AM, Takashi Iwai wrote:
> On Tue, 03 Nov 2015 17:06:45 +0100,
> Shuah Khan wrote:
>>
>> On 10/25/2015 03:37 PM, Shuah Khan wrote:
>>> On 10/22/2015 01:16 AM, Takashi Iwai wrote:
>>>> On Wed, 21 Oct 2015 01:25:15 +0200,
>>>> Shuah Khan wrote:
>>>>>
>>>>> Add support for creating MEDIA_ENT_F_AUDIO_MIXER entity for
>>>>> each mixer and a MEDIA_INTF_T_ALSA_CONTROL control interface
>>>>> entity that links to mixer entities. MEDIA_INTF_T_ALSA_CONTROL
>>>>> entity corresponds to the control device for the card.
>>>>>
>>>>> Signed-off-by: Shuah Khan <shuahkh@xxxxxxxxxxxxxxx>
>>>>> ---
>>>>> sound/usb/card.c | 5 +++
>>>>> sound/usb/media.c | 89
>>>>> ++++++++++++++++++++++++++++++++++++++++++++++++++++
>>>>> sound/usb/media.h | 20 ++++++++++++
>>>>> sound/usb/mixer.h | 1 +
>>>>> sound/usb/usbaudio.h | 1 +
>>>>> 5 files changed, 116 insertions(+)
>>>>>
>>>>> diff --git a/sound/usb/card.c b/sound/usb/card.c
>>>>> index 469d2bf..d004cb4 100644
>>>>> --- a/sound/usb/card.c
>>>>> +++ b/sound/usb/card.c
>>>>> @@ -560,6 +560,9 @@ static int usb_audio_probe(struct usb_interface
>>>>> *intf,
>>>>> if (err < 0)
>>>>> goto __error;
>>>>>
>>>>> + /* Create media entities for mixer and control dev */
>>>>> + media_mixer_init(chip);
>>>>> +
>>>>> usb_chip[chip->index] = chip;
>>>>> chip->num_interfaces++;
>>>>> chip->probing = 0;
>>>>> @@ -616,6 +619,8 @@ static void usb_audio_disconnect(struct
>>>>> usb_interface *intf)
>>>>> list_for_each(p, &chip->midi_list) {
>>>>> snd_usbmidi_disconnect(p);
>>>>> }
>>>>> + /* delete mixer media resources */
>>>>> + media_mixer_delete(chip);
>>>>> /* release mixer resources */
>>>>> list_for_each_entry(mixer, &chip->mixer_list, list) {
>>>>> snd_usb_mixer_disconnect(mixer);
>>>>> diff --git a/sound/usb/media.c b/sound/usb/media.c
>>>>> index 0cbfee6..a26ea8b 100644
>>>>> --- a/sound/usb/media.c
>>>>> +++ b/sound/usb/media.c
>>>>> @@ -199,4 +199,93 @@ void media_stop_pipeline(struct
>>>>> snd_usb_substream *subs)
>>>>> if (mctl)
>>>>> media_disable_source(mctl);
>>>>> }
>>>>> +
>>>>> +int media_mixer_init(struct snd_usb_audio *chip)
>>>>> +{
>>>>> + struct device *ctl_dev = &chip->card->ctl_dev;
>>>>> + struct media_intf_devnode *ctl_intf;
>>>>> + struct usb_mixer_interface *mixer;
>>>>> + struct media_device *mdev;
>>>>> + struct media_mixer_ctl *mctl;
>>>>> + u32 intf_type = MEDIA_INTF_T_ALSA_CONTROL;
>>>>> + int ret;
>>>>> +
>>>>> + mdev = media_device_find_devres(&chip->dev->dev);
>>>>> + if (!mdev)
>>>>> + return -ENODEV;
>>>>> +
>>>>> + ctl_intf = (struct media_intf_devnode *)
>>>>> chip->ctl_intf_media_devnode;
>>>>
>>>> Why do we need cast? Can't chip->ctl_intf_media_devnode itself be
>>>> struct media_intf_devndoe pointer?
>>>
>>> Yeah. There is no need to cast here. I will fix it.
>>
>> Sorry I misspoke. The reason for this cast is ctl_intf_media_devnode
>> is void to avoid including media.h and other media files in usbaudio.h
>
> You can declare the struct without definition in each header file.
> So just declare it and use it in usbaudio.h like:
>
> struct media_intf_devnode;
>
> struct snd_usb_audio {
> ....
> struct media_intf_devnode *ctl_intf_media_devnode;
> ....
>
> And even if you're using a void pointer there instead of the explicit
> struct pointer, the cast is superfluous. The implicit cast between a
> void pointer and any other pointer is valid in plain C.
>
Yes. cast is definitely not necessary. I will drop the cast and leave
the rest alone.
thanks,
-- Shuah
--
Shuah Khan
Sr. Linux Kernel Developer
Open Source Innovation Group
Samsung Research America (Silicon Valley)
shuahkh@xxxxxxxxxxxxxxx | (970) 217-8978
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