Commit 74914dc1 authored by Wesley Cheng's avatar Wesley Cheng Committed by Greg Kroah-Hartman
Browse files

ALSA: usb-audio: Introduce USB SND platform op callbacks 



Allow for different platforms to be notified on USB SND connect/disconnect
sequences.  This allows for platform USB SND modules to properly initialize
and populate internal structures with references to the USB SND chip
device.

Tested-by: default avatarPuma Hsu <pumahsu@google.com>
Tested-by: default avatarDaehwan Jung <dh10.jung@samsung.com>
Signed-off-by: default avatarWesley Cheng <quic_wcheng@quicinc.com>
Acked-by: default avatarMark Brown <broonie@kernel.org>
Link: https://lore.kernel.org/r/20250409194804.3773260-13-quic_wcheng@quicinc.com


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent f15d1e55

sound/usb/card.c

+49 −0
Original line number Diff line number Diff line
@@ -118,6 +118,42 @@ MODULE_PARM_DESC(skip_validation, "Skip unit descriptor validation (default: no) 
static DEFINE_MUTEX(register_mutex);

static struct snd_usb_audio *usb_chip[SNDRV_CARDS];

static struct usb_driver usb_audio_driver;

static struct snd_usb_platform_ops *platform_ops;



/*

 * Register platform specific operations that will be notified on events

 * which occur in USB SND.  The platform driver can utilize this path to

 * enable features, such as USB audio offloading, which allows for audio data

 * to be queued by an audio DSP.

 *

 * Only one set of platform operations can be registered to USB SND.  The

 * platform register operation is protected by the register_mutex.

 */

int snd_usb_register_platform_ops(struct snd_usb_platform_ops *ops)

{

	guard(mutex)(&register_mutex);

	if (platform_ops)

		return -EEXIST;



	platform_ops = ops;

	return 0;

}

EXPORT_SYMBOL_GPL(snd_usb_register_platform_ops);



/*

 * Unregisters the current set of platform operations.  This allows for

 * a new set to be registered if required.

 *

 * The platform unregister operation is protected by the register_mutex.

 */

int snd_usb_unregister_platform_ops(void)

{

	guard(mutex)(&register_mutex);

	platform_ops = NULL;



	return 0;

}

EXPORT_SYMBOL_GPL(snd_usb_unregister_platform_ops);



/*

 * Checks to see if requested audio profile, i.e sample rate, # of
@@ -954,7 +990,11 @@ static int usb_audio_probe(struct usb_interface *intf, 
	chip->num_interfaces++;

	usb_set_intfdata(intf, chip);

	atomic_dec(&chip->active);



	if (platform_ops && platform_ops->connect_cb)

		platform_ops->connect_cb(chip);

	mutex_unlock(&register_mutex);



	return 0;



 __error:
@@ -991,6 +1031,9 @@ static void usb_audio_disconnect(struct usb_interface *intf) 
	card = chip->card;



	mutex_lock(&register_mutex);

	if (platform_ops && platform_ops->disconnect_cb)

		platform_ops->disconnect_cb(chip);



	if (atomic_inc_return(&chip->shutdown) == 1) {

		struct snd_usb_stream *as;

		struct snd_usb_endpoint *ep;
@@ -1138,6 +1181,9 @@ static int usb_audio_suspend(struct usb_interface *intf, pm_message_t message) 
		chip->system_suspend = chip->num_suspended_intf;

	}



	if (platform_ops && platform_ops->suspend_cb)

		platform_ops->suspend_cb(intf, message);



	return 0;

}
@@ -1178,6 +1224,9 @@ static int usb_audio_resume(struct usb_interface *intf) 


	snd_usb_midi_v2_resume_all(chip);



	if (platform_ops && platform_ops->resume_cb)

		platform_ops->resume_cb(intf);



 out:

	if (chip->num_suspended_intf == chip->system_suspend) {

		snd_power_change_state(chip->card, SNDRV_CTL_POWER_D0);

sound/usb/card.h

+10 −0
Original line number Diff line number Diff line
@@ -209,7 +209,17 @@ struct snd_usb_stream { 
	struct list_head list;

};



struct snd_usb_platform_ops {

	void (*connect_cb)(struct snd_usb_audio *chip);

	void (*disconnect_cb)(struct snd_usb_audio *chip);

	void (*suspend_cb)(struct usb_interface *intf, pm_message_t message);

	void (*resume_cb)(struct usb_interface *intf);

};



struct snd_usb_stream *

snd_usb_find_suppported_substream(int card_idx, struct snd_pcm_hw_params *params,

				  int direction);



int snd_usb_register_platform_ops(struct snd_usb_platform_ops *ops);

int snd_usb_unregister_platform_ops(void);

#endif /* __USBAUDIO_CARD_H */