Commit e42a09bc authored by Takashi Iwai's avatar Takashi Iwai
Browse files

ALSA: usb-audio: Add snd_usb_get_host_interface() helper 



Add a helper function to retrieve the usb_host_interface object from
the given interface and altsetting number pair, which is a commonly
used procedure in the driver code.

No functional changes, just minor code refactoring.

Tested-by: default avatarKeith Milner <kamilner@superlative.org>
Tested-by: default avatarDylan Robinson <dylan_robinson@motu.com>
Link: https://lore.kernel.org/r/20201123085347.19667-17-tiwai@suse.de


Signed-off-by: default avatarTakashi Iwai <tiwai@suse.de>
parent 98215056

sound/usb/helper.c

+10 −0
Original line number Diff line number Diff line
@@ -121,3 +121,13 @@ unsigned char snd_usb_parse_datainterval(struct snd_usb_audio *chip, 
	return 0;

}



struct usb_host_interface *

snd_usb_get_host_interface(struct snd_usb_audio *chip, int ifnum, int altsetting)

{

	struct usb_interface *iface;



	iface = usb_ifnum_to_if(chip->dev, ifnum);

	if (!iface)

		return NULL;

	return usb_altnum_to_altsetting(iface, altsetting);

}

sound/usb/helper.h

+3 −0
Original line number Diff line number Diff line
@@ -14,6 +14,9 @@ int snd_usb_ctl_msg(struct usb_device *dev, unsigned int pipe, 
unsigned char snd_usb_parse_datainterval(struct snd_usb_audio *chip,

					 struct usb_host_interface *alts);



struct usb_host_interface *

snd_usb_get_host_interface(struct snd_usb_audio *chip, int ifnum, int altsetting);



/*

 * retrieve usb_interface descriptor from the host interface

 * (conditional for compatibility with the older API)

sound/usb/pcm.c

+11 −27
Original line number Diff line number Diff line
@@ -289,20 +289,16 @@ static int snd_usb_pcm_sync_stop(struct snd_pcm_substream *substream) 
}



/* Check whether the given iface:altsetting points to an implicit fb source */

static bool search_generic_implicit_fb(struct usb_device *dev, int ifnum,

static bool search_generic_implicit_fb(struct snd_usb_audio *chip, int ifnum,

				       unsigned int altsetting,

				       struct usb_host_interface **altsp,

				       unsigned int *ep)

{

	struct usb_interface *iface;

	struct usb_host_interface *alts;

	struct usb_interface_descriptor *altsd;

	struct usb_endpoint_descriptor *epd;



	iface = usb_ifnum_to_if(dev, ifnum);

	if (!iface)

		return false;

	alts = usb_altnum_to_altsetting(iface, altsetting);

	alts = snd_usb_get_host_interface(chip, ifnum, altsetting);

	if (!alts)

		return false;

	altsd = get_iface_desc(alts);
@@ -322,20 +318,16 @@ static bool search_generic_implicit_fb(struct usb_device *dev, int ifnum, 
}



/* Like the function above, but specific to Roland with vendor class and hack */

static bool search_roland_implicit_fb(struct usb_device *dev, int ifnum,

static bool search_roland_implicit_fb(struct snd_usb_audio *chip, int ifnum,

				      unsigned int altsetting,

				      struct usb_host_interface **altsp,

				      unsigned int *ep)

{

	struct usb_interface *iface;

	struct usb_host_interface *alts;

	struct usb_interface_descriptor *altsd;

	struct usb_endpoint_descriptor *epd;



	iface = usb_ifnum_to_if(dev, ifnum);

	if (!iface)

		return false;

	alts = usb_altnum_to_altsetting(iface, altsetting);

	alts = snd_usb_get_host_interface(chip, ifnum, altsetting);

	if (!alts)

		return false;

	altsd = get_iface_desc(alts);
@@ -359,11 +351,11 @@ static bool search_roland_implicit_fb(struct usb_device *dev, int ifnum, 
 */

static int audioformat_implicit_fb_quirk(struct snd_usb_audio *chip,

					 struct audioformat *fmt,

					 struct usb_interface *iface,

					 struct usb_host_interface *alts)

{

	struct usb_device *dev = chip->dev;

	struct usb_interface_descriptor *altsd = get_iface_desc(alts);

	struct usb_interface *iface;

	unsigned int attr = fmt->ep_attr & USB_ENDPOINT_SYNCTYPE;

	unsigned int ep;

	unsigned int ifnum;
@@ -431,7 +423,7 @@ static int audioformat_implicit_fb_quirk(struct snd_usb_audio *chip, 
	    altsd->bInterfaceProtocol == UAC_VERSION_2 &&

	    altsd->bNumEndpoints == 1) {

		ifnum = altsd->bInterfaceNumber + 1;

		if (search_generic_implicit_fb(dev, ifnum,

		if (search_generic_implicit_fb(chip, ifnum,

					       altsd->bAlternateSetting,

					       &alts, &ep))

			goto add_sync_ep;
@@ -444,7 +436,7 @@ static int audioformat_implicit_fb_quirk(struct snd_usb_audio *chip, 
	    altsd->bNumEndpoints == 1 &&

	    USB_ID_VENDOR(chip->usb_id) == 0x0582 /* Roland */) {

		ifnum = altsd->bInterfaceNumber + 1;

		if (search_roland_implicit_fb(dev, ifnum,

		if (search_roland_implicit_fb(chip, ifnum,

					      altsd->bAlternateSetting,

					      &alts, &ep))

			goto add_sync_ep;
@@ -477,24 +469,20 @@ int snd_usb_audioformat_set_sync_ep(struct snd_usb_audio *chip, 
				    struct audioformat *fmt)

{

	struct usb_device *dev = chip->dev;

	struct usb_interface *iface;

	struct usb_host_interface *alts;

	struct usb_interface_descriptor *altsd;

	unsigned int ep, attr, sync_attr;

	bool is_playback;

	int err;



	iface = usb_ifnum_to_if(dev, fmt->iface);

	if (!iface)

		return 0;

	alts = usb_altnum_to_altsetting(iface, fmt->altsetting);

	alts = snd_usb_get_host_interface(chip, fmt->iface, fmt->altsetting);

	if (!alts)

		return 0;

	altsd = get_iface_desc(alts);



	is_playback = !(get_endpoint(alts, 0)->bEndpointAddress & USB_DIR_IN);

	if (is_playback) {

		err = audioformat_implicit_fb_quirk(chip, fmt, iface, alts);

		err = audioformat_implicit_fb_quirk(chip, fmt, alts);

		if (err > 0)

			return 0;

	}
@@ -564,7 +552,6 @@ static int set_sync_endpoint(struct snd_usb_substream *subs, 
			     struct audioformat *fmt)

{

	struct usb_device *dev = subs->dev;

	struct usb_interface *iface;

	struct usb_host_interface *alts;

	int is_playback = subs->direction == SNDRV_PCM_STREAM_PLAYBACK;

	unsigned int ep;
@@ -577,11 +564,8 @@ static int set_sync_endpoint(struct snd_usb_substream *subs, 
	if (!ep)

		return 0;



	iface = usb_ifnum_to_if(dev, fmt->sync_iface);

	if (!iface)

		return 0;



	alts = usb_altnum_to_altsetting(iface, fmt->altsetting);

	alts = snd_usb_get_host_interface(subs->stream->chip, fmt->sync_iface,

					  fmt->altsetting);

	if (!alts)

		return 0;