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: Keith Milner <kamilner@superlative.org>
Tested-by: Dylan Robinson <dylan_robinson@motu.com>
Link: https://lore.kernel.org/r/20201123085347.19667-17-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/usb/helper.c b/sound/usb/helper.c
index cf92d71..a441026 100644 (file)
--- a/sound/usb/helper.c
+++ b/sound/usb/helper.c
@@ -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);
+}

diff --git a/sound/usb/helper.h b/sound/usb/helper.h
index f5b4c66..e2b51ec 100644 (file)
--- a/sound/usb/helper.h
+++ b/sound/usb/helper.h
@@ -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)

diff --git a/sound/usb/pcm.c b/sound/usb/pcm.c
index 392aa1c..b0961eb 100644 (file)
--- a/sound/usb/pcm.c
+++ b/sound/usb/pcm.c
@@ -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;