usb:gadget: f_uac1: fixed sync playback

The u_audio param fb_max was not set to its default value in f_uac1.c.
As a result the maximum value of Playback Pitch ctl was kept at 1000000,
not allowing to set faster playback pitch for UAC1.

The setting required moving the default constant UAC2_DEF_FB_MAX from
u_uac2.h to FBACK_FAST_MAX in u_audio.h as that header is common for
f_uac1.c and f_uac2.c.

Fixes: 6fec018 ("usb: gadget: u_audio.c: Adding Playback Pitch ctl for sync playback")
Signed-off-by: Pavel Hofman <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: pavhofman

drivers/usb/gadget/function/f_uac1.c

@@ -1321,6 +1321,7 @@ static int f_audio_bind(struct usb_configuration *c, struct usb_function *f)
 		audio->params.c_fu.volume_res = audio_opts->c_volume_res;
 	}
 	audio->params.req_number = audio_opts->req_number;
+	audio->params.fb_max = FBACK_FAST_MAX;
 	if (FUOUT_EN(audio_opts) || FUIN_EN(audio_opts))
 		audio->notify = audio_notify;
 

drivers/usb/gadget/function/f_uac2.c

@@ -15,6 +15,7 @@
 #include <linux/module.h>
 
 #include "u_audio.h"
+
 #include "u_uac2.h"
 
 /* UAC2 spec: 4.1 Audio Channel Cluster Descriptor */
@@ -1932,7 +1933,7 @@ static struct usb_function_instance *afunc_alloc_inst(void)
 	opts->c_volume_res = UAC2_DEF_RES_DB;
 
 	opts->req_number = UAC2_DEF_REQ_NUM;
-	opts->fb_max = UAC2_DEF_FB_MAX;
+	opts->fb_max = FBACK_FAST_MAX;
 	return &opts->func_inst;
 }
 

drivers/usb/gadget/function/u_audio.h

@@ -14,11 +14,17 @@
 /*
  * Same maximum frequency deviation on the slower side as in
  * sound/usb/endpoint.c. Value is expressed in per-mil deviation.
- * The maximum deviation on the faster side will be provided as
- * parameter, as it impacts the endpoint required bandwidth.
  */
 #define FBACK_SLOW_MAX	250
 
+/*
+ * Maximum frequency deviation on the faster side, default value for UAC1/2.
+ * Value is expressed in per-mil deviation.
+ * UAC2 provides the value as a parameter as it impacts the endpoint required
+ * bandwidth.
+ */
+#define FBACK_FAST_MAX 5
+
 /* Feature Unit parameters */
 struct uac_fu_params {
 	int id;			/* Feature Unit ID */

drivers/usb/gadget/function/u_uac2.h

@@ -30,7 +30,6 @@
 #define UAC2_DEF_RES_DB		(1*256)		/* 1 dB */
 
 #define UAC2_DEF_REQ_NUM 2
-#define UAC2_DEF_FB_MAX 5
 #define UAC2_DEF_INT_REQ_NUM	10
 
 struct f_uac2_opts {