[PATCH v3] usb: gadget: f_midi: Add checking if it need align buffer's size to an ep's maxpacketsize

[Baolin Wang]

Some gadget device (such as dwc3 gadget) requires quirk_ep_out_aligned_size
attribute, which means it need to align the request buffer's size to an ep's
maxpacketsize.

Thus we add usb_ep_align_maybe() function to check if it is need to align
the request buffer's size to an ep's maxpacketsize.

Signed-off-by: Baolin Wang <baolin.wang@xxxxxxxxxx>
Acked-by: Michal Nazarewicz <mina86@xxxxxxxxxx>
---
Changelog:
v2:
 - Simplify the method to get buffer length.
v1:
 - Remove the in_ep modification.
 - Remove max_t() function.

 drivers/usb/gadget/function/f_midi.c |   11 +++++++----
 1 file changed, 7 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/gadget/function/f_midi.c b/drivers/usb/gadget/function/f_midi.c
index 58fc199..3486941 100644
--- a/drivers/usb/gadget/function/f_midi.c
+++ b/drivers/usb/gadget/function/f_midi.c
@@ -359,10 +359,13 @@ static int f_midi_set_alt(struct usb_function *f, unsigned intf, unsigned alt)
 
 	/* allocate a bunch of read buffers and queue them all at once. */
 	for (i = 0; i < midi->qlen && err == 0; i++) {
-		struct usb_request *req =
-			midi_alloc_ep_req(midi->out_ep,
-				max_t(unsigned, midi->buflen,
-					bulk_out_desc.wMaxPacketSize));
+		struct usb_request *req;
+		unsigned length;
+
+		length = usb_ep_align_maybe(midi->gadget, midi->out_ep,
+					    midi->buflen);
+
+		req = midi_alloc_ep_req(midi->out_ep, length);
 		if (req == NULL)
 			return -ENOMEM;
 
-- 
1.7.9.5