From bea20cd152066c1deee6f1acbf68cf1fcc569927 Mon Sep 17 00:00:00 2001
From: cinap_lenrek <cinap_lenrek@felloff.net>
Date: Wed, 23 Feb 2022 18:00:34 +0000
Subject: [PATCH] nusb/lib: provide a setalt() function to set the interface to
 its altsetting

---
 sys/src/cmd/nusb/lib/dev.c | 10 ++++++++++
 sys/src/cmd/nusb/lib/usb.h |  1 +
 2 files changed, 11 insertions(+)

diff --git a/sys/src/cmd/nusb/lib/dev.c b/sys/src/cmd/nusb/lib/dev.c
index f692b33fa..ccd75bfdb 100644
--- a/sys/src/cmd/nusb/lib/dev.c
+++ b/sys/src/cmd/nusb/lib/dev.c
@@ -482,6 +482,16 @@ unstall(Dev *dev, Dev *ep, int dir)
 	return 0;
 }
 
+int
+setalt(Dev *d, Iface *ifc)
+{
+	if(usbcmd(d, Rh2d|Rstd|Riface, Rsetiface, ifc->alt, ifc->id, nil, 0) < 0){
+		werrstr("setalt: %s: %r", d->dir);
+		return -1;
+	}
+	return 0;
+}
+
 /*
  * To be sure it uses a single write.
  */
diff --git a/sys/src/cmd/nusb/lib/usb.h b/sys/src/cmd/nusb/lib/usb.h
index 3ed953d5b..c34df7082 100644
--- a/sys/src/cmd/nusb/lib/usb.h
+++ b/sys/src/cmd/nusb/lib/usb.h
@@ -353,5 +353,6 @@ int	parsedev(Dev *xd, uchar *b, int n);
 int	unstall(Dev *dev, Dev *ep, int dir);
 int	usbcmd(Dev *d, int type, int req, int value, int index, uchar *data, int count);
 Dev*	getdev(char *devid);
+int	setalt(Dev *d, Iface *ifc);
 
 extern int usbdebug;	/* more messages for bigger values */