brcmfmac: assure USB dongle firmware is reset upon module unload

Upon unloading the brcmfmac module the USB firmware should be reset
as the device remains powered. The reset assures a known device
state when a new brcmfmac driver load is being done.

Reviewed-by: Pieter-Paul Giesberts <pieterpg@broadcom.com>
Reviewed-by: Hante Meuleman <meuleman@broadcom.com>
Signed-off-by: Arend van Spriel <arend@broadcom.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/brcm80211/brcmfmac/usb.c b/drivers/net/wireless/brcm80211/brcmfmac/usb.c
index 22eae57..1df8595 100644
--- a/drivers/net/wireless/brcm80211/brcmfmac/usb.c
+++ b/drivers/net/wireless/brcm80211/brcmfmac/usb.c
@@ -1524,10 +1524,23 @@
 	}
 }
 
+static int brcmf_usb_reset_device(struct device *dev, void *notused)
+{
+	/* device past is the usb interface so we
+	 * need to use parent here.
+	 */
+	brcmf_dev_reset(dev->parent);
+	return 0;
+}
 
 void brcmf_usb_exit(void)
 {
+	struct device_driver *drv = &brcmf_usbdrvr.drvwrap.driver;
+	int ret;
+
 	brcmf_dbg(USB, "Enter\n");
+	ret = driver_for_each_device(drv, NULL, NULL,
+				     brcmf_usb_reset_device);
 	usb_deregister(&brcmf_usbdrvr);
 	brcmf_release_fw(&fw_image_list);
 }