usb: misc: usb3503: make sure reset is low for at least 100us

commit b8626f1 upstream. When using a GPIO which is high by default, and initialize the driver in USB Hub mode, initialization fails with: [ 111.757794] usb3503 0-0008: SP_ILOCK failed (-5) The reason seems to be that the chip is not properly reset. Probe does initialize reset low, however some lines later the code already set it back high, which is not long enouth. Make sure reset is asserted for at least 100us by inserting a delay after initializing the reset pin during probe. Signed-off-by: Stefan Agner <[email protected]> Signed-off-by: Greg Kroah-Hartman <[email protected]>
TechNexion · Jan 17, 2018 · 9f6ca0e · 9f6ca0e
1 parent 11632d0
commit 9f6ca0e
Showing 1 changed file with 2 additions and 0 deletions.
diff --git a/drivers/usb/misc/usb3503.c b/drivers/usb/misc/usb3503.c
@@ -292,6 +292,8 @@ static int usb3503_probe(struct usb3503 *hub)
 	if (gpio_is_valid(hub->gpio_reset)) {
 		err = devm_gpio_request_one(dev, hub->gpio_reset,
 				GPIOF_OUT_INIT_LOW, "usb3503 reset");
+		/* Datasheet defines a hardware reset to be at least 100us */
+		usleep_range(100, 10000);
 		if (err) {
 			dev_err(dev,
 				"unable to request GPIO %d as reset pin (%d)\n",