From a71b086491da4a279105be7d7b95c02f727f7a95 Mon Sep 17 00:00:00 2001 From: Stefan Agner Date: Thu, 11 Jan 2018 14:40:38 +0100 Subject: usb: misc: usb3503: make sure reset is low for at least 100us 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 --- drivers/usb/misc/usb3503.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/usb/misc/usb3503.c b/drivers/usb/misc/usb3503.c index 8e7737d7ac0a..03be5d574f23 100644 --- 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", -- cgit v1.2.3