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

b8626f1d · Stefan Agner <[email protected]> · 2018-01-11 14:47:40 +01:00

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]>
Cc: stable <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Commit: b8626f1dc29d3eee444bfaa92146ec7b291ef41c
Parents: ceb17611

Changes

1 files changed · +2 −0

File	Status	Add	Del	Content
drivers/usb/misc/usb3503.c	modified	+2	−0	View file

drivers/usb/misc/usb3503.c

View file

diff --git a/drivers/usb/misc/usb3503.c b/drivers/usb/misc/usb3503.c
index 465dbf6..f723f7b 100644
--- a/drivers/usb/misc/usb3503.c
+++ b/drivers/usb/misc/usb3503.c
@@ -279,6 +279,8 @@ 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",