Patch "usb: misc: usb3503: make sure reset is low for at least 100us" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

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

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:

     usb-misc-usb3503-make-sure-reset-is-low-for-at-least-100us.patch

and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Stefan Agner <[email protected]>
Date: Thu, 11 Jan 2018 14:47:40 +0100
Subject: usb: misc: usb3503: make sure reset is low for at least 100us

From: Stefan Agner <[email protected]>

commit b8626f1dc29d3eee444bfaa92146ec7b291ef41c 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.

---
 drivers/usb/misc/usb3503.c |    2 ++
 1 file changed, 2 insertions(+)

@@ -292,6 +292,8 @@ static int usb3503_probe(struct usb3503
 	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",

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/usb-misc-usb3503-make-sure-reset-is-low-for-at-least-100us.patch