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 my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From b8626f1dc29d3eee444bfaa92146ec7b291ef41c Mon Sep 17 00:00:00 2001
From: Stefan Agner <stefan@xxxxxxxx>
Date: Thu, 11 Jan 2018 14:47:40 +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 <stefan@xxxxxxxx>
Cc: stable <stable@xxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
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 465dbf68b463..f723f7b8c9ac 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",
--
2.15.1