On Mon, Nov 11, 2019 at 06:59:53AM +0100, gregkh@xxxxxxxxxxxxxxxxxxx wrote:
The patch below does not apply to the 4.19-stable tree.
If someone wants it applied there, or to any other stable or longterm
tree, then please email the backport, including the original git commit
id to <stable@xxxxxxxxxxxxxxx>.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 29c2c6aa32405dfee4a29911a51ba133edcedb0f Mon Sep 17 00:00:00 2001
From: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Date: Mon, 14 Oct 2019 12:51:04 +0300
Subject: [PATCH] pinctrl: intel: Avoid potential glitches if pin is in GPIO
mode
When consumer requests a pin, in order to be on the safest side,
we switch it first to GPIO mode followed by immediate transition
to the input state. Due to posted writes it's luckily to be a single
I/O transaction.
However, if firmware or boot loader already configures the pin
to the GPIO mode, user expects no glitches for the requested pin.
We may check if the pin is pre-configured and leave it as is
till the actual consumer toggles its state to avoid glitches.
I've queued it up for 4.19, it was just a minor conflict with
e58926e781d8 ("pinctrl: intel: Use GENMASK() consistently").
However, for 4.14 and older:
Fixes: 7981c0015af2 ("pinctrl: intel: Add Intel Sunrisepoint pin controller and GPIO support")
Depends-on: f5a26acf0162 ("pinctrl: intel: Initialize GPIO properly when used through irqchip")
We need to take this "Depends-on" commit, but in the past we have
reverted it:
https://lore.kernel.org/lkml/20180427135732.999030511@xxxxxxxxxxxxxxxxxxx/
So I didn't do anything with this patch for <=4.14.
--
Thanks,
Sasha
