On Mon, Nov 11, 2019 at 08:19:07AM -0500, Sasha Levin wrote:
On Mon, Nov 11, 2019 at 06:59:53AM +0100, gregkh@linuxfoundation.org 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@vger.kernel.org.
thanks,
greg k-h
------------------ original commit in Linus's tree ------------------
From 29c2c6aa32405dfee4a29911a51ba133edcedb0f Mon Sep 17 00:00:00 2001 From: Andy Shevchenko andriy.shevchenko@linux.intel.com 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").
Thank you!
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@linuxfoundation.org/
Yes, as the commit says that we have a lot of dependencies.
So I didn't do anything with this patch for <=4.14.
So far so good, thanks!
P.S. In case we need it in the future, we will prepare a backport patch ourselves.