Thread (34 messages) 34 messages, 7 authors, 2023-06-01

Re: [PATCH v4 7/9] serial: sc16is7xx: fix regression with GPIO configuration

From: Greg KH <gregkh@linuxfoundation.org>
Date: 2023-05-30 10:28:15
Also in: linux-gpio, linux-serial, lkml

On Mon, May 29, 2023 at 10:07:09AM -0400, Hugo Villeneuve wrote:
From: Hugo Villeneuve <hvilleneuve@dimonoff.com>

Commit 679875d1d880 ("sc16is7xx: Separate GPIOs from modem control lines")
and commit 21144bab4f11 ("sc16is7xx: Handle modem status lines")
changed the function of the GPIOs pins to act as modem control
lines without any possibility of selecting GPIO function.

As a consequence, applications that depends on GPIO lines configured
by default as GPIO pins no longer work as expected.

Also, the change to select modem control lines function was done only
for channel A of dual UART variants (752/762). This was not documented
in the log message.

Allow to specify GPIO or modem control line function in the device
tree, and for each of the ports (A or B).

Do so by using the new device-tree property named
"modem-control-line-ports" (property added in separate patch).

When registering GPIO chip controller, mask-out GPIO pins declared as
modem control lines according to this new "modem-control-line-ports"
DT property.

Boards that need to have GPIOS configured as modem control lines
should add that property to their device tree. Here is a list of
boards using the sc16is7xx driver in their device tree and that may
need to be modified:
    arm64/boot/dts/freescale/fsl-ls1012a-frdm.dts
    mips/boot/dts/ingenic/cu1830-neo.dts
    mips/boot/dts/ingenic/cu1000-neo.dts

Fixes: 679875d1d880 ("sc16is7xx: Separate GPIOs from modem control lines")
Fixes: 21144bab4f11 ("sc16is7xx: Handle modem status lines")
So you are marking this as a "bugfix" and yet, it is at the end of a
much larger series of patches.  Does this fix require all of them?  If
so, it's not really relevant for stable kernels, right?  Or is it?

I'm confused, what should I, as a maintainer, do here?  Take just this
one fix for 6.4-final, and the rest for 6.5-rc1?  And add a proper cc:
stable@ tag?  Or queue them all up for 6.4-final?  Or all for 6.5-rc1?
Or something else?

What would you want to see if you were in my position here to help make
your life easier?

thanks,

greg k-h
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