Re: [PATCH] USB: serial: cp210x: fix CP2105 GPIO registration

Greg KH
2021-11-26T09:59:00Z

On Fri, Nov 26, 2021 at 10:43:48AM +0100, Johan Hovold wrote:
> When generalising GPIO support and adding support for CP2102N, the GPIO
> registration for some CP2105 devices accidentally broke. Specifically,
> when all the pins of a port are in "modem" mode, and thus unavailable
> for GPIO use, the GPIO chip would now be registered without having
> initialised the number of GPIO lines. This would in turn be rejected by
> gpiolib and some errors messages would be printed (but importantly probe
> would still succeed).
>
> Fix this by initialising the number of GPIO lines before registering the
> GPIO chip.
>
> Note that as for the other device types, and as when all CP2105 pins are
> muxed for LED function, the GPIO chip is registered also when no pins
> are available for GPIO use.
>
> Reported-by: Maarten Brock <m.brock@vanmierlo.com>
> Link: https://lore.kernel.org/r/5eb560c81d2ea1a2b4602a92d9f48a89@vanmierlo.com
> Fixes: c8acfe0aadbe ("USB: serial: cp210x: implement GPIO support for CP2102N")
> Cc: stable@vger.kernel.org # 4.19
> Cc: Karoly Pados <pados@pados.hu>
> Signed-off-by: Johan Hovold <johan@kernel.org>

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>