[PATCH v2] tty: serial: cpm_uart: Fix behaviour for non existing GPIOs

[Linus Walleij]

On Fri, Jun 12, 2020 at 8:26 PM Christophe Leroy
<christophe.leroy at csgroup.eu> wrote:

> devm_gpiod_get_index() doesn't return NULL but -ENOENT when the
> requested GPIO doesn't exist,  leading to the following messages:
>
> [    2.742468] gpiod_direction_input: invalid GPIO (errorpointer)
> [    2.748147] can't set direction for gpio #2: -2
> [    2.753081] gpiod_direction_input: invalid GPIO (errorpointer)
> [    2.758724] can't set direction for gpio #3: -2
> [    2.763666] gpiod_direction_output: invalid GPIO (errorpointer)
> [    2.769394] can't set direction for gpio #4: -2
> [    2.774341] gpiod_direction_input: invalid GPIO (errorpointer)
> [    2.779981] can't set direction for gpio #5: -2
> [    2.784545] ff000a20.serial: ttyCPM1 at MMIO 0xfff00a20 (irq = 39, base_baud = 8250000) is a CPM UART
>
> Use devm_gpiod_get_index_optional() instead.
>
> At the same time, handle the error case and properly exit
> with an error.
>
> Fixes: 97cbaf2c829b ("tty: serial: cpm_uart: Convert to use GPIO descriptors")
> Cc: stable at vger.kernel.org
> Cc: Linus Walleij <linus.walleij at linaro.org>
> Signed-off-by: Christophe Leroy <christophe.leroy at csgroup.eu>
> ---
> v2: Using devm_gpiod_get_index_optional() and exiting if error

Excellent!
Reviewed-by: Linus Walleij <linus.walleij at linaro.org>

Yours,
Linus Walleij