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References: <20220824131428.31904-1-henning.schild@siemens.com>
In-Reply-To: <20220824131428.31904-1-henning.schild@siemens.com>
From:   Andy Shevchenko <andy.shevchenko@gmail.com>
Date:   Wed, 24 Aug 2022 18:53:49 +0300
Message-ID: <CAHp75Veu5CpRcmtvKwqhwqpjSgrvw03V6k7WrO8v=+cLhABcsA@mail.gmail.com>
Subject: Re: [PATCH v2] leds: simatic-ipc-leds-gpio: make sure we have the
 GPIO providing driver
To:     Henning Schild <henning.schild@siemens.com>
Cc:     Andy Shevchenko <andriy.shevchenko@linux.intel.com>,
        Pavel Machek <pavel@ucw.cz>, Lee Jones <lee@kernel.org>,
        Linux LED Subsystem <linux-leds@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
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Precedence: bulk

On Wed, Aug 24, 2022 at 4:27 PM Henning Schild
<henning.schild@siemens.com> wrote:
>
> If we register a "leds-gpio" platform device for GPIO pins that do not
> exist we get a -EPROBE_DEFER and the probe will be tried again later.
> If there is not driver to provide that pin we will poll forever and also

not --> no

> create a lot of log messages.
>
> So check if that GPIO driver is configured, if so it will come up
> eventually. If not we exit our probe function early and do not even

not, we

> bother registering the "leds-gpio". This method was chosen over "Kconfig
> depends" since this way we can add support for more devices and GPIO
> backends more easily without "depends"ing on all GPIO backends.

"depends":ing

The code is fine from my perspective,
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
thanks!

> Fixes: a6c80bec3c93 ("leds: simatic-ipc-leds-gpio: Add GPIO version of Siemens driver")
> Signed-off-by: Henning Schild <henning.schild@siemens.com>
> ---
>  drivers/leds/simple/simatic-ipc-leds-gpio.c | 2 ++
>  1 file changed, 2 insertions(+)
>
> diff --git a/drivers/leds/simple/simatic-ipc-leds-gpio.c b/drivers/leds/simple/simatic-ipc-leds-gpio.c
> index 4c9e663a90ba..0c96ba98e338 100644
> --- a/drivers/leds/simple/simatic-ipc-leds-gpio.c
> +++ b/drivers/leds/simple/simatic-ipc-leds-gpio.c
> @@ -57,6 +57,8 @@ static int simatic_ipc_leds_gpio_probe(struct platform_device *pdev)
>         struct gpio_desc *gpiod;
>         int err;
>
> +       if (!IS_ENABLED(CONFIG_PINCTRL_BROXTON))
> +               return -ENODEV;
>         gpiod_add_lookup_table(&simatic_ipc_led_gpio_table);
>         simatic_leds_pdev = platform_device_register_resndata(NULL,
>                 "leds-gpio", PLATFORM_DEVID_NONE, NULL, 0,
> --
> 2.35.1
>


-- 
With Best Regards,
Andy Shevchenko