linux-kernel - Re: [PATCH v2 01/13] gpiolib: add gpiod_multi_set_value

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Message-ID: <74ec33db-6721-4b86-86a6-e18b0a01fc47@baylibre.com>
Date: Fri, 7 Feb 2025 10:29:11 -0600
From: David Lechner <dlechner@...libre.com>
To: Geert Uytterhoeven <geert@...ux-m68k.org>
Cc: Linus Walleij <linus.walleij@...aro.org>,
 Bartosz Golaszewski <brgl@...ev.pl>, Andy Shevchenko <andy@...nel.org>,
 Lars-Peter Clausen <lars@...afoo.de>,
 Michael Hennerich <Michael.Hennerich@...log.com>,
 Jonathan Cameron <jic23@...nel.org>, Ulf Hansson <ulf.hansson@...aro.org>,
 Peter Rosin <peda@...ntia.se>, Andrew Lunn <andrew@...n.ch>,
 Heiner Kallweit <hkallweit1@...il.com>, Russell King
 <linux@...linux.org.uk>, "David S. Miller" <davem@...emloft.net>,
 Eric Dumazet <edumazet@...gle.com>, Jakub Kicinski <kuba@...nel.org>,
 Paolo Abeni <pabeni@...hat.com>, Vinod Koul <vkoul@...nel.org>,
 Kishon Vijay Abraham I <kishon@...nel.org>, Nuno Sá
 <nuno.sa@...log.com>, Liam Girdwood <lgirdwood@...il.com>,
 Mark Brown <broonie@...nel.org>, Jaroslav Kysela <perex@...ex.cz>,
 Takashi Iwai <tiwai@...e.com>, linux-gpio@...r.kernel.org,
 linux-kernel@...r.kernel.org, linux-iio@...r.kernel.org,
 linux-mmc@...r.kernel.org, netdev@...r.kernel.org,
 linux-phy@...ts.infradead.org, linux-sound@...r.kernel.org
Subject: Re: [PATCH v2 01/13] gpiolib: add gpiod_multi_set_value_cansleep()

On 2/7/25 3:10 AM, Geert Uytterhoeven wrote:
> Hi David,
> 
> On Thu, 6 Feb 2025 at 23:48, David Lechner <dlechner@...libre.com> wrote:
>> Add a new gpiod_multi_set_value_cansleep() helper function with fewer
>> parameters than gpiod_set_array_value_cansleep().
>>
>> Calling gpiod_set_array_value_cansleep() can get quite verbose. In many
>> cases, the first arguments all come from the same struct gpio_descs, so
>> having a separate function where we can just pass that cuts down on the
>> boilerplate.
>>
>> Reviewed-by: Linus Walleij <linus.walleij@...aro.org>
>> Signed-off-by: David Lechner <dlechner@...libre.com>
> 
> Thanks for your patch!
> 
>> --- a/include/linux/gpio/consumer.h
>> +++ b/include/linux/gpio/consumer.h
>> @@ -655,4 +655,11 @@ static inline void gpiod_unexport(struct gpio_desc *desc)
>>
>>  #endif /* CONFIG_GPIOLIB && CONFIG_GPIO_SYSFS */
>>
>> +static inline int gpiod_multi_set_value_cansleep(struct gpio_descs *descs,
>> +                                                unsigned long *value_bitmap)
>> +{
>> +       return gpiod_set_array_value_cansleep(descs->ndescs, descs->desc,
>> +                                             descs->info, value_bitmap);
> 
> I am wondering whether this needs a check for !IS_ERR_OR_NULL(descs),
> to handle the !CONFIG_GPIOLIB and gpiod_get_array_optional() cases?

I don't think it is strictly needed, but could be convenient for future use
cases. If we add it, should it be:

	if (IS_ERR_OR_NULL(descs))
		return PTR_ERR(descs);

or:

	if (!descs)
		return -EINVAL;

	if (IS_ERR(descs))
		return PTR_ERR(descs);

?

For comparison, gpiod_set_array_value_cansleep() will return -EINVAL if the
first argument is NULL.

> 
> Slightly related: shouldn't gpiod_put_array() (both the implementation
> and the !CONFIG_GPIOLIB dummy) allow the caller to pass NULL, to
> streamline the gpiod_get_array_optional() case?
> 
>> +}
>> +
>>  #endif
> 
> Gr{oetje,eeting}s,
> 
>                         Geert
>