linux-kernel - Re: [PATCH] gpio: don't WARN() on NULL descs if gpiolib is disabled

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Message-ID: <1562581119.10420.8.camel@phaseone.com>
Date:   Mon, 8 Jul 2019 12:18:39 +0200
From:   "Claus H. Stovgaard" <cst@...seone.com>
To:     Bartosz Golaszewski <brgl@...ev.pl>,
        Linus Walleij <linus.walleij@...aro.org>
CC:     <linux-gpio@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        "Bartosz Golaszewski" <bgolaszewski@...libre.com>
Subject: Re: [PATCH] gpio: don't WARN() on NULL descs if gpiolib is disabled

On Mon, 2019-07-08 at 10:23 +0200, Bartosz Golaszewski wrote:
> From: Bartosz Golaszewski <bgolaszewski@...libre.com>
> 
> If gpiolib is disabled, we use the inline stubs from gpio/consumer.h
> instead of regular definitions of GPIO API. The stubs for 'optional'
> variants of gpiod_get routines return NULL in this case as if the
> relevant GPIO wasn't found. This is correct so far.
> 
> Calling other (non-gpio_get) stubs from this header triggers a
> warning
> because the GPIO descriptor couldn't have been requested. The warning
> however is unconditional (WARN_ON(1)) and is emitted even if the
> passed
> descriptor pointer is NULL.
> 
> We don't want to force the users of 'optional' gpio_get to check the
> returned pointer before calling e.g. gpiod_set_value() so let's only
> WARN on non-NULL descriptors.
> 
> Reported-by: Claus H. Stovgaard <cst@...seone.com>
> Signed-off-by: Bartosz Golaszewski <bgolaszewski@...libre.com>
> ---
>  include/linux/gpio/consumer.h | 64 +++++++++++++++++--------------
> ----
>  1 file changed, 32 insertions(+), 32 deletions(-)

Have tested it on my setup (ZynqMP with AT24 EEPROM), where it works
great. This have removed the warnings in the log regarding settting
wp_gpio for AT24.

Thanks
Claus