linux-kernel - Re: [RFC 3/3] gpiolib: coldfire: remove custom asm/gpio.h

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Date:   Tue, 9 Nov 2021 00:21:46 +1000
From:   Greg Ungerer <gerg@...ux-m68k.org>
To:     Geert Uytterhoeven <geert@...ux-m68k.org>,
        Arnd Bergmann <arnd@...nel.org>
Cc:     "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Linus Walleij <linus.walleij@...aro.org>,
        linux-m68k <linux-m68k@...ts.linux-m68k.org>,
        Russell King <linux@...linux.org.uk>,
        Linux ARM <linux-arm-kernel@...ts.infradead.org>,
        Linux-sh list <linux-sh@...r.kernel.org>,
        Rich Felker <dalias@...c.org>,
        Yoshinori Sato <ysato@...rs.sourceforge.jp>,
        Arnd Bergmann <arnd@...db.de>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [RFC 3/3] gpiolib: coldfire: remove custom asm/gpio.h

Hi arnd, Geert,

On 8/11/21 6:24 pm, Geert Uytterhoeven wrote:
> Hi Arnd,
> 
> On Fri, Nov 5, 2021 at 2:05 PM Arnd Bergmann <arnd@...nel.org> wrote:
>> From: Arnd Bergmann <arnd@...db.de>
>>
>> Now that coldfire is the only user of a custom asm/gpio.h, it seems
>> better to remove this as well, and have the same interface everywhere.
>>
>> For the gpio_get_value()/gpio_set_value()/gpio_to_irq(), gpio_cansleep()
>> functions, the custom version is only a micro-optimization to inline the
>> function for constant GPIO numbers. However, in the coldfire defconfigs,
>> I was unable to find a single instance where this micro-optimization
>> was even used, so to my best knowledge removing this has no downsides.
> 
> The only user seems to be QSPI chip select handling (not bit-banged
> data transfer) in arch/m68k/coldfire/device.c, but that indeed depends
> on CONFIG_SPI_COLDFIRE_QSPI, which is not set in any of the defconfigs.
> That doesn't mean there were/are no real users, though ;-)

That is definitely used by some.
But the generalization and removal of the special casing seems like a win to me.


>> The custom gpio_request_one() function is even less useful, as it is
>> guarded by an #ifdef that is never true.
>>
>> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> 
> Reviewed-by: Geert Uytterhoeven <geert@...ux-m68k.org>

Reviewed-by: Greg Ungerer <gerg@...ux-m68k.org>

Regards
Greg



> Gr{oetje,eeting}s,
> 
>                          Geert
> 
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@...ux-m68k.org
> 
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                  -- Linus Torvalds
>