linux-kernel - Re: [RFC 1/3] gpiolib: remove irq_to

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Message-ID: <YYUwWFOeiFBC2Nhd@smile.fi.intel.com>
Date:   Fri, 5 Nov 2021 15:23:36 +0200
From:   Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:     Arnd Bergmann <arnd@...nel.org>
Cc:     linux-gpio@...r.kernel.org, Bartosz Golaszewski <brgl@...ev.pl>,
        Linus Walleij <linus.walleij@...aro.org>,
        linux-m68k@...ts.linux-m68k.org, geert@...ux-m68k.org,
        gerg@...ux-m68k.org, linux@...linux.org.uk,
        linux-arm-kernel@...ts.infradead.org, linux-sh@...r.kernel.org,
        dalias@...c.org, ysato@...rs.sourceforge.jp,
        Arnd Bergmann <arnd@...db.de>,
        Fu Wei <tekkamanninja@...il.com>, Alex Shi <alexs@...nel.org>,
        Hu Haowen <src.res@...il.cn>,
        linux-doc-tw-discuss@...ts.sourceforge.net,
        Jonathan Corbet <corbet@....net>,
        Drew Fustini <drew@...gleboard.org>, linux-doc@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [RFC 1/3] gpiolib: remove irq_to_gpio() definition

On Fri, Nov 05, 2021 at 02:03:03PM +0100, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@...db.de>
> 
> All implementations other than coldfire have returned an error since
> the avr32 and blackfin architectures got removed, and the last user in
> driver code was removed in 2016, so just remove this old interface.
> 
> The only reference is now in the Chinese documentation, which should be
> changed to remove this reference as well.

FWIW,
Reviewed-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>

Thanks, Arnd, for cleaning this up!

> Cc: Fu Wei <tekkamanninja@...il.com>
> Cc: Alex Shi <alexs@...nel.org>
> Cc: Hu Haowen <src.res@...il.cn>
> Cc: linux-doc-tw-discuss@...ts.sourceforge.net
> Signed-off-by: Arnd Bergmann <arnd@...db.de>
> ---
>  Documentation/driver-api/gpio/legacy.rst | 20 +++++---------------
>  arch/m68k/include/asm/gpio.h             |  7 -------
>  arch/sh/include/asm/gpio.h               |  5 -----
>  include/linux/gpio.h                     | 12 ------------
>  4 files changed, 5 insertions(+), 39 deletions(-)
> 
> diff --git a/Documentation/driver-api/gpio/legacy.rst b/Documentation/driver-api/gpio/legacy.rst
> index 9b12eeb89170..06c05e2d62c1 100644
> --- a/Documentation/driver-api/gpio/legacy.rst
> +++ b/Documentation/driver-api/gpio/legacy.rst
> @@ -382,22 +382,18 @@ GPIOs mapped to IRQs
>  --------------------
>  GPIO numbers are unsigned integers; so are IRQ numbers.  These make up
>  two logically distinct namespaces (GPIO 0 need not use IRQ 0).  You can
> -map between them using calls like::
> +map between them using::
>  
>  	/* map GPIO numbers to IRQ numbers */
>  	int gpio_to_irq(unsigned gpio);
>  
> -	/* map IRQ numbers to GPIO numbers (avoid using this) */
> -	int irq_to_gpio(unsigned irq);
> -
> -Those return either the corresponding number in the other namespace, or
> +This returns an irq number corresponding to the gpio number, or
>  else a negative errno code if the mapping can't be done.  (For example,
>  some GPIOs can't be used as IRQs.)  It is an unchecked error to use a GPIO
> -number that wasn't set up as an input using gpio_direction_input(), or
> -to use an IRQ number that didn't originally come from gpio_to_irq().
> +number that wasn't set up as an input using gpio_direction_input().
>  
> -These two mapping calls are expected to cost on the order of a single
> -addition or subtraction.  They're not allowed to sleep.
> +The mapping call is expected to cost on the order of a single
> +addition or subtraction.  It is not allowed to sleep.
>  
>  Non-error values returned from gpio_to_irq() can be passed to request_irq()
>  or free_irq().  They will often be stored into IRQ resources for platform
> @@ -405,12 +401,6 @@ devices, by the board-specific initialization code.  Note that IRQ trigger
>  options are part of the IRQ interface, e.g. IRQF_TRIGGER_FALLING, as are
>  system wakeup capabilities.
>  
> -Non-error values returned from irq_to_gpio() would most commonly be used
> -with gpio_get_value(), for example to initialize or update driver state
> -when the IRQ is edge-triggered.  Note that some platforms don't support
> -this reverse mapping, so you should avoid using it.
> -
> -
>  Emulating Open Drain Signals
>  ----------------------------
>  Sometimes shared signals need to use "open drain" signaling, where only the
> diff --git a/arch/m68k/include/asm/gpio.h b/arch/m68k/include/asm/gpio.h
> index a50b27719a58..5cfc0996ba94 100644
> --- a/arch/m68k/include/asm/gpio.h
> +++ b/arch/m68k/include/asm/gpio.h
> @@ -66,13 +66,6 @@ static inline int gpio_to_irq(unsigned gpio)
>  		return __gpio_to_irq(gpio);
>  }
>  
> -static inline int irq_to_gpio(unsigned irq)
> -{
> -	return (irq >= MCFGPIO_IRQ_VECBASE &&
> -		irq < (MCFGPIO_IRQ_VECBASE + MCFGPIO_IRQ_MAX)) ?
> -		irq - MCFGPIO_IRQ_VECBASE : -ENXIO;
> -}
> -
>  static inline int gpio_cansleep(unsigned gpio)
>  {
>  	return gpio < MCFGPIO_PIN_MAX ? 0 : __gpio_cansleep(gpio);
> diff --git a/arch/sh/include/asm/gpio.h b/arch/sh/include/asm/gpio.h
> index d643250f0a0f..588c1380e4cb 100644
> --- a/arch/sh/include/asm/gpio.h
> +++ b/arch/sh/include/asm/gpio.h
> @@ -40,11 +40,6 @@ static inline int gpio_to_irq(unsigned gpio)
>  	return __gpio_to_irq(gpio);
>  }
>  
> -static inline int irq_to_gpio(unsigned int irq)
> -{
> -	return -ENOSYS;
> -}
> -
>  #endif /* CONFIG_GPIOLIB */
>  
>  #endif /* __ASM_SH_GPIO_H */
> diff --git a/include/linux/gpio.h b/include/linux/gpio.h
> index 008ad3ee56b7..d8d7daa7eb94 100644
> --- a/include/linux/gpio.h
> +++ b/include/linux/gpio.h
> @@ -81,11 +81,6 @@ static inline int gpio_to_irq(unsigned int gpio)
>  	return __gpio_to_irq(gpio);
>  }
>  
> -static inline int irq_to_gpio(unsigned int irq)
> -{
> -	return -EINVAL;
> -}
> -
>  #endif /* ! CONFIG_ARCH_HAVE_CUSTOM_GPIO_H */
>  
>  /* CONFIG_GPIOLIB: bindings for managed devices that want to request gpios */
> @@ -219,13 +214,6 @@ static inline int gpio_to_irq(unsigned gpio)
>  	return -EINVAL;
>  }
>  
> -static inline int irq_to_gpio(unsigned irq)
> -{
> -	/* irq can never have been returned from gpio_to_irq() */
> -	WARN_ON(1);
> -	return -EINVAL;
> -}
> -
>  static inline int devm_gpio_request(struct device *dev, unsigned gpio,
>  				    const char *label)
>  {
> -- 
> 2.29.2
> 

-- 
With Best Regards,
Andy Shevchenko