linux-kernel - Re: [PATCH v1 4/5] gpio: xilinx: Replace bitmap

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Message-ID: <ZRK1PA2vZBdfAozG@sol>
Date:   Tue, 26 Sep 2023 18:41:00 +0800
From:   Kent Gibson <warthog618@...il.com>
To:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Bartosz Golaszewski <bartosz.golaszewski@...aro.org>,
        Yury Norov <yury.norov@...il.com>, linux-gpio@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
        Shubhrajyoti Datta <shubhrajyoti.datta@....com>,
        Srinivas Neeli <srinivas.neeli@....com>,
        Michal Simek <michal.simek@....com>,
        Bartosz Golaszewski <brgl@...ev.pl>,
        Andy Shevchenko <andy@...nel.org>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        Marek Behún <kabel@...nel.org>
Subject: Re: [PATCH v1 4/5] gpio: xilinx: Replace bitmap_bitremap() calls

On Tue, Sep 26, 2023 at 08:20:06AM +0300, Andy Shevchenko wrote:
> We have sparse and dence masks of the line mappings based on

dense

> the view point (Linux numbering or hardware numbering). Since
> the Linux side uses sequential bits for the mask, we can simply
> convert a Linux number to the hardware one and vise versa by

vice

> counting set bits in the respective mask. Hence replace
> bitmap_bitremap() calls by simpler equivalents.
> 
> With this done the dence mask is not needed and thus dropped.
> 

And dense again.

Cheers,
Kent.

> Signed-off-by: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
> ---
>  drivers/gpio/gpio-xilinx.c | 9 ++-------
>  1 file changed, 2 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c
> index f103c30cc74f..14ca3097563a 100644
> --- a/drivers/gpio/gpio-xilinx.c
> +++ b/drivers/gpio/gpio-xilinx.c
> @@ -46,7 +46,6 @@
>   * @gc: GPIO chip
>   * @regs: register block
>   * @hw_map: GPIO pin mapping on hardware side
> - * @sw_map: GPIO pin mapping on software side
>   * @state: GPIO write state shadow register
>   * @last_irq_read: GPIO read state register from last interrupt
>   * @dir: GPIO direction shadow register
> @@ -62,7 +61,6 @@ struct xgpio_instance {
>  	struct gpio_chip gc;
>  	void __iomem *regs;
>  	DECLARE_BITMAP(hw_map, 64);
> -	DECLARE_BITMAP(sw_map, 64);
>  	DECLARE_BITMAP(state, 64);
>  	DECLARE_BITMAP(last_irq_read, 64);
>  	DECLARE_BITMAP(dir, 64);
> @@ -76,12 +74,12 @@ struct xgpio_instance {
>  
>  static inline int xgpio_from_bit(struct xgpio_instance *chip, int bit)
>  {
> -	return bitmap_bitremap(bit, chip->hw_map, chip->sw_map, 64);
> +	return bitmap_weight(chip->hw_map, bit + 1);
>  }
>  
>  static inline int xgpio_to_bit(struct xgpio_instance *chip, int gpio)
>  {
> -	return bitmap_bitremap(gpio, chip->sw_map, chip->hw_map, 64);
> +	return find_nth_bit(chip->hw_map, 64, gpio);
>  }
>  
>  static inline u32 xgpio_get_value32(const unsigned long *map, int bit)
> @@ -619,9 +617,6 @@ static int xgpio_probe(struct platform_device *pdev)
>  	if (width[1] > 32)
>  		return -EINVAL;
>  
> -	/* Setup software pin mapping */
> -	bitmap_set(chip->sw_map, 0, width[0] + width[1]);
> -
>  	/* Setup hardware pin mapping */
>  	bitmap_set(chip->hw_map,  0, width[0]);
>  	bitmap_set(chip->hw_map, 32, width[1]);
> -- 
> 2.40.0.1.gaa8946217a0b
>