linux-kernel - Re: [PATCH v2 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set

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Message-ID: <YCjIgV5FLRI6Is0y@shinobu>
Date:   Sun, 14 Feb 2021 15:51:45 +0900
From:   William Breathitt Gray <vilhelm.gray@...il.com>
To:     Syed Nayyar Waris <syednwaris@...il.com>
Cc:     bgolaszewski@...libre.com, andriy.shevchenko@...ux.intel.com,
        michal.simek@...inx.com, arnd@...db.de, rrichter@...vell.com,
        linus.walleij@...aro.org, yamada.masahiro@...ionext.com,
        akpm@...ux-foundation.org, rui.zhang@...el.com,
        daniel.lezcano@...aro.org, amit.kucheria@...durent.com,
        linux-arch@...r.kernel.org, linux-gpio@...r.kernel.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        linux-pm@...r.kernel.org
Subject: Re: [PATCH v2 3/3] gpio: xilinx: Utilize generic bitmap_get_value
 and _set_value

On Fri, Feb 12, 2021 at 06:52:00PM +0530, Syed Nayyar Waris wrote:
> This patch reimplements the xgpio_set_multiple() function in
> drivers/gpio/gpio-xilinx.c to use the new generic functions:
> bitmap_get_value() and bitmap_set_value(). The code is now simpler
> to read and understand. Moreover, instead of looping for each bit
> in xgpio_set_multiple() function, now we can check each channel at
> a time and save cycles.
> 
> Cc: William Breathitt Gray <vilhelm.gray@...il.com>
> Cc: Bartosz Golaszewski <bgolaszewski@...libre.com>
> Cc: Michal Simek <michal.simek@...inx.com>
> Signed-off-by: Syed Nayyar Waris <syednwaris@...il.com>

Acked-by: William Breathitt Gray <vilhelm.gray@...il.com>

> ---
>  drivers/gpio/gpio-xilinx.c | 63 +++++++++++++++++++-------------------
>  1 file changed, 32 insertions(+), 31 deletions(-)
> 
> diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c
> index be539381fd82..8445e69cf37b 100644
> --- a/drivers/gpio/gpio-xilinx.c
> +++ b/drivers/gpio/gpio-xilinx.c
> @@ -15,6 +15,7 @@
>  #include <linux/of_device.h>
>  #include <linux/of_platform.h>
>  #include <linux/slab.h>
> +#include "gpiolib.h"
>  
>  /* Register Offset Definitions */
>  #define XGPIO_DATA_OFFSET   (0x0)	/* Data register  */
> @@ -141,37 +142,37 @@ static void xgpio_set_multiple(struct gpio_chip *gc, unsigned long *mask,
>  {
>  	unsigned long flags;
>  	struct xgpio_instance *chip = gpiochip_get_data(gc);
> -	int index = xgpio_index(chip, 0);
> -	int offset, i;
> -
> -	spin_lock_irqsave(&chip->gpio_lock[index], flags);
> -
> -	/* Write to GPIO signals */
> -	for (i = 0; i < gc->ngpio; i++) {
> -		if (*mask == 0)
> -			break;
> -		/* Once finished with an index write it out to the register */
> -		if (index !=  xgpio_index(chip, i)) {
> -			xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
> -				       index * XGPIO_CHANNEL_OFFSET,
> -				       chip->gpio_state[index]);
> -			spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
> -			index =  xgpio_index(chip, i);
> -			spin_lock_irqsave(&chip->gpio_lock[index], flags);
> -		}
> -		if (__test_and_clear_bit(i, mask)) {
> -			offset =  xgpio_offset(chip, i);
> -			if (test_bit(i, bits))
> -				chip->gpio_state[index] |= BIT(offset);
> -			else
> -				chip->gpio_state[index] &= ~BIT(offset);
> -		}
> -	}
> -
> -	xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
> -		       index * XGPIO_CHANNEL_OFFSET, chip->gpio_state[index]);
> -
> -	spin_unlock_irqrestore(&chip->gpio_lock[index], flags);
> +	u32 *const state = chip->gpio_state;
> +	unsigned int *const width = chip->gpio_width;
> +
> +	DECLARE_BITMAP(old, 64);
> +	DECLARE_BITMAP(new, 64);
> +	DECLARE_BITMAP(changed, 64);
> +
> +	spin_lock_irqsave(&chip->gpio_lock[0], flags);
> +	spin_lock(&chip->gpio_lock[1]);
> +
> +	bitmap_set_value(old, 64, state[0], width[0], 0);
> +	bitmap_set_value(old, 64, state[1], width[1], width[0]);
> +	bitmap_replace(new, old, bits, mask, gc->ngpio);
> +
> +	bitmap_set_value(old, 64, state[0], 32, 0);
> +	bitmap_set_value(old, 64, state[1], 32, 32);
> +	state[0] = bitmap_get_value(new, 0, width[0]);
> +	state[1] = bitmap_get_value(new, width[0], width[1]);
> +	bitmap_set_value(new, 64, state[0], 32, 0);
> +	bitmap_set_value(new, 64, state[1], 32, 32);
> +	bitmap_xor(changed, old, new, 64);
> +
> +	if (((u32 *)changed)[0])
> +		xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET,
> +				state[0]);
> +	if (((u32 *)changed)[1])
> +		xgpio_writereg(chip->regs + XGPIO_DATA_OFFSET +
> +				XGPIO_CHANNEL_OFFSET, state[1]);
> +
> +	spin_unlock(&chip->gpio_lock[1]);
> +	spin_unlock_irqrestore(&chip->gpio_lock[0], flags);
>  }
>  
>  /**
> -- 
> 2.29.0
> 

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