linux-kernel - Re: [PATCH v4 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set

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Message-ID: <CACG_h5rCPSdQApNzGziqxpd9aVc4uP9Q7zKRnBW5NBrH=ZxTcw@mail.gmail.com>
Date:   Fri, 2 Apr 2021 22:04:25 +0530
From:   Syed Nayyar Waris <syednwaris@...il.com>
To:     bgolaszewski@...libre.com
Cc:     andriy.shevchenko@...ux.intel.com, vilhelm.gray@...il.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 v4 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set_value

On Fri, Apr 2, 2021 at 3:42 PM Syed Nayyar Waris <syednwaris@...il.com> 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: 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 | 60 +++++++++++++++++++-------------------
>  1 file changed, 30 insertions(+), 30 deletions(-)
>
> diff --git a/drivers/gpio/gpio-xilinx.c b/drivers/gpio/gpio-xilinx.c
> index b411d3156e0b..e0ad3a81f216 100644
> --- a/drivers/gpio/gpio-xilinx.c
> +++ b/drivers/gpio/gpio-xilinx.c
> @@ -18,6 +18,7 @@
>  #include <linux/of_platform.h>
>  #include <linux/pm_runtime.h>
>  #include <linux/slab.h>
> +#include "gpiolib.h"
>
>  /* Register Offset Definitions */
>  #define XGPIO_DATA_OFFSET   (0x0)      /* Data register  */
> @@ -161,37 +162,36 @@ 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, 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, flags);
> -                       index =  xgpio_index(chip, i);
> -                       spin_lock_irqsave(&chip->gpio_lock, 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, flags);
> +    u32 *state = chip->gpio_state;
> +    unsigned int *width = chip->gpio_width;
> +    DECLARE_BITMAP(old, 64);
> +    DECLARE_BITMAP(new, 64);
> +    DECLARE_BITMAP(changed, 64);
> +
> +    spin_lock_irqsave(&chip->gpio_lock, flags);
> +
> +    /* Copy initial value of state bits into 'old' bit-wise */
> +    bitmap_set_value(old, 64, state[0], width[0], 0);
> +    bitmap_set_value(old, 64, state[1], width[1], width[0]);
> +    /* Copy value from 'old' into 'new' with mask applied */
> +    bitmap_replace(new, old, bits, mask, gc->ngpio);
> +
> +    bitmap_from_arr32(old, state, 64);
> +    /* Update 'state' */
> +    state[0] = bitmap_get_value(new, 0, width[0]);
> +    state[1] = bitmap_get_value(new, width[0], width[1]);
> +    bitmap_from_arr32(new, state, 64);
> +    /* XOR operation sets only changed bits */
> +    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_irqrestore(&chip->gpio_lock, flags);
>  }
>
>  /**
> --
> 2.29.0
>

Hi All,

There were indentation errors reported. I am Re-sending the patchset.
I am keeping the version same as v4.

Kindly consider the "RESEND" prefixed v4 patchset for future.

Regards
Syed Nayyar Waris