Re: [PATCH v2 3/3] gpio: xilinx: Utilize generic bitmap_get_value and _set_value

William Breathitt Gray
2021-02-14T06:52:51Z

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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@gmail.com>
> Cc: Bartosz Golaszewski <bgolaszewski@baylibre.com>
> Cc: Michal Simek <michal.simek@xilinx.com>
> Signed-off-by: Syed Nayyar Waris <syednwaris@gmail.com>

Acked-by: William Breathitt Gray <vilhelm.gray@gmail.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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