linux-kernel - Re: [PATCH v9 9/9] gpio: uniphier: Utilize for_each_set

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Date:   Tue, 12 Mar 2019 13:36:57 +0900
From:   Masahiro Yamada <yamada.masahiro@...ionext.com>
To:     William Breathitt Gray <vilhelm.gray@...il.com>
Cc:     Linus Walleij <linus.walleij@...aro.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        "open list:GPIO SUBSYSTEM" <linux-gpio@...r.kernel.org>,
        linux-arch <linux-arch@...r.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Rasmus Villemoes <linux@...musvillemoes.dk>,
        bgolaszewski@...libre.com,
        linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>
Subject: Re: [PATCH v9 9/9] gpio: uniphier: Utilize for_each_set_clump8 macro

On Sun, Mar 3, 2019 at 4:51 PM William Breathitt Gray
<vilhelm.gray@...il.com> wrote:
>
> Replace verbose implementation in set_multiple callback with
> for_each_set_clump8 macro to simplify code and improve clarity. An
> improvement in this case is that banks that are not masked will now be
> skipped.
>
> Cc: Masahiro Yamada <yamada.masahiro@...ionext.com>
> Signed-off-by: William Breathitt Gray <vilhelm.gray@...il.com>
> ---
>  drivers/gpio/gpio-uniphier.c | 16 ++++++----------
>  1 file changed, 6 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/gpio/gpio-uniphier.c b/drivers/gpio/gpio-uniphier.c
> index 0f662b297a95..df640cb29b9c 100644
> --- a/drivers/gpio/gpio-uniphier.c
> +++ b/drivers/gpio/gpio-uniphier.c
> @@ -15,9 +15,6 @@
>  #include <linux/spinlock.h>
>  #include <dt-bindings/gpio/uniphier-gpio.h>
>
> -#define UNIPHIER_GPIO_BANK_MASK                \
> -                               GENMASK((UNIPHIER_GPIO_LINES_PER_BANK) - 1, 0)
> -
>  #define UNIPHIER_GPIO_IRQ_MAX_NUM      24
>
>  #define UNIPHIER_GPIO_PORT_DATA                0x0     /* data */
> @@ -147,15 +144,14 @@ static void uniphier_gpio_set(struct gpio_chip *chip,
>  static void uniphier_gpio_set_multiple(struct gpio_chip *chip,
>                                        unsigned long *mask, unsigned long *bits)
>  {
> -       unsigned int bank, shift, bank_mask, bank_bits;
> -       int i;
> +       unsigned int i;
> +       unsigned long bank_mask;
> +       unsigned int bank;
> +       unsigned int bank_bits;
>
> -       for (i = 0; i < chip->ngpio; i += UNIPHIER_GPIO_LINES_PER_BANK) {
> +       for_each_set_clump8(i, bank_mask, mask, chip->ngpio) {
>                 bank = i / UNIPHIER_GPIO_LINES_PER_BANK;
> -               shift = i % BITS_PER_LONG;
> -               bank_mask = (mask[BIT_WORD(i)] >> shift) &
> -                                               UNIPHIER_GPIO_BANK_MASK;
> -               bank_bits = bits[BIT_WORD(i)] >> shift;
> +               bank_bits = bitmap_get_value8(bits, chip->ngpio, i);
>
>                 uniphier_gpio_bank_write(chip, bank, UNIPHIER_GPIO_PORT_DATA,
>                                          bank_mask, bank_bits);


Please do not do this.

Nothing in this driver says the GPIO width is 8-bit.

You are hard-coding '8-bit'.







> --
> 2.21.0
>


-- 
Best Regards
Masahiro Yamada