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    SubjectRe: [PATCH v9 9/9] gpio: uniphier: Utilize for_each_set_clump8 macro
    On Tue, Mar 12, 2019 at 01:36:57PM +0900, Masahiro Yamada wrote:
    > On Sun, Mar 3, 2019 at 4:51 PM William Breathitt Gray
    > <vilhelm.gray@gmail.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@socionext.com>
    > > Signed-off-by: William Breathitt Gray <vilhelm.gray@gmail.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'.

    The for_each_set_clump8 macro is hardcoded to 8-bit clumps because the
    current drivers utilizing this functionality are only updating their
    GPIO ports 8-bits at a time.

    However, if this driver updates more or less GPIO at a time, we can
    easily update the macro by replacing the hardcoded '8' value with a
    variable, thus giving us the generic for_each_set_clump macro.

    How many GPIO can be updated at a time for this device?

    William Breathitt Gray

    >
    >
    >
    >
    >
    >
    >
    > > --
    > > 2.21.0
    > >
    >
    >
    > --
    > Best Regards
    > Masahiro Yamada

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