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    SubjectRe: [PATCH] gpio: pca953x: Fix pca953x_gpio_set_multiple() on 64-bit
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    On 12/03/2016 12:31 AM, Geert Uytterhoeven wrote:
    > pca953x_gpio_set_multiple() divides by 4 to convert from longs to bytes,
    > which assumes a 32-bit platform, and is not correct on 64-bit platforms.
    > Use "sizeof(...)" instead to fix this.
    >
    > Fixes: b4818afeacbd8182 ("gpio: pca953x: Add set_multiple to allow multiple bits to be set in one write.")
    > Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

    Acked-by: Phil Reid <preid@electromag.com.au>

    > ---
    > Untested, found by code inspection.
    >
    > This bug was introduced in v4.5-rc1, but unless Linus (the other one ;-)
    > will make a v4.5-rc8, it's probably too late to get this fixed in v4.5.
    > ---
    > drivers/gpio/gpio-pca953x.c | 6 ++++--
    > 1 file changed, 4 insertions(+), 2 deletions(-)
    >
    > diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
    > index 23196c5fc17ceb6b..99b375c959987fe9 100644
    > --- a/drivers/gpio/gpio-pca953x.c
    > +++ b/drivers/gpio/gpio-pca953x.c
    > @@ -367,9 +367,11 @@ static void pca953x_gpio_set_multiple(struct gpio_chip *gc,
    > memcpy(reg_val, chip->reg_output, NBANK(chip));
    > mutex_lock(&chip->i2c_lock);
    > for(bank=0; bank<NBANK(chip); bank++) {
    > - unsigned bankmask = mask[bank/4] >> ((bank % 4) * 8);
    > + unsigned bankmask = mask[bank / sizeof(*mask)] >>
    > + ((bank % sizeof(*mask)) * 8);
    > if(bankmask) {
    > - unsigned bankval = bits[bank/4] >> ((bank % 4) * 8);
    > + unsigned bankval = bits[bank / sizeof(*bits)] >>
    > + ((bank % sizeof(*bits)) * 8);
    > reg_val[bank] = (reg_val[bank] & ~bankmask) | bankval;
    > }
    > }
    >


    --
    Regards
    Phil Reid

    ElectroMagnetic Imaging Technology Pty Ltd
    Development of Geophysical Instrumentation & Software
    www.electromag.com.au

    3 The Avenue, Midland WA 6056, AUSTRALIA
    Ph: +61 8 9250 8100
    Fax: +61 8 9250 7100
    Email: preid@electromag.com.au

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