From: Bartosz Golaszewski <bgolaszewski@baylibre.com>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Cc: Linus Walleij <linus.walleij@linaro.org>,
linux-gpio <linux-gpio@vger.kernel.org>
Subject: Re: [PATCH v1 2/2] gpio: pca953x: Correctly initialize registers 6 and 7 for PCA957x
Date: Thu, 1 Oct 2020 09:27:41 +0200 [thread overview]
Message-ID: <CAMpxmJXRJxDsKeD10VdpWLgYBYnTPH-7vxpG8YaVpnc0a=J+aQ@mail.gmail.com> (raw)
In-Reply-To: <20200930142013.59247-2-andriy.shevchenko@linux.intel.com>
On Wed, Sep 30, 2020 at 4:20 PM Andy Shevchenko
<andriy.shevchenko@linux.intel.com> wrote:
>
> When driver has been converted to the bitmap API the non-bitmap functions
> started behaving differently on 32-bit BE architectures since the bytes in
> two consequent unsigned longs are in different order in comparison to byte
> array. Hence if the chip had had more than 32 lines the memset() call over
> it would have not set up upper lines correctly.
> Although it's currently a theoretical case (no supported chips of this type
> has 32+ lines), it's better to provide a clean code to avoid people thinking
> this is okay and potentially producing not fully working things.
>
> Fixes: 35d13d94893f ("gpio: pca953x: convert to use bitmap API")
> Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
> ---
> drivers/gpio/gpio-pca953x.c | 5 ++++-
> 1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/gpio/gpio-pca953x.c b/drivers/gpio/gpio-pca953x.c
> index 3f24cfabb1d7..6263a4d55f8b 100644
> --- a/drivers/gpio/gpio-pca953x.c
> +++ b/drivers/gpio/gpio-pca953x.c
> @@ -942,6 +942,7 @@ static int device_pca95xx_init(struct pca953x_chip *chip, u32 invert)
> static int device_pca957x_init(struct pca953x_chip *chip, u32 invert)
> {
> DECLARE_BITMAP(val, MAX_LINE);
> + unsigned int i;
> int ret;
>
> ret = device_pca95xx_init(chip, invert);
> @@ -949,7 +950,9 @@ static int device_pca957x_init(struct pca953x_chip *chip, u32 invert)
> goto out;
>
> /* To enable register 6, 7 to control pull up and pull down */
> - memset(val, 0x02, NBANK(chip));
> + for (i = 0; i < NBANK(chip); i++)
> + bitmap_set_value8(val, 0x02, i * BANK_SZ);
> +
> ret = pca953x_write_regs(chip, PCA957X_BKEN, val);
> if (ret)
> goto out;
> --
> 2.28.0
>
Reviewed-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
next prev parent reply other threads:[~2020-10-01 7:27 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-30 14:20 [PATCH v1 1/2] gpio: pca953x: Use bitmap API over implicit GCC extension Andy Shevchenko
2020-09-30 14:20 ` [PATCH v1 2/2] gpio: pca953x: Correctly initialize registers 6 and 7 for PCA957x Andy Shevchenko
2020-10-01 7:27 ` Bartosz Golaszewski [this message]
2020-10-01 7:26 ` [PATCH v1 1/2] gpio: pca953x: Use bitmap API over implicit GCC extension Bartosz Golaszewski
2020-10-01 8:02 ` Linus Walleij
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