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gpio: pca953x: Correctly initialize registers 6 and 7 for PCA957x

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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: 35d13d9489 ("gpio: pca953x: convert to use bitmap API")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reviewed-by: Bartosz Golaszewski <bgolaszewski@baylibre.com>
Link: https://lore.kernel.org/r/20200930142013.59247-2-andriy.shevchenko@linux.intel.com
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Andy Shevchenko 2020-09-30 17:20:13 +03:00 committed by Linus Walleij
parent e09e200e07
commit 8c1f1c3477
1 changed files with 4 additions and 1 deletions
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5
drivers/gpio/gpio-pca953x.c
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@ -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;