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From: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: Linus Walleij <linus.walleij@linaro.org>,
	linux-gpio@vger.kernel.org,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>
Cc: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Subject: [PATCH v1 2/2] gpio: pca953x: Correctly initialize registers 6 and 7 for PCA957x
Date: Wed, 30 Sep 2020 17:20:13 +0300	[thread overview]
Message-ID: <20200930142013.59247-2-andriy.shevchenko@linux.intel.com> (raw)
In-Reply-To: <20200930142013.59247-1-andriy.shevchenko@linux.intel.com>

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


  reply	other threads:[~2020-09-30 14:20 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 ` Andy Shevchenko [this message]
2020-10-01  7:27   ` [PATCH v1 2/2] gpio: pca953x: Correctly initialize registers 6 and 7 for PCA957x Bartosz Golaszewski
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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