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Commit 6e66a659 authored by Axel Lin's avatar Axel Lin Committed by Linus Walleij
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gpio: tpic2810: Make sure cached buffer has consistent status with h/w status 



i2c_smbus_write_byte_data() can fail. To ensure the
cached buffer has consistent status with h/w status, don't
update the cached gpio->buffer if write fails.

Also refactor the code a bit by adding a tpic2810_set_mask_bits()
helper and use it to simplify the code.

Signed-off-by: default avatarAxel Lin <axel.lin@ingics.com>
Reviewed-by: default avatarAlexandre Courbot <acourbot@nvidia.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 18fb0a98

drivers/gpio/gpio-tpic2810.c

+15 −20
Original line number Diff line number Diff line
@@ -57,39 +57,34 @@ static int tpic2810_direction_output(struct gpio_chip *chip, 
	return 0;

}



static void tpic2810_set(struct gpio_chip *chip, unsigned offset, int value)

static void tpic2810_set_mask_bits(struct gpio_chip *chip, u8 mask, u8 bits)

{

	struct tpic2810 *gpio = gpiochip_get_data(chip);

	u8 buffer;

	int err;



	mutex_lock(&gpio->lock);



	if (value)

		gpio->buffer |= BIT(offset);

	else

		gpio->buffer &= ~BIT(offset);

	buffer = gpio->buffer & ~mask;

	buffer |= (mask & bits);



	i2c_smbus_write_byte_data(gpio->client, TPIC2810_WS_COMMAND,

				  gpio->buffer);

	err = i2c_smbus_write_byte_data(gpio->client, TPIC2810_WS_COMMAND,

					buffer);

	if (!err)

		gpio->buffer = buffer;



	mutex_unlock(&gpio->lock);

}



static void tpic2810_set(struct gpio_chip *chip, unsigned offset, int value)

{

	tpic2810_set_mask_bits(chip, BIT(offset), value ? BIT(offset) : 0);

}



static void tpic2810_set_multiple(struct gpio_chip *chip, unsigned long *mask,

				  unsigned long *bits)

{

	struct tpic2810 *gpio = gpiochip_get_data(chip);



	mutex_lock(&gpio->lock);



	/* clear bits under mask */

	gpio->buffer &= ~(*mask);

	/* set bits under mask */

	gpio->buffer |= ((*mask) & (*bits));



	i2c_smbus_write_byte_data(gpio->client, TPIC2810_WS_COMMAND,

				  gpio->buffer);



	mutex_unlock(&gpio->lock);

	tpic2810_set_mask_bits(chip, *mask, *bits);

}



static struct gpio_chip template_chip = {