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: Axel Lin <axel.lin@ingics.com>
Reviewed-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/gpio/gpio-tpic2810.c b/drivers/gpio/gpio-tpic2810.c
index 9f020aa4..cace79c 100644
--- a/drivers/gpio/gpio-tpic2810.c
+++ b/drivers/gpio/gpio-tpic2810.c
@@ -57,39 +57,34 @@
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 = {