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authorAxel Lin <axel.lin@ingics.com>2016-03-23 14:49:41 +0300
committerLinus Walleij <linus.walleij@linaro.org>2016-03-31 16:14:37 +0300
commit6e66a6599a813abfc9ebe2e295c9d557c434812a (patch)
treec91ccdb0443c7e07a3f207eb56cf730da31ca27d /drivers/gpio/gpio-tpic2810.c
parent18fb0a981e18b91c6eb1a00f8b06f2fb5be2e9aa (diff)
downloadlinux-6e66a6599a813abfc9ebe2e295c9d557c434812a.tar.xz
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>
Diffstat (limited to 'drivers/gpio/gpio-tpic2810.c')
-rw-r--r--drivers/gpio/gpio-tpic2810.c35
1 files changed, 15 insertions, 20 deletions
diff --git a/drivers/gpio/gpio-tpic2810.c b/drivers/gpio/gpio-tpic2810.c
index 9f020aa4b067..cace79c1b70a 100644
--- a/drivers/gpio/gpio-tpic2810.c
+++ b/drivers/gpio/gpio-tpic2810.c
@@ -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 = {