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gpio: pca953x: use regmap_update_bits() to improve performance

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Using regmap_update_bits() allows to reduce the number of I2C transfers
when updating bits that haven't changed on non-volatile registers.

For example on a PCAL6416, when changing a GPIO direction from input to
output, the number of I2C transfers can be reduced from 4 to just 1 if
the pull resistors configuration hasn't changed and the output value
is the same as before.

Signed-off-by: Hugo Villeneuve <hvilleneuve@dimonoff.com>
Link: https://lore.kernel.org/r/20250714133730.6353-1-hugo@hugovil.com
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
This commit is contained in:
Hugo Villeneuve
2025-07-14 09:37:30 -04:00
committed by Bartosz Golaszewski
parent e70513bd98
commit 2aa8ccab5a
1 changed files with 10 additions and 10 deletions
Download Patch File Download Diff File Expand all files Collapse all files

20
drivers/gpio/gpio-pca953x.c
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@@ -611,9 +611,9 @@ static int pca953x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
guard(mutex)(&chip->i2c_lock);
if (PCA_CHIP_TYPE(chip->driver_data) == TCA6418_TYPE)
return regmap_write_bits(chip->regmap, dirreg, bit, 0);
return regmap_update_bits(chip->regmap, dirreg, bit, 0);
return regmap_write_bits(chip->regmap, dirreg, bit, bit);
return regmap_update_bits(chip->regmap, dirreg, bit, bit);
}
static int pca953x_gpio_direction_output(struct gpio_chip *gc,
@@ -628,7 +628,7 @@ static int pca953x_gpio_direction_output(struct gpio_chip *gc,
guard(mutex)(&chip->i2c_lock);
/* set output level */
ret = regmap_write_bits(chip->regmap, outreg, bit, val ? bit : 0);
ret = regmap_update_bits(chip->regmap, outreg, bit, val ? bit : 0);
if (ret)
return ret;
@@ -637,9 +637,9 @@ static int pca953x_gpio_direction_output(struct gpio_chip *gc,
* (in/out logic is inverted on TCA6418)
*/
if (PCA_CHIP_TYPE(chip->driver_data) == TCA6418_TYPE)
return regmap_write_bits(chip->regmap, dirreg, bit, bit);
return regmap_update_bits(chip->regmap, dirreg, bit, bit);
return regmap_write_bits(chip->regmap, dirreg, bit, 0);
return regmap_update_bits(chip->regmap, dirreg, bit, 0);
}
static int pca953x_gpio_get_value(struct gpio_chip *gc, unsigned off)
@@ -667,7 +667,7 @@ static int pca953x_gpio_set_value(struct gpio_chip *gc, unsigned int off,
guard(mutex)(&chip->i2c_lock);
return regmap_write_bits(chip->regmap, outreg, bit, val ? bit : 0);
return regmap_update_bits(chip->regmap, outreg, bit, val ? bit : 0);
}
static int pca953x_gpio_get_direction(struct gpio_chip *gc, unsigned off)
@@ -751,9 +751,9 @@ static int pca953x_gpio_set_pull_up_down(struct pca953x_chip *chip,
/* Configure pull-up/pull-down */
if (param == PIN_CONFIG_BIAS_PULL_UP)
ret = regmap_write_bits(chip->regmap, pull_sel_reg, bit, bit);
ret = regmap_update_bits(chip->regmap, pull_sel_reg, bit, bit);
else if (param == PIN_CONFIG_BIAS_PULL_DOWN)
ret = regmap_write_bits(chip->regmap, pull_sel_reg, bit, 0);
ret = regmap_update_bits(chip->regmap, pull_sel_reg, bit, 0);
else
ret = 0;
if (ret)
@@ -761,9 +761,9 @@ static int pca953x_gpio_set_pull_up_down(struct pca953x_chip *chip,
/* Disable/Enable pull-up/pull-down */
if (param == PIN_CONFIG_BIAS_DISABLE)
return regmap_write_bits(chip->regmap, pull_en_reg, bit, 0);
return regmap_update_bits(chip->regmap, pull_en_reg, bit, 0);
else
return regmap_write_bits(chip->regmap, pull_en_reg, bit, bit);
return regmap_update_bits(chip->regmap, pull_en_reg, bit, bit);
}
static int pca953x_gpio_set_config(struct gpio_chip *gc, unsigned int offset,