[PATCH v2 08/11] leds: aw200xx: improve autodim calculation method

From: Dmitry Rokosov
Date: Wed Oct 18 2023 - 14:30:38 EST


From: George Stark <gnstark@xxxxxxxxxxxxxxxxx>

It is highly recommended to leverage the DIV_ROUND_UP() function as a
more refined and mathematically precise alternative to employing a
coarse division method.

Signed-off-by: George Stark <gnstark@xxxxxxxxxxxxxxxxx>
Signed-off-by: Dmitry Rokosov <ddrokosov@xxxxxxxxxxxxxxxxx>
---
drivers/leds/leds-aw200xx.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/drivers/leds/leds-aw200xx.c b/drivers/leds/leds-aw200xx.c
index ad4bfb9f0938..7b8802bd9497 100644
--- a/drivers/leds/leds-aw200xx.c
+++ b/drivers/leds/leds-aw200xx.c
@@ -87,6 +87,8 @@
#define AW200XX_REG_DIM(x, columns) \
AW200XX_REG(AW200XX_PAGE4, AW200XX_LED2REG(x, columns) * 2)
#define AW200XX_REG_DIM2FADE(x) ((x) + 1)
+#define AW200XX_REG_FADE2DIM(fade) \
+ DIV_ROUND_UP((fade) * AW200XX_DIM_MAX, AW200XX_FADE_MAX)

/*
* Duty ratio of display scan (see p.15 of datasheet for formula):
@@ -195,9 +197,7 @@ static int aw200xx_brightness_set(struct led_classdev *cdev,

dim = led->dim;
if (dim < 0)
- dim = max_t(int,
- brightness / (AW200XX_FADE_MAX / AW200XX_DIM_MAX),
- 1);
+ dim = AW200XX_REG_FADE2DIM(brightness);

ret = regmap_write(chip->regmap, reg, dim);
if (ret)
@@ -460,6 +460,7 @@ static int aw200xx_probe_fw(struct device *dev, struct aw200xx *chip)
led->num = source;
led->chip = chip;
led->cdev.brightness_set_blocking = aw200xx_brightness_set;
+ led->cdev.max_brightness = AW200XX_FADE_MAX;
led->cdev.groups = dim_groups;
init_data.fwnode = child;

--
2.36.0