Re: [PATCH v3 4/4] backlight: pwm_bl: Set scale type for brightness curves specified in the DT
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From: Lee Jones <hidden>
Date: 2019-09-02 09:42:17
Also in:
dri-devel, linux-pwm, lkml
On Tue, 09 Jul 2019, Matthias Kaehlcke wrote:
Check if a brightness curve specified in the device tree is linear or
not and set the corresponding property accordingly. This makes the
scale type available to userspace via the 'scale' sysfs attribute.
To determine if a curve is linear it is compared to a interpolated linear
curve between min and max brightness. The curve is considered linear if
no value deviates more than +/-5% of ${brightness_range} from their
interpolated value.
Signed-off-by: Matthias Kaehlcke <mka@chromium.org>
Acked-by: Daniel Thompson <redacted>
---
Changes in v3:
- none
Changes in v2:
- use 128 (power of two) instead of 100 as factor for the slope
- add comment about max quantization error
- added Daniel's 'Acked-by' tag
---
drivers/video/backlight/pwm_bl.c | 30 ++++++++++++++++++++++++++++++
1 file changed, 30 insertions(+)Applied, thanks. -- Lee Jones [李琼斯] Linaro Services Technical Lead Linaro.org │ Open source software for ARM SoCs Follow Linaro: Facebook | Twitter | Blog