I was trying to adjust the brightness-levels for the trogdor boards: https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/2... Like on a lot of panels, trogdor's low end needs to be cropped, and now that we have the interpolation stuff I wanted to make use of it and bake in even the curve that's customary to have on chromebooks.
I found the current behavior of the pwm_bl driver a little unintuitive and non-linear. See patch 1 for a suggested fix for this.
A few veyron dts files were relying on this (perhaps weird) behavior. Those devices also want a minimum brightness like trogdor, so changed them to use the new way.
Finally, given that trogdor's dts is part of linux-next now, add the brightness-levels to it, since that's the original reason I was looking at this.
Changes in v2: - Fixed type promotion in the driver - Removed "backlight: pwm_bl: Artificially add 0% during interpolation", userspace works just fine without it because it already knows how to use bl_power for turning off the display. - Added brightness-levels to trogdor as well, now the dts is upstream.
Alexandru Stan (3): backlight: pwm_bl: Fix interpolation ARM: dts: rockchip: veyron: Remove 0 point from brightness-levels arm64: dts: qcom: trogdor: Add brightness-levels
arch/arm/boot/dts/rk3288-veyron-jaq.dts | 2 +- arch/arm/boot/dts/rk3288-veyron-minnie.dts | 2 +- arch/arm/boot/dts/rk3288-veyron-tiger.dts | 2 +- arch/arm64/boot/dts/qcom/sc7180-trogdor.dtsi | 9 +++ drivers/video/backlight/pwm_bl.c | 70 +++++++++----------- 5 files changed, 43 insertions(+), 42 deletions(-)