Linux-Rockchip Archive on lore.kernel.org
 help / color / Atom feed
* [PATCH v2 0/3] PWM backlight interpolation adjustments
@ 2020-10-13  8:01 Alexandru Stan
  2020-10-13  8:01 ` [PATCH v2 2/3] ARM: dts: rockchip: veyron: Remove 0 point from brightness-levels Alexandru Stan
  0 siblings, 1 reply; 4+ messages in thread
From: Alexandru Stan @ 2020-10-13  8:01 UTC (permalink / raw)
  To: Thierry Reding, Uwe Kleine-König, Lee Jones,
	Daniel Thompson, Jingoo Han, Bartlomiej Zolnierkiewicz,
	Heiko Stuebner, Rob Herring, Andy Gross, Bjorn Andersson
  Cc: devicetree, linux-fbdev, Alexandru Stan, linux-pwm,
	linux-arm-msm, Douglas Anderson, dri-devel, linux-kernel,
	linux-rockchip, Matthias Kaehlcke, Enric Balletbo i Serra,
	linux-arm-kernel

I was trying to adjust the brightness-levels for the trogdor boards:
https://chromium-review.googlesource.com/c/chromiumos/third_party/kernel/+/2291209
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(-)

-- 
2.28.0


_______________________________________________
Linux-rockchip mailing list
Linux-rockchip@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-rockchip

^ permalink raw reply	[flat|nested] 4+ messages in thread

end of thread, back to index

Thread overview: 4+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2020-10-13  8:01 [PATCH v2 0/3] PWM backlight interpolation adjustments Alexandru Stan
2020-10-13  8:01 ` [PATCH v2 2/3] ARM: dts: rockchip: veyron: Remove 0 point from brightness-levels Alexandru Stan
2020-10-14 14:19   ` Daniel Thompson
2020-10-15 21:29     ` Alexandru M Stan

Linux-Rockchip Archive on lore.kernel.org

Archives are clonable:
	git clone --mirror https://lore.kernel.org/linux-rockchip/0 linux-rockchip/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 linux-rockchip linux-rockchip/ https://lore.kernel.org/linux-rockchip \
		linux-rockchip@lists.infradead.org
	public-inbox-index linux-rockchip

Example config snippet for mirrors

Newsgroup available over NNTP:
	nntp://nntp.lore.kernel.org/org.infradead.lists.linux-rockchip


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git