On Thu, Jul 25, 2013 at 09:20:53PM +0400, Alexander Shiyan wrote:

On Thu, 25 Jul 2013 15:38:56 +0200
Markus Pargmann [off-list ref] wrote:

quoted

Hi,

On Sun, Jul 21, 2013 at 12:35:09PM +0400, Alexander Shiyan wrote:

quoted

This patch adds feature to setup PWM Contrast Control Register.
This register is used to control the signal output at the contrast pin,
which controls contrast of the LCD panel.

http://www.spinics.net/lists/linux-fbdev/msg10002.html

PWM? I can not understand how the PWM driver will be connected to the
framebuffer driver. It is not backlight, this is contrast.
Even if we imagine that the driver will be connected through phandle,
then we will need to have at least 4! additional parameters in the framebuffer
driver: freq source, frequency and active pulse period + phandle to PWM.
Is it worth it, given that these parameters should not be adjustable?
On my opinion, the only one additional parameter in framebuffer is enough.
Thanks.

Why should the contrast of a display not be adjustable?

Sascha

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