Linux/AM5728: adjust the saturation, contrast, brightness. ...

kim yoochang

Intellectual 720 points

Part Number: AM5728

Tool/software: Linux

Hello,

I using PSDK-03.01.00.06 & AM5728

I would like to adjust the saturation, contrast, brightness.

I found information on tv_properties (margin, saturation, contrast, brightness, hue ...) in "/drivers/gpu/drm/drm_crtc.c".
function name is drm_mode_create_tv_properties().

I looked up the information to use it, but I could not find it.
Is it appropriate to use this?

please Could give some documents or examples how to achieve this?

Thank you.

over 8 years ago

0 Pavel Botev over 8 years ago

TI__Guru**** 170625 points

Hi Aupers,

I made a search and I found option to control brightness of LCD screen through PWM:

processors.wiki.ti.com/.../Linux_Core_PWM_User's_Guide
processors.wiki.ti.com/.../Sitara_Linux_LCDC_Porting_Guide

See also:
e2e.ti.com/.../384622

Regards,
Pavel

0 Pavel Botev over 8 years ago in reply to Pavel Botev

TI__Guru**** 170625 points

0 kim yoochang over 8 years ago in reply to Pavel Botev

Intellectual 720 points

Thank you, Pavel.

This information gives us a lot of help.
Please, Can you provide more detailed guidelines or sample code?

We used DM 816x from previous development.

In DM816x, it provided mcfw_api, Vdis_setColorControl API.
For example, if you change the saturation, the value of "/ sys / devices / platform / vpss / display% d / saturation" has been changed.
After that, it was found that the values of multiple registers were changed via the kernel vpss driver and reflected on the LCD.

Currently AM5728 does not have a simple API like Vdis_setColorControl.
And we do not know how to change the register to DSS, saturation, contrast, brightness effect applied.
At present, it seems difficult to apply this.
Is there a scheduled update for this in the next PSDK release?

Best regards,

0 Pavel Botev over 8 years ago in reply to kim yoochang

TI__Guru**** 170625 points

Aupers,

You should first read AM572x TRM (chapter 11 Display Subsystem, chapter 29 Pulse-Width Modulation Subsystem), then proceed to the wiki pages provided in my previous posts. Then you can explore the linux kernel source code (the files pointed from within the wiki pages), and check the options there (i.e. drm_crtc.h, v4l2-ctrls.c)

Regards,
Pavel

0 kim yoochang over 8 years ago in reply to Pavel Botev

Intellectual 720 points

Thank you, Pavel.

I would like to ask another one.
It seems there is a few problem with communication.

The DM816x is also the case of HDMI.

We want to change 'saturation', 'contrast', 'brightness' of HDMI.
There is no LCD, I want to change HDMI.

Please, Can you provide more guidelines?

Best regards,

0 Pavel Botev over 8 years ago in reply to kim yoochang

TI__Guru**** 170625 points

Hi Aupers,

HDMI is part of the DSS (Display Subsystem), so the above wiki pages are still valid. The linux drivers relevant to DSS and HDMI are located inside the below folders:

linux-kernel/drivers/gpu/drm/omapdrm/
linux-kernel/drivers/video/fbdev/omap2/

I made a search regarding "saturation", "contrast" and "brightness" in this code, but I was not able to find such parameters configuration for DSS/HDMI.

Thus I can conclude that we have no linux driver for DSS/HDMI that can be used to configure these 3 parameters.

Also I am not able to find user space API that can be used to change these 3 parameters of the DSS/HDMI

Regards,
Pavel

0 kim yoochang over 8 years ago in reply to Pavel Botev

Intellectual 720 points

Thank you, Pavel.

Do you have any plans to add this feature?
I would appreciate it if you let me know.

Best regards,

0 Pavel Botev over 8 years ago in reply to kim yoochang

TI__Guru**** 170625 points

I have not heard about such future plans.

Regards,
Pavel

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Linux/AM5728: adjust the saturation, contrast, brightness. ...