AM5728: Enabling DPI ports in Linux

Amritpreet Singh93

Other Parts Discussed in Thread: AM5728

Hi All

In our custom board based on AM5728 we would like to use LCD1 and LCD3 video output ports. I would like to use default panel-dpi driver for them.

SDK:- ti-processor-sdk-linux-am57xx-evm-02.00.02.11
I have following questions regarding this:

Doing pin-muxing for VOUT1/VOUT3 in u-boot and adding panel-dpi driver for the same DSS ports in device tree will be enough to enable these ports??
From user-space how can i verify whether the clocks are configured correctly for these ports? Is there any sys interface for that?
As we know DPI1 can display LCD1/2/3/HDMI and we can configure the same in DSS_CTRL[17:16] PARALLEL_SEL bit field. But where should i change the same in the driver?
How can i change the resolution of HDMI out?

Regards

Amrit

over 9 years ago

0 Biser Gatchev-XID over 9 years ago

TI__Guru**** 393215 points

Hi,

I will forward this to the software team.

0 Yordan Kovachev over 9 years ago

TI__Guru**** 161600 points

Hi Armit,

For questions 1 & 3 about DPI/display/hdmi settings in linux kernel, you can see how this is done in am57xx-beagle-x15.dts & am57xx-evm.dts and modify referencing these settings. Changing only pinmux settings in device tree is not enough.

For question 2, the easiest way is to check the PRCM registers with devmem2 or omapconf.

For question 4, try changing the bootargs, as described here: e2e.ti.com/.../1550427

Best Regards,
Yordan

0 Amritpreet Singh93 over 9 years ago in reply to Yordan Kovachev

Expert 1285 points

HI Yordan
Thanks for replying.
1. So device-tree changes should be enough to enable the LCD1 and LCD3 outputs?
2. How will i be able to verify that configuration is correct from user-space? any /dev nodes?
3. Will they be automatically visible in modetest command output?

Regards
Amrit

0 Yordan Kovachev over 9 years ago in reply to Amritpreet Singh93

TI__Guru**** 161600 points

Hi Armit,

Yes, dts settings should be enough and the lcdc driver should enable lcd1 & lcd3 outputs. Also modetest should detect them.

Best Regards,
Yordan

0 Amritpreet Singh93 over 9 years ago in reply to Yordan Kovachev

Expert 1285 points

Thanks a lot Yordon. This clears my low level doubts
Appreciated.
If i do "/etc/init.d/weston start", it will take control of all ports automatically?

Regards
Amrit

0 Amritpreet Singh93 over 9 years ago in reply to Yordan Kovachev

Expert 1285 points

Hi Yordon
And also how can i display the same QT GUI on all DPI ports and HDMI??
Right now i am able to display the GUI on either LCD1 or HDMI.
Is it possible to display the GUI on some ports and send a raw video as feedback to FPGA on another port?

Regards
Amrit

0 Yordan Kovachev over 9 years ago in reply to Amritpreet Singh93

TI__Guru**** 161600 points

Hi Armit,

Refer to the following link, to see how you can start weston on all ports:
processors.wiki.ti.com/.../Processor_Linux_SDK_Graphics_and_Display

You may need to adjust the weston init script, in order to do this upon board boot up.

Best Regards
Yordan

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AM5728: Enabling DPI ports in Linux