Linux pinmux lcd, wrong pinmux in mux33xx.c

Laurens Miers

Other Parts Discussed in Thread: AM3354

Hi,

I have a board loosely based on the AM335x EVM. I am using the u-boot-2013.01.01-psp06.00.00.00 version and the arago linux distribution from the TI board port labs ( kernel version 3.2 ).

My board is able to boot when I include the lcd driver (da8xx-fb) as module but my lcd is showing the wrong colours ( red is supposed to be blue and vica versa ). When I built the module in the kernel the Linux logo is showing with the right colours but the board doesn't want to boot, it hangs on "Waiting for root device /dev/mmcblk0p2".

I thought it maybe a problem with the initial pinmux being overwritten by Linux. In the file <Linux>/arch/arm/mach-omap2/mux33xx.c the pinmux there isn't what's described in the datasheets of my processer, the AM3354. My lcd uses 2 extra pins, the gpmc_AD14 and AD15. These are muxed to lcd_data16 and lcd_data17 in my code and in the datasheets but in the above file these are muxed to lcd_data22 and lcd_data23.

Is there a specific reason for this or can I change this pinmux in mux33xx.c and achieve the right colours on my LCD?

Thanks in advance.

over 11 years ago

0 Biser Gatchev-XID over 11 years ago

TI__Guru**** 393215 points

For LCD color assignments please check the AM335X Errata Rev. E, section 3.1.1.

0 Laurens Miers over 11 years ago in reply to Biser Gatchev-XID

Intellectual 640 points

The board i received was already running Windows CE, with the right colors, and they assured me they have taken this errata into account.

Is the mux33xx.c file the right one to alter? or am I missing something?

0 Laurens Miers over 11 years ago in reply to Laurens Miers

Intellectual 640 points

I changed the pinmux in <Linux>/arch/arm/mach-omap2/mux33x.c and the board is able to boot with the lcd driver built-in. The Linux logo and the Texas Instruments logo are showing the right colours but when the matrix app shows up, the colours are still wrong. I'm starting to think there's something wrong with the matrix app. Is there another app I can launch on my board to check this or is there a way to show a photo on my board using the command line?

0 Laurens Miers over 11 years ago in reply to Laurens Miers

Intellectual 640 points

The colours blue and red were switched on the LCD, so we switched de red.offset and blue.offset values in the function fb_setcolreg, which is located in the file <linux>/drivers/video/da8xx-fb.c

The colours were fine then, except in startup, de Linux logo is blue now but the matrix app and other applications have the right colours so it's ok for us.

Thank you all for the help.

0 ashok kumar6 over 10 years ago in reply to Laurens Miers

Expert 1800 points

Hi Laurens Miers,

I am also facing similar issue. I am getting proper colors in application except startup logo.
Do you have any solution to fix the startup de Linux logo color issue?

Thanks
Ashok

0 Laurens Miers over 10 years ago in reply to ashok kumar6

Intellectual 640 points

Hey Ashok,

Unfortunately, I have not found any solution for the startup color issue.

We didn't look into it anymore due to time shortage.

I'm also not sure where the problem could be, the last idea we had was that we look into how the u-boot and linux pinmuxes were being overwritten (in a specific order? ...) but I am not sure about this, this is just the last idea we had.

Sorry I couldn't be of more help. If you find the problem, I would be grateful if you let me know (just out of curiosity :) ).

KR,

Laurens

0 ashok kumar6 over 10 years ago in reply to Laurens Miers

Expert 1800 points

Hi Laurens,

Thanks for the reply. I could able to get the expected colors in kernel and rootfs. Please go through this post

https://e2e.ti.com/support/embedded/android/f/509/p/442103/1594484#1594484.

The bootloader yet to configure.

Regards

ashok

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Linux pinmux lcd, wrong pinmux in mux33xx.c