IMX8mp mipi dsi in command mode

[persandberg]

Hi,

We have a cutom board with iMX8MP and a AMOLED display with a CH13721C controller. We have video mode working but would like to use command mode and use the internal frame buffer in the display controller to show a static image on the display.
From the reference manual of iMX8mp in table 13-26 a initialization sequence is described of how to get command mode woring but I can not get it to work. I can also not find a Linux driver that fully utilyze the command mode.
Any help is much appreciated.

[persandberg]

I am unable to figure out how to configure command mode for the IMX8MP processor.

If bit 25 (Video mode) is cleared in register DSI_CONFIG and bit 31 is set in register DSI_MDRESOL, nothing is transfered from the fifo, not even commands to the display. If i clear bit 31, I can send commands but no image data is transfered.
Please  help

[jerrymarlowe45]

Hello,

I understand it correctly thanks so much share this correct guidance.

[AldoG]

Hello,

For this you may refer to the Linux driver:

https://github.com/nxp-imx/linux-imx/blob/lf-6.12.y/drivers/video/fbdev/mxc/mipi_dsi.c#L472

Best regards/Saludos,
Aldo.

[persandberg]

If I follow the guide for command mode, the mipi interface dose not send out any data to the display, only when using video mode.

There is a samsung driver that implement support for IMX8MP (samsung-dsim.c).

Is that a better choices when using command mode?

[persandberg]

Hi,

Is that implementation rellay for theiMX8MP processor?

[persandberg]

Thanks for responding!

Are the registers used in mipi_dsi.c the same as the ones in iMX8MP?

Have I understand it correctlly that the internal bus (S-i80) in the CPU writes to the FIFO if command mode is activated by setting bit 31 in DSIM_RGB_STATUS?

Pleas let me know if you need more information.