Lookup tables for color transformations in LVDS / HDMI / etc. scanout on i.MX8m plus?

[crg7475]

I'd like to apply a lookup table on the pixels before they are scanned out to the display. My SoC is an i.MX8m plus. Unfortunately, I did not find anything like that mentioned in the reference manual.

Does that SoC have such a feature? If not, I guess the only option is to use the GPU's 3D core, since the 2D core does not seem to have anything like that either.

[joanxie]

hdmi has table under drivers/phy/freescale/phy-fsl-samsung-hdmi.c, which is offered by the IP vendor and based on the pixel clock, lvds is defined in the driver, do you mean the table you can scan according to the display pixel clock or anything else? i don't know what you mean table on the pixels

[crg7475]

I mean a look-up table, for transforming R, G, and B values. Like this:

output_r = lookup_table_r[input_r];
output_g = lookup_table_g[input_g];
output_b = lookup_table_b[input_b];

This would typically be tables with 256 entries (since RGB values usually are 8-bit). It is also OK if there is only one table for all three channels.

[joanxie]

what is the table for? 8mp ISI has CSC table for rgb to yuv or yuv to rgb, but the table you need is for what?

[crg7475]

The table is used for color correction. The devices that use the SoC have to be calibrated to have the exact same color output, and this requires transforming the pixel color values according to a device specific table.

[joanxie]

no such table, you need do it by GPU