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clock source selection for i.mx6 parallel lcd port with 205MHz pixel clock

Question asked by lonsn on Dec 9, 2015
Latest reply on Dec 22, 2015 by Gary Bisson

Hi,

I connected a RGB to eDP adapter board with parallel lcd port of a nitrogen6_max i.mx6 eval board. The required paralled lcd port pixel clock is 205MHz for 2048x1536 retina panel. We can't see any image from the LCD panel. If we decrase to 800x400 resolution, then image displayed in LCD panel although it is disordered caused by uncorrect resolution. So we doubt the 205MHz clock output is not good in the paralled lcd port. Which pll clock source is most suitable for this ipu0_di0 clock? Any other quality improvement for the parallel port clock and data from hardware/software?

We use android 5.0/kernel 3.10. Current ipu clock settings are as below:

imx_clk_set_parent(clk[ipu1_di0_pre_sel], clk[pll5_video_div]);
imx_clk_set_parent(clk[ipu1_di1_pre_sel], clk[pll5_video_div]);
imx_clk_set_parent(clk[ipu2_di0_pre_sel], clk[pll5_video_div]);
imx_clk_set_parent(clk[ipu2_di1_pre_sel], clk[pll5_video_div]);
imx_clk_set_parent(clk[ipu1_di0_sel], clk[ipu1_di0_pre]);
imx_clk_set_parent(clk[ipu1_di1_sel], clk[ipu1_di1_pre]);
imx_clk_set_parent(clk[ipu2_di0_sel], clk[ipu2_di0_pre]);
imx_clk_set_parent(clk[ipu2_di1_sel], clk[ipu2_di1_pre]);

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