Messages in this thread | | | From | Heiko Stübner <> | Subject | Re: [PATCH] clk: rockchip: change PLL setting for better clock jitter | Date | Wed, 29 Oct 2014 20:51:50 +0100 |
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Am Donnerstag, 9. Oktober 2014, 22:23:57 schrieb Kever Yang: > dclk_vop0/1 is the source of HDMI TMDS clock in rk3288, usually we > use 594MHz for clock source of dclk_vop0/1. > > HDMI CTS 7-9 require TMDS Clock jitter is lower than 0.25*Tbit: > TMDS clock(MHz) CTS require jitter (ps) > 297 84.2 > 148.5 168 > 74.25 336 > 27 1247 > > PLL BW and VCO frequency effects the jitter of PLL output clock, > clock jitter is better if BW is lower or VCO frequency is higher. > > If PLL use default setting of RK3066_PLL_RATE( 594000000, 2, 198, 4), > the TMDS Clock jitter is higher than 250ps, which means we can't > pass the test when TMDS clock is 297MHz or 148.5MHz. > > If we use RK3066_PLL_RATE_BWADJ(594000000, 1, 198, 8, 1), > the TMDS Clock jitter is about 60ps and we can pass all test case. > > So we need this patch to make hdmi si test pass. > > Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
I've applied this to my v3.19-clk branch with Dougs Review-Tag.
Heiko
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