• K
    clk: rockchip: change PLL setting for better clock jitter · 49ed9ee4
    Kever Yang 提交于
    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: NKever Yang <kever.yang@rock-chips.com>
    Reviewed-by: NDoug Anderson <dianders@chromium.org>
    Signed-off-by: NHeiko Stuebner <heiko@sntech.de>
    49ed9ee4
clk.h 10.5 KB