Re: [PATCH 1/2] ARM: tegra: Add Tegra20 host1x support

[Thierry Reding]

On Tue, Nov 13, 2012 at 03:45:00PM +0800, Mark Zhang wrote:
> On 11/09/2012 09:20 PM, Thierry Reding wrote:
> > @@ -116,6 +122,9 @@ static __initdata struct tegra_clk_init_table tegra_dt_clk_init_table[] = {
> >         { "sbc2",       "pll_p",        100000000,      false },
> >         { "sbc3",       "pll_p",        100000000,      false },
> >         { "sbc4",       "pll_p",        100000000,      false },
> > +       { "host1x",     "pll_c",        144000000,      false },
> > +       { "disp1",      "pll_p",        600000000,      false },
> > +       { "disp2",      "pll_p",        600000000,      false },
> 
> I think here the parent of disp2 should be "pll_d_out0", not "pll_p".
> Right now pll_p has not a proper clock setting to make 148.5MHz 1080p
> HDMI happy. In addition, you add the 297MHz in pll_d frequency table
> next and I think this is for disp2 has a proper clock rate to support HDMI.
[...]
> > @@ -1051,6 +1053,9 @@ static struct clk_duplicate tegra_clk_duplicates[] = {
> >         CLK_DUPLICATE("pll_p_out3", "tegra-i2c.1", "fast-clk"),
> >         CLK_DUPLICATE("pll_p_out3", "tegra-i2c.2", "fast-clk"),
> >         CLK_DUPLICATE("pll_p_out3", "tegra-i2c.3", "fast-clk"),
> > +       CLK_DUPLICATE("pll_p", "tegra-dc.0", "parent"),
> > +       CLK_DUPLICATE("pll_p", "tegra-dc.1", "parent"),
> > +       CLK_DUPLICATE("pll_d_out0", "tegra-hdmi", "parent"),
> >  };
> 
> The same with my above comments, the tegra-dc.1's parent should be
> pll_d_out0.

The way this works is that for HDMI it is required that the DC and HDMI
blocks have the same parent. So what really happens is that once you
setup one of the DCs to work with HDMI, its clock will automatically be
reparented to the HDMI parent clock, which in this case is "pll_d_out0".

Thierry

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