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SubjectRe: [PATCH 2/2] clk: meson-g12a: Add AO Clock controller driver
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On Tue, 2018-08-28 at 11:35 +0800, Jian Hu wrote:
> Hi: Jerome
>
> On 2018/8/27 21:07, Jerome Brunet wrote:
> > On Fri, 2018-08-24 at 21:34 +0800, Jian Hu wrote:
> > > >
> > >
> > > I am confued about aoclk81's parent clocks.
> > >
> > > I can not get the example of axg audio clock driver, Could you provide
> > > the link? Had it merged into clk-meson.git?
> >
> > Yes and mainline as well : drivers/clk/meson/axg-audio.c
> >
> > Basically this driver is creating bypass input clocks (audio_pclk, mst_in[0-9],
> > etc...) .
> >
> > This allows to collect input clocks from DT (like any consumer should) will
> > keeping constant in the controller clock tree.
> >
> > > From what I've seen of your controller drivers, the EE controller should have
> >
> > one input, the AO should have 3.
> >
> >
> >
> > .
> >
>
> I still can not get the example meaning in axg audio driver.

here is one specific example:


https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/drivers/clk/meson/axg-audio.c?h=v4.19-rc1#n785


>
> In 26 page of A113D_Datasheet V0.7 20170725-Baylibre.pdf,We can see the
> aoclk81 has two parents. clk81 and ao_slow_clk. I can not get 3 parents.
>
> clk81|\
> -------| \ aoclk81
> src0 |\ | |-------------------
> -----| \ ao_slow_clk | |
> | |---------------------| /
> -----| / |/
> src1|/
>
>
> src0 is from xtal, if can generate 32k clock, but it is never used.
> src1 is from gpio clock, It is never used. If necessary, the ao_slow_clk
> maybe described.
>
> So why aoclk81 has 3 parents?

I never said that. I said your clock controller driver should have 3 input
clocks. These clock are the one used by the controller but not produced by it:
for the AO controller xtal, ao_xtal, and ee controller clk81.



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