Messages in this thread | | | From | Jagan Teki <> | Date | Thu, 15 Nov 2018 20:51:04 +0530 | Subject | Re: [PATCH v4 03/26] clk: sunxi-ng: Add check for maximum rate to NKM PLLs |
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On Tue, Nov 13, 2018 at 6:57 PM Maxime Ripard <maxime.ripard@bootlin.com> wrote: > > On Tue, Nov 13, 2018 at 04:46:10PM +0530, Jagan Teki wrote: > > Some NKM PLLs, frequency can be set above PLL working range. > > > > Add a constraint for maximum supported rate. This way, drivers can > > specify which is maximum allowed rate for PLL. > > > > Signed-off-by: Jagan Teki <jagan@amarulasolutions.com> > > Acked-by: Stephen Boyd <sboyd@kernel.org> > > As Vasily reported on a previous version, this should be squashed with > the patch 2.
Sorry, I missed it.
> > > --- > > drivers/clk/sunxi-ng/ccu_nkm.c | 3 +++ > > drivers/clk/sunxi-ng/ccu_nkm.h | 1 + > > 2 files changed, 4 insertions(+) > > > > diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c > > index 6b5ad990f802..b8b66cdd30bf 100644 > > --- a/drivers/clk/sunxi-ng/ccu_nkm.c > > +++ b/drivers/clk/sunxi-ng/ccu_nkm.c > > @@ -128,6 +128,9 @@ static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux, > > if (rate < nkm->min_rate) > > return nkm->min_rate; > > > > + if (nkm->max_rate && rate > nkm->max_rate) > > + return nkm->max_rate; > > + > > I would expect the test to be the same for the minimum and maximum cases.
I don't have proper use-case for max rate test, I do verify by using higher the rate on dclock, but nor sure. May be I can skip the max_rate patch?
Apart from this, any idea about this issue where SUN4I_TCON0_DCLK_REG will only work with div upto 6 on A64 DSI panels[1], did you find the same issue on A33?
With parent rate 330MHz, the resulting tcon divider for 30MHz [2] clock is 11 and for the same for 55MHz [3] clock is 6.
[3] https://paste.ubuntu.com/p/drvzfHFMtY/ [2] https://paste.ubuntu.com/p/hz29CTJY2J/ [1] https://elixir.bootlin.com/linux/v4.20-rc2/source/drivers/gpu/drm/sun4i/sun4i_dotclock.c#L125
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