Messages in this thread | | | Date | Mon, 29 Oct 2018 09:58:43 +0100 | From | Maxime Ripard <> | Subject | Re: [PATCH v2 02/15] clk: sunxi-ng: Add check for minimal rate to NKM PLLs |
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On Thu, Oct 25, 2018 at 04:25:59PM +0530, Jagan Teki wrote: > On Wed, Oct 24, 2018 at 11:34 PM Maxime Ripard > <maxime.ripard@bootlin.com> wrote: > > > > On Tue, Oct 23, 2018 at 09:20:22PM +0530, Jagan Teki wrote: > > > Some NKM PLLs doesn't work well when their output clock rate is set below > > > certain rate. > > > > > > So, add support for minimal rate for relevant PLLs. > > > > > > Signed-off-by: Jagan Teki <jagan@amarulasolutions.com> > > > --- > > > Changes for v2: > > > - new patch > > > > > > drivers/clk/sunxi-ng/ccu_nkm.c | 7 +++++++ > > > drivers/clk/sunxi-ng/ccu_nkm.h | 1 + > > > 2 files changed, 8 insertions(+) > > > > > > diff --git a/drivers/clk/sunxi-ng/ccu_nkm.c b/drivers/clk/sunxi-ng/ccu_nkm.c > > > index 841840e35e61..d17539dc88dd 100644 > > > --- a/drivers/clk/sunxi-ng/ccu_nkm.c > > > +++ b/drivers/clk/sunxi-ng/ccu_nkm.c > > > @@ -125,6 +125,13 @@ static unsigned long ccu_nkm_round_rate(struct ccu_mux_internal *mux, > > > if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV) > > > rate *= nkm->fixed_post_div; > > > > > > + if (rate < nkm->min_rate) { > > > + rate = nkm->min_rate; > > > + if (nkm->common.features & CCU_FEATURE_FIXED_POSTDIV) > > > + rate /= nkm->fixed_post_div; > > > > I'm not sure this is right. Is the post divider taken into account to > > calculate the minimum, or is the minimum on the rate before the fixed > > post divider. > > Since we are returning from here, we need to take care post div which > is actually doing at the end of round_rate.
That's not my point though. Does the rate needs to be superior to min / post_div, or min?
> > > > How did you test this? > > I've not used this on PLL_MIPI atleast, so I didn't test this.
If you've never tested this, why are you adding that code?
Maxime
-- Maxime Ripard, Bootlin Embedded Linux and Kernel engineering https://bootlin.com [unhandled content-type:application/pgp-signature] | |