Messages in this thread | | | Subject | Re: [linux-sunxi] Re: [PATCH v2 02/15] clk: sunxi-ng: Add check for minimal rate to NKM PLLs | From | Jagan Teki <> | Date | Mon, 29 Oct 2018 18:10:47 +0530 |
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On 29/10/18 2:28 PM, Maxime Ripard wrote: > 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?
ie what I'm trying to say, since it's common code min or max should / post_div and PLL_MIPI doesn't use any post_div.
We need to take care post_div though the current test (PLL_MIPI) in not used since it's common code. just like nkmp, nm etc.
> >>> >>> 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?
Like above, it's common code. otherwise might effect.
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