Re: [linux-sunxi] Re: [PATCH v5 15/17] clk: sunxi-ng: a64: Add minimum rate for PLL_MIPI

From: Maxime Ripard
Date: Tue Dec 11 2018 - 11:50:56 EST


On Tue, Dec 11, 2018 at 10:05:43PM +0530, Jagan Teki wrote:
>
>
> On 11/12/18 10:02 PM, Maxime Ripard wrote:
> > On Mon, Dec 10, 2018 at 09:47:27PM +0530, Jagan Teki wrote:
> > > Minimum PLL used for MIPI is 500MHz, as per manual, but
> > > lowering the min rate by 300MHz can result proper working
> > > nkms divider with the help of desired dclock rate from
> > > panel driver.
> > >
> > > Signed-off-by: Jagan Teki <jagan@xxxxxxxxxxxxxxxxxxxx>
> > > Acked-by: Stephen Boyd <sboyd@xxxxxxxxxx>
> > > ---
> > > drivers/clk/sunxi-ng/ccu-sun50i-a64.c | 1 +
> > > 1 file changed, 1 insertion(+)
> > >
> > > diff --git a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
> > > index 181b599dc163..b623c8150b4f 100644
> > > --- a/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
> > > +++ b/drivers/clk/sunxi-ng/ccu-sun50i-a64.c
> > > @@ -183,6 +183,7 @@ static struct ccu_nkm pll_mipi_clk = {
> > > .n = _SUNXI_CCU_MULT(8, 4),
> > > .k = _SUNXI_CCU_MULT_MIN(4, 2, 2),
> > > .m = _SUNXI_CCU_DIV(0, 4),
> > > + .min_rate = 300000000, /* Actual rate is 500MHz */
> >
> > That comment still doesn't make any sense. Is it running at 500MHz or 300?
>
> It running in 300MHz, actual rate is 500MHz.

If it's running at 300MHz, its actual rate should be 300MHz...

> > Also, IIRC you had a patch adding support for maximum boundaries in
> > your previous patch, where did it go?
>
> Since I don't have any usecase to test I droped it. the same mentioned on
> the previous version.

Ok.

Maxime

--
Maxime Ripard, Bootlin
Embedded Linux and Kernel engineering
https://bootlin.com

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