Re: [PATCH 6/9] arm64: dts: rockchip: add missing rk3568 cru phandles

From: Peter Geis <pgwipeout@gmail.com>
To: "Heiko Stübner" <heiko@sntech.de>
Cc: Linus Walleij <linus.walleij@linaro.org>,
	Bartosz Golaszewski <bgolaszewski@baylibre.com>,
	Rob Herring <robh+dt@kernel.org>,
	"open list:GPIO SUBSYSTEM" <linux-gpio@vger.kernel.org>,
	devicetree@vger.kernel.org,
	arm-mail-list <linux-arm-kernel@lists.infradead.org>,
	"open list:ARM/Rockchip SoC..."
	<linux-rockchip@lists.infradead.org>,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 6/9] arm64: dts: rockchip: add missing rk3568 cru phandles
Date: Wed, 28 Jul 2021 11:16:54 -0400	[thread overview]
Message-ID: <CAMdYzYqz-i1X2oORi6SjSqi6_KwRcbt2u04+cVxcSonX9gxOew@mail.gmail.com> (raw)
In-Reply-To: <6063626.MhkbZ0Pkbq@diego>

On Wed, Jul 28, 2021 at 10:41 AM Heiko Stübner <heiko@sntech.de> wrote:
>
> Am Mittwoch, 28. Juli 2021, 16:18:49 CEST schrieb Peter Geis:
> > On Wed, Jul 28, 2021 at 10:06 AM Heiko Stübner <heiko@sntech.de> wrote:
> > >
> > > Hi Peter,
> > >
> > > Am Mittwoch, 28. Juli 2021, 15:55:31 CEST schrieb Peter Geis:
> > > > The grf and pmugrf phandles are necessary for the pmucru and cru to
> > > > modify clocks. Add these phandles to permit adjusting the clock rates
> > > > and muxes.
> > > >
> > > > Signed-off-by: Peter Geis <pgwipeout@gmail.com>
> > > > ---
> > > >  arch/arm64/boot/dts/rockchip/rk356x.dtsi | 3 +++
> > > >  1 file changed, 3 insertions(+)
> > > >
> > > > diff --git a/arch/arm64/boot/dts/rockchip/rk356x.dtsi b/arch/arm64/boot/dts/rockchip/rk356x.dtsi
> > > > index 0905fac0726a..8ba0516eedd8 100644
> > > > --- a/arch/arm64/boot/dts/rockchip/rk356x.dtsi
> > > > +++ b/arch/arm64/boot/dts/rockchip/rk356x.dtsi
> > > > @@ -218,6 +218,8 @@ grf: syscon@fdc60000 {
> > > >       pmucru: clock-controller@fdd00000 {
> > > >               compatible = "rockchip,rk3568-pmucru";
> > > >               reg = <0x0 0xfdd00000 0x0 0x1000>;
> > > > +             rockchip,grf = <&grf>;
> > > > +             rockchip,pmugrf = <&pmugrf>;
> > >
> > > I don't think the pmucru needs both and in fact the mainline
> > > clock driver should just reference its specific grf at all, i.e.
> > >         pmucru -> pmugrf (via the rockchip,grf handle)
> > >         cru -> grf
> > >
> > > I've not seen anything breaking this scope so far.
> >
> > I thought the same thing as well, but for some reason the driver
> > refuses to apply assigned-clocks to the plls unless these are all
> > present.
> > If the driver can get these assignments automatically eventually,
> > perhaps it's a loading order issue?
> >
> > Thinking about it, it's probably the grf and pmugrf haven't probed
> > when the driver is attempting to assign these, and tying them together
> > forces the probe to happen first.
>
> though nothing references the regular grf from the pmucru I think.
>
> I.e. the pmucru PLL read their lock state from RK3568_PMU_MODE_CON
>
> The rk3568 reuses the pll_rk3328-type which in turn is a modified pll_rk3036
> and uses their ops. Which in turn means the pll shouldn't access the GRF at
> all, as it uses the pll's own register to check the locked state.
>
> Can you try to change clk-pll.c from
>
>         switch (pll_type) {
>         case pll_rk3036:
>         case pll_rk3328:
>                 if (!pll->rate_table || IS_ERR(ctx->grf))
>                         init.ops = &rockchip_rk3036_pll_clk_norate_ops;
> ...
> to
>         switch (pll_type) {
>         case pll_rk3036:
>         case pll_rk3328:
>                 if (!pll->rate_table)
>                         init.ops = &rockchip_rk3036_pll_clk_norate_ops;
>
> similar to rk3399?

Thanks, I'll test this!

>
> Heiko
>
> > > >               #clock-cells = <1>;
> > > >               #reset-cells = <1>;
> > > >       };
> > > > @@ -225,6 +227,7 @@ pmucru: clock-controller@fdd00000 {
> > > >       cru: clock-controller@fdd20000 {
> > > >               compatible = "rockchip,rk3568-cru";
> > > >               reg = <0x0 0xfdd20000 0x0 0x1000>;
> > > > +             rockchip,grf = <&grf>;
> > > >               #clock-cells = <1>;
> > > >               #reset-cells = <1>;
> > > >       };
> > > >
> > >
> > >
> > >
> > >
> >
>
>
>
>