Re: [PATCH 7/8] arm64: dts: rockchip: Add SDMMC/SDIO controllers for RK3528

From: "Heiko Stübner" <heiko@sntech.de>
To: Yao Zi <ziyao@disroot.org>, Jonas Karlman <jonas@kwiboo.se>
Cc: Ulf Hansson <ulf.hansson@linaro.org>,
	Rob Herring <robh@kernel.org>,
	Krzysztof Kozlowski <krzk+dt@kernel.org>,
	Conor Dooley <conor+dt@kernel.org>,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>,
	Frank Wang <frank.wang@rock-chips.com>,
	Shresth Prasad <shresthprasad7@gmail.com>,
	Cristian Ciocaltea <cristian.ciocaltea@collabora.com>,
	Detlev Casanova <detlev.casanova@collabora.com>,
	linux-mmc@vger.kernel.org, devicetree@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	linux-rockchip@lists.infradead.org, linux-kernel@vger.kernel.org,
	linux-clk@vger.kernel.org
Subject: Re: [PATCH 7/8] arm64: dts: rockchip: Add SDMMC/SDIO controllers for RK3528
Date: Sat, 01 Mar 2025 13:55:53 +0100	[thread overview]
Message-ID: <3574922.QJadu78ljV@diego> (raw)
In-Reply-To: <9fd51bcb-3e6a-46b6-b1f7-ff16fa562d9e@kwiboo.se>

Hey Joas,

Am Samstag, 1. März 2025, 13:47:47 MEZ schrieb Jonas Karlman:
> On 2025-03-01 11:47, Yao Zi wrote:
> > RK3528 features two SDIO controllers and one SD/MMC controller, describe
> > them in devicetree. Since their sample and drive clocks are located in
> > the VO and VPU GRFs, corresponding syscons are added to make these
> > clocks available.
> > 
> > Signed-off-by: Yao Zi <ziyao@disroot.org>
> > ---
> >  arch/arm64/boot/dts/rockchip/rk3528.dtsi | 62 ++++++++++++++++++++++++
> >  1 file changed, 62 insertions(+)
> > 
> > diff --git a/arch/arm64/boot/dts/rockchip/rk3528.dtsi b/arch/arm64/boot/dts/rockchip/rk3528.dtsi
> > index 5b334690356a..078c97fa1d9f 100644
> > --- a/arch/arm64/boot/dts/rockchip/rk3528.dtsi
> > +++ b/arch/arm64/boot/dts/rockchip/rk3528.dtsi
> > @@ -7,6 +7,7 @@
> >  #include <dt-bindings/interrupt-controller/arm-gic.h>
> >  #include <dt-bindings/interrupt-controller/irq.h>
> >  #include <dt-bindings/clock/rockchip,rk3528-cru.h>
> > +#include <dt-bindings/reset/rockchip,rk3528-cru.h>
> >  
> >  / {
> >  	compatible = "rockchip,rk3528";
> > @@ -122,6 +123,16 @@ gic: interrupt-controller@fed01000 {
> >  			#interrupt-cells = <3>;
> >  		};
> >  
> > +		vpu_grf: syscon@ff340000 {
> > +			compatible = "rockchip,rk3528-vpu-grf", "syscon";
> 
> vpu_grf is also used for gmac1, so should possible be a "syscon",
> "simple-mfd", or have I misunderstood when to use simple-mfd ?

simple-mfd is needed when the additional device is completely contained
inside the particular syscon.

For example, the usb2phy0 on rk3588 is completely living inside the
usb2phy0-grf.

Similarly the power-domains are living inside the rk3588 pmugrf.
But the pmugrf also contains more stuff, so the power-domains are a
subset of the pmugrf.

Both of these above are a case for a simple-mfd.

Similarly, gmac1 on rk3588 is ethernet@fe1c0000 , so a completely separate
io-memory area, but references both the sysgrf as well as the php-grf
as syscons for additional settings.

So here the syscon does not need to be a simple-mfd.

Hope that helps a bit
Heiko