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Date:   Mon, 3 May 2021 17:40:55 +0800
From:   Steven Lee <steven_lee@aspeedtech.com>
To:     Andrew Jeffery <andrew@aj.id.au>
CC:     Ulf Hansson <ulf.hansson@linaro.org>,
        Rob Herring <robh+dt@kernel.org>,
        Joel Stanley <joel@jms.id.au>,
        Ryan Chen <ryanchen.aspeed@gmail.com>,
        "moderated list:ASPEED SD/MMC DRIVER" <linux-aspeed@lists.ozlabs.org>,
        "moderated list:ASPEED SD/MMC DRIVER" <openbmc@lists.ozlabs.org>,
        linux-mmc <linux-mmc@vger.kernel.org>,
        "open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS" 
        <devicetree@vger.kernel.org>,
        "moderated list:ARM/ASPEED MACHINE SUPPORT" 
        <linux-arm-kernel@lists.infradead.org>,
        open list <linux-kernel@vger.kernel.org>,
        Hongwei Zhang <Hongweiz@ami.com>,
        Ryan Chen <ryan_chen@aspeedtech.com>,
        Chin-Ting Kuo <chin-ting_kuo@aspeedtech.com>
Subject: Re: [PATCH v2 1/3] dt-bindings: mmc: sdhci-of-aspeed: Add
 description for AST2600 EVB.
Message-ID: <20210503094054.GA12520@aspeedtech.com>
References: <20210503014336.20256-1-steven_lee@aspeedtech.com>
 <20210503014336.20256-2-steven_lee@aspeedtech.com>
 <75226402-503c-4e9b-96dc-e4bd74cf20ac@www.fastmail.com>
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The 05/03/2021 12:19, Andrew Jeffery wrote:
> Hi Steven,
> 
> On Mon, 3 May 2021, at 11:13, Steven Lee wrote:
> > Add the description for describing the AST 2600 EVB reference design of
> > GPIO regulators and provide the example in the document.
> > 
> > AST2600-A2 EVB has the reference design for enabling SD bus
> > power and toggling SD bus signal voltage by GPIO pins.
> > 
> > In the reference design, GPIOV0 of AST2600-A2 EVB is connected to
> > power load switch that providing 3.3v to SD1 bus vdd. GPIOV1 is
> > connected to a 1.8v and a 3.3v power load switch that providing
> > signal voltage to
> > SD1 bus.
> > 
> > If GPIOV0 is active high, SD1 bus is enabled. Otherwise, SD1 bus is
> > disabled.
> > If GPIOV1 is active high, 3.3v power load switch is enabled, SD1
> > signal voltage is 3.3v. Otherwise, 1.8v power load switch will be
> > enabled, SD1 signal voltage becomes 1.8v.
> > 
> > AST2600-A2 EVB also support toggling signal voltage for SD2 bus.
> > The design is the same as SD1 bus. It uses GPIOV2 as power-gpio and
> > GPIOV3 as power-switch-gpio.
> > 
> > Signed-off-by: Steven Lee <steven_lee@aspeedtech.com>
> > ---
> >  .../devicetree/bindings/mmc/aspeed,sdhci.yaml | 99 +++++++++++++++++++
> >  1 file changed, 99 insertions(+)
> > 
> > diff --git a/Documentation/devicetree/bindings/mmc/aspeed,sdhci.yaml 
> > b/Documentation/devicetree/bindings/mmc/aspeed,sdhci.yaml
> > index 987b287f3bff..dd894aba0bb7 100644
> > --- a/Documentation/devicetree/bindings/mmc/aspeed,sdhci.yaml
> > +++ b/Documentation/devicetree/bindings/mmc/aspeed,sdhci.yaml
> > @@ -20,6 +20,19 @@ description: |+
> >    the slots are dependent on the common configuration area, they are 
> > described
> >    as child nodes.
> >  
> > +  The signal voltage of SDHCIs on AST2600-A2 EVB is able to be toggled 
> > by GPIO
> > +  pins. In the reference design, GPIOV0 of AST2600-A2 EVB is connected 
> > to the
> > +  power load switch that providing 3.3v to SD1 bus vdd, GPIOV1 is 
> > connected to
> > +  a 1.8v and a 3.3v power load switch that providing signal voltage to
> > +  SD1 bus.
> > +  If GPIOV0 is active high, SD1 bus is enabled. Otherwise, SD1 bus is
> > +  disabled. If GPIOV1 is active high, 3.3v power load switch is 
> > enabled, SD1
> > +  signal voltage is 3.3v. Otherwise, 1.8v power load switch will be 
> > enabled, SD1
> > +  signal voltage becomes 1.8v.
> > +  AST2600-A2 EVB also support toggling signal voltage for SD2 bus.
> > +  The design is the same as SD1 bus. It uses GPIOV2 as power-gpio and 
> > GPIOV3
> > +  as power-switch-gpio.
> 
> I don't think we should be describing design-specific details in the 
> binding document. However, I think this would be a great comment in the 
> AST2600 EVB devicetree. Can you please move it there?
> 

Ok, I will move it to the device tree.

I was wondering if the following place is a good place to put the
comment

at line 534 of aspeed-g6.dtsi
sdc: sdc@1e740000 {
	// Comment here...

	compatible = "aspeed,ast2600-sd-controller";
	reg = <0x1e740000 0x100>;

	sdhci0: sdhci@1e740100 {
		compatible = "aspeed,ast2600-sdhci", "sdhci";
		reg = <0x100 0x100>;
		interrupts = <GIC_SPI 43 IRQ_TYPE_LEVEL_HIGH>;
...
}

> > +
> >  properties:
> >    compatible:
> >      enum:
> > @@ -78,6 +91,7 @@ required:
> >    - clocks
> >  
> >  examples:
> > +  //Example 1
> >    - |
> >      #include <dt-bindings/clock/aspeed-clock.h>
> >      sdc@1e740000 {
> > @@ -104,3 +118,88 @@ examples:
> >                      clocks = <&syscon ASPEED_CLK_SDIO>;
> >              };
> >      };
> > +
> > +  //Example 2 (AST2600EVB with GPIO regulator)
> 
> I feel you didn't test this with `make dt_binding_check` as `//` isn't
> a valid YAML comment token. You need to use `#` for comments (
> https://yaml.org/spec/1.2/spec.html#id2780069 ).
> 

Sorry, I don't know that there is a binding check command for valiating
YAML document.
Regardless, thanks for the reference link.
I will test with dt_binding_check.

> > +  - |
> > +    #include <dt-bindings/clock/aspeed-clock.h>
> > +    #include <dt-bindings/gpio/aspeed-gpio.h>
> > +    vcc_sdhci0: regulator-vcc-sdhci0 {
> > +            compatible = "regulator-fixed";
> > +
> > +            regulator-name = "SDHCI0 Vcc";
> > +            regulator-min-microvolt = <3300000>;
> > +            regulator-max-microvolt = <3300000>;
> > +            gpios = <&gpio0 ASPEED_GPIO(V, 0)
> > +                            GPIO_ACTIVE_HIGH>;
> > +            enable-active-high;
> > +    };
> > +
> > +    vccq_sdhci0: regulator-vccq-sdhci0 {
> > +            compatible = "regulator-gpio";
> > +
> > +            regulator-name = "SDHCI0 VccQ";
> > +            regulator-min-microvolt = <1800000>;
> > +            regulator-max-microvolt = <3300000>;
> > +            gpios = <&gpio0 ASPEED_GPIO(V, 1)
> > +                            GPIO_ACTIVE_HIGH>;
> > +            gpios-states = <1>;
> > +            states = <3300000 1
> > +                      1800000 0>;
> > +    };
> > +
> > +    vcc_sdhci1: regulator-vcc-sdhci1 {
> > +            compatible = "regulator-fixed";
> > +
> > +            regulator-name = "SDHCI1 Vcc";
> > +            regulator-min-microvolt = <3300000>;
> > +            regulator-max-microvolt = <3300000>;
> > +            gpios = <&gpio0 ASPEED_GPIO(V, 2)
> > +                            GPIO_ACTIVE_HIGH>;
> > +            enable-active-high;
> > +    };
> > +
> > +    vccq_sdhci1: regulator-vccq-sdhci1 {
> > +            compatible = "regulator-gpio";
> > +
> > +            regulator-name = "SDHCI1 VccQ";
> > +            regulator-min-microvolt = <1800000>;
> > +            regulator-max-microvolt = <3300000>;
> > +            gpios = <&gpio0 ASPEED_GPIO(V, 3)
> > +                            GPIO_ACTIVE_HIGH>;
> > +            gpios-states = <1>;
> > +            states = <3300000 1
> > +                      1800000 0>;
> > +    };
> > +
> > +    sdc@1e740000 {
> > +            compatible = "aspeed,ast2600-sd-controller";
> > +            reg = <0x1e740000 0x100>;
> > +            #address-cells = <1>;
> > +            #size-cells = <1>;
> > +            ranges = <0 0x1e740000 0x20000>;
> > +            clocks = <&syscon ASPEED_CLK_GATE_SDCLK>;
> > +
> > +            sdhci0: sdhci@100 {
> > +                    compatible = "aspeed,ast2600-sdhci", "sdhci";
> > +                    reg = <0x100 0x100>;
> > +                    interrupts = <GIC_SPI 43 IRQ_TYPE_LEVEL_HIGH>;
> > +                    sdhci,auto-cmd12;
> > +                    clocks = <&syscon ASPEED_CLK_SDIO>;
> > +                    vmmc-supply = <&vcc_sdhci0>;
> > +                    vqmmc-supply = <&vccq_sdhci0>;
> > +                    sd-uhs-sdr104;
> > +                    clk-phase-uhs-sdr104 = <180>, <180>;
> > +            };
> > +
> > +            sdhci1: sdhci@200 {
> > +                    compatible = "aspeed,ast2600-sdhci", "sdhci";
> > +                    reg = <0x200 0x100>;
> > +                    interrupts = <GIC_SPI 43 IRQ_TYPE_LEVEL_HIGH>;
> > +                    sdhci,auto-cmd12;
> > +                    clocks = <&syscon ASPEED_CLK_SDIO>;
> > +                    vmmc-supply = <&vcc_sdhci1>;
> > +                    vqmmc-supply = <&vccq_sdhci1>;
> > +                    sd-uhs-sdr104;
> > +                    clk-phase-uhs-sdr104 = <0>, <0>;
> > +            };
> > +    };
> 
> This is a good example, so can we keep this and just drop the comment 
> from the binding document?

Ok, I will remove the comment.

> 
> Cheers,
> 
> Andrew