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Date:   Fri, 9 Apr 2021 13:41:18 -0500
From:   Rob Herring <robh@kernel.org>
To:     Steven Lee <steven_lee@aspeedtech.com>
Cc:     Andrew Jeffery <andrew@aj.id.au>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Joel Stanley <joel@jms.id.au>,
        Adrian Hunter <adrian.hunter@intel.com>,
        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>,
        "open list:ASPEED SD/MMC DRIVER" <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>,
        ryan_chen@aspeedtech.com, chin-ting_kuo@aspeedtech.com
Subject: Re: [PATCH v1 1/2] dt-bindings: mmc: sdhci-of-aspeed: Add power-gpio
 and power-switch-gpio
Message-ID: <20210409184118.GA3934798@robh.at.kernel.org>
References: <20210408015218.20560-1-steven_lee@aspeedtech.com>
 <20210408015218.20560-2-steven_lee@aspeedtech.com>
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In-Reply-To: <20210408015218.20560-2-steven_lee@aspeedtech.com>
Precedence: bulk

On Thu, Apr 08, 2021 at 09:52:17AM +0800, Steven Lee wrote:
> AST2600-A2 EVB provides the reference design for enabling SD bus power
> and toggling SD bus signal voltage by GPIO pins.
> Add the definition and example for power-gpio and power-switch-gpio
> properties.
> 
> 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 | 25 +++++++++++++++++++
>  1 file changed, 25 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/mmc/aspeed,sdhci.yaml b/Documentation/devicetree/bindings/mmc/aspeed,sdhci.yaml
> index 987b287f3bff..515a74614f3c 100644
> --- a/Documentation/devicetree/bindings/mmc/aspeed,sdhci.yaml
> +++ b/Documentation/devicetree/bindings/mmc/aspeed,sdhci.yaml
> @@ -37,6 +37,14 @@ properties:
>    clocks:
>      maxItems: 1
>      description: The SD/SDIO controller clock gate
> +  power-gpio:

'-gpios' is the preferred form even if just 1.

> +    description:
> +      The GPIO for enabling/disabling SD bus power.
> +    maxItems: 1

blank line

> +  power-switch-gpio:
> +    description:
> +      The GPIO for toggling the signal voltage between 3.3v and 1.8v.
> +    maxItems: 1
>  
>  patternProperties:
>    "^sdhci@[0-9a-f]+$":
> @@ -61,6 +69,14 @@ patternProperties:
>        sdhci,auto-cmd12:
>          type: boolean
>          description: Specifies that controller should use auto CMD12
> +      power-gpio:
> +        description:
> +          The GPIO for enabling/disabling SD bus power.
> +        maxItems: 1
> +      power-switch-gpio:
> +        description:
> +          The GPIO for toggling the signal voltage between 3.3v and 1.8v.
> +        maxItems: 1
>      required:
>        - compatible
>        - reg
> @@ -80,6 +96,7 @@ required:
>  examples:
>    - |
>      #include <dt-bindings/clock/aspeed-clock.h>
> +    #include <dt-bindings/gpio/aspeed-gpio.h>
>      sdc@1e740000 {
>              compatible = "aspeed,ast2500-sd-controller";
>              reg = <0x1e740000 0x100>;
> @@ -94,6 +111,10 @@ examples:
>                      interrupts = <26>;
>                      sdhci,auto-cmd12;
>                      clocks = <&syscon ASPEED_CLK_SDIO>;
> +                    power-gpio = <&gpio0 ASPEED_GPIO(V, 0)
> +                                     GPIO_ACTIVE_HIGH>;
> +                    power-switch-gpio = <&gpio0 ASPEED_GPIO(V, 1)
> +                                     GPIO_ACTIVE_HIGH>;
>              };
>  
>              sdhci1: sdhci@200 {
> @@ -102,5 +123,9 @@ examples:
>                      interrupts = <26>;
>                      sdhci,auto-cmd12;
>                      clocks = <&syscon ASPEED_CLK_SDIO>;
> +                    power-gpio = <&gpio0 ASPEED_GPIO(V, 2)
> +                                     GPIO_ACTIVE_HIGH>;
> +                    power-switch-gpio = <&gpio0 ASPEED_GPIO(V, 3)
> +                                     GPIO_ACTIVE_HIGH>;
>              };
>      };
> -- 
> 2.17.1
>