Re: [PATCH v2 1/3] dt-bindings: mmc: sdhci-of-aspeed: Add description for AST2600 EVB.

From: Andrew Jeffery
Date: Mon May 03 2021 - 00:21:50 EST

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@xxxxxxxxxxxxxx>
> ---
> .../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?

> +
> 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 ).

> + - |
> + #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?

Cheers,

Andrew