On Thu, 8 Apr 2021 at 03:52, Steven Lee <steven_lee@xxxxxxxxxxxxxx> 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.
Thanks for sharing the details, it certainly helps while reviewing.
>
> Signed-off-by: Steven Lee <steven_lee@xxxxxxxxxxxxxx>
> ---
> .../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:
> + 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
>
> 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:
Please do not model these as GPIO pins like this. Instead, it's better
to model them as gpio regulators, since the mmc core manages them as
regulators.
We have a vmmc regulator (corresponding to vdd) and a vqmmc regulator
(corresponding the signal-voltage level). These are also described in
the common mmc DT bindings, see
Documentation/devicetree/bindings/mmc/mmc-controller.yaml.
> - 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>;
> };
> };
Kind regards
Uffe
