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

From: Andrew Jeffery
Date: Mon May 03 2021 - 06:33:26 EST

On Mon, 3 May 2021, at 19:10, Steven Lee wrote:
> 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@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?
> >
>
> 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

What you're describing is specific to the AST2600 EVB, so I suggest you
put it in the EVB dts, e.g. at:

https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/tree/arch/arm/boot/dts/aspeed-ast2600-evb.dts#n103

> 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.

No worries! There's also `make dtbs_check` to validate the devicetree files
against the bindings. It's useful to run both, as usually when you're adding to
the binding you're modifying a devicetree as well.

Unfortunately we need to do a bit of a cleanup of the Aspeed dts files, they
generate a number of warnings right now.

> 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.

Thanks.

Andrew