On Fri, Jan 20, 2017 at 10:06:03PM -0500, Chris Brandt wrote:
> In the case of a single clock source, you don't need names. However,
> if the controller has 2 clock sources, you need to name them correctly
> so the driver can find the 2nd one. The 2nd clock is for the internal
> card detect logic.
>
> Signed-off-by: Chris Brandt <chris.brandt@xxxxxxxxxxx>
> ---
> v4:
> * just explain there might be 2 clocks, don't explain how
> we will use them in the driver
> v3:
> * add more clarification about why there are sometimes 2 clocks
> and what you should do with them.
> * remove 'status = "disabled"' from example
> v2:
> * fix spelling and change wording
> * changed clock name from "carddetect" to "cd"
> ---
> Documentation/devicetree/bindings/mmc/tmio_mmc.txt | 24 ++++++++++++++++++++++
> 1 file changed, 24 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/mmc/tmio_mmc.txt b/Documentation/devicetree/bindings/mmc/tmio_mmc.txt
> index a1650ed..1464c16 100644
> --- a/Documentation/devicetree/bindings/mmc/tmio_mmc.txt
> +++ b/Documentation/devicetree/bindings/mmc/tmio_mmc.txt
> @@ -25,8 +25,32 @@ Required properties:
> "renesas,sdhi-r8a7795" - SDHI IP on R8A7795 SoC
> "renesas,sdhi-r8a7796" - SDHI IP on R8A7796 SoC
>
> +- clocks: Most controllers only have 1 clock source per channel. However, on
> + some variations of this controller, the internal card detection
This should be explicit as to which compatible strings have 2 clocks and
which have 1 clock.
> + logic that exists in this controller is sectioned off to be run by a
> + separate second clock source to allow the main core clock to be turned
> + off to save power.
> + If 2 clocks are specified by the hardware, you must name them as
> + "core" and "cd".
> + If the controller only has 1 clock, naming is not required.
> +
> Optional properties:
> - toshiba,mmc-wrprotect-disable: write-protect detection is unavailable
> - pinctrl-names: should be "default", "state_uhs"
> - pinctrl-0: should contain default/high speed pin ctrl
> - pinctrl-1: should contain uhs mode pin ctrl
> +
> +Example showing 2 clocks:
> + sdhi0: sd@e804e000 {
mmc@...
> + compatible = "renesas,sdhi-r7s72100";
> + reg = <0xe804e000 0x100>;
> + interrupts = <GIC_SPI 270 IRQ_TYPE_LEVEL_HIGH
> + GIC_SPI 271 IRQ_TYPE_LEVEL_HIGH
> + GIC_SPI 272 IRQ_TYPE_LEVEL_HIGH>;
> +
> + clocks = <&mstp12_clks R7S72100_CLK_SDHI00>,
> + <&mstp12_clks R7S72100_CLK_SDHI01>;
> + clock-names = "core", "cd";
> + cap-sd-highspeed;
> + cap-sdio-irq;
> + };
> --
> 2.10.1
>
>
