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> Reviewed-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx> --- v5: * add Reviewed-by: Geert Uytterhoeven * list number of clocks for each SoC * remove example because it already exists in mmc.txt 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 | 13 +++++++++++++ 1 file changed, 13 insertions(+) diff --git a/Documentation/devicetree/bindings/mmc/tmio_mmc.txt b/Documentation/devicetree/bindings/mmc/tmio_mmc.txt index a1650ed..4fd8b7a 100644 --- a/Documentation/devicetree/bindings/mmc/tmio_mmc.txt +++ b/Documentation/devicetree/bindings/mmc/tmio_mmc.txt @@ -25,6 +25,19 @@ 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 + 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. + Below is the number clocks for each supported SoC: + 1: SH73A0, R8A73A4, R8A7740, R8A7778, R8A7779, R8A7790 + R8A7791, R8A7792, R8A7793, R8A7794, R8A7795, R8A7796 + 2: R7S72100 + Optional properties: - toshiba,mmc-wrprotect-disable: write-protect detection is unavailable - pinctrl-names: should be "default", "state_uhs" -- 2.10.1
