On 2016/6/8 6:44, Douglas Anderson wrote: > As can be seen in Arasan's datasheet [1] there are several "corecfg" > settings in their SDHCI IP Block that are supposed to be controlled by > software. Although the datasheet referenced is a bit vague about how to > access corecfg, in Figure 5 you can see that for Arasan's PHY (a > separate component than their SDHCI component) they describe the > "phyctrl" registers as being "FROM SOC CTL REG", implying that it's up > to the licensee of the Arasan IP block to implement these registers. It > seems sane to assume that the "corecfg" registers in their SDHCI IP > block works in a similar way for all licensees of the IP Block. > > Device tree has a model that allows a device to get a reference to > random registers located elsewhere in the SoC: sysctl. Let's leverage > this model and allow adding a sysctl reference to access the control > registers for the Arasan SDHCI PHYs. > > Having a reference to the control registers doesn't do much for us on > its own since the Arasan spec doesn't specify how these corecfg values > are laid out in memory. In the SDHCI driver we'll need a map detailing > where each corecfg can be found in each implementation. This map can be > found using the primary compatible string of the SDHCI device. In that > spirit, document that existing rk3399 device trees already have a > specific compatible string, though up to now they've always been relying > on the driver supporting the generic. > > Note that since existing devices seem to work fairly well as-is, we'll > list the syscon reference as "optional", but it's likely that we'll run > into much fewer problems if we can actually set the proper values in the > syscon, so it is strongly suggested that any SoCs where we have a map to > set the corecfg also include a reference to the syscon. yes, the interaction of phy and controller should be more explicitly now. Why not make it mandatory for arasan,sdhci-5.1. > > [1]: https://arasan.com/wp-content/media/eMMC-5-1-Total-Solution_Rev-1-3.pdf > > Signed-off-by: Douglas Anderson <dianders at chromium.org> > --- > .../devicetree/bindings/mmc/arasan,sdhci.txt | 27 ++++++++++++++++++++-- > 1 file changed, 25 insertions(+), 2 deletions(-) > > diff --git a/Documentation/devicetree/bindings/mmc/arasan,sdhci.txt b/Documentation/devicetree/bindings/mmc/arasan,sdhci.txt > index 31b35c3a5e47..b67e623ca1ff 100644 > --- a/Documentation/devicetree/bindings/mmc/arasan,sdhci.txt > +++ b/Documentation/devicetree/bindings/mmc/arasan,sdhci.txt > @@ -9,8 +9,12 @@ Device Tree Bindings for the Arasan SDHCI Controller > [4] Documentation/devicetree/bindings/phy/phy-bindings.txt > > Required Properties: > - - compatible: Compatibility string. Must be 'arasan,sdhci-8.9a' or > - 'arasan,sdhci-4.9a' or 'arasan,sdhci-5.1' > + - compatible: Compatibility string. One of: > + - "arasan,sdhci-8.9a" > + - "arasan,sdhci-4.9a" > + - "arasan,sdhci-5.1" > + - "rockchip,rk3399-sdhci-5.1", "arasan,sdhci-5.1": The PHY in rk3399. The PHY in rk3399? > + For this device it is strongly suggested to include arasan,soc-ctl-syscon. > - reg: From mmc bindings: Register location and length. > - clocks: From clock bindings: Handles to clock inputs. > - clock-names: From clock bindings: Tuple including "clk_xin" and "clk_ahb" > @@ -22,6 +26,11 @@ Required Properties for "arasan,sdhci-5.1": > - phys: From PHY bindings: Phandle for the Generic PHY for arasan. > - phy-names: MUST be "phy_arasan". > > +Optional Properties: > + - arasan,soc-ctl-syscon: A phandle to a syscon device (see ../mfd/syscon.txt) > + used to access core corecfg registers. Offsets of registers in this > + syscon are determined based on the main compatible string for the device. > + > Example: > sdhci at e0100000 { > compatible = "arasan,sdhci-8.9a"; > @@ -42,3 +51,17 @@ Example: > phys = <&emmc_phy>; > phy-names = "phy_arasan"; > } ; > + > + sdhci: sdhci at fe330000 { > + compatible = "rockchip,rk3399-sdhci-5.1", "arasan,sdhci-5.1"; > + reg = <0x0 0xfe330000 0x0 0x10000>; > + interrupts = <GIC_SPI 11 IRQ_TYPE_LEVEL_HIGH>; > + clocks = <&cru SCLK_EMMC>, <&cru ACLK_EMMC>; > + clock-names = "clk_xin", "clk_ahb"; > + arasan,soc-ctl-syscon = <&grf>; > + assigned-clocks = <&cru SCLK_EMMC>; > + assigned-clock-rates = <200000000>; > + phys = <&emmc_phy>; > + phy-names = "phy_arasan"; > + status = "disabled"; > + }; > -- Best Regards Shawn Lin
