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SubjectRe: [PATCH v2 03/11] Documentation: mmc: sdhci-of-arasan: Add soc-ctl-syscon for corecfg regs
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在 2016/6/14 7:04, Douglas Anderson 写道:
> 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.
>
> [1]: https://arasan.com/wp-content/media/eMMC-5-1-Total-Solution_Rev-1-3.pdf


Looks good.

Reviewed-by: Shawn Lin <shawn.lin@rock-chips.com>

>
> Signed-off-by: Douglas Anderson <dianders@chromium.org>
> Acked-by: Rob Herring <robh@kernel.org>
> ---
> Changes in v2:
> - Clean up description of rk3399 PHY (Shawn)
> - Add Rob Herring's Ack.
>
> .../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..476604e6ce2a 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": generic Arasan SDHCI 8.9a PHY
> + - "arasan,sdhci-4.9a": generic Arasan SDHCI 4.9a PHY
> + - "arasan,sdhci-5.1": generic Arasan SDHCI 5.1 PHY
> + - "rockchip,rk3399-sdhci-5.1", "arasan,sdhci-5.1": rk3399 eMMC PHY
> + 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@e0100000 {
> compatible = "arasan,sdhci-8.9a";
> @@ -42,3 +51,17 @@ Example:
> phys = <&emmc_phy>;
> phy-names = "phy_arasan";
> } ;
> +
> + sdhci: sdhci@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

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