On Thu, Dec 08, 2016 at 09:50:55PM +0900, Masahiro Yamada wrote:
> Add a driver for the Cadence SD4HC SD/SDIO/eMMC Controller.
>
> For SD, it basically relies on the SDHCI standard code.
> For eMMC, this driver provides some callbacks to support the
> hardware part that is specific to this IP design.
>
> Signed-off-by: Masahiro Yamada <yamada.masah...@socionext.com>
> Acked-by: Adrian Hunter <adrian.hun...@intel.com>
> ---
>
> Changes in v5:
> - Fix calculation of the center of the tuned window
>
> Changes in v4:
> - Override mmc_host_ops.execute_tuning instead of the
> .platform_execute_tuning implementation
>
> Changes in v3:
> - Remove unneeded explanation about HRS and SRS from DT binding;
> the offsets to HRS/SRS are fixed for this hardware and this is
> quite normal, like each hardware has a fixed register view except
> the register base. The detailed register map is what the driver
> cares about, so no need to explain it in the binding.
>
> Changes in v2:
> - Remove unnecessary "select MMC_SDHCI_IO_ACCESSORS"
>
> .../devicetree/bindings/mmc/sdhci-cadence.txt | 30 +++
> drivers/mmc/host/Kconfig | 11 +
> drivers/mmc/host/Makefile | 1 +
> drivers/mmc/host/sdhci-cadence.c | 283
> +++++++++++++++++++++
> 4 files changed, 325 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/mmc/sdhci-cadence.txt
> create mode 100644 drivers/mmc/host/sdhci-cadence.c
>
> diff --git a/Documentation/devicetree/bindings/mmc/sdhci-cadence.txt
> b/Documentation/devicetree/bindings/mmc/sdhci-cadence.txt
> new file mode 100644
> index 0000000..750374f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mmc/sdhci-cadence.txt
> @@ -0,0 +1,30 @@
> +* Cadence SD/SDIO/eMMC Host Controller
> +
> +Required properties:
> +- compatible: should be "cdns,sd4hc".
Needs SoC specific compatible strings too.
> +- reg: offset and length of the register set for the device.
> +- interrupts: a single interrupt specifier.
> +- clocks: phandle to the input clock.
> +
> +Optional properties:
> +For eMMC configuration, supported speed modes are not indicated by the SDHCI
> +Capabilities Register. Instead, the following properties should be specified
> +if supported. See mmc.txt for details.
> +- mmc-ddr-1_8v
> +- mmc-ddr-1_2v
> +- mmc-hs200-1_8v
> +- mmc-hs200-1_2v
> +- mmc-hs400-1_8v
> +- mmc-hs400-1_2v
There's now a property to override SDHCI capabilities register. Maybe
you should use that instead? I'll defer to Ulf.
> +
> +Example:
> + emmc: sdhci@5a000000 {
> + compatible = "cdns,sd4hc";
> + reg = <0x5a000000 0x400>;
> + interrupts = <0 78 4>;
> + clocks = <&clk 4>;
> + bus-width = <8>;
> + mmc-ddr-1_8v;
> + mmc-hs200-1_8v;
> + mmc-hs400-1_8v;
> + };
