Re: [PATCH 5/10] dt: bindings: Add bindings for Marvell Xenon SD Host Controller

From: Rob Herring
Date: Mon Oct 10 2016 - 17:34:38 EST


On Fri, Oct 07, 2016 at 05:22:51PM +0200, Gregory CLEMENT wrote:
> From: Ziji Hu <huziji@xxxxxxxxxxx>
>
> Marvell Xenon SDHC can support eMMC/SD/SDIO.
> Add Xenon-specific properties.
> Also add properties for Xenon PHY setting.
>
> Signed-off-by: Hu Ziji <huziji@xxxxxxxxxxx>
> Reviewed-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx>
> Signed-off-by: Gregory CLEMENT <gregory.clement@xxxxxxxxxxxxxxxxxx>
> ---
> Documentation/devicetree/bindings/mmc/marvell,sdhci-xenon.txt | 164 +++++++-
> MAINTAINERS | 1 +-
> 2 files changed, 165 insertions(+), 0 deletions(-)
> create mode 100644 Documentation/devicetree/bindings/mmc/marvell,sdhci-xenon.txt
>
> diff --git a/Documentation/devicetree/bindings/mmc/marvell,sdhci-xenon.txt b/Documentation/devicetree/bindings/mmc/marvell,sdhci-xenon.txt
> new file mode 100644
> index 000000000000..8b25ad28ebbd
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/mmc/marvell,sdhci-xenon.txt
> @@ -0,0 +1,164 @@
> +Marvell's Xenon SDHCI Controller device tree bindings
> +This file documents differences between the core mmc properties
> +described by mmc.txt and the properties used by the Xenon implementation.
> +
> +A single Xenon IP can support multiple slots.
> +Each slot acts as an independent SDHC. It owns independent resources, such
> +as register sets clock and PHY.

Is the phy really part of the same block?

> +Each slot should have an independent device tree node.
> +
> +Required Properties:
> +- compatible: should be "marvell,sdhci-xenon" or "marvell,armada-3700-sdhci".

Perhaps some consistent ordering (w/ -sdhci on the end).

> +
> +- Input Clock Name

Your formatting of properties is a bit strange. Please restructure like
most bindings so the property names are before all the description.

> + Some SOCs require additional clock for AXI bus.

Those SoCs should have a specific compatible string and you need to
define which compatible strings have 2 clocks vs. 1 clock.

> + The input clock for Xenon IP core should be named as "core".
> + The optional AXI clock should be named as "axi".
> + - clocks = <&core_clk>, <&axi_clock>;
> + - clock-names = "core", "axi";
> +
> +- Register Set Size

Is this a property name?

> + Different Xenon SDHC release has different register set size.
> + The specific size should also refer to the SOC implementation.
> +
> +Optional Properties:
> +- Slot Index
> + A single Xenon IP can support multiple slots.
> + During initialization, each slot should set corresponding setting bit in
> + some Xenon-specific registers. The corresponding bit is determined by
> + this property.
> + - xenon,slotno = <slot_index>;

Slots should probably be represented as child nodes with the reg
property being the slot number.

Also, xenon is not a vendor prefix.

> + If this property is not provided, Xenon IP should contain only one slot
> + and the slot index will be 0x0 by default.
> +
> +- PHY Type

You're going to need to come of with a common binding for this.

> + Xenon support mutilple types of PHYs.
> + To select eMMC 5.1 PHY, set:
> + - xenon,phy-type = "emmc 5.1 phy"
> + eMMC 5.1 PHY is the default choice if this property is not provided.
> + To select eMMC 5.0 PHY, set:
> + - xenon,phy-type = "emmc 5.0 phy"
> + To select SDH PHY, set:
> + - xenon,phy-type = "sdh phy"
> + Please note that eMMC PHY is a general PHY for eMMC/SD/SDIO, other than for
> + eMMC only.
> +
> +- Customized eMMC PHY Parameters
> + Some boards require different values of some specific eMMC PHY parameters.
> + Some SOCs also require specific workaround to set eMMC PHY.
> + These properties enable diverse boards to customize the eMMC PHY.
> + The supported eMMC PHY parameters are listed in below. All those properties
> + are only available for eMMC PHY 5.1 and eMMC PHY 5.0.
> + ZNR
> + valid range = [0:0x1F].
> + ZNR is set as 0xF by default if this property is not provided.
> + - xenon,phy-znr = <value>;
> +
> + ZPR
> + valid range = [0:0x1F].
> + ZPR is set as 0xF by default if this property is not provided.
> + - xenon,phy-zpr = <value>;

marvell is the vendor prefix.

> +
> + Number of successful tuning times
> + Set the number of required consecutive successful sampling points used to
> + identify a valid sampling window, in tuning process.
> + Valid range = [1:7]. Set as 0x4 by default if this property is not provided.
> + - xenon,phy-nr-tun-times = <nr_times>;
> +
> + Divider for TUN_STEP
> + Set the divider for calculating TUN_STEP.
> + Set as 64 by default if this property is not provided.
> + - xenon,phy-tun-step-divider = <divider>;
> +
> + Force PHY into slow mode.
> + Only available when bus frequency lower than 50MHz in SDR mde.
> + Disabled by default. Please do not enable it unless it is necessary.
> + - xenon,phy-slow-mode;
> +
> +- Mask Conflict Error Report
> + Disable Conflict Error alert on some SOC. Disabled by default.
> + xenon,mask-conflict-err;
> +
> +- Re-tuning Counter
> + Xenon SDHC SOC usually doesn't provide re-tuning counter in
> + Capabilities Register 3 Bit[11:8].
> + This property provides the re-tuning counter.
> + xenon,tuning-count = <count>;
> + If this property is not set, default re-tuning counter will
> + be set as 0x9 in driver.
> +
> +- SOC PHY PAD Voltage Control register
> + Some SOCs have SOC PHY PAD Voltage Control register outside Xenon IP.
> + This register sets SOC PHY PAD Voltage to keep aligh with Vccq.
> + Two properties provide information of this control register.
> + These two properties are only valid when "marvell,armada-3700-sdhci"
> + is selected. Both of them must be provided when "marvell,armada-3700-sdhci"
> + is selected.
> + - xenon,pad-type
> + Two types: "sd" and "fixed-1-8v".
> + If "sd" is slected, SOC PHY PAD is set as 3.3V at the beginning and is
> + switched to 1.8V when SD in UHS-I.
> + If "fixed-1-8v" is slected, SOC PHY PAD is fixed 1.8V, such as for eMMC.

You should be able to existing, common properties for i/o voltage
capabilities/constraints.

> + - reg
> + Physical address and size of SOC PHY PAD register.
> + Append after Xenon SDHC register space, as a second register field.
> +
> + Please follow the examples with compatible "marvell,armada-3700-sdhci"
> + in below.
> +
> +Example:
> +- For eMMC slot:
> +
> + sdhci@aa0000 {
> + compatible = "marvell,sdhci-xenon";
> + reg = <0xaa0000 0x1000>;
> + interrupts = <GIC_SPI 13 IRQ_TYPE_LEVEL_HIGH>
> + clocks = <&emmcclk>;
> + clock-names = "core";
> + xenon,slotno = <0>;
> + xenon,phy-type = "emmc 5.1 phy";
> + bus-width = <8>;
> + tuning-count = <11>;
> + };
> +
> +- For SD/SDIO slot:
> +
> + sdhci@ab0000 {
> + compatible = "marvell,sdhci-xenon";
> + reg = <0xab0000 0x1000>;
> + interrupts = <GIC_SPI 55 IRQ_TYPE_LEVEL_HIGH>
> + vqmmc-supply = <&sd_regulator>;
> + clocks = <&sdclk>;
> + clock-names = "core";
> + bus-width = <4>;
> + tuning-count = <9>;
> + };
> +
> +- For eMMC slot with compatible "marvell,armada-3700-sdhci":
> +
> + sdhci@aa0000 {
> + compatible = "marvell,armada-3700-sdhci";
> + reg = <0xaa0000 0x1000>,
> + <phy_addr 0x4>;
> + interrupts = <GIC_SPI 13 IRQ_TYPE_LEVEL_HIGH>
> + clocks = <&emmcclk>;
> + clock-names = "core";
> + bus-width = <8>;
> +
> + xenon,pad-type = "fixed-1-8v";
> + };
> +
> +- For SD/SDIO slot with compatible "marvell,armada-3700-sdhci":
> +
> + sdhci@ab0000 {
> + compatible = "marvell,armada-3700-sdhci";
> + reg = <0xab0000 0x1000>,
> + <phy_addr 0x4>;
> + interrupts = <GIC_SPI 55 IRQ_TYPE_LEVEL_HIGH>
> + vqmmc-supply = <&sd_regulator>;
> + clocks = <&sdclk>;
> + clock-names = "core";
> + bus-width = <4>;
> +
> + xenon,pad-type = "sd";
> + };
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 89adcd57aa25..4aa0eac9bfc7 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -7582,6 +7582,7 @@ MARVELL XENON MMC/SD/SDIO HOST CONTROLLER DRIVER
> M: Ziji Hu <huziji@xxxxxxxxxxx>
> L: linux-mmc@xxxxxxxxxxxxxxx
> S: Supported
> +F: Documentation/devicetree/bindings/mmc/marvell,sdhci-xenon.txt
>
> MATROX FRAMEBUFFER DRIVER
> L: linux-fbdev@xxxxxxxxxxxxxxx
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