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SubjectRe: [PATCH v12 3/3] dt-bindings: mfd: Document Renesas R-Car Gen3 RPC-IF MFD bindings
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On 05/14/2019 12:46 PM, masonccyang@mxic.com.tw wrote:

>>>> There's precedence for such constructs being an MFD: please see
>>>> drivers/mfd/at91-usart.c, which registers a single MFD cell for
> either
>>>> serial or SPI.
>>
>> Thanks fir your example, Geert! :-)

s/fir/for/, not the firtree season anymore. :-)

>>> okay, many thanks for your information.
>>>
>>> How about to patch RPF-IF dts to:
>>> -------------------------------------------------------------->
>>>
>>> Renesas R-Car Gen3 RPC-IF controller Device Tree Bindings
>>> ---------------------------------------------------------
>>>
>>> RPC-IF supports both SPI NOR and HyperFlash (CFI-compliant flash)
>>>
>>> Required properties:
>>> - compatible: should be an SoC-specific compatible value, followed
> by
>>> "renesas,rcar-gen3-rpc" as a fallback.
>>> supported SoC-specific values are:
>>> "renesas,r8a77995-rpc" (R-Car D3)
>>> - reg: should contain three register areas:
>>> first for the base address of RPC-IF registers,
>>
>> I'd drop "the base address" here.
>
> okay.
>
>>> second for the direct mapping read mode and
>>> third for the write buffer area.
>>> - reg-names: should contain "regs", "dirmap" and "wbuf"
>>> - clocks: should contain 1 entries for the module's clock
>>> - clock-names: should contain "rpc"
>>
>> I suspect we'd need the RPC/RPCD2 clocks mentioned as well (not sure
> yet)...
>
> Need it ?

You seem to call clk_get_rate() on the module clock, I doubt that's
correct topologically...

> RPCD2 is derived from RPC and it's value is half of RPC,
> i.e., RPC = 160MHz, RPCD2 = 80 MHz

I know.

>> And how about "power-domains", "resets" (seen in the example below),
>> also what about #address-cells & #size-cells?
>>
>>>
>>> Example:
>>
>> Could you please indent with 1 or 2 tabs where you used 8 or 16
> spaces?
>>
>>> - SPI mode:
>>>
>>> rpc: rpc-if@ee200000 {
>>
>> The node names should be generic, based on the device class. And in
> this
>> case I'd like to use "spi@ee200000" as otherwise dtc keeps bitching like
> below:
>
> okay, patch to
>
> rpc_if: spi@<...>

That, or just keep the node label.

>> arch/arm64/boot/dts/renesas/r8a77980.dtsi:1344.21-1359.5: Warning
> (spi_bus_bridge):
>> /soc/rpc@ee200000: node name for SPI buses should be 'spi'
>> also defined at
> arch/arm64/boot/dts/renesas/r8a77980-condor.dts:283.6-343.3
>> arch/arm64/boot/dts/renesas/r8a77980-condor.dtb: Warning (spi_bus_reg):
>> Failed prerequisite 'spi_bus_bridge'
>>
>>
>>> - HF mode:
>>> rpc: rpc-if@ee200000 {
>>
>> Again, spi@<...>.
>
> what about rpc_if: hf@<...>

Can't change the node name, as it's declared in the .dtsi files, not *.dts
ones. And "spi" works for the HF case as well -- no complaints from dtc. :-)

>>> compatible = "renesas,r8a77995-rpc",
> "renesas,rcar-gen3-rpc";
>>> reg = <0 0xee200000 0 0x200>, <0 0x08000000 0
> 0x4000000>,
>>> <0 0xee208000 0 0x100>;
>>> reg-names = "regs", "dirmap", "wbuf";
>>> clocks = <&cpg CPG_MOD 917>;
>>> clock-names = "rpc";
>>> power-domains = <&sysc R8A77995_PD_ALWAYS_ON>;
>>> resets = <&cpg 917>;
>>> #address-cells = <1>;
>>> #size-cells = <1>;
>>>
>>> flash@0 {
>>> compatible = "cfi-flash";
>>
>> The working HF implementation has "cypress,hyperflash" before
> "cfi-flash".
>>
>>> reg = <0 0x4000000>;
>>> };
>>> };
>>>
>>> --------------------------------------------------------------<
>>>
>>> Is it OK ?
>>
>> Yeah, seems good (assuming you fix the issues above).
>
> Patch new DTS to
> ===============================================================>
>
> +Renesas R-Car Gen3 RPC-IF controller Device Tree Bindings
> +---------------------------------------------------------
> +
> +RPC-IF supports both SPI NOR and HyperFlash (CFI-compliant flash)
> +
> +Required properties:
> +- compatible: should be an SoC-specific compatible value, followed by
> + "renesas,rcar-gen3-rpc" as a fallback.
> + supported SoC-specific values are:
> + "renesas,r8a77995-rpc" (R-Car
> D3)
> +- reg: should contain three register areas:
> + first for RPC-IF registers,
> + second for the direct mapping read mode and
> + third for the write buffer area.
> +- reg-names: should contain "regs", "dirmap" and "wbuf"
> +- clocks: should contain 1 entries for the module's clock
> +- clock-names: should contain "rpc"
> +- #address-cells: should be 1
> +- #size-cells: should be 0

Still nothing about the "oower-domains" and "resets" props... :-(

> +
> +Example:
> +- SPI mode:
> +
> + rpc_if: spi@ee200000 {
> + compatible = "renesas,r8a77995-rpc",
> "renesas,rcar-gen3-rpc";
> + reg = <0 0xee200000 0 0x200>, <0
> 0x08000000 0 0x4000000>,
> + <0 0xee208000 0 0x100>;
> + reg-names = "regs", "dirmap", "wbuf";
> + clocks = <&cpg CPG_MOD 917>;
> + clock-names = "rpc";
> + power-domains = <&sysc
> R8A77995_PD_ALWAYS_ON>;
> + resets = <&cpg 917>;
> + #address-cells = <1>;
> + #size-cells = <0>;
[...]
> =======================================================================<
>
> OK ?

Yes, with the remaining issue fixed.

> thanks & best regards,
> Mason

[...]

MBR, Sergei

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