Re: [PATCH v4 1/5] [RFC] clk: shmobile: Add new Renesas CPG/MSSR DT bindings

[Michael Turquette <mturquette@baylibre.com>]

Hi Geert,

Quoting Geert Uytterhoeven (2015-10-16 05:49:16)
> On Renesas ARM SoCs (SH/R-Mobile, R-Car, RZ), the CPG (Clock Pulse
> Generator) and MSSR (Module Standby and Software Reset) blocks are
> intimately connected, and share the same register block.
> 
> Hence it makes sense to describe these two blocks using a
> single device node in DT, instead of using a hierarchical structure with
> multiple nodes, using a mix of generic and SoC-specific bindings.
> 
> These new DT bindings are intended to replace the existing DT bindings
> for CPG core clocks ("renesas,*-cpg-clocks", "renesas,cpg-div6-clock")
> and module clocks ("renesas,*-mstp-clocks"), at least for new SoCs.
> 
> This will make it easier to add module reset support later, which is
> currently not implemented, and difficult to achieve using the existing
> bindings due to the intertwined register layout.
> 
> Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>

Thanks for re-working the binding per our discussion at ELC-E. Please
feel free to add my Ack to patches #1 and #2.

Regards,
Mike

> ---
> v4:
>   - No changes,
> 
> v3:
>   - Integrate CPG and MSSR,
> 
> v2:
>   - Switch from MSTP to MSSR.
> ---
>  .../devicetree/bindings/clock/renesas,cpg-mssr.txt | 71 ++++++++++++++++++++++
>  include/dt-bindings/clock/renesas-cpg-mssr.h       | 15 +++++
>  2 files changed, 86 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/clock/renesas,cpg-mssr.txt
>  create mode 100644 include/dt-bindings/clock/renesas-cpg-mssr.h
> 
> diff --git a/Documentation/devicetree/bindings/clock/renesas,cpg-mssr.txt b/Documentation/devicetree/bindings/clock/renesas,cpg-mssr.txt
> new file mode 100644
> index 0000000000000000..a56836aa2131a8db
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/clock/renesas,cpg-mssr.txt
> @@ -0,0 +1,71 @@
> +* Renesas Clock Pulse Generator / Module Standby and Software Reset
> +
> +On Renesas ARM SoCs (SH/R-Mobile, R-Car, RZ), the CPG (Clock Pulse Generator)
> +and MSSR (Module Standby and Software Reset) blocks are intimately connected,
> +and share the same register block.
> +
> +They provide the following functionalities:
> +  - The CPG block generates various core clocks,
> +  - The MSSR block provides two functions:
> +      1. Module Standby, providing a Clock Domain to control the clock supply
> +        to individual SoC devices,
> +      2. Reset Control, to perform a software reset of individual SoC devices.
> +
> +Required Properties:
> +  - compatible: Must be one of:
> +      - "renesas,r8a7791-cpg-mssr" for the r8a7791 SoC
> +      - "renesas,r8a7795-cpg-mssr" for the r8a7795 SoC
> +
> +  - reg: Base address and length of the memory resource used by the CPG/MSSR
> +    block
> +
> +  - clocks: References to external parent clocks, one entry for each entry in
> +    clock-names
> +  - clock-names: List of external parent clock names. Valid names are:
> +      - "extal" (r8a7791, r8a7795)
> +      - "extalr" (r8a7795)
> +      - "usb_extal" (r8a7791)
> +
> +  - #clock-cells: Must be 2
> +      - For CPG core clocks, the two clock specifier cells must be "CPG_CORE"
> +       and a core clock reference, as defined in
> +       <dt-bindings/clock/*-cpg-mssr.h>.
> +      - For module clocks, the two clock specifier cells must be "CPG_MOD" and
> +       a module number, as defined in the datasheet.
> +
> +  - #power-domain-cells: Must be 0
> +      - SoC devices that are part of the CPG/MSSR Clock Domain and can be
> +       power-managed through Module Standby should refer to the CPG device
> +       node in their "power-domains" property, as documented by the generic PM
> +       Domain bindings in
> +       Documentation/devicetree/bindings/power/power_domain.txt.
> +
> +
> +Examples
> +--------
> +
> +  - CPG device node:
> +
> +       cpg: clock-controller@e6150000 {
> +               compatible = "renesas,r8a7795-cpg-mssr";
> +               reg = <0 0xe6150000 0 0x1000>;
> +               clocks = <&extal_clk>, <&extalr_clk>;
> +               clock-names = "extal", "extalr";
> +               #clock-cells = <2>;
> +               #power-domain-cells = <0>;
> +       };
> +
> +
> +  - CPG/MSSR Clock Domain member device node:
> +
> +       scif2: serial@e6e88000 {
> +               compatible = "renesas,scif-r8a7795", "renesas,scif";
> +               reg = <0 0xe6e88000 0 64>;
> +               interrupts = <GIC_SPI 164 IRQ_TYPE_LEVEL_HIGH>;
> +               clocks = <&cpg CPG_MOD 310>;
> +               clock-names = "sci_ick";
> +               dmas = <&dmac1 0x13>, <&dmac1 0x12>;
> +               dma-names = "tx", "rx";
> +               power-domains = <&cpg>;
> +               status = "disabled";
> +       };
> diff --git a/include/dt-bindings/clock/renesas-cpg-mssr.h b/include/dt-bindings/clock/renesas-cpg-mssr.h
> new file mode 100644
> index 0000000000000000..569a3cc33ffb5bc7
> --- /dev/null
> +++ b/include/dt-bindings/clock/renesas-cpg-mssr.h
> @@ -0,0 +1,15 @@
> +/*
> + * Copyright (C) 2015 Renesas Electronics Corp.
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License as published by
> + * the Free Software Foundation; either version 2 of the License, or
> + * (at your option) any later version.
> + */
> +#ifndef __DT_BINDINGS_CLOCK_RENESAS_CPG_MSSR_H__
> +#define __DT_BINDINGS_CLOCK_RENESAS_CPG_MSSR_H__
> +
> +#define CPG_CORE                       0       /* Core Clock */
> +#define CPG_MOD                                1       /* Module Clock */
> +
> +#endif /* __DT_BINDINGS_CLOCK_RENESAS_CPG_MSSR_H__ */
> -- 
> 1.9.1
>