Hi Geert,
Thank you for the patch.
On Monday 15 February 2016 22:16:50 Geert Uytterhoeven wrote:
> The Renesas R-Car System Controller provides power management for the
> CPU cores and various coprocessors, following the generic PM domain
> bindings in Documentation/devicetree/bindings/power/power_domain.txt.
>
> This supports R-Car Gen1, Gen2, and Gen3.
>
> Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
> ---
> Alternatives I considered:
>
> - Using a single node per power register block, even if it contains
> multiple domains, e.g.:
>
> pd_ca15_scu: ca15_scu@180 {
> reg = <0x180 0x20>;
> #address-cells = <1>;
> #size-cells = <0>;
> #power-domain-cells = <0>;
> renesas,interrupt-bits = <12>;
>
> pd_ca15_cpu: ca15_cpu@40 {
> reg = <0x40 0x20>;
> #power-domain-cells = <1>;
> renesas,pm-domain-indices = <0 1>;
> renesas,pm-domain-names =
> "ca15_cpu0", "ca15_cpu1";
> renesas,interrupt-bits = <0 1>;
> };
> };
>
> Notes:
> - You cannot just have a property with the number of domains, as
> index 0 is not used on R-Car H1. Hence the need for
> "renesas,pm-domain-indices" and "renesas,interrupt-bits",
> - "#power-domain-cells = <1>" for nodes with multiple domains,
> which allows typos in "power-domains = <&pd_ca15_cpu n>", using
> an invalid value of "n".
>
> - Using a linear description in DT:
> - Needs parent links for subdomains,
> - More complicated to parse (lesson learned from R-Mobile PM
> Domain support).
>
> - Keeping the power register block offset and the bit number as separate
> "reg" cells, increasing "#address-cells" from 2 to 3,
>
> - Merging the interrupt bit (which needs only 5 bits) in the other "reg"
> cell, decreasing "#address-cells" from 2 to 1.
>
> v2:
> - Add R-Car H3 (r8a7795) support,
> - Use "renesas,<type>-sysc" instead of "renesas,sysc-<type>",
> - Add fallback compatibility strings for R-Car Gen2 and Gen3.
> ---
> .../bindings/power/renesas,sysc-rcar.txt | 87 +++++++++++++++++++
> 1 file changed, 87 insertions(+) create mode 100644
> Documentation/devicetree/bindings/power/renesas,sysc-rcar.txt
>
> diff --git a/Documentation/devicetree/bindings/power/renesas,sysc-rcar.txt
> b/Documentation/devicetree/bindings/power/renesas,sysc-rcar.txt new file
> mode 100644
> index 0000000000000000..92ddc0da7b755215
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/power/renesas,sysc-rcar.txt
> @@ -0,0 +1,87 @@
> +DT bindings for the Renesas R-Car System Controller
> +
> +== System Controller Node ==
> +
> +The R-Car System Controller provides power management for the CPU cores and
> +various coprocessors.
> +
> +Required properties:
> + - compatible: Must contain one or more of the following:
> + - "renesas,r8a7779-sysc" (R-Car H1)
> + - "renesas,r8a7790-sysc" (R-Car H2)
> + - "renesas,r8a7791-sysc" (R-Car M2-W)
> + - "renesas,r8a7792-sysc" (R-Car V2H)
> + - "renesas,r8a7793-sysc" (R-Car M2-N)
> + - "renesas,r8a7794-sysc" (R-Car E2)
> + - "renesas,r8a7795-sysc" (R-Car H3)
> + - "renesas,rcar-gen2-sysc" (Generic R-Car Gen2)
> + - "renesas,rcar-gen3-sysc" (Generic R-Car Gen3)
> + When compatible with the generic version, nodes must list the
> SoC-specific
> + version corresponding to the platform first, followed by the generic
> + version.
> + - reg: Address start and address range for the device.
This isn't correct. I'll refrain from saying we abuse the reg property, as
using the first cell as a power domain number should be fine (the second cell
feels a bit more of an abuse to me though, but I won't complain too much), but
the bindings document should describe what the reg cells contain.
> + - pm-domains: This node contains a hierarchy of PM Domain Nodes.
Can't it be an issue that the node happens to have the same name as the
standard pm-domains property ?
> + Dependencies (e.g. parent SCUs should not be powered off while child
> CPUs
> + are on) should be reflected using subnodes.
> +
> +
> +== PM Domain Nodes ==
> +
> +Each of the PM domain nodes represents a PM domain, as documented by the
> +generic PM domain bindings in
> +Documentation/devicetree/bindings/power/power_domain.txt.
> +
> +Required properties:
> + - #power-domain-cells: Must be 0.
> + - reg: This property must contain 2 values:
> + - The first value is the number of the interrupt bit representing
> + the power area in the various Interrupt Registers (e.g. SYSCISR,
> + Interrupt Status Register),
> + - The second value encodes the power register block offset (which is
> + a multiple of 64), and the number of the bit representing the
> + power area in the various Power Control Registers (e.g. PWROFFSR,
> + Power Shutoff Status Register). This value is created by ORing
> + these two numbers.
> + The parent's node must contain the following two properties:
> + - #address-cells: Must be 2,
> + - #size-cells: Must be 0.
> +
> +
> +Example:
> +
> + sysc: system-controller@e6180000 {
> + compatible = "renesas,r8a7791-sysc", "renesas,rcar-gen2-sysc";
> + reg = <0 0xe6180000 0 0x0200>;
> +
> + pm-domains {
> + #address-cells = <2>;
> + #size-cells = <0>;
> +
> + pd_ca15_scu: scu@12 {
> + reg = <12 0x180>;
> + #address-cells = <2>;
> + #size-cells = <0>;
> + #power-domain-cells = <0>;
> +
> + pd_ca15_cpu0: cpu@0 {
> + reg = <0 0x40>;
> + #power-domain-cells = <0>;
> + };
> +
> + pd_ca15_cpu1: cpu@1 {
> + reg = <1 0x41>;
> + #power-domain-cells = <0>;
> + };
> + };
> +
> + pd_sh: sh@16 {
> + reg = <16 0x80>;
> + #power-domain-cells = <0>;
> + };
> +
> + pd_sgx: sgx@20 {
> + reg = <20 0xc0>;
> + #power-domain-cells = <0>;
> + };
> + };
> + };
--
Regards,
Laurent Pinchart
