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.
+ - pm-domains: This node contains a hierarchy of PM Domain Nodes.
+ 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>;
+ };
+ };
+ };
--
1.9.1
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