[PATCH/RFC v2 01/11] PM / Domains: Add DT bindings for the R-Car System Controller
From: laurent.pinchart@ideasonboard.com (Laurent Pinchart)
Date: 2016-02-15 23:08:18
Also in:
linux-devicetree, linux-pm, linux-renesas-soc
Hi Geert, Thank you for the patch. On Monday 15 February 2016 22:16:50 Geert Uytterhoeven wrote:
quoted hunk ↗ jump to hunk
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@glider.be> --- Alternatives I considered: - Using a single node per power register block, even if it contains multiple domains, e.g.: pd_ca15_scu: ca15_scu at 180 { reg = <0x180 0x20>; #address-cells = <1>; #size-cells = <0>; #power-domain-cells = <0>; renesas,interrupt-bits = <12>; pd_ca15_cpu: ca15_cpu at 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.txtdiff --git a/Documentation/devicetree/bindings/power/renesas,sysc-rcar.txtb/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 theSoC-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 at 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 at 12 {
+ reg = <12 0x180>;
+ #address-cells = <2>;
+ #size-cells = <0>;
+ #power-domain-cells = <0>;
+
+ pd_ca15_cpu0: cpu at 0 {
+ reg = <0 0x40>;
+ #power-domain-cells = <0>;
+ };
+
+ pd_ca15_cpu1: cpu at 1 {
+ reg = <1 0x41>;
+ #power-domain-cells = <0>;
+ };
+ };
+
+ pd_sh: sh at 16 {
+ reg = <16 0x80>;
+ #power-domain-cells = <0>;
+ };
+
+ pd_sgx: sgx at 20 {
+ reg = <20 0xc0>;
+ #power-domain-cells = <0>;
+ };
+ };
+ };-- Regards, Laurent Pinchart