ARM: rockchip: add option to access the pmu via a phandle in smp_operations

Makes it possible to define a rockchip,pmu phandle in the cpus node directly
referencing the pmu syscon instead of searching for specific compatible.

The old way of finding the pmu stays of course available.

Signed-off-by: Kever Yang <kever.yang@rock-chips.com>
Tested-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Heiko Stuebner <heiko@sntech.de>

2 files changed, 22 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/arm/cpus.txt b/Documentation/devicetree/bindings/arm/cpus.txt
index fc446347ab6d..b2aacbe16ed9 100644
--- a/Documentation/devicetree/bindings/arm/cpus.txt
+++ b/Documentation/devicetree/bindings/arm/cpus.txt
@@ -227,6 +227,15 @@ nodes to be present and contain the properties described below.
                         # List of phandles to idle state nodes supported
                           by this cpu [3].
 
+        - rockchip,pmu
+                Usage: optional for systems that have an "enable-method"
+                       property value of "rockchip,rk3066-smp"
+                       While optional, it is the preferred way to get access to
+                       the cpu-core power-domains.
+                Value type: <phandle>
+                Definition: Specifies the syscon node controlling the cpu core
+                            power domains.
+
 Example 1 (dual-cluster big.LITTLE system 32-bit):
 
         cpus {
diff --git a/arch/arm/mach-rockchip/platsmp.c b/arch/arm/mach-rockchip/platsmp.c
index 4c36fbf99afb..57b53b32e103 100644
--- a/arch/arm/mach-rockchip/platsmp.c
+++ b/arch/arm/mach-rockchip/platsmp.c
@@ -155,6 +155,19 @@ static int __init rockchip_smp_prepare_pmu(void)
         struct device_node *node;
         void __iomem *pmu_base;
 
+        /*
+         * This function is only called via smp_ops->smp_prepare_cpu().
+         * That only happens if a "/cpus" device tree node exists
+         * and has an "enable-method" property that selects the SMP
+         * operations defined herein.
+         */
+        node = of_find_node_by_path("/cpus");
+
+        pmu = syscon_regmap_lookup_by_phandle(node, "rockchip,pmu");
+        of_node_put(node);
+        if (!IS_ERR(pmu))
+                return 0;
+
         pmu = syscon_regmap_lookup_by_compatible("rockchip,rk3066-pmu");
         if (!IS_ERR(pmu))
                 return 0;