drivers: mfd: vexpress: add Serial Power Controller (SPC) support

The TC2 versatile express core tile integrates a logic block that provides the
interface between the dual cluster test-chip and the M3 microcontroller that
carries out power management. The logic block, called Serial Power Controller
(SPC), contains several memory mapped registers to control among other things
low-power states, operating points and reset control.

This patch provides a driver that enables run-time control of features
implemented by the SPC control logic.

The driver also provides a bridge interface through the vexpress config
infrastructure. Operations allowing to read/write operating points are
made to go via the same interface as configuration transactions so that
all requests to M3 are serialized.

Device tree bindings documentation for the SPC component is provided with
the patchset.

Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: Pawel Moll <pawel.moll@arm.com>
Cc: Nicolas Pitre <nicolas.pitre@linaro.org>
Cc: Amit Kucheria <amit.kucheria@linaro.org>
Cc: Jon Medhurst <tixy@linaro.org>
Signed-off-by: Achin Gupta <achin.gupta@arm.com>
Signed-off-by: Lorenzo Pieralisi <lorenzo.pieralisi@arm.com>
Signed-off-by: Sudeep KarkadaNagesha <Sudeep.KarkadaNagesha@arm.com>
Reviewed-by: Nicolas Pitre <nico@linaro.org>

1 files changed, 35 insertions, 0 deletions

diff --git a/Documentation/devicetree/bindings/mfd/vexpress-spc.txt b/Documentation/devicetree/bindings/mfd/vexpress-spc.txt
new file mode 100644
index 00000000000..1d71dc2ff15
--- /dev/null
+++ b/Documentation/devicetree/bindings/mfd/vexpress-spc.txt
@@ -0,0 +1,35 @@
+* ARM Versatile Express Serial Power Controller device tree bindings
+
+Latest ARM development boards implement a power management interface (serial
+power controller - SPC) that is capable of managing power/voltage and
+operating point transitions, through memory mapped registers interface.
+
+On testchips like TC2 it also provides a configuration interface that can
+be used to read/write values which cannot be read/written through simple
+memory mapped reads/writes.
+
+- spc node
+
+	- compatible:
+		Usage: required
+		Value type: <stringlist>
+		Definition: must be
+			    "arm,vexpress-spc,v2p-ca15_a7","arm,vexpress-spc"
+	- reg:
+		Usage: required
+		Value type: <prop-encode-array>
+		Definition: A standard property that specifies the base address
+			    and the size of the SPC address space
+	- interrupts:
+		Usage: required
+		Value type: <prop-encoded-array>
+		Definition:  SPC interrupt configuration. A standard property
+			     that follows ePAPR interrupts specifications
+
+Example:
+
+spc: spc@7fff0000 {
+	compatible = "arm,vexpress-spc,v2p-ca15_a7","arm,vexpress-spc";
+	reg = <0 0x7FFF0000 0 0x1000>;
+	interrupts = <0 95 4>;
+};