path: root/Documentation/devicetree/bindings/arm/vexpress-sysreg.txt
diff options
authorPawel Moll <>2014-04-30 16:46:29 +0100
committerPawel Moll <>2014-05-15 17:02:18 +0100
commit3b9334ac835bb431e2186645230c9f1eb94b5d49 (patch)
tree631e00349363927a6e49c6810332d92295103446 /Documentation/devicetree/bindings/arm/vexpress-sysreg.txt
parentc6e126de43e7d4abfd6cf796b40589db3a046167 (diff)
mfd: vexpress: Convert custom func API to regmap
Components of the Versatile Express platform (configuration microcontrollers on motherboard and daughterboards in particular) talk to each other over a custom configuration bus. They provide miscellaneous functions (from clock generator control to energy sensors) which are represented as platform devices (and Device Tree nodes). The transactions on the bus can be generated by different "bridges" in the system, some of which are universal for the whole platform (for the price of high transfer latencies), others restricted to a subsystem (but much faster). Until now drivers for such functions were using custom "func" API, which is being replaced in this patch by regmap calls. This required: * a rework (and move to drivers/bus directory, as suggested by Samuel and Arnd) of the config bus core, which is much simpler now and uses device model infrastructure (class) to keep track of the bridges; non-DT case (soon to be retired anyway) is simply covered by a special device registration function * the new config-bus driver also takes over device population, so there is no need for special matching table for of_platform_populate nor "simple-bus" hack in the arm64 model dtsi file (relevant bindings documentation has been updated); this allows all the vexpress devices fit into normal device model, making it possible to remove plenty of early inits and other hacks in the near future * adaptation of the syscfg bridge implementation in the sysreg driver, again making it much simpler; there is a special case of the "energy" function spanning two registers, where they should be both defined in the tree now, but backward compatibility is maintained in the code * modification of the relevant drivers: * hwmon - just a straight-forward API change * power/reset driver - API change * regulator - API change plus error handling simplification * osc clock driver - this one required larger rework in order to turn in into a standard platform driver Signed-off-by: Pawel Moll <> Acked-by: Mark Brown <> Acked-by: Lee Jones <> Acked-by: Guenter Roeck <> Acked-by: Mike Turquette <>
Diffstat (limited to 'Documentation/devicetree/bindings/arm/vexpress-sysreg.txt')
1 files changed, 32 insertions, 11 deletions
diff --git a/Documentation/devicetree/bindings/arm/vexpress-sysreg.txt b/Documentation/devicetree/bindings/arm/vexpress-sysreg.txt
index 5580e9c4bd85..57b423f78995 100644
--- a/Documentation/devicetree/bindings/arm/vexpress-sysreg.txt
+++ b/Documentation/devicetree/bindings/arm/vexpress-sysreg.txt
@@ -27,24 +27,45 @@ Example:
This block also can also act a bridge to the platform's configuration
bus via "system control" interface, addressing devices with site number,
position in the board stack, config controller, function and device
-numbers - see motherboard's TRM for more details.
-The node describing a config device must refer to the sysreg node via
-"arm,vexpress,config-bridge" phandle (can be also defined in the node's
-parent) and relies on the board topology properties - see main vexpress
-node documentation for more details. It must also define the following
-- arm,vexpress-sysreg,func : must contain two cells:
- - first cell defines function number (eg. 1 for clock generator,
- 2 for voltage regulators etc.)
- - device number (eg. osc 0, osc 1 etc.)
+numbers - see motherboard's TRM for more details. All configuration
+controller accessible via this interface must reference the sysreg
+node via "arm,vexpress,config-bridge" phandle and define appropriate
+topology properties - see main vexpress node documentation for more
+details. Each child of such node describes one function and must
+define the following properties:
+- compatible value : must be one of (corresponding to the TRM):
+ "arm,vexpress-amp"
+ "arm,vexpress-dvimode"
+ "arm,vexpress-energy"
+ "arm,vexpress-muxfpga"
+ "arm,vexpress-osc"
+ "arm,vexpress-power"
+ "arm,vexpress-reboot"
+ "arm,vexpress-reset"
+ "arm,vexpress-scc"
+ "arm,vexpress-shutdown"
+ "arm,vexpress-temp"
+ "arm,vexpress-volt"
+- arm,vexpress-sysreg,func : must contain a set of two cells long groups:
+ - first cell of each group defines the function number
+ (eg. 1 for clock generator, 2 for voltage regulators etc.)
+ - second cell of each group defines device number (eg. osc 0,
+ osc 1 etc.)
+ - some functions (eg. energy meter, with its 64 bit long counter)
+ are using more than one function/device number pair
mcc {
+ compatible = "arm,vexpress,config-bus";
arm,vexpress,config-bridge = <&v2m_sysreg>;
osc@0 {
compatible = "arm,vexpress-osc";
arm,vexpress-sysreg,func = <1 0>;
+ energy@0 {
+ compatible = "arm,vexpress-energy";
+ arm,vexpress-sysreg,func = <13 0>, <13 1>;
+ };