From e5fd91f1ef340da553f7a79da9540c3db711c937 Mon Sep 17 00:00:00 2001 From: André Fabian Silva Delgado Date: Tue, 8 Sep 2015 01:01:14 -0300 Subject: Linux-libre 4.2-gnu --- Documentation/devicetree/bindings/mfd/mfd.txt | 41 +++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) create mode 100644 Documentation/devicetree/bindings/mfd/mfd.txt (limited to 'Documentation/devicetree/bindings/mfd/mfd.txt') diff --git a/Documentation/devicetree/bindings/mfd/mfd.txt b/Documentation/devicetree/bindings/mfd/mfd.txt new file mode 100644 index 000000000..af9d6931a --- /dev/null +++ b/Documentation/devicetree/bindings/mfd/mfd.txt @@ -0,0 +1,41 @@ +Multi-Function Devices (MFD) + +These devices comprise a nexus for heterogeneous hardware blocks containing +more than one non-unique yet varying hardware functionality. + +A typical MFD can be: + +- A mixed signal ASIC on an external bus, sometimes a PMIC (Power Management + Integrated Circuit) that is manufactured in a lower technology node (rough + silicon) that handles analog drivers for things like audio amplifiers, LED + drivers, level shifters, PHY (physical interfaces to things like USB or + ethernet), regulators etc. + +- A range of memory registers containing "miscellaneous system registers" also + known as a system controller "syscon" or any other memory range containing a + mix of unrelated hardware devices. + +Optional properties: + +- compatible : "simple-mfd" - this signifies that the operating system should + consider all subnodes of the MFD device as separate devices akin to how + "simple-bus" inidicates when to see subnodes as children for a simple + memory-mapped bus. For more complex devices, when the nexus driver has to + probe registers to figure out what child devices exist etc, this should not + be used. In the latter case the child devices will be determined by the + operating system. + +Example: + +foo@1000 { + compatible = "syscon", "simple-mfd"; + reg = <0x01000 0x1000>; + + led@08.0 { + compatible = "register-bit-led"; + offset = <0x08>; + mask = <0x01>; + label = "myled"; + default-state = "on"; + }; +}; -- cgit v1.2.3-54-g00ecf