diff options
-rw-r--r-- | Documentation/devicetree/bindings/mfd/mfd.txt | 41 | ||||
-rw-r--r-- | drivers/of/platform.c | 1 |
2 files changed, 42 insertions, 0 deletions
diff --git a/Documentation/devicetree/bindings/mfd/mfd.txt b/Documentation/devicetree/bindings/mfd/mfd.txt new file mode 100644 index 0000000..af9d693 --- /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"; + }; +}; diff --git a/drivers/of/platform.c b/drivers/of/platform.c index a01f57c..ddf8e42 100644 --- a/drivers/of/platform.c +++ b/drivers/of/platform.c @@ -25,6 +25,7 @@ const struct of_device_id of_default_bus_match_table[] = { { .compatible = "simple-bus", }, + { .compatible = "simple-mfd", }, #ifdef CONFIG_ARM_AMBA { .compatible = "arm,amba-bus", }, #endif /* CONFIG_ARM_AMBA */ |