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authorLinus Torvalds <torvalds@linux-foundation.org>2015-06-26 11:54:29 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-06-26 11:54:29 -0700
commitf5dcb68086ba2e033b2af32b0da0c7a7c7872a09 (patch)
tree89c41089b492f8d8d411185bd7cb07538802e837 /Documentation/devicetree/bindings/mfd
parent3d9f96d850e4bbfae24dc9aee03033dd77c81596 (diff)
parent4af34b572a85c44c55491a10693535a79627c478 (diff)
downloadop-kernel-dev-f5dcb68086ba2e033b2af32b0da0c7a7c7872a09.zip
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Merge tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc
Pull ARM SoC driver updates from Kevin Hilman: "Some of these are for drivers/soc, where we're now putting SoC-specific drivers these days. Some are for other driver subsystems where we have received acks from the appropriate maintainers. Some highlights: - simple-mfd: document DT bindings and misc updates - migrate mach-berlin to simple-mfd for clock, pinctrl and reset - memory: support for Tegra132 SoC - memory: introduce tegra EMC driver for scaling memory frequency - misc. updates for ARM CCI and CCN busses" * tag 'armsoc-drivers' of git://git.kernel.org/pub/scm/linux/kernel/git/arm/arm-soc: (48 commits) drivers: soc: sunxi: Introduce SoC driver to map SRAMs arm-cci: Add aliases for PMU events arm-cci: Add CCI-500 PMU support arm-cci: Sanitise CCI400 PMU driver specific code arm-cci: Abstract handling for CCI events arm-cci: Abstract out the PMU counter details arm-cci: Cleanup PMU driver code arm-cci: Do not enable CCI-400 PMU by default firmware: qcom: scm: Add HDCP Support ARM: berlin: add an ADC node for the BG2Q ARM: berlin: remove useless chip and system ctrl compatibles clk: berlin: drop direct of_iomap of nodes reg property ARM: berlin: move BG2Q clock node ARM: berlin: move BG2CD clock node ARM: berlin: move BG2 clock node clk: berlin: prepare simple-mfd conversion pinctrl: berlin: drop SoC stub provided regmap ARM: berlin: move pinctrl to simple-mfd nodes pinctrl: berlin: prepare to use regmap provided by syscon reset: berlin: drop arch_initcall initialization ...
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+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";
+ };
+};
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