From 88e0abcd7a8171ca7af3402373e7bd81fe9b6754 Mon Sep 17 00:00:00 2001 From: Pawel Moll Date: Tue, 18 Sep 2012 12:24:57 +0100 Subject: mfd: Versatile Express system registers driver This is a platform driver for Versatile Express' "system register" block. It's a random collection of registers providing the following functionality: - low level platform functions like board ID access; in order to use those, the driver must be initialized early, either statically or based on the DT - config bus bridge via "system control" interface; as the response from the controller does not generate interrupt (yet), the status register is periodically polled using a timer - pseudo GPIO lines providing MMC card status and Flash WP# signal control - LED interface for a set of 8 LEDs on the motherboard, with "heartbeat", "mmc0" and "cpu0" to "cpu5" as default triggers Signed-off-by: Pawel Moll --- .../devicetree/bindings/arm/vexpress-sysreg.txt | 50 ++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 Documentation/devicetree/bindings/arm/vexpress-sysreg.txt (limited to 'Documentation/devicetree/bindings/arm/vexpress-sysreg.txt') diff --git a/Documentation/devicetree/bindings/arm/vexpress-sysreg.txt b/Documentation/devicetree/bindings/arm/vexpress-sysreg.txt new file mode 100644 index 000000000000..9cf3f25544c7 --- /dev/null +++ b/Documentation/devicetree/bindings/arm/vexpress-sysreg.txt @@ -0,0 +1,50 @@ +ARM Versatile Express system registers +-------------------------------------- + +This is a system control registers block, providing multiple low level +platform functions like board detection and identification, software +interrupt generation, MMC and NOR Flash control etc. + +Required node properties: +- compatible value : = "arm,vexpress,sysreg"; +- reg : physical base address and the size of the registers window +- gpio-controller : specifies that the node is a GPIO controller +- #gpio-cells : size of the GPIO specifier, should be 2: + - first cell is the pseudo-GPIO line number: + 0 - MMC CARDIN + 1 - MMC WPROT + 2 - NOR FLASH WPn + - second cell can take standard GPIO flags (currently ignored). + +Example: + v2m_sysreg: sysreg@10000000 { + compatible = "arm,vexpress-sysreg"; + reg = <0x10000000 0x1000>; + gpio-controller; + #gpio-cells = <2>; + }; + +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 must also define the +following property: +- 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.) + +Example: + mcc { + arm,vexpress,config-bridge = <&v2m_sysreg>; + + osc@0 { + compatible = "arm,vexpress-osc"; + arm,vexpress-sysreg,func = <1 0>; + }; + }; -- cgit v1.2.3-59-g8ed1b