powerpc: Add support for CTS-1000 GPIO controlled system poweroff

CTS-1000 is based on P4080. GPIO 27 is used to signal the FPGA to
switch off power, and also associates IRQ 8 with front-panel button
press (which we use to call orderly_poweroff()).

The relevant device-tree looks like this:

	gpio0: gpio@130000 {
		compatible = "fsl,qoriq-gpio";
		reg = <0x130000 0x1000>;
		interrupts = <55 2 0 0>;
		#gpio-cells = <2>;
		gpio-controller;

		/* Allows powering off the system via GPIO signal. */
		gpio-halt@27 {
			compatible = "sgy,gpio-halt";
			gpios = <&gpio0 27 0>;
			interrupts = <8 1 0 0>;
		};
	};

Because the driver cannot match on sgy,gpio-halt (because the node is never
processed through of_platform), it matches on fsl,qoriq-gpio and then
checks child nodes for the matching sgy,gpio-halt. This also ensures that
the GPIO controller is detected prior to sgy_cts1000's probe callback,
since that node wont match via of_platform until the controller is
registered.

Also, because the GPIO handler for triggering system poweroff might sleep,
the IRQ uses a workqueue to call orderly_poweroff().

As a final note, this driver may be expanded for other features specific to
the CTS-1000.

Signed-off-by: Ben Collins <ben.c@servergy.com>
Cc: Jack Smith <jack.s@servergy.com>
Cc: Vihar Rai <vihar.r@servergy.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 8 insertions, 0 deletions

diff --git a/arch/powerpc/platforms/85xx/Kconfig b/arch/powerpc/platforms/85xx/Kconfig
index 02d02a09942d..651788cbc6e6 100644
--- a/arch/powerpc/platforms/85xx/Kconfig
+++ b/arch/powerpc/platforms/85xx/Kconfig
@@ -245,6 +245,14 @@ config P4080_DS
         help
           This option enables support for the P4080 DS board
 
+config SGY_CTS1000
+        tristate "Servergy CTS-1000 support"
+        select GPIOLIB
+        select OF_GPIO
+        depends on P4080_DS
+        help
+          Enable this to support functionality in Servergy's CTS-1000 systems.
+
 endif # PPC32
 
 config P5020_DS