ARM: mach-shmobile: kzm9g: Reference DT implementation

Hi,

*** This series is wip and does not currently function
I am posting to provide a status update and ask for help ***

this is a second pass at at providing a refernce DT implementation for the kzm9g baord which is intended to act as a guide for mach-shmobile developers.

Major difference to v1:

* Drop touchscreen initialisation, it requires INTC
* Drop SDHI initialisation, the driver seems to need some work
* Add extra entries to clock-sh73a0.c:lookups[] and
remove auxdata. Ultimtely the clocks will be described
in DT, but the code isn't there yet.
* Drop MMCIF patch, it is not needed if regulators are enabled
* Drop PCF hacks, instead, the series is based on Laruent Pinchart's * series:
[PATCH v2 00/77] SH pin control and GPIO rework with OF support
* Use shmobile_setup_delay()

Unfortunately the last point seems to introduce problems. It seems to prevent SMP from booting to the point of printing anything on the early console. And with CONFIG_SMP disabled the boot halts when the MMCIF driver initialisation calls mmc_delay().

I've poked around a bit but I haven't had any luck working out why this is the case. I would appreciate any pointers on what to investigate.

Git and diffstat information provided to aid review.

----------------------------------------------------------------
The following changes since commit 940956fe1d8de5cbcc963214fe592f76d8354bef:

ARM: shmobile: kzm9g: Add LED1-LED4 to the device tree (2012-11-27 00:59:10 +0100)

are available in the git repository at:

git://git.kernel.org/pub/scm/linux/kernel/git/horms/renesas.git devel/of-kzm9g

for you to fetch changes up to 7018db4354c445d401782dc38df5e2d8afb43bc2:

ARM: mach-shmobile: kzm9g: Reference DT implementation (2012-11-30 16:55:46 +0900)

----------------------------------------------------------------
Simon Horman (5):
ARM: mach-shmobile: sh73a0: Allow initialisation of GIC by DT
ARM: mach-shmobile: sh73a0: Minimal setup using DT
ARM: mach-shmobile: sh73a0: Initialise MMCIF using DT
ARM: shmobile: kzm9g: use voltage regulators by default
ARM: mach-shmobile: kzm9g: Reference DT implementation

 arch/arm/boot/dts/Makefile                     |    3 +-
 arch/arm/boot/dts/sh73a0-kzm9g-reference.dts   |   37 ++++++++++
 arch/arm/boot/dts/sh73a0-reference.dtsi        |   24 +++++++
 arch/arm/boot/dts/sh73a0.dtsi                  |   69 ++++++++++++++++++
 arch/arm/configs/kzm9g_defconfig               |    1 +
 arch/arm/mach-shmobile/Kconfig                 |   10 +++
 arch/arm/mach-shmobile/Makefile                |    8 ++-
 arch/arm/mach-shmobile/board-kzm9g-reference.c |   92 ++++++++++++++++++++++++
 arch/arm/mach-shmobile/clock-sh73a0.c          |    6 ++
 arch/arm/mach-shmobile/include/mach/common.h   |    3 +
 arch/arm/mach-shmobile/intc-sh73a0.c           |   14 ++++
 arch/arm/mach-shmobile/setup-sh73a0.c          |   39 +++++++++-
 12 files changed, 303 insertions(+), 3 deletions(-)
 create mode 100644 arch/arm/boot/dts/sh73a0-kzm9g-reference.dts
 create mode 100644 arch/arm/boot/dts/sh73a0-reference.dtsi
 create mode 100644 arch/arm/mach-shmobile/board-kzm9g-reference.c

From: Simon Horman <[email protected]>

This allows the GIC interrupt controller of the sh73a0 SoC to be initialised using a flattened device tree blob.

It does not allow the INTC interrupt controller which is also present on the sh73a0 SoC to be enabled via device tree. Nor does it handle sharing of interrupts between the GIC and INTC interrupt controllers.

This limits the usefulness of this code to applications which only wish to access devices which use interrupts that can be handled by the GIC interrupt controller. Other applications should, for now, continue using non-device tree initialisation of the sh72a0 interrupt controllers.

---
 arch/arm/boot/dts/sh73a0.dtsi                |    9 +++++++++
 arch/arm/mach-shmobile/include/mach/common.h |    1 +
 arch/arm/mach-shmobile/intc-sh73a0.c         |   14 ++++++++++++++
 3 files changed, 24 insertions(+)

index 6b374ff..77c8e43 100644
@@ -29,4 +29,13 @@
 		gpio-controller;
 		#gpio-cells = <2>;
 	};
+
+	gic: interrupt-controller at f0001000 {
+		compatible = "arm,cortex-a9-gic";
+		#interrupt-cells = <3>;
+		#address-cells = <1>;
+		interrupt-controller;
+		reg = <0xf0001000 0x1000>,
+		      <0xf0000100 0x100>;
+	};
 };

index d47e215..b50447e 100644
@@ -49,6 +49,7 @@ extern struct clk sh7372_extal1_clk;
 extern struct clk sh7372_extal2_clk;
 
 extern void sh73a0_init_irq(void);
+extern void sh73a0_init_irq_dt(void);
 extern void sh73a0_map_io(void);
 extern void sh73a0_add_early_devices(void);
 extern void sh73a0_add_standard_devices(void);

index f0c5e51..e492350 100644
@@ -21,6 +21,7 @@
 #include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/irq.h>
+#include <linux/of_irq.h>
 #include <linux/io.h>
 #include <linux/sh_intc.h>
 #include <mach/intc.h>

@@ -464,3 +465,16 @@ void __init sh73a0_init_irq(void)
 	sh73a0_pint1_cascade.handler = sh73a0_pint1_demux;
 	setup_irq(gic_spi(34), &sh73a0_pint1_cascade);
 }
+
+#ifdef CONFIG_OF
+static const struct of_device_id irq_of_match[] __initconst = {
+	{ .compatible = "arm,cortex-a9-gic", .data = gic_of_init, },
+	{ },
+};
+
+void __init sh73a0_init_irq_dt(void)
+{
+	of_irq_init(irq_of_match);
+	gic_arch_extn.irq_set_wake = sh73a0_set_wake;
+}
+#endif

1.7.10.4

From: Simon Horman <[email protected]>

Allow a minimal setup of the sh73a0 SoC using a flattened device tree.

* Configure the i2c controllers using a flattened device tree.

SCI serial controller and CMT clock source, whose drivers do not yet support configuration using a flattened device tree, are still configured using C code in order to allow booting of a board with this SoC.

---

v2
* Add extra entries to clock-sh73a0.c:lookups[] and
remove auxdata. Ultimtely the clocks will be described
in DT, but the code isn't there yet.
* Use shmobile_setup_delay() and perform late initialisation of clocks

---
 arch/arm/boot/dts/sh73a0.dtsi                |   60 ++++++++++++++++++++++++++
 arch/arm/mach-shmobile/clock-sh73a0.c        |    5 +++
 arch/arm/mach-shmobile/include/mach/common.h |    2 +
 arch/arm/mach-shmobile/setup-sh73a0.c        |   39 ++++++++++++++++-
 4 files changed, 105 insertions(+), 1 deletion(-)

index 77c8e43..fc7f0fd 100644
@@ -38,4 +38,64 @@
 		reg = <0xf0001000 0x1000>,
 		      <0xf0000100 0x100>;
 	};
+
+	i2c0: i2c at 0xe6820000 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "renesas,rmobile-iic";
+		reg = <0xe6820000 0x425>;
+		interrupt-parent = <&gic>;
+		interrupts = <0 167 0x4
+			      0 168 0x4
+			      0 169 0x4
+			      0 170 0x4>;
+	};
+
+	i2c1: i2c at 0xe6822000 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "renesas,rmobile-iic";
+		reg = <0xe6822000 0x425>;
+		interrupt-parent = <&gic>;
+		interrupts = <0 51 0x4
+			      0 52 0x4
+			      0 53 0x4
+			      0 54 0x4>;
+	};
+
+	i2c2: i2c at 0xe6824000 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "renesas,rmobile-iic";
+		reg = <0xe6824000 0x425>;
+		interrupt-parent = <&gic>;
+		interrupts = <0 171 0x4
+			      0 172 0x4
+			      0 173 0x4
+			      0 174 0x4>;
+	};
+
+	i2c3: i2c at 0xe6826000 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "renesas,rmobile-iic";
+		reg = <0xe6826000 0x425>;
+		interrupt-parent = <&gic>;
+		interrupts = <0 183 0x4
+			      0 184 0x4
+			      0 185 0x4
+			      0 186 0x4>;
+	};
+
+	i2c4: i2c at 0xe6828000 {
+		#address-cells = <1>;
+		#size-cells = <0>;
+		compatible = "renesas,rmobile-iic";
+		reg = <0xe6828000 0x425>;
+		interrupt-parent = <&gic>;
+		interrupts = <0 187 0x4
+			      0 188 0x4
+			      0 189 0x4
+			      0 190 0x4>;
+	};
 };

index 516ff7f..8bc7a2b 100644
@@ -545,6 +545,7 @@ static struct clk_lookup lookups[] = {
 
 	/* MSTP32 clocks */
 	CLKDEV_DEV_ID("i2c-sh_mobile.2", &mstp_clks[MSTP001]), /* I2C2 */
+	CLKDEV_DEV_ID("e6824000.i2c", &mstp_clks[MSTP001]), /* I2C2 */
 	CLKDEV_DEV_ID("sh_mobile_ceu.1", &mstp_clks[MSTP129]), /* CEU1 */
 	CLKDEV_DEV_ID("sh-mobile-csi2.1", &mstp_clks[MSTP128]), /* CSI2-RX1 */
 	CLKDEV_DEV_ID("sh_mobile_ceu.0", &mstp_clks[MSTP127]), /* CEU0 */

@@ -553,6 +554,7 @@ static struct clk_lookup lookups[] = {
 	CLKDEV_DEV_ID("sh_tmu.1", &mstp_clks[MSTP125]), /* TMU01 */
 	CLKDEV_DEV_ID("sh-mipi-dsi.0", &mstp_clks[MSTP118]), /* DSITX */
 	CLKDEV_DEV_ID("i2c-sh_mobile.0", &mstp_clks[MSTP116]), /* I2C0 */
+	CLKDEV_DEV_ID("e6820000.i2c", &mstp_clks[MSTP116]), /* I2C0 */
 	CLKDEV_DEV_ID("sh_mobile_lcdc_fb.0", &mstp_clks[MSTP100]), /* LCDC0 */
 	CLKDEV_DEV_ID("sh-sci.7", &mstp_clks[MSTP219]), /* SCIFA7 */
 	CLKDEV_DEV_ID("sh-dma-engine.0", &mstp_clks[MSTP218]), /* SY-DMAC */

@@ -569,6 +571,7 @@ static struct clk_lookup lookups[] = {
 	CLKDEV_DEV_ID("sh_fsi2", &mstp_clks[MSTP328]), /* FSI */
 	CLKDEV_DEV_ID("sh_irda.0", &mstp_clks[MSTP325]), /* IrDA */
 	CLKDEV_DEV_ID("i2c-sh_mobile.1", &mstp_clks[MSTP323]), /* I2C1 */
+	CLKDEV_DEV_ID("e6822000.i2c", &mstp_clks[MSTP323]), /* I2C1 */
 	CLKDEV_DEV_ID("renesas_usbhs", &mstp_clks[MSTP322]), /* USB */
 	CLKDEV_DEV_ID("sh_mobile_sdhi.0", &mstp_clks[MSTP314]), /* SDHI0 */
 	CLKDEV_DEV_ID("sh_mobile_sdhi.1", &mstp_clks[MSTP313]), /* SDHI1 */

@@ -579,7 +582,9 @@ static struct clk_lookup lookups[] = {
 	CLKDEV_DEV_ID("leds-renesas-tpu.30", &mstp_clks[MSTP301]), /* TPU3 */
 	CLKDEV_DEV_ID("leds-renesas-tpu.41", &mstp_clks[MSTP300]), /* TPU4 */
 	CLKDEV_DEV_ID("i2c-sh_mobile.3", &mstp_clks[MSTP411]), /* I2C3 */
+	CLKDEV_DEV_ID("e6826000.i2c", &mstp_clks[MSTP411]), /* I2C3 */
 	CLKDEV_DEV_ID("i2c-sh_mobile.4", &mstp_clks[MSTP410]), /* I2C4 */
+	CLKDEV_DEV_ID("e6828000.i2c", &mstp_clks[MSTP410]), /* I2C4 */
 	CLKDEV_DEV_ID("sh_keysc.0", &mstp_clks[MSTP403]), /* KEYSC */
 };
 

index b50447e..06b905e 100644
@@ -52,7 +52,9 @@ extern void sh73a0_init_irq(void);
 extern void sh73a0_init_irq_dt(void);
 extern void sh73a0_map_io(void);
 extern void sh73a0_add_early_devices(void);
+extern void sh73a0_add_early_devices_dt(void);
 extern void sh73a0_add_standard_devices(void);
+extern void sh73a0_add_standard_devices_dt(void);
 extern void sh73a0_clock_init(void);
 extern void sh73a0_pinmux_init(void);
 extern struct clk sh73a0_extal1_clk;

index eab1bae..f8bdac4 100644
@@ -23,6 +23,7 @@
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/platform_device.h>
+#include <linux/of_platform.h>
 #include <linux/delay.h>
 #include <linux/input.h>
 #include <linux/io.h>

@@ -35,6 +36,7 @@
 #include <mach/irqs.h>
 #include <mach/sh73a0.h>
 #include <mach/common.h>
+#include <asm/hardware/gic.h>
 #include <asm/mach-types.h>
 #include <asm/mach/map.h>
 #include <asm/mach/arch.h>

@@ -779,7 +781,7 @@ static struct platform_device pmu_device = {
 	.resource	= pmu_resources,
 };
 
-static struct platform_device *sh73a0_early_devices[] __initdata = {
+static struct platform_device *sh73a0_early_devices_dt[] __initdata = {
 	&scif0_device,
 	&scif1_device,
 	&scif2_device,

@@ -790,6 +792,9 @@ static struct platform_device *sh73a0_early_devices[] __initdata = {
 	&scif7_device,
 	&scif8_device,
 	&cmt10_device,
+};
+
+static struct platform_device *sh73a0_early_devices[] __initdata = {
 	&tmu00_device,
 	&tmu01_device,
 };

@@ -812,6 +817,8 @@ void __init sh73a0_add_standard_devices(void)
 	/* Clear software reset bit on SY-DMAC module */
 	__raw_writel(__raw_readl(SRCR2) & ~(1 << 18), SRCR2);
 
+	platform_add_devices(sh73a0_early_devices_dt,
+			    ARRAY_SIZE(sh73a0_early_devices_dt));
 	platform_add_devices(sh73a0_early_devices,
 			    ARRAY_SIZE(sh73a0_early_devices));
 	platform_add_devices(sh73a0_late_devices,

@@ -830,6 +837,8 @@ static void __init sh73a0_earlytimer_init(void)
 
 void __init sh73a0_add_early_devices(void)
 {
+	early_platform_add_devices(sh73a0_early_devices_dt,
+				   ARRAY_SIZE(sh73a0_early_devices_dt));
 	early_platform_add_devices(sh73a0_early_devices,
 				   ARRAY_SIZE(sh73a0_early_devices));
 

@@ -839,3 +848,31 @@ void __init sh73a0_add_early_devices(void)
 	/* override timer setup with soc-specific code */
 	shmobile_timer.init = sh73a0_earlytimer_init;
 }
+
+#ifdef CONFIG_USE_OF
+static const struct of_dev_auxdata sh73a0_auxdata_lookup[] __initconst = {
+	{},
+};
+
+void __init sh73a0_add_early_devices_dt(void)
+{
+	shmobile_setup_delay(1196, 44, 46); /* Cortex-A9 @ 1196MHz */
+
+	early_platform_add_devices(sh73a0_early_devices_dt,
+				   ARRAY_SIZE(sh73a0_early_devices_dt));
+
+	/* setup early console here as well */
+	shmobile_setup_console();
+}
+
+void __init sh73a0_add_standard_devices_dt(void)
+{
+	/* clocks are setup late during boot in the case of DT */
+	sh73a0_clock_init();
+
+	platform_add_devices(sh73a0_early_devices_dt,
+			     ARRAY_SIZE(sh73a0_early_devices_dt));
+	of_platform_populate(NULL, of_default_bus_match_table,
+			     sh73a0_auxdata_lookup, NULL);
+}
+#endif /* CONFIG_USE_OF */

1.7.10.4

From: Simon Horman <[email protected]>

This device also requires a voltage regulator which should be defined in a board-specific maner. An example dts snipped follows.

/ {
	fixedregulator1v8: fixedregulator at 0 {
		compatible = "regulator-fixed";
		regulator-name = "fixed-1.8V";
		regulator-min-microvolt = <1800000>;
		regulator-max-microvolt = <1800000>;
	};
};

&mmcif {
	vmmc-supply = <&fixedregulator1v8>;
	vqmmc-supply = <&fixedregulator1v8>;
};

---

v2
* Removed SDHI intitialisation as the driver needs updating first
* Moved MMC DT from sh73a0.dtsi to sh73a0-reference.dtsi as it is not appropriate for use by sh73a0-kzm9g.dts yet. This is because sh73a0-kzm9g.dts and board-kzm9g.c use both the GIC and INTC interrupt controllers to provide access to a rich set of devices. This is achieved by initilising the interrupt controllers using C code. Work on allowing the INC controller to be initialised using DT is in progress, however, until that is complete only GIC may be initialised using DT.
* Add extra entries to clock-sh73a0.c:lookups[] and remove auxdata. Ultimtely the clocks will be described in DT, but the code isn't there yet.

---
 arch/arm/boot/dts/sh73a0-reference.dtsi |   24 ++++++++++++++++++++++++
 arch/arm/mach-shmobile/clock-sh73a0.c   |    1 +
 2 files changed, 25 insertions(+)
 create mode 100644 arch/arm/boot/dts/sh73a0-reference.dtsi

new file mode 100644
index 0000000..d4bb012
@@ -0,0 +1,24 @@
+/*
+ * Device Tree Source for the SH73A0 SoC
+ *
+ * Copyright (C) 2012 Renesas Solutions Corp.
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2.  This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+
+/include/ "sh73a0.dtsi"
+
+/ {
+	compatible = "renesas,sh73a0";
+
+	mmcif: mmcif at 0x10010000 {
+		compatible = "renesas,sh-mmcif";
+		reg = <0xe6bd0000 0x100>;
+		interrupt-parent = <&gic>;
+		interrupts = <0 140 0x4
+			      0 141 0x4>;
+		reg-io-width = <4>;
+	};
+};

index 8bc7a2b..0908123 100644
@@ -576,6 +576,7 @@ static struct clk_lookup lookups[] = {
 	CLKDEV_DEV_ID("sh_mobile_sdhi.0", &mstp_clks[MSTP314]), /* SDHI0 */
 	CLKDEV_DEV_ID("sh_mobile_sdhi.1", &mstp_clks[MSTP313]), /* SDHI1 */
 	CLKDEV_DEV_ID("sh_mmcif.0", &mstp_clks[MSTP312]), /* MMCIF0 */
+	CLKDEV_DEV_ID("e6bd0000.mmcif", &mstp_clks[MSTP312]), /* MMCIF0 */
 	CLKDEV_DEV_ID("sh_mobile_sdhi.2", &mstp_clks[MSTP311]), /* SDHI2 */
 	CLKDEV_DEV_ID("leds-renesas-tpu.12", &mstp_clks[MSTP303]), /* TPU1 */
 	CLKDEV_DEV_ID("leds-renesas-tpu.21", &mstp_clks[MSTP302]), /* TPU2 */

1.7.10.4

Hi Simon,

Thank you for the patch.

Could you please add this as a TO-DO item either in the commit message or in arch/arm/mach-shmobile/clock-sh73a0.c ?

Regards,

Laurent Pinchart

Sure, will do.

This is needed to initialise the MMCIF device in the absence of platform data.

---
 arch/arm/configs/kzm9g_defconfig |    1 +
 1 file changed, 1 insertion(+)

index c88b578..6d7fd53 100644
@@ -83,6 +83,7 @@ CONFIG_I2C_CHARDEV=y
 CONFIG_I2C_SH_MOBILE=y
 CONFIG_GPIO_PCF857X=y
 # CONFIG_HWMON is not set
+CONFIG_REGULATOR=y
 CONFIG_FB=y
 CONFIG_FB_SH_MOBILE_LCDC=y
 CONFIG_FRAMEBUFFER_CONSOLE=y

1.7.10.4

From: Simon Horman <[email protected]>

Provide alternate board code for the kzm9g to demonstrate how DT may be used given the current state of driver device tree support. This is intended to act as a reference for mach-shmobile developers.

Some notes:

* Brings up the GIC interrupt handler using device tree
* Brings up the following device using device tree:
- MMCIF (MMC)
* Does not bring up the INTC interrupt controller at all, thus external devices may not be used
* Uses existing C code and not device tree to initialise the following, which are needed for a working board:
- SCIF (Serial)
- CMT (Clock)
- PFC (GPIO)

To use this alternate board code instead of the normal board code, CONFIG_MACH_KZM9G_REFERENCE should be selected in the kernel config. And the sh73a0-kzm9g-reference.dtb flattened device tree blob should be used.

---

v2
* Do not initialise touchscreen, it requires the INTC interrupt controller but for now this configuration only has the GIC interrupt controller.
* Define mmcif and sdhi in SoC dtsi and reference in board dts.
* Do not initialise SDHI, the driver needs to be updated

---
 arch/arm/boot/dts/Makefile                     |    3 +-
 arch/arm/boot/dts/sh73a0-kzm9g-reference.dts   |   37 ++++++++++
 arch/arm/mach-shmobile/Kconfig                 |   10 +++
 arch/arm/mach-shmobile/Makefile                |    8 ++-
 arch/arm/mach-shmobile/board-kzm9g-reference.c |   92 ++++++++++++++++++++++++
 5 files changed, 148 insertions(+), 2 deletions(-)
 create mode 100644 arch/arm/boot/dts/sh73a0-kzm9g-reference.dts
 create mode 100644 arch/arm/mach-shmobile/board-kzm9g-reference.c

index f37cf9f..c606375 100644
@@ -77,7 +77,8 @@ dtb-$(CONFIG_ARCH_PRIMA2) += prima2-evb.dtb
 dtb-$(CONFIG_ARCH_U8500) += snowball.dtb
 dtb-$(CONFIG_ARCH_SHMOBILE) += emev2-kzm9d.dtb \
 	r8a7740-armadillo800eva.dtb \
-	sh73a0-kzm9g.dtb
+	sh73a0-kzm9g.dtb \
+	sh73a0-kzm9g-reference.dtb
 dtb-$(CONFIG_ARCH_SPEAR13XX) += spear1310-evb.dtb \
 	spear1340-evb.dtb
 dtb-$(CONFIG_ARCH_SPEAR3XX)+= spear300-evb.dtb \

new file mode 100644
index 0000000..588016e
@@ -0,0 +1,37 @@
+/*
+ * Device Tree Source for the KZM-A9-GT board
+ *
+ * Copyright (C) 2012 Horms Solutions Ltd.
+ *
+ * Based on sh73a0-kzm9g.dts
+ * Copyright (C) 2012 Renesas Solutions Corp.
+ *
+ * This file is licensed under the terms of the GNU General Public License
+ * version 2.  This program is licensed "as is" without any warranty of any
+ * kind, whether express or implied.
+ */
+
+/dts-v1/;
+/include/ "sh73a0-reference.dtsi"
+
+/ {
+	model = "KZM-A9-GT";
+	compatible = "renesas,kzm9g-reference", "renesas,sh73a0";
+
+	memory {
+		device_type = "memory";
+		reg = <0x41000000 0x1e800000>;
+	};
+
+	fixedregulator1v8: fixedregulator at 0 {
+		compatible = "regulator-fixed";
+		regulator-name = "fixed-1.8V";
+		regulator-min-microvolt = <1800000>;
+		regulator-max-microvolt = <1800000>;
+	};
+};
+
+&mmcif {
+	vmmc-supply = <&fixedregulator1v8>;
+	vqmmc-supply = <&fixedregulator1v8>;
+};

index 8ae100c..ca95c2b 100644
@@ -136,6 +136,16 @@ config MACH_KZM9G
 	select SND_SOC_AK4642 if SND_SIMPLE_CARD
 	select USE_OF
 
+config MACH_KZM9G_REFERENCE
+	bool "KZM-A9-GT board - Reference Device Tree Implementation"
+	depends on MACH_KZM9G
+	---help---
+	   Use reference implementation of KZM-A9-GT board support
+	   which makes as greater use of device tree at the expense
+	   of not supporting a number of devices.
+
+	   This is intended to aid developers
+
 comment "SH-Mobile System Configuration"
 
 config CPU_HAS_INTEVT

index e3556c6..7ffa428 100644
@@ -51,7 +51,13 @@ obj-$(CONFIG_MACH_BONITO)	+= board-bonito.o
 obj-$(CONFIG_MACH_MARZEN)	+= board-marzen.o
 obj-$(CONFIG_MACH_ARMADILLO800EVA)	+= board-armadillo800eva.o
 obj-$(CONFIG_MACH_KZM9D)	+= board-kzm9d.o
-obj-$(CONFIG_MACH_KZM9G)	+= board-kzm9g.o
+ifeq ($(CONFIG_MACH_KZM9G),y)
+ifeq ($(CONFIG_MACH_KZM9G_REFERENCE),y)
+obj-y	+= board-kzm9g-reference.o
+else
+obj-y	+= board-kzm9g.o
+endif
+endif
 
 # Framework support
 obj-$(CONFIG_SMP)		+= $(smp-y)

1.7.10.4