ARM: at91: pm: Add sama5d2 backup mode

The sama5d2 has a mode were it is possible to cut power to the SoC while
keeping the RAM in self refresh.
Resuming from that mode needs support in the firmware/bootloader.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Wenyou Yang <wenyou.yang@atmel.com>
diff --git a/arch/arm/mach-at91/sama5.c b/arch/arm/mach-at91/sama5.c
index 6d157d0..3d0bf95 100644
--- a/arch/arm/mach-at91/sama5.c
+++ b/arch/arm/mach-at91/sama5.c
@@ -34,7 +34,6 @@
 MACHINE_END
 
 static const char *const sama5_alt_dt_board_compat[] __initconst = {
-	"atmel,sama5d2",
 	"atmel,sama5d4",
 	NULL
 };
@@ -45,3 +44,21 @@
 	.dt_compat	= sama5_alt_dt_board_compat,
 	.l2c_aux_mask	= ~0UL,
 MACHINE_END
+
+static void __init sama5d2_init(void)
+{
+	of_platform_default_populate(NULL, NULL, NULL);
+	sama5d2_pm_init();
+}
+
+static const char *const sama5d2_compat[] __initconst = {
+	"atmel,sama5d2",
+	NULL
+};
+
+DT_MACHINE_START(sama5d2, "Atmel SAMA5")
+	/* Maintainer: Atmel */
+	.init_machine	= sama5d2_init,
+	.dt_compat	= sama5d2_compat,
+	.l2c_aux_mask	= ~0UL,
+MACHINE_END