at91: Add support for the AT91 slow clock controller

This is available on AT91SAM9G45. Add the peripheral address and flag
definitions.

Signed-off-by: Andre Renaud <andre@designa-electronics.com>
Signed-off-by: Simon Glass <sjg@chromium.org>
Reviewed-by: Heiko Schocher <hs@denx.de>
Reviewed-by: Andreas Bießmann <andreas@biessmann.org>

arch/arm/mach-at91/include/mach/at91_sck.h

@@ -0,0 +1,21 @@
+/*
+ * Copyright (C) 2016 Google, Inc
+ * Written by Simon Glass <sjg@chromium.org>
+ *
+ * SPDX-License-Identifier:	GPL-2.0+
+ */
+
+#ifndef AT91_SCK_H
+#define AT91_SCK_H
+
+/*
+ * SCKCR flags
+ */
+#define AT91SAM9G45_SCKCR_RCEN	    (1 << 0)	/* RC Oscillator Enable */
+#define AT91SAM9G45_SCKCR_OSC32EN   (1 << 1)	/* 32kHz Oscillator Enable */
+#define AT91SAM9G45_SCKCR_OSC32BYP  (1 << 2)	/* 32kHz Oscillator Bypass */
+#define AT91SAM9G45_SCKCR_OSCSEL    (1 << 3)	/* Slow Clock Selector */
+#define		AT91SAM9G45_SCKCR_OSCSEL_RC	(0 << 3)
+#define		AT91SAM9G45_SCKCR_OSCSEL_32	(1 << 3)
+
+#endif

arch/arm/mach-at91/include/mach/at91sam9g45.h

@@ -109,6 +109,7 @@
 #define ATMEL_BASE_RTT		0xfffffd20
 #define ATMEL_BASE_PIT		0xfffffd30
 #define ATMEL_BASE_WDT		0xfffffd40
+#define ATMEL_BASE_SCKCR	0xfffffd50
 #define ATMEL_BASE_GPBR		0xfffffd60
 #define ATMEL_BASE_RTC		0xfffffdb0
 /* Reserved:	0xfffffdc0 - 0xffffffff */