1 files changed, 58 insertions, 0 deletions
diff --git a/arch/arm/mach-footbridge/isa-rtc.c b/arch/arm/mach-footbridge/isa-rtc.c
new file mode 100644
index 000000000..b8f741a3a
--- /dev/null
+++ b/arch/arm/mach-footbridge/isa-rtc.c
@@ -0,0 +1,58 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *  arch/arm/mach-footbridge/isa-rtc.c
+ *
+ *  Copyright (C) 1998 Russell King.
+ *  Copyright (C) 1998 Phil Blundell
+ *
+ * CATS has a real-time clock, though the evaluation board doesn't.
+ *
+ * Changelog:
+ *  21-Mar-1998	RMK	Created
+ *  27-Aug-1998	PJB	CATS support
+ *  28-Dec-1998	APH	Made leds optional
+ *  20-Jan-1999	RMK	Started merge of EBSA285, CATS and NetWinder
+ *  16-Mar-1999	RMK	More support for EBSA285-like machines with RTCs in
+ */
+
+#define RTC_PORT(x)		(0x70+(x))
+#define RTC_ALWAYS_BCD		0
+
+#include <linux/init.h>
+#include <linux/mc146818rtc.h>
+#include <linux/bcd.h>
+#include <linux/io.h>
+
+#include "common.h"
+
+void __init isa_rtc_init(void)
+{
+	int reg_d, reg_b;
+
+	/*
+	 * Probe for the RTC.
+	 */
+	reg_d = CMOS_READ(RTC_REG_D);
+
+	/*
+	 * make sure the divider is set
+	 */
+	CMOS_WRITE(RTC_REF_CLCK_32KHZ, RTC_REG_A);
+
+	/*
+	 * Set control reg B
+	 *   (24 hour mode, update enabled)
+	 */
+	reg_b = CMOS_READ(RTC_REG_B) & 0x7f;
+	reg_b |= 2;
+	CMOS_WRITE(reg_b, RTC_REG_B);
+
+	if ((CMOS_READ(RTC_REG_A) & 0x7f) == RTC_REF_CLCK_32KHZ &&
+	    CMOS_READ(RTC_REG_B) == reg_b) {
+		/*
+		 * We have a RTC.  Check the battery
+		 */
+		if ((reg_d & 0x80) == 0)
+			printk(KERN_WARNING "RTC: *** warning: CMOS battery bad\n");
+	}
+}