summaryrefslogtreecommitdiffstats
path: root/arch/arm/mach-footbridge/isa-rtc.c
diff options
context:
space:
mode:
Diffstat (limited to 'arch/arm/mach-footbridge/isa-rtc.c')
-rw-r--r--arch/arm/mach-footbridge/isa-rtc.c58
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");
+ }
+}