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Diffstat (limited to 'arch/mips/ddb5xxx/common/rtc_ds1386.c')
-rw-r--r--arch/mips/ddb5xxx/common/rtc_ds1386.c164
1 files changed, 164 insertions, 0 deletions
diff --git a/arch/mips/ddb5xxx/common/rtc_ds1386.c b/arch/mips/ddb5xxx/common/rtc_ds1386.c
new file mode 100644
index 000000000000..f5b11508ff2f
--- /dev/null
+++ b/arch/mips/ddb5xxx/common/rtc_ds1386.c
@@ -0,0 +1,164 @@
+/*
+ * Copyright 2001 MontaVista Software Inc.
+ * Author: jsun@mvista.com or jsun@junsun.net
+ *
+ * arch/mips/ddb5xxx/common/rtc_ds1386.c
+ * low-level RTC hookups for s for Dallas 1396 chip.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or (at your
+ * option) any later version.
+ */
+
+
+/*
+ * This file exports a function, rtc_ds1386_init(), which expects an
+ * uncached base address as the argument. It will set the two function
+ * pointers expected by the MIPS generic timer code.
+ */
+
+#include <linux/types.h>
+#include <linux/time.h>
+#include <linux/bcd.h>
+
+#include <asm/time.h>
+#include <asm/addrspace.h>
+
+#include <asm/mc146818rtc.h>
+#include <asm/debug.h>
+
+#define EPOCH 2000
+
+#define READ_RTC(x) *(volatile unsigned char*)(rtc_base+x)
+#define WRITE_RTC(x, y) *(volatile unsigned char*)(rtc_base+x) = y
+
+static unsigned long rtc_base;
+
+static unsigned long
+rtc_ds1386_get_time(void)
+{
+ u8 byte;
+ u8 temp;
+ unsigned int year, month, day, hour, minute, second;
+
+ /* let us freeze external registers */
+ byte = READ_RTC(0xB);
+ byte &= 0x3f;
+ WRITE_RTC(0xB, byte);
+
+ /* read time data */
+ year = BCD2BIN(READ_RTC(0xA)) + EPOCH;
+ month = BCD2BIN(READ_RTC(0x9) & 0x1f);
+ day = BCD2BIN(READ_RTC(0x8));
+ minute = BCD2BIN(READ_RTC(0x2));
+ second = BCD2BIN(READ_RTC(0x1));
+
+ /* hour is special - deal with it later */
+ temp = READ_RTC(0x4);
+
+ /* enable time transfer */
+ byte |= 0x80;
+ WRITE_RTC(0xB, byte);
+
+ /* calc hour */
+ if (temp & 0x40) {
+ /* 12 hour format */
+ hour = BCD2BIN(temp & 0x1f);
+ if (temp & 0x20) hour += 12; /* PM */
+ } else {
+ /* 24 hour format */
+ hour = BCD2BIN(temp & 0x3f);
+ }
+
+ return mktime(year, month, day, hour, minute, second);
+}
+
+static int
+rtc_ds1386_set_time(unsigned long t)
+{
+ struct rtc_time tm;
+ u8 byte;
+ u8 temp;
+ u8 year, month, day, hour, minute, second;
+
+ /* let us freeze external registers */
+ byte = READ_RTC(0xB);
+ byte &= 0x3f;
+ WRITE_RTC(0xB, byte);
+
+ /* convert */
+ to_tm(t, &tm);
+
+
+ /* check each field one by one */
+ year = BIN2BCD(tm.tm_year - EPOCH);
+ if (year != READ_RTC(0xA)) {
+ WRITE_RTC(0xA, year);
+ }
+
+ temp = READ_RTC(0x9);
+ month = BIN2BCD(tm.tm_mon+1); /* tm_mon starts from 0 to 11 */
+ if (month != (temp & 0x1f)) {
+ WRITE_RTC( 0x9,
+ (month & 0x1f) | (temp & ~0x1f) );
+ }
+
+ day = BIN2BCD(tm.tm_mday);
+ if (day != READ_RTC(0x8)) {
+ WRITE_RTC(0x8, day);
+ }
+
+ temp = READ_RTC(0x4);
+ if (temp & 0x40) {
+ /* 12 hour format */
+ hour = 0x40;
+ if (tm.tm_hour > 12) {
+ hour |= 0x20 | (BIN2BCD(hour-12) & 0x1f);
+ } else {
+ hour |= BIN2BCD(tm.tm_hour);
+ }
+ } else {
+ /* 24 hour format */
+ hour = BIN2BCD(tm.tm_hour) & 0x3f;
+ }
+ if (hour != temp) WRITE_RTC(0x4, hour);
+
+ minute = BIN2BCD(tm.tm_min);
+ if (minute != READ_RTC(0x2)) {
+ WRITE_RTC(0x2, minute);
+ }
+
+ second = BIN2BCD(tm.tm_sec);
+ if (second != READ_RTC(0x1)) {
+ WRITE_RTC(0x1, second);
+ }
+
+ return 0;
+}
+
+void
+rtc_ds1386_init(unsigned long base)
+{
+ unsigned char byte;
+
+ /* remember the base */
+ rtc_base = base;
+ db_assert((rtc_base & 0xe0000000) == KSEG1);
+
+ /* turn on RTC if it is not on */
+ byte = READ_RTC(0x9);
+ if (byte & 0x80) {
+ byte &= 0x7f;
+ WRITE_RTC(0x9, byte);
+ }
+
+ /* enable time transfer */
+ byte = READ_RTC(0xB);
+ byte |= 0x80;
+ WRITE_RTC(0xB, byte);
+
+ /* set the function pointers */
+ rtc_get_time = rtc_ds1386_get_time;
+ rtc_set_time = rtc_ds1386_set_time;
+}