diff options
Diffstat (limited to 'arch/mips/ddb5xxx/common/rtc_ds1386.c')
| -rw-r--r-- | arch/mips/ddb5xxx/common/rtc_ds1386.c | 164 |
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 00000000000..f5b11508ff2 --- /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; +} |