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