Files
android/arch/arm/mach-footbridge/isa-rtc.c
T
threeeye bc1d038eac REVVL 6 Pro kernel bring-up: full working tree snapshot (2026-09-12)
Squashed backup commit (no shallow-clone history issues) of
xiaomi-mt6833-dev/kernel_xiaomi_mt6833 (lineage-23.2 branch, upstream
commit 9eece662e) plus all fixes applied to get everpal_defconfig building
clean against a modern (GCC 15.2.0) toolchain -- see the previous commit
message on the lineage-23.2 branch (also in this repo history is not
available here since this is a squashed snapshot; full incremental history
lives in the local DL380 checkout and the upstream GitHub remote).

Upstream: https://github.com/xiaomi-mt6833-dev/kernel_xiaomi_mt6833 (lineage-23.2)
2026-09-12 13:36:46 +00:00

59 lines
1.2 KiB
C

// 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");
}
}