| // 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"); |
| } |
| } |