1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * DS1287 clockevent driver
4 *
5 * Copyright (C) 2008 Yoichi Yuasa <yuasa@linux-mips.org>
6 */
7#include <linux/clockchips.h>
8#include <linux/init.h>
9#include <linux/interrupt.h>
10#include <linux/mc146818rtc.h>
11#include <linux/irq.h>
12
13#include <asm/time.h>
14
15int ds1287_timer_state(void)
16{
17 return (CMOS_READ(RTC_REG_C) & RTC_PF) != 0;
18}
19
20int ds1287_set_base_clock(unsigned int hz)
21{
22 u8 rate;
23
24 switch (hz) {
25 case 128:
26 rate = 0x9;
27 break;
28 case 256:
29 rate = 0x8;
30 break;
31 case 1024:
32 rate = 0x6;
33 break;
34 default:
35 return -EINVAL;
36 }
37
38 CMOS_WRITE(RTC_REF_CLCK_32KHZ | rate, RTC_REG_A);
39
40 return 0;
41}
42
43static int ds1287_set_next_event(unsigned long delta,
44 struct clock_event_device *evt)
45{
46 return -EINVAL;
47}
48
49static int ds1287_shutdown(struct clock_event_device *evt)
50{
51 u8 val;
52
53 spin_lock(lock: &rtc_lock);
54
55 val = CMOS_READ(RTC_REG_B);
56 val &= ~RTC_PIE;
57 CMOS_WRITE(val, RTC_REG_B);
58
59 spin_unlock(lock: &rtc_lock);
60 return 0;
61}
62
63static int ds1287_set_periodic(struct clock_event_device *evt)
64{
65 u8 val;
66
67 spin_lock(lock: &rtc_lock);
68
69 val = CMOS_READ(RTC_REG_B);
70 val |= RTC_PIE;
71 CMOS_WRITE(val, RTC_REG_B);
72
73 spin_unlock(lock: &rtc_lock);
74 return 0;
75}
76
77static void ds1287_event_handler(struct clock_event_device *dev)
78{
79}
80
81static struct clock_event_device ds1287_clockevent = {
82 .name = "ds1287",
83 .features = CLOCK_EVT_FEAT_PERIODIC,
84 .set_next_event = ds1287_set_next_event,
85 .set_state_shutdown = ds1287_shutdown,
86 .set_state_periodic = ds1287_set_periodic,
87 .tick_resume = ds1287_shutdown,
88 .event_handler = ds1287_event_handler,
89};
90
91static irqreturn_t ds1287_interrupt(int irq, void *dev_id)
92{
93 struct clock_event_device *cd = &ds1287_clockevent;
94
95 /* Ack the RTC interrupt. */
96 CMOS_READ(RTC_REG_C);
97
98 cd->event_handler(cd);
99
100 return IRQ_HANDLED;
101}
102
103int __init ds1287_clockevent_init(int irq)
104{
105 unsigned long flags = IRQF_PERCPU | IRQF_TIMER;
106 struct clock_event_device *cd;
107
108 cd = &ds1287_clockevent;
109 cd->rating = 100;
110 cd->irq = irq;
111 clockevent_set_clock(cd, 32768);
112 cd->max_delta_ns = clockevent_delta2ns(latch: 0x7fffffff, evt: cd);
113 cd->max_delta_ticks = 0x7fffffff;
114 cd->min_delta_ns = clockevent_delta2ns(latch: 0x300, evt: cd);
115 cd->min_delta_ticks = 0x300;
116 cd->cpumask = cpumask_of(0);
117
118 clockevents_register_device(dev: &ds1287_clockevent);
119
120 return request_irq(irq, handler: ds1287_interrupt, flags, name: "ds1287", NULL);
121}
122

source code of linux/arch/mips/kernel/cevt-ds1287.c