1/*
2 *  DS1287 clockevent driver
3 *
4 *  Copyright (C) 2008	Yoichi Yuasa <yuasa@linux-mips.org>
5 *
6 *  This program is free software; you can redistribute it and/or modify
7 *  it under the terms of the GNU General Public License as published by
8 *  the Free Software Foundation; either version 2 of the License, or
9 *  (at your option) any later version.
10 *
11 *  This program is distributed in the hope that it will be useful,
12 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
13 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
14 *  GNU General Public License for more details.
15 *
16 *  You should have received a copy of the GNU General Public License
17 *  along with this program; if not, write to the Free Software
18 *  Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20#include <linux/clockchips.h>
21#include <linux/init.h>
22#include <linux/interrupt.h>
23#include <linux/mc146818rtc.h>
24#include <linux/irq.h>
25
26#include <asm/time.h>
27
28int ds1287_timer_state(void)
29{
30	return (CMOS_READ(RTC_REG_C) & RTC_PF) != 0;
31}
32
33int ds1287_set_base_clock(unsigned int hz)
34{
35	u8 rate;
36
37	switch (hz) {
38	case 128:
39		rate = 0x9;
40		break;
41	case 256:
42		rate = 0x8;
43		break;
44	case 1024:
45		rate = 0x6;
46		break;
47	default:
48		return -EINVAL;
49	}
50
51	CMOS_WRITE(RTC_REF_CLCK_32KHZ | rate, RTC_REG_A);
52
53	return 0;
54}
55
56static int ds1287_set_next_event(unsigned long delta,
57				 struct clock_event_device *evt)
58{
59	return -EINVAL;
60}
61
62static void ds1287_set_mode(enum clock_event_mode mode,
63			    struct clock_event_device *evt)
64{
65	u8 val;
66
67	spin_lock(&rtc_lock);
68
69	val = CMOS_READ(RTC_REG_B);
70
71	switch (mode) {
72	case CLOCK_EVT_MODE_PERIODIC:
73		val |= RTC_PIE;
74		break;
75	default:
76		val &= ~RTC_PIE;
77		break;
78	}
79
80	CMOS_WRITE(val, RTC_REG_B);
81
82	spin_unlock(&rtc_lock);
83}
84
85static void ds1287_event_handler(struct clock_event_device *dev)
86{
87}
88
89static struct clock_event_device ds1287_clockevent = {
90	.name		= "ds1287",
91	.features	= CLOCK_EVT_FEAT_PERIODIC,
92	.set_next_event = ds1287_set_next_event,
93	.set_mode	= ds1287_set_mode,
94	.event_handler	= ds1287_event_handler,
95};
96
97static irqreturn_t ds1287_interrupt(int irq, void *dev_id)
98{
99	struct clock_event_device *cd = &ds1287_clockevent;
100
101	/* Ack the RTC interrupt. */
102	CMOS_READ(RTC_REG_C);
103
104	cd->event_handler(cd);
105
106	return IRQ_HANDLED;
107}
108
109static struct irqaction ds1287_irqaction = {
110	.handler	= ds1287_interrupt,
111	.flags		= IRQF_PERCPU | IRQF_TIMER,
112	.name		= "ds1287",
113};
114
115int __init ds1287_clockevent_init(int irq)
116{
117	struct clock_event_device *cd;
118
119	cd = &ds1287_clockevent;
120	cd->rating = 100;
121	cd->irq = irq;
122	clockevent_set_clock(cd, 32768);
123	cd->max_delta_ns = clockevent_delta2ns(0x7fffffff, cd);
124	cd->min_delta_ns = clockevent_delta2ns(0x300, cd);
125	cd->cpumask = cpumask_of(0);
126
127	clockevents_register_device(&ds1287_clockevent);
128
129	return setup_irq(irq, &ds1287_irqaction);
130}
131