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 | |
15 | int ds1287_timer_state(void) |
16 | { |
17 | return (CMOS_READ(RTC_REG_C) & RTC_PF) != 0; |
18 | } |
19 | |
20 | int 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 | |
43 | static int ds1287_set_next_event(unsigned long delta, |
44 | struct clock_event_device *evt) |
45 | { |
46 | return -EINVAL; |
47 | } |
48 | |
49 | static 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 | |
63 | static 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 | |
77 | static void ds1287_event_handler(struct clock_event_device *dev) |
78 | { |
79 | } |
80 | |
81 | static 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 | |
91 | static 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 | |
103 | int __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 | |