1#include <linux/clocksource.h>
2#include <linux/sched_clock.h>
3#include <linux/of_address.h>
4#include <linux/printk.h>
5#include <linux/delay.h>
6#include <linux/init.h>
7#include <linux/clk.h>
8
9static void __iomem *xtal_in_cnt;
10static struct delay_timer delay_timer;
11
12static unsigned long notrace read_xtal_counter(void)
13{
14	return readl_relaxed(xtal_in_cnt);
15}
16
17static u64 notrace read_sched_clock(void)
18{
19	return read_xtal_counter();
20}
21
22static cycle_t read_clocksource(struct clocksource *cs)
23{
24	return read_xtal_counter();
25}
26
27static struct clocksource tango_xtal = {
28	.name	= "tango-xtal",
29	.rating	= 350,
30	.read	= read_clocksource,
31	.mask	= CLOCKSOURCE_MASK(32),
32	.flags	= CLOCK_SOURCE_IS_CONTINUOUS,
33};
34
35static void __init tango_clocksource_init(struct device_node *np)
36{
37	struct clk *clk;
38	int xtal_freq, ret;
39
40	xtal_in_cnt = of_iomap(np, 0);
41	if (xtal_in_cnt == NULL) {
42		pr_err("%s: invalid address\n", np->full_name);
43		return;
44	}
45
46	clk = of_clk_get(np, 0);
47	if (IS_ERR(clk)) {
48		pr_err("%s: invalid clock\n", np->full_name);
49		return;
50	}
51
52	xtal_freq = clk_get_rate(clk);
53	delay_timer.freq = xtal_freq;
54	delay_timer.read_current_timer = read_xtal_counter;
55
56	ret = clocksource_register_hz(&tango_xtal, xtal_freq);
57	if (ret != 0) {
58		pr_err("%s: registration failed\n", np->full_name);
59		return;
60	}
61
62	sched_clock_register(read_sched_clock, 32, xtal_freq);
63	register_current_timer_delay(&delay_timer);
64}
65
66CLOCKSOURCE_OF_DECLARE(tango, "sigma,tick-counter", tango_clocksource_init);
67