1// SPDX-License-Identifier: GPL-2.0
 2#include <linux/clocksource.h>
 3#include <linux/sched_clock.h>
 4#include <linux/of_address.h>
 5#include <linux/printk.h>
 6#include <linux/delay.h>
 7#include <linux/init.h>
 8#include <linux/clk.h>
 9
10static void __iomem *xtal_in_cnt;
11static struct delay_timer delay_timer;
12
13static unsigned long notrace read_xtal_counter(void)
14{
15	return readl_relaxed(xtal_in_cnt);
16}
17
18static u64 notrace read_sched_clock(void)
19{
20	return read_xtal_counter();
21}
22
23static int __init tango_clocksource_init(struct device_node *np)
24{
25	struct clk *clk;
26	int xtal_freq, ret;
27
28	xtal_in_cnt = of_iomap(np, 0);
29	if (xtal_in_cnt == NULL) {
30		pr_err("%pOF: invalid address\n", np);
31		return -ENXIO;
32	}
33
34	clk = of_clk_get(np, 0);
35	if (IS_ERR(clk)) {
36		pr_err("%pOF: invalid clock\n", np);
37		return PTR_ERR(clk);
38	}
39
40	xtal_freq = clk_get_rate(clk);
41	delay_timer.freq = xtal_freq;
42	delay_timer.read_current_timer = read_xtal_counter;
43
44	ret = clocksource_mmio_init(xtal_in_cnt, "tango-xtal", xtal_freq, 350,
45				    32, clocksource_mmio_readl_up);
46	if (ret) {
47		pr_err("%pOF: registration failed\n", np);
48		return ret;
49	}
50
51	sched_clock_register(read_sched_clock, 32, xtal_freq);
52	register_current_timer_delay(&delay_timer);
53
54	return 0;
55}
56
57TIMER_OF_DECLARE(tango, "sigma,tick-counter", tango_clocksource_init);