tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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 void __init tango_clocksource_init(struct device_node *np)
23{
24 struct clk *clk;
25 int xtal_freq, ret;
26
27 xtal_in_cnt = of_iomap(np, 0);
28 if (xtal_in_cnt == NULL) {
29 pr_err("%s: invalid address\n", np->full_name);
30 return;
31 }
32
33 clk = of_clk_get(np, 0);
34 if (IS_ERR(clk)) {
35 pr_err("%s: invalid clock\n", np->full_name);
36 return;
37 }
38
39 xtal_freq = clk_get_rate(clk);
40 delay_timer.freq = xtal_freq;
41 delay_timer.read_current_timer = read_xtal_counter;
42
43 ret = clocksource_mmio_init(xtal_in_cnt, "tango-xtal", xtal_freq, 350,
44 32, clocksource_mmio_readl_up);
45 if (!ret) {
46 pr_err("%s: registration failed\n", np->full_name);
47 return;
48 }
49
50 sched_clock_register(read_sched_clock, 32, xtal_freq);
51 register_current_timer_delay(&delay_timer);
52}
53
54CLOCKSOURCE_OF_DECLARE(tango, "sigma,tick-counter", tango_clocksource_init);