tango_xtal.c
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#include <linux/clocksource.h>
#include <linux/sched_clock.h>
#include <linux/of_address.h>
#include <linux/printk.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/clk.h>
static void __iomem *xtal_in_cnt;
static struct delay_timer delay_timer;
static unsigned long notrace read_xtal_counter(void)
{
return readl_relaxed(xtal_in_cnt);
}
static u64 notrace read_sched_clock(void)
{
return read_xtal_counter();
}
static cycle_t read_clocksource(struct clocksource *cs)
{
return read_xtal_counter();
}
static struct clocksource tango_xtal = {
.name = "tango-xtal",
.rating = 350,
.read = read_clocksource,
.mask = CLOCKSOURCE_MASK(32),
.flags = CLOCK_SOURCE_IS_CONTINUOUS,
};
static void __init tango_clocksource_init(struct device_node *np)
{
struct clk *clk;
int xtal_freq, ret;
xtal_in_cnt = of_iomap(np, 0);
if (xtal_in_cnt == NULL) {
pr_err("%s: invalid address\n", np->full_name);
return;
}
clk = of_clk_get(np, 0);
if (IS_ERR(clk)) {
pr_err("%s: invalid clock\n", np->full_name);
return;
}
xtal_freq = clk_get_rate(clk);
delay_timer.freq = xtal_freq;
delay_timer.read_current_timer = read_xtal_counter;
ret = clocksource_register_hz(&tango_xtal, xtal_freq);
if (ret != 0) {
pr_err("%s: registration failed\n", np->full_name);
return;
}
sched_clock_register(read_sched_clock, 32, xtal_freq);
register_current_timer_delay(&delay_timer);
}
CLOCKSOURCE_OF_DECLARE(tango, "sigma,tick-counter", tango_clocksource_init);