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kernel/linux-rt-4.4.41/drivers/clocksource/tango_xtal.c 1.45 KB
5113f6f70   김현기   kernel add
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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
  ", np->full_name);
  		return;
  	}
  
  	clk = of_clk_get(np, 0);
  	if (IS_ERR(clk)) {
  		pr_err("%s: invalid clock
  ", 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
  ", 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);