2015-01-27 17:52:42 +00:00
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/*
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* linux/arch/h8300/kernel/cpu/timer/timer8.c
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*
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* Yoshinori Sato <ysato@users.sourcefoge.jp>
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*
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* 8bit Timer driver
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*
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*/
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#include <linux/errno.h>
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#include <linux/kernel.h>
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#include <linux/interrupt.h>
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#include <linux/init.h>
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#include <linux/clockchips.h>
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#include <linux/clk.h>
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#include <linux/io.h>
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#include <linux/of.h>
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2015-11-06 16:31:44 +00:00
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#include <linux/of_address.h>
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#include <linux/of_irq.h>
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2015-01-27 17:52:42 +00:00
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#define _8TCR 0
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#define _8TCSR 2
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#define TCORA 4
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#define TCORB 6
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#define _8TCNT 8
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#define FLAG_SKIPEVENT (1 << 1)
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#define FLAG_IRQCONTEXT (1 << 2)
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#define FLAG_STARTED (1 << 3)
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#define ONESHOT 0
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#define PERIODIC 1
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2015-11-06 16:31:44 +00:00
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#define SCALE 64
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2015-01-27 17:52:42 +00:00
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struct timer8_priv {
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struct clock_event_device ced;
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unsigned long mapbase;
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raw_spinlock_t lock;
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unsigned long flags;
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unsigned int rate;
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unsigned int tcora;
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struct clk *pclk;
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};
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static unsigned long timer8_get_counter(struct timer8_priv *p)
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{
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unsigned long v1, v2, v3;
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int o1, o2;
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o1 = ctrl_inb(p->mapbase + _8TCSR) & 0x20;
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/* Make sure the timer value is stable. Stolen from acpi_pm.c */
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do {
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o2 = o1;
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v1 = ctrl_inw(p->mapbase + _8TCNT);
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v2 = ctrl_inw(p->mapbase + _8TCNT);
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v3 = ctrl_inw(p->mapbase + _8TCNT);
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o1 = ctrl_inb(p->mapbase + _8TCSR) & 0x20;
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} while (unlikely((o1 != o2) || (v1 > v2 && v1 < v3)
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|| (v2 > v3 && v2 < v1) || (v3 > v1 && v3 < v2)));
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v2 |= o1 << 10;
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return v2;
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}
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static irqreturn_t timer8_interrupt(int irq, void *dev_id)
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{
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struct timer8_priv *p = dev_id;
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ctrl_outb(ctrl_inb(p->mapbase + _8TCSR) & ~0x40,
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p->mapbase + _8TCSR);
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p->flags |= FLAG_IRQCONTEXT;
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ctrl_outw(p->tcora, p->mapbase + TCORA);
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if (!(p->flags & FLAG_SKIPEVENT)) {
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2015-07-27 09:32:00 +00:00
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if (clockevent_state_oneshot(&p->ced))
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2015-01-27 17:52:42 +00:00
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ctrl_outw(0x0000, p->mapbase + _8TCR);
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p->ced.event_handler(&p->ced);
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}
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p->flags &= ~(FLAG_SKIPEVENT | FLAG_IRQCONTEXT);
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return IRQ_HANDLED;
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}
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static void timer8_set_next(struct timer8_priv *p, unsigned long delta)
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{
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unsigned long flags;
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unsigned long now;
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raw_spin_lock_irqsave(&p->lock, flags);
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if (delta >= 0x10000)
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2015-11-09 08:02:38 +00:00
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pr_warn("delta out of range\n");
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2015-01-27 17:52:42 +00:00
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now = timer8_get_counter(p);
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p->tcora = delta;
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ctrl_outb(ctrl_inb(p->mapbase + _8TCR) | 0x40, p->mapbase + _8TCR);
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if (delta > now)
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ctrl_outw(delta, p->mapbase + TCORA);
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else
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ctrl_outw(now + 1, p->mapbase + TCORA);
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raw_spin_unlock_irqrestore(&p->lock, flags);
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}
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static int timer8_enable(struct timer8_priv *p)
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{
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2015-11-06 16:31:44 +00:00
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p->rate = clk_get_rate(p->pclk) / SCALE;
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2015-01-27 17:52:42 +00:00
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ctrl_outw(0xffff, p->mapbase + TCORA);
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ctrl_outw(0x0000, p->mapbase + _8TCNT);
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ctrl_outw(0x0c02, p->mapbase + _8TCR);
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return 0;
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}
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static int timer8_start(struct timer8_priv *p)
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{
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int ret = 0;
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unsigned long flags;
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raw_spin_lock_irqsave(&p->lock, flags);
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if (!(p->flags & FLAG_STARTED))
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ret = timer8_enable(p);
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if (ret)
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goto out;
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p->flags |= FLAG_STARTED;
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out:
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raw_spin_unlock_irqrestore(&p->lock, flags);
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return ret;
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}
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static void timer8_stop(struct timer8_priv *p)
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{
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unsigned long flags;
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raw_spin_lock_irqsave(&p->lock, flags);
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ctrl_outw(0x0000, p->mapbase + _8TCR);
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raw_spin_unlock_irqrestore(&p->lock, flags);
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}
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static inline struct timer8_priv *ced_to_priv(struct clock_event_device *ced)
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{
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return container_of(ced, struct timer8_priv, ced);
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}
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static void timer8_clock_event_start(struct timer8_priv *p, int periodic)
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{
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struct clock_event_device *ced = &p->ced;
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timer8_start(p);
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ced->shift = 32;
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ced->mult = div_sc(p->rate, NSEC_PER_SEC, ced->shift);
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ced->max_delta_ns = clockevent_delta2ns(0xffff, ced);
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ced->min_delta_ns = clockevent_delta2ns(0x0001, ced);
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timer8_set_next(p, periodic?(p->rate + HZ/2) / HZ:0x10000);
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}
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2015-07-27 09:32:00 +00:00
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static int timer8_clock_event_shutdown(struct clock_event_device *ced)
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{
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timer8_stop(ced_to_priv(ced));
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return 0;
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}
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static int timer8_clock_event_periodic(struct clock_event_device *ced)
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2015-01-27 17:52:42 +00:00
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{
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struct timer8_priv *p = ced_to_priv(ced);
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2015-11-06 16:31:44 +00:00
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pr_info("%s: used for periodic clock events\n", ced->name);
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2015-07-27 09:32:00 +00:00
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timer8_stop(p);
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timer8_clock_event_start(p, PERIODIC);
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return 0;
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}
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static int timer8_clock_event_oneshot(struct clock_event_device *ced)
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{
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struct timer8_priv *p = ced_to_priv(ced);
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2015-11-06 16:31:44 +00:00
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pr_info("%s: used for oneshot clock events\n", ced->name);
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2015-07-27 09:32:00 +00:00
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timer8_stop(p);
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timer8_clock_event_start(p, ONESHOT);
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return 0;
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2015-01-27 17:52:42 +00:00
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}
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static int timer8_clock_event_next(unsigned long delta,
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struct clock_event_device *ced)
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{
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struct timer8_priv *p = ced_to_priv(ced);
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2015-07-27 09:32:00 +00:00
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BUG_ON(!clockevent_state_oneshot(ced));
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2015-01-27 17:52:42 +00:00
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timer8_set_next(p, delta - 1);
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return 0;
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}
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2015-11-06 16:31:44 +00:00
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static struct timer8_priv timer8_priv = {
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.ced = {
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.name = "h8300_8timer",
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.features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_ONESHOT,
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.rating = 200,
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.set_next_event = timer8_clock_event_next,
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.set_state_shutdown = timer8_clock_event_shutdown,
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.set_state_periodic = timer8_clock_event_periodic,
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.set_state_oneshot = timer8_clock_event_oneshot,
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},
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};
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static void __init h8300_8timer_init(struct device_node *node)
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2015-01-27 17:52:42 +00:00
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{
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2015-11-06 16:31:44 +00:00
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void __iomem *base;
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2015-01-27 17:52:42 +00:00
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int irq;
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2015-11-06 16:31:44 +00:00
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int ret = 0;
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int rate;
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struct clk *clk;
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2015-01-27 17:52:42 +00:00
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2015-11-06 16:31:44 +00:00
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clk = of_clk_get(node, 0);
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if (IS_ERR(clk)) {
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pr_err("failed to get clock for clockevent\n");
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return;
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}
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2015-01-27 17:52:42 +00:00
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2015-11-06 16:31:44 +00:00
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base = of_iomap(node, 0);
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if (!base) {
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pr_err("failed to map registers for clockevent\n");
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goto free_clk;
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2015-01-27 17:52:42 +00:00
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}
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2015-11-06 16:31:44 +00:00
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irq = irq_of_parse_and_map(node, 0);
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2015-01-27 17:52:42 +00:00
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if (irq < 0) {
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2015-11-06 16:31:44 +00:00
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pr_err("failed to get irq for clockevent\n");
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goto unmap_reg;
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2015-01-27 17:52:42 +00:00
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}
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2015-11-06 16:31:44 +00:00
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timer8_priv.mapbase = (unsigned long)base;
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timer8_priv.pclk = clk;
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2015-01-27 17:52:42 +00:00
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2015-11-06 16:31:44 +00:00
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ret = request_irq(irq, timer8_interrupt,
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IRQF_TIMER, timer8_priv.ced.name, &timer8_priv);
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2015-01-27 17:52:42 +00:00
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if (ret < 0) {
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2015-11-06 16:31:44 +00:00
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pr_err("failed to request irq %d for clockevent\n", irq);
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goto unmap_reg;
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2015-01-27 17:52:42 +00:00
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}
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2015-11-06 16:31:44 +00:00
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rate = clk_get_rate(clk) / SCALE;
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clockevents_config_and_register(&timer8_priv.ced, rate, 1, 0x0000ffff);
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return;
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unmap_reg:
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iounmap(base);
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free_clk:
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clk_put(clk);
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2015-01-27 17:52:42 +00:00
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}
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2015-11-06 16:31:44 +00:00
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CLOCKSOURCE_OF_DECLARE(h8300_8bit, "renesas,8bit-timer", h8300_8timer_init);
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