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/*
* Cirrus Logic CLPS711X clocksource driver
*
* Copyright (C) 2014 Alexander Shiyan <shc_work@mail.ru>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*/
#include <linux/clk.h>
#include <linux/clockchips.h>
#include <linux/clocksource.h>
#include <linux/interrupt.h>
#include <linux/io.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#include <linux/sched_clock.h>
#include <linux/slab.h>
enum {
CLPS711X_CLKSRC_CLOCKSOURCE,
CLPS711X_CLKSRC_CLOCKEVENT,
};
static void __iomem *tcd;
static u64 notrace clps711x_sched_clock_read(void)
{
return ~readw(tcd);
}
static void __init clps711x_clksrc_init(struct clk *clock, void __iomem *base)
{
unsigned long rate = clk_get_rate(clock);
tcd = base;
clocksource_mmio_init(tcd, "clps711x-clocksource", rate, 300, 16,
clocksource_mmio_readw_down);
sched_clock_register(clps711x_sched_clock_read, 16, rate);
}
static irqreturn_t clps711x_timer_interrupt(int irq, void *dev_id)
{
struct clock_event_device *evt = dev_id;
evt->event_handler(evt);
return IRQ_HANDLED;
}
static int __init _clps711x_clkevt_init(struct clk *clock, void __iomem *base,
unsigned int irq)
{
struct clock_event_device *clkevt;
unsigned long rate;
clkevt = kzalloc(sizeof(*clkevt), GFP_KERNEL);
if (!clkevt)
return -ENOMEM;
rate = clk_get_rate(clock);
/* Set Timer prescaler */
writew(DIV_ROUND_CLOSEST(rate, HZ), base);
clkevt->name = "clps711x-clockevent";
clkevt->rating = 300;
clkevt->features = CLOCK_EVT_FEAT_PERIODIC | CLOCK_EVT_FEAT_C3STOP;
clkevt->cpumask = cpumask_of(0);
clockevents_config_and_register(clkevt, HZ, 0, 0);
return request_irq(irq, clps711x_timer_interrupt, IRQF_TIMER,
"clps711x-timer", clkevt);
}
static int __init clps711x_timer_init(struct device_node *np)
{
unsigned int irq = irq_of_parse_and_map(np, 0);
struct clk *clock = of_clk_get(np, 0);
void __iomem *base = of_iomap(np, 0);
if (!base)
return -ENOMEM;
if (!irq)
return -EINVAL;
if (IS_ERR(clock))
return PTR_ERR(clock);
switch (of_alias_get_id(np, "timer")) {
case CLPS711X_CLKSRC_CLOCKSOURCE:
clps711x_clksrc_init(clock, base);
break;
case CLPS711X_CLKSRC_CLOCKEVENT:
return _clps711x_clkevt_init(clock, base, irq);
default:
return -EINVAL;
}
return 0;
}
TIMER_OF_DECLARE(clps711x, "cirrus,ep7209-timer", clps711x_timer_init);
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