forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
101 lines
2.3 KiB
101 lines
2.3 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
|
/* |
|
* Cirrus Logic CLPS711X clocksource driver |
|
* |
|
* Copyright (C) 2014 Alexander Shiyan <[email protected]> |
|
*/ |
|
|
|
#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);
|
|
|