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clocksource: atmel-st: use syscon/regmap

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The register range from the system timer is also used by the watchdog driver.
Use a regmap to handle concurrent accesses.

Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
Acked-by: Daniel Lezcano <daniel.lezcano@linaro.org>
Signed-off-by: Nicolas Ferre <nicolas.ferre@atmel.com>
This commit is contained in:
Alexandre Belloni 2015-03-12 13:07:32 +01:00 committed by Nicolas Ferre
parent b53cdd0322
commit adf2edfd60
1 changed files with 35 additions and 59 deletions
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94
drivers/clocksource/timer-atmel-st.c
View File

@ -24,18 +24,19 @@
#include <linux/irq.h>
#include <linux/clockchips.h>
#include <linux/export.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/mfd/syscon.h>
#include <linux/mfd/syscon/atmel-st.h>
#include <linux/of_irq.h>
#include <linux/regmap.h>
#include <asm/mach/time.h>
#include <mach/at91_st.h>
#include <mach/hardware.h>
static unsigned long last_crtr;
static u32 irqmask;
static struct clock_event_device clkevt;
static struct regmap *regmap_st;
#define RM9200_TIMER_LATCH ((AT91_SLOW_CLOCK + HZ/2) / HZ)
@ -46,11 +47,11 @@ static struct clock_event_device clkevt;
*/
static inline unsigned long read_CRTR(void)
{
unsigned long x1, x2;
unsigned int x1, x2;
x1 = at91_st_read(AT91_ST_CRTR);
regmap_read(regmap_st, AT91_ST_CRTR, &x1);
do {
x2 = at91_st_read(AT91_ST_CRTR);
regmap_read(regmap_st, AT91_ST_CRTR, &x2);
if (x1 == x2)
break;
x1 = x2;
@ -63,7 +64,10 @@ static inline unsigned long read_CRTR(void)
*/
static irqreturn_t at91rm9200_timer_interrupt(int irq, void *dev_id)
{
u32 sr = at91_st_read(AT91_ST_SR) & irqmask;
u32 sr;
regmap_read(regmap_st, AT91_ST_SR, &sr);
sr &= irqmask;
/*
* irqs should be disabled here, but as the irq is shared they are only
@ -115,23 +119,25 @@ static struct clocksource clk32k = {
static void
clkevt32k_mode(enum clock_event_mode mode, struct clock_event_device *dev)
{
unsigned int val;
/* Disable and flush pending timer interrupts */
at91_st_write(AT91_ST_IDR, AT91_ST_PITS | AT91_ST_ALMS);
at91_st_read(AT91_ST_SR);
regmap_write(regmap_st, AT91_ST_IDR, AT91_ST_PITS | AT91_ST_ALMS);
regmap_read(regmap_st, AT91_ST_SR, &val);
last_crtr = read_CRTR();
switch (mode) {
case CLOCK_EVT_MODE_PERIODIC:
/* PIT for periodic irqs; fixed rate of 1/HZ */
irqmask = AT91_ST_PITS;
at91_st_write(AT91_ST_PIMR, RM9200_TIMER_LATCH);
regmap_write(regmap_st, AT91_ST_PIMR, RM9200_TIMER_LATCH);
break;
case CLOCK_EVT_MODE_ONESHOT:
/* ALM for oneshot irqs, set by next_event()
* before 32 seconds have passed
*/
irqmask = AT91_ST_ALMS;
at91_st_write(AT91_ST_RTAR, last_crtr);
regmap_write(regmap_st, AT91_ST_RTAR, last_crtr);
break;
case CLOCK_EVT_MODE_SHUTDOWN:
case CLOCK_EVT_MODE_UNUSED:
@ -139,7 +145,7 @@ clkevt32k_mode(enum clock_event_mode mode, struct clock_event_device *dev)
irqmask = 0;
break;
}
at91_st_write(AT91_ST_IER, irqmask);
regmap_write(regmap_st, AT91_ST_IER, irqmask);
}
static int
@ -147,6 +153,7 @@ clkevt32k_next_event(unsigned long delta, struct clock_event_device *dev)
{
u32 alm;
int status = 0;
unsigned int val;
BUG_ON(delta < 2);
@ -162,12 +169,12 @@ clkevt32k_next_event(unsigned long delta, struct clock_event_device *dev)
alm = read_CRTR();
/* Cancel any pending alarm; flush any pending IRQ */
at91_st_write(AT91_ST_RTAR, alm);
at91_st_read(AT91_ST_SR);
regmap_write(regmap_st, AT91_ST_RTAR, alm);
regmap_read(regmap_st, AT91_ST_SR, &val);
/* Schedule alarm by writing RTAR. */
alm += delta;
at91_st_write(AT91_ST_RTAR, alm);
regmap_write(regmap_st, AT91_ST_RTAR, alm);
return status;
}
@ -180,57 +187,26 @@ static struct clock_event_device clkevt = {
.set_mode = clkevt32k_mode,
};
void __iomem *at91_st_base;
EXPORT_SYMBOL_GPL(at91_st_base);
static const struct of_device_id at91rm9200_st_timer_ids[] = {
{ .compatible = "atmel,at91rm9200-st" },
{ /* sentinel */ }
};
static int __init of_at91rm9200_st_init(void)
{
struct device_node *np;
int ret;
np = of_find_matching_node(NULL, at91rm9200_st_timer_ids);
if (!np)
goto err;
at91_st_base = of_iomap(np, 0);
if (!at91_st_base)
goto node_err;
/* Get the interrupts property */
ret = irq_of_parse_and_map(np, 0);
if (!ret)
goto ioremap_err;
at91rm9200_timer_irq.irq = ret;
of_node_put(np);
return 0;
ioremap_err:
iounmap(at91_st_base);
node_err:
of_node_put(np);
err:
return -EINVAL;
}
/*
* ST (system timer) module supports both clockevents and clocksource.
*/
static void __init atmel_st_timer_init(struct device_node *node)
{
/* For device tree enabled device: initialize here */
of_at91rm9200_st_init();
unsigned int val;
regmap_st = syscon_node_to_regmap(node);
if (IS_ERR(regmap_st))
panic(pr_fmt("Unable to get regmap\n"));
/* Disable all timer interrupts, and clear any pending ones */
at91_st_write(AT91_ST_IDR,
regmap_write(regmap_st, AT91_ST_IDR,
AT91_ST_PITS | AT91_ST_WDOVF | AT91_ST_RTTINC | AT91_ST_ALMS);
at91_st_read(AT91_ST_SR);
regmap_read(regmap_st, AT91_ST_SR, &val);
/* Get the interrupts property */
at91rm9200_timer_irq.irq = irq_of_parse_and_map(node, 0);
if (!at91rm9200_timer_irq.irq)
panic(pr_fmt("Unable to get IRQ from DT\n"));
/* Make IRQs happen for the system timer */
setup_irq(at91rm9200_timer_irq.irq, &at91rm9200_timer_irq);
@ -239,7 +215,7 @@ static void __init atmel_st_timer_init(struct device_node *node)
* directly for the clocksource and all clockevents, after adjusting
* its prescaler from the 1 Hz default.
*/
at91_st_write(AT91_ST_RTMR, 1);
regmap_write(regmap_st, AT91_ST_RTMR, 1);
/* Setup timer clockevent, with minimum of two ticks (important!!) */
clkevt.cpumask = cpumask_of(0);