[PATCH v4 8/9] clocksource: atmel-st: use syscon/regmap

Alexandre Belloni
2015-03-05T15:50:48Z

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>
---
drivers/clocksource/timer-atmel-st.c | 99 ++++++++++++++----------------------
1 file changed, 37 insertions(+), 62 deletions(-)

diff --git a/drivers/clocksource/timer-atmel-st.c b/drivers/clocksource/timer-atmel-st.c
index 7d062ab32674..c4a52e32675e 100644
--- a/drivers/clocksource/timer-atmel-st.c
+++ b/drivers/clocksource/timer-atmel-st.c
@@ -24,19 +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 AT91_SLOW_CLOCK 32768
#define RM9200_TIMER_LATCH ((AT91_SLOW_CLOCK + HZ/2) / HZ)

/*
@@ -46,11 +46,11 @@ 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 +63,10 @@ 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
@@ -96,7 +99,7 @@ static struct irqaction at91rm9200_timer_irq = {
.name = "at91_tick",
.flags = IRQF_SHARED | IRQF_TIMER | IRQF_IRQPOLL,
.handler = at91rm9200_timer_interrupt,
- .irq = NR_IRQS_LEGACY + AT91_ID_SYS,
+ .irq = 0,
};

static cycle_t read_clk32k(struct clocksource *cs)
@@ -115,23 +118,25 @@ 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 +144,7 @@ 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 +152,7 @@ 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 +168,12 @@ 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 +186,26 @@ 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 +214,7 @@ 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);
--
2.1.0