clocksource: atmel-st: use syscon/regmap

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>

1 files changed, 35 insertions, 59 deletions

diff --git a/drivers/clocksource/timer-atmel-st.c b/drivers/clocksource/timer-atmel-st.c
index 7d062ab32674..674ef2519d6b 100644
--- a/drivers/clocksource/timer-atmel-st.c
+++ b/drivers/clocksource/timer-atmel-st.c
@@ -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);