Merge tag 'sunxi-dt-for-3.11-2' of git://github.com/mripard/linux into next/dt

[karo-tx-linux.git] / drivers / rtc / rtc-at91rm9200.c

diff --git a/drivers/rtc/rtc-at91rm9200.c b/drivers/rtc/rtc-at91rm9200.c
index ab2024b159fa3757b6f8818b9a70ab82cf960226..f296f3f7db9bb72574396182f3a8dfd115e16786 100644 (file)
--- a/drivers/rtc/rtc-at91rm9200.c
+++ b/drivers/rtc/rtc-at91rm9200.c
@@ -25,6 +25,7 @@
 #include <linux/rtc.h>
 #include <linux/bcd.h>
 #include <linux/interrupt.h>
+#include <linux/spinlock.h>
 #include <linux/ioctl.h>
 #include <linux/completion.h>
 #include <linux/io.h>
@@ -43,6 +44,7 @@
 #define AT91_RTC_EPOCH         1900UL  /* just like arch/arm/common/rtctime.c */
 
 struct at91_rtc_config {
+       bool use_shadow_imr;
 };
 
 static const struct at91_rtc_config *at91_rtc_config;
@@ -50,6 +52,56 @@ static DECLARE_COMPLETION(at91_rtc_updated);
 static unsigned int at91_alarm_year = AT91_RTC_EPOCH;
 static void __iomem *at91_rtc_regs;
 static int irq;
+static DEFINE_SPINLOCK(at91_rtc_lock);
+static u32 at91_rtc_shadow_imr;
+
+static void at91_rtc_write_ier(u32 mask)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&at91_rtc_lock, flags);
+       at91_rtc_shadow_imr |= mask;
+       at91_rtc_write(AT91_RTC_IER, mask);
+       spin_unlock_irqrestore(&at91_rtc_lock, flags);
+}
+
+static void at91_rtc_write_idr(u32 mask)
+{
+       unsigned long flags;
+
+       spin_lock_irqsave(&at91_rtc_lock, flags);
+       at91_rtc_write(AT91_RTC_IDR, mask);
+       /*
+        * Register read back (of any RTC-register) needed to make sure
+        * IDR-register write has reached the peripheral before updating
+        * shadow mask.
+        *
+        * Note that there is still a possibility that the mask is updated
+        * before interrupts have actually been disabled in hardware. The only
+        * way to be certain would be to poll the IMR-register, which is is
+        * the very register we are trying to emulate. The register read back
+        * is a reasonable heuristic.
+        */
+       at91_rtc_read(AT91_RTC_SR);
+       at91_rtc_shadow_imr &= ~mask;
+       spin_unlock_irqrestore(&at91_rtc_lock, flags);
+}
+
+static u32 at91_rtc_read_imr(void)
+{
+       unsigned long flags;
+       u32 mask;
+
+       if (at91_rtc_config->use_shadow_imr) {
+               spin_lock_irqsave(&at91_rtc_lock, flags);
+               mask = at91_rtc_shadow_imr;
+               spin_unlock_irqrestore(&at91_rtc_lock, flags);
+       } else {
+               mask = at91_rtc_read(AT91_RTC_IMR);
+       }
+
+       return mask;
+}
 
 /*
  * Decode time/date into rtc_time structure
@@ -114,9 +166,9 @@ static int at91_rtc_settime(struct device *dev, struct rtc_time *tm)
        cr = at91_rtc_read(AT91_RTC_CR);
        at91_rtc_write(AT91_RTC_CR, cr | AT91_RTC_UPDCAL | AT91_RTC_UPDTIM);
 
-       at91_rtc_write(AT91_RTC_IER, AT91_RTC_ACKUPD);
+       at91_rtc_write_ier(AT91_RTC_ACKUPD);
        wait_for_completion(&at91_rtc_updated); /* wait for ACKUPD interrupt */
-       at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD);
+       at91_rtc_write_idr(AT91_RTC_ACKUPD);
 
        at91_rtc_write(AT91_RTC_TIMR,
                          bin2bcd(tm->tm_sec) << 0
@@ -148,7 +200,7 @@ static int at91_rtc_readalarm(struct device *dev, struct rtc_wkalrm *alrm)
        tm->tm_yday = rtc_year_days(tm->tm_mday, tm->tm_mon, tm->tm_year);
        tm->tm_year = at91_alarm_year - 1900;
 
-       alrm->enabled = (at91_rtc_read(AT91_RTC_IMR) & AT91_RTC_ALARM)
+       alrm->enabled = (at91_rtc_read_imr() & AT91_RTC_ALARM)
                        ? 1 : 0;
 
        dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
@@ -173,7 +225,7 @@ static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
        tm.tm_min = alrm->time.tm_min;
        tm.tm_sec = alrm->time.tm_sec;
 
-       at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ALARM);
+       at91_rtc_write_idr(AT91_RTC_ALARM);
        at91_rtc_write(AT91_RTC_TIMALR,
                  bin2bcd(tm.tm_sec) << 0
                | bin2bcd(tm.tm_min) << 8
@@ -186,7 +238,7 @@ static int at91_rtc_setalarm(struct device *dev, struct rtc_wkalrm *alrm)
 
        if (alrm->enabled) {
                at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
-               at91_rtc_write(AT91_RTC_IER, AT91_RTC_ALARM);
+               at91_rtc_write_ier(AT91_RTC_ALARM);
        }
 
        dev_dbg(dev, "%s(): %4d-%02d-%02d %02d:%02d:%02d\n", __func__,
@@ -202,9 +254,9 @@ static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
 
        if (enabled) {
                at91_rtc_write(AT91_RTC_SCCR, AT91_RTC_ALARM);
-               at91_rtc_write(AT91_RTC_IER, AT91_RTC_ALARM);
+               at91_rtc_write_ier(AT91_RTC_ALARM);
        } else
-               at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ALARM);
+               at91_rtc_write_idr(AT91_RTC_ALARM);
 
        return 0;
 }
@@ -213,7 +265,7 @@ static int at91_rtc_alarm_irq_enable(struct device *dev, unsigned int enabled)
  */
 static int at91_rtc_proc(struct device *dev, struct seq_file *seq)
 {
-       unsigned long imr = at91_rtc_read(AT91_RTC_IMR);
+       unsigned long imr = at91_rtc_read_imr();
 
        seq_printf(seq, "update_IRQ\t: %s\n",
                        (imr & AT91_RTC_ACKUPD) ? "yes" : "no");
@@ -233,7 +285,7 @@ static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
        unsigned int rtsr;
        unsigned long events = 0;
 
-       rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read(AT91_RTC_IMR);
+       rtsr = at91_rtc_read(AT91_RTC_SR) & at91_rtc_read_imr();
        if (rtsr) {             /* this interrupt is shared!  Is it ours? */
                if (rtsr & AT91_RTC_ALARM)
                        events |= (RTC_AF | RTC_IRQF);
@@ -257,11 +309,18 @@ static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
 static const struct at91_rtc_config at91rm9200_config = {
 };
 
+static const struct at91_rtc_config at91sam9x5_config = {
+       .use_shadow_imr = true,
+};
+
 #ifdef CONFIG_OF
 static const struct of_device_id at91_rtc_dt_ids[] = {
        {
                .compatible = "atmel,at91rm9200-rtc",
                .data = &at91rm9200_config,
+       }, {
+               .compatible = "atmel,at91sam9x5-rtc",
+               .data = &at91sam9x5_config,
        }, {
                /* sentinel */
        }
@@ -328,7 +387,7 @@ static int __init at91_rtc_probe(struct platform_device *pdev)
        at91_rtc_write(AT91_RTC_MR, 0);         /* 24 hour mode */
 
        /* Disable all interrupts */
-       at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
+       at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
                                        AT91_RTC_SECEV | AT91_RTC_TIMEV |
                                        AT91_RTC_CALEV);
 
@@ -373,7 +432,7 @@ static int __exit at91_rtc_remove(struct platform_device *pdev)
        struct rtc_device *rtc = platform_get_drvdata(pdev);
 
        /* Disable all interrupts */
-       at91_rtc_write(AT91_RTC_IDR, AT91_RTC_ACKUPD | AT91_RTC_ALARM |
+       at91_rtc_write_idr(AT91_RTC_ACKUPD | AT91_RTC_ALARM |
                                        AT91_RTC_SECEV | AT91_RTC_TIMEV |
                                        AT91_RTC_CALEV);
        free_irq(irq, pdev);
@@ -396,13 +455,13 @@ static int at91_rtc_suspend(struct device *dev)
        /* this IRQ is shared with DBGU and other hardware which isn't
         * necessarily doing PM like we are...
         */
-       at91_rtc_imr = at91_rtc_read(AT91_RTC_IMR)
+       at91_rtc_imr = at91_rtc_read_imr()
                        & (AT91_RTC_ALARM|AT91_RTC_SECEV);
        if (at91_rtc_imr) {
                if (device_may_wakeup(dev))
                        enable_irq_wake(irq);
                else
-                       at91_rtc_write(AT91_RTC_IDR, at91_rtc_imr);
+                       at91_rtc_write_idr(at91_rtc_imr);
        }
        return 0;
 }
@@ -413,7 +472,7 @@ static int at91_rtc_resume(struct device *dev)
                if (device_may_wakeup(dev))
                        disable_irq_wake(irq);
                else
-                       at91_rtc_write(AT91_RTC_IER, at91_rtc_imr);
+                       at91_rtc_write_ier(at91_rtc_imr);
        }
        return 0;
 }