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path: root/drivers/rtc/rtc-at91rm9200.c
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Diffstat (limited to 'drivers/rtc/rtc-at91rm9200.c')
-rw-r--r--drivers/rtc/rtc-at91rm9200.c131
1 files changed, 111 insertions, 20 deletions
diff --git a/drivers/rtc/rtc-at91rm9200.c b/drivers/rtc/rtc-at91rm9200.c
index 0eab77b22340..f296f3f7db9b 100644
--- 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>
@@ -42,10 +43,65 @@
#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;
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
@@ -110,9 +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
@@ -144,7 +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__,
@@ -169,7 +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
@@ -182,7 +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__,
@@ -198,9 +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;
}
@@ -209,7 +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");
@@ -229,7 +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);
@@ -250,6 +306,43 @@ static irqreturn_t at91_rtc_interrupt(int irq, void *dev_id)
return IRQ_NONE; /* not handled */
}
+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 */
+ }
+};
+MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
+#endif
+
+static const struct at91_rtc_config *
+at91_rtc_get_config(struct platform_device *pdev)
+{
+ const struct of_device_id *match;
+
+ if (pdev->dev.of_node) {
+ match = of_match_node(at91_rtc_dt_ids, pdev->dev.of_node);
+ if (!match)
+ return NULL;
+ return (const struct at91_rtc_config *)match->data;
+ }
+
+ return &at91rm9200_config;
+}
+
static const struct rtc_class_ops at91_rtc_ops = {
.read_time = at91_rtc_readtime,
.set_time = at91_rtc_settime,
@@ -268,6 +361,10 @@ static int __init at91_rtc_probe(struct platform_device *pdev)
struct resource *regs;
int ret = 0;
+ at91_rtc_config = at91_rtc_get_config(pdev);
+ if (!at91_rtc_config)
+ return -ENODEV;
+
regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!regs) {
dev_err(&pdev->dev, "no mmio resource defined\n");
@@ -290,7 +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);
@@ -335,7 +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);
@@ -358,13 +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;
}
@@ -375,7 +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;
}
@@ -383,12 +480,6 @@ static int at91_rtc_resume(struct device *dev)
static SIMPLE_DEV_PM_OPS(at91_rtc_pm_ops, at91_rtc_suspend, at91_rtc_resume);
-static const struct of_device_id at91_rtc_dt_ids[] = {
- { .compatible = "atmel,at91rm9200-rtc" },
- { /* sentinel */ }
-};
-MODULE_DEVICE_TABLE(of, at91_rtc_dt_ids);
-
static struct platform_driver at91_rtc_driver = {
.remove = __exit_p(at91_rtc_remove),
.driver = {
generated by cgit v1.2.3 (git 2.46.0) at 2025-11-03 23:44:45 +0000