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-rw-r--r--drivers/rtc/rtc-at91sam9.c28
1 files changed, 24 insertions, 4 deletions
diff --git a/drivers/rtc/rtc-at91sam9.c b/drivers/rtc/rtc-at91sam9.c
index be9c28b9d057..abac38abd38e 100644
--- a/drivers/rtc/rtc-at91sam9.c
+++ b/drivers/rtc/rtc-at91sam9.c
@@ -23,6 +23,7 @@
#include <linux/io.h>
#include <linux/mfd/syscon.h>
#include <linux/regmap.h>
+#include <linux/clk.h>
/*
* This driver uses two configurable hardware resources that live in the
@@ -61,8 +62,6 @@
#define AT91_RTT_ALMS (1 << 0) /* Real-time Alarm Status */
#define AT91_RTT_RTTINC (1 << 1) /* Real-time Timer Increment */
-#define AT91_SLOW_CLOCK 32768
-
/*
* We store ALARM_DISABLED in ALMV to record that no alarm is set.
* It's also the reset value for that field.
@@ -77,6 +76,7 @@ struct sam9_rtc {
struct regmap *gpbr;
unsigned int gpbr_offset;
int irq;
+ struct clk *sclk;
};
#define rtt_readl(rtc, field) \
@@ -328,6 +328,7 @@ static int at91_rtc_probe(struct platform_device *pdev)
struct sam9_rtc *rtc;
int ret, irq;
u32 mr;
+ unsigned int sclk_rate;
irq = platform_get_irq(pdev, 0);
if (irq < 0) {
@@ -385,11 +386,27 @@ static int at91_rtc_probe(struct platform_device *pdev)
return -ENOMEM;
}
+ rtc->sclk = devm_clk_get(&pdev->dev, NULL);
+ if (IS_ERR(rtc->sclk))
+ return PTR_ERR(rtc->sclk);
+
+ sclk_rate = clk_get_rate(rtc->sclk);
+ if (!sclk_rate || sclk_rate > AT91_RTT_RTPRES) {
+ dev_err(&pdev->dev, "Invalid slow clock rate\n");
+ return -EINVAL;
+ }
+
+ ret = clk_prepare_enable(rtc->sclk);
+ if (ret) {
+ dev_err(&pdev->dev, "Could not enable slow clock\n");
+ return ret;
+ }
+
mr = rtt_readl(rtc, MR);
/* unless RTT is counting at 1 Hz, re-initialize it */
- if ((mr & AT91_RTT_RTPRES) != AT91_SLOW_CLOCK) {
- mr = AT91_RTT_RTTRST | (AT91_SLOW_CLOCK & AT91_RTT_RTPRES);
+ if ((mr & AT91_RTT_RTPRES) != sclk_rate) {
+ mr = AT91_RTT_RTTRST | (sclk_rate & AT91_RTT_RTPRES);
gpbr_writel(rtc, 0);
}
@@ -434,6 +451,9 @@ static int at91_rtc_remove(struct platform_device *pdev)
/* disable all interrupts */
rtt_writel(rtc, MR, mr & ~(AT91_RTT_ALMIEN | AT91_RTT_RTTINCIEN));
+ if (!IS_ERR(rtc->sclk))
+ clk_disable_unprepare(rtc->sclk);
+
return 0;
}