After setting alarm or time the driver is waiting for UDR register to be
cleared indicating that registers data have been transferred.
Limit the endless loop to only 5 retries.
Signed-off-by: Krzysztof Kozlowski <k.kozlow...@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.p...@samsung.com>
---
drivers/rtc/rtc-s5m.c | 37 +++++++++++++++++++++++++++++++------
1 file changed, 31 insertions(+), 6 deletions(-)
diff --git a/drivers/rtc/rtc-s5m.c b/drivers/rtc/rtc-s5m.c
index 66686d9..51471c1 100644
--- a/drivers/rtc/rtc-s5m.c
+++ b/drivers/rtc/rtc-s5m.c
@@ -28,6 +28,16 @@
#include <linux/mfd/samsung/irq.h>
#include <linux/mfd/samsung/rtc.h>
+/*
+ * Maximum number of retries for checking changes in UDR field
+ * of SEC_RTC_UDR_CON register (to limit possible endless loop).
+ *
+ * After writing to RTC registers (setting time or alarm) read the UDR field
+ * in SEC_RTC_UDR_CON register. UDR is auto-cleared when data have
+ * been transferred.
+ */
+#define UDR_READ_RETRY_CNT 5
+
struct s5m_rtc_info {
struct device *dev;
struct sec_pmic_dev *s5m87xx;
@@ -84,6 +94,25 @@ static int s5m8767_tm_to_data(struct rtc_time *tm, u8 *data)
}
}
+/*
+ * Read RTC_UDR_CON register and wait till UDR field is cleared.
+ * This indicates that time/alarm update ended.
+ */
+static inline int s5m8767_wait_for_udr_update(struct s5m_rtc_info *info)
+{
+ int ret, retry = UDR_READ_RETRY_CNT;
+ unsigned int data;
+
+ do {
+ ret = regmap_read(info->regmap, SEC_RTC_UDR_CON, &data);
+ } while (--retry && (data & RTC_UDR_MASK) && !ret);
+
+ if (!retry)
+ dev_err(info->dev, "waiting for UDR update, reached max number
of retries\n");
+
+ return ret;
+}
+
static inline int s5m8767_rtc_set_time_reg(struct s5m_rtc_info *info)
{
int ret;
@@ -104,9 +133,7 @@ static inline int s5m8767_rtc_set_time_reg(struct
s5m_rtc_info *info)
return ret;
}
- do {
- ret = regmap_read(info->regmap, SEC_RTC_UDR_CON, &data);
- } while ((data & RTC_UDR_MASK) && !ret);
+ ret = s5m8767_wait_for_udr_update(info);
return ret;
}
@@ -133,9 +160,7 @@ static inline int s5m8767_rtc_set_alarm_reg(struct
s5m_rtc_info *info)
return ret;
}
- do {
- ret = regmap_read(info->regmap, SEC_RTC_UDR_CON, &data);
- } while ((data & RTC_UDR_MASK) && !ret);
+ ret = s5m8767_wait_for_udr_update(info);
return ret;
}
--
1.7.9.5
--
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