rtc: s5m: limit endless loop waiting for register update

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.

Krzysztof Kozlowski committed 12 years ago

Commit d73238d1 parent 7b003be1 file · +31 −6Browse files

Unified · Split

drivers/rtc/rtc-s5m.c+31−6

@@ -28,6 +28,16 @@ · 27 unmodified lines
28	28	#include <linux/mfd/samsung/irq.h>
29	29	#include <linux/mfd/samsung/rtc.h>
30	30
	31	+/*
	32	+ * Maximum number of retries for checking changes in UDR field
	33	+ * of SEC_RTC_UDR_CON register (to limit possible endless loop).
	34	+ *
	35	+ * After writing to RTC registers (setting time or alarm) read the UDR field
	36	+ * in SEC_RTC_UDR_CON register. UDR is auto-cleared when data have
	37	+ * been transferred.
	38	+ */
	39	+#define UDR_READ_RETRY_CNT 5
	40	+
31	41	struct s5m_rtc_info {
32	42	struct device *dev;
33	43	struct sec_pmic_dev *s5m87xx;
@@ -84,6 +94,25 @@ static int s5m8767_tm_to_data(struct rtc_time tm, u8 data) · 50 unmodified lines
84	94	}
85	95	}
86	96
	97	+/*
	98	+ * Read RTC_UDR_CON register and wait till UDR field is cleared.
	99	+ * This indicates that time/alarm update ended.
	100	+ */
	101	+static inline int s5m8767_wait_for_udr_update(struct s5m_rtc_info *info)
	102	+{
	103	+ int ret, retry = UDR_READ_RETRY_CNT;
	104	+ unsigned int data;
	105	+
	106	+ do {
	107	+ ret = regmap_read(info->regmap, SEC_RTC_UDR_CON, &data);
	108	+ } while (--retry && (data & RTC_UDR_MASK) && !ret);
	109	+
	110	+ if (!retry)
	111	+ dev_err(info->dev, "waiting for UDR update, reached max number of retries\n");
	112	+
	113	+ return ret;
	114	+}
	115	+
87	116	static inline int s5m8767_rtc_set_time_reg(struct s5m_rtc_info *info)
88	117	{
89	118	int ret;
@@ -104,9 +133,7 @@ static inline int s5m8767_rtc_set_time_reg(struct s5m_rtc_info *info) · 14 unmodified lines
104	133	return ret;
105	134	}
106	135
107		− do {
108		− ret = regmap_read(info->regmap, SEC_RTC_UDR_CON, &data);
109		− } while ((data & RTC_UDR_MASK) && !ret);
	136	+ ret = s5m8767_wait_for_udr_update(info);
110	137
111	138	return ret;
112	139	}
@@ -133,9 +160,7 @@ static inline int s5m8767_rtc_set_alarm_reg(struct s5m_rtc_info *info) · 20 unmodified lines
133	160	return ret;
134	161	}
135	162
136		− do {
137		− ret = regmap_read(info->regmap, SEC_RTC_UDR_CON, &data);
138		− } while ((data & RTC_UDR_MASK) && !ret);
	163	+ ret = s5m8767_wait_for_udr_update(info);
139	164
140	165	return ret;
141	166	}