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rtc: s5m: limit endless loop waiting for register update

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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.kozlowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Mark Brown <broonie@linaro.org>
Acked-by: Sangbeom Kim <sbkim73@samsung.com>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: Lee Jones <lee.jones@linaro.org>
Cc: Liam Girdwood <lgirdwood@gmail.com>
Cc: Alessandro Zummo <a.zummo@towertech.it>
Cc: Marek Szyprowski <m.szyprowski@samsung.com>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
Krzysztof Kozlowski 2013-12-12 17:12:28 -08:00 committed by Linus Torvalds
parent 7b003be826
commit d73238d4a6
1 changed files with 31 additions and 6 deletions
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37
drivers/rtc/rtc-s5m.c
View File

@ -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;
}