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rtc: ds1307: ds3231 temperature s16 overflow

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while retrieving temperature from ds3231, the result may be overflow
since s16 is too small for a multiplication with 250.

ie. if temp_buf[0] == 0x2d, the result (s16 temp) will be negative.

Signed-off-by: Akinobu Mita <akinobu.mita@gmail.com>
Tested-by: Michael Tatarinov <kukabu@gmail.com>
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
This commit is contained in:
Zhuang Yuyao 2016-04-18 09:21:42 +09:00 committed by Alexandre Belloni
parent 00c9329ebe
commit 9a3dce62cc
1 changed files with 2 additions and 2 deletions
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4
drivers/rtc/rtc-ds1307.c
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@ -863,7 +863,7 @@ static void ds1307_trickle_of_init(struct i2c_client *client,
* A user-initiated temperature conversion is not started by this function,
* so the temperature is updated once every 64 seconds.
*/
static int ds3231_hwmon_read_temp(struct device *dev, s16 *mC)
static int ds3231_hwmon_read_temp(struct device *dev, s32 *mC)
{
struct ds1307 *ds1307 = dev_get_drvdata(dev);
u8 temp_buf[2];
@ -892,7 +892,7 @@ static ssize_t ds3231_hwmon_show_temp(struct device *dev,
struct device_attribute *attr, char *buf)
{
int ret;
s16 temp;
s32 temp;
ret = ds3231_hwmon_read_temp(dev, &temp);
if (ret)