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rtc: pcf8563: stop caching voltage_low

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voltage_low is only updated when reading the time, this means that using
RTC_VL_READ will miss the VL flag if the time has not been read before
using the ioctl. Always read the status from the hardware.

Link: https://lore.kernel.org/r/20191214220259.621996-9-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
This commit is contained in:
Alexandre Belloni 2019-12-14 23:02:50 +01:00
parent 75d26f5c23
commit 935272aade
1 changed files with 9 additions and 7 deletions
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16
drivers/rtc/rtc-pcf8563.c
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@ -76,7 +76,6 @@ struct pcf8563 {
* 1970...2069.
*/
int c_polarity; /* 0: MO_C=1 means 19xx, otherwise MO_C=1 means 20xx */
int voltage_low; /* incicates if a low_voltage was detected */
struct i2c_client *client;
#ifdef CONFIG_COMMON_CLK
@ -208,7 +207,6 @@ static int pcf8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
return err;
if (buf[PCF8563_REG_SC] & PCF8563_SC_LV) {
pcf8563->voltage_low = 1;
dev_err(&client->dev,
"low voltage detected, date/time is not reliable.\n");
return -EINVAL;
@ -278,15 +276,19 @@ static int pcf8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
static int pcf8563_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg)
{
struct pcf8563 *pcf8563 = i2c_get_clientdata(to_i2c_client(dev));
struct i2c_client *client = to_i2c_client(dev);
int vl, ret;
switch (cmd) {
case RTC_VL_READ:
if (pcf8563->voltage_low)
dev_info(dev, "low voltage detected, date/time is not reliable.\n");
if (copy_to_user((void __user *)arg, &pcf8563->voltage_low,
sizeof(int)))
ret = i2c_smbus_read_byte_data(client, PCF8563_REG_SC);
if (ret < 0)
return ret;
vl = ret & PCF8563_SC_LV ? 1 : 0;
if (copy_to_user((void __user *)arg, &vl, sizeof(int)))
return -EFAULT;
return 0;
default: