@@ -194,6 +194,20 @@ static int ds1307_get_time(struct device *dev, struct rtc_time *t)
const struct chip_desc *chip = &chips[ds1307->type];
u8 regs[7];
+ if (ds1307->type == rx_8130) {
+ unsigned int regflag;
+ ret = regmap_read(ds1307->regmap, RX8130_REG_FLAG, ®flag);
+ if (ret) {
+ dev_err(dev, "%s error %d\n", "read", ret);
+ return ret;
+ }
+
+ if (regflag & RX8130_REG_FLAG_VLF) {
+ dev_warn_once(dev, "oscillator failed, set time!\n");
+ return -EINVAL;
+ }
+ }
+
/* read the RTC date and time registers all at once */
ret = regmap_bulk_read(ds1307->regmap, chip->offset, regs,
sizeof(regs));
@@ -293,6 +307,17 @@ static int ds1307_set_time(struct device *dev, struct rtc_time *t)
dev_err(dev, "%s error %d\n", "write", result);
return result;
}
+
+ if (ds1307->type == rx_8130) {
+ /* clear Voltage Loss Flag as data is available now */
+ result = regmap_write(ds1307->regmap, RX8130_REG_FLAG,
+ ~(u8)RX8130_REG_FLAG_VLF);
+ if (result) {
+ dev_err(dev, "%s error %d\n", "write", result);
+ return result;
+ }
+ }
+
return 0;
}
When voltage dropped since the RTC was last set the reported time is not reliable. In this case return an error indicator instead of a bogus time. Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de> --- drivers/rtc/rtc-ds1307.c | 25 +++++++++++++++++++++++++ 1 file changed, 25 insertions(+)