From cff2e4d278265b595864f882f17f60509713c913 Mon Sep 17 00:00:00 2001 From: Alexandre Belloni Date: Sat, 14 Dec 2019 23:10:17 +0100 Subject: [PATCH] rtc: rv3029: correctly handle PON and VLOW2 In case the data is invalid (PON or VLOW2 are set in STATUS, explicitly tell userspace that the time is invalid. Only remove VLOW2 when setting a new valid time. Link: https://lore.kernel.org/r/20191214221022.622482-12-alexandre.belloni@bootlin.com Signed-off-by: Alexandre Belloni --- drivers/rtc/rtc-rv3029c2.c | 21 +++++++++++++++------ 1 file changed, 15 insertions(+), 6 deletions(-) diff --git a/drivers/rtc/rtc-rv3029c2.c b/drivers/rtc/rtc-rv3029c2.c index f4c6d6e..afe1d3b 100644 --- a/drivers/rtc/rtc-rv3029c2.c +++ b/drivers/rtc/rtc-rv3029c2.c @@ -159,20 +159,21 @@ static int rv3029_eeprom_enter(struct rv3029_data *rv3029) ret = regmap_read(rv3029->regmap, RV3029_STATUS, &sr); if (ret < 0) return ret; - if (sr & (RV3029_STATUS_VLOW1 | RV3029_STATUS_VLOW2)) { + if (sr & RV3029_STATUS_VLOW2) + return -ENODEV; + if (sr & RV3029_STATUS_VLOW1) { /* We clear the bits and retry once just in case * we had a brown out in early startup. */ ret = regmap_update_bits(rv3029->regmap, RV3029_STATUS, - RV3029_STATUS_VLOW1 | - RV3029_STATUS_VLOW2, 0); + RV3029_STATUS_VLOW1, 0); if (ret < 0) return ret; usleep_range(1000, 10000); ret = regmap_read(rv3029->regmap, RV3029_STATUS, &sr); if (ret < 0) return ret; - if (sr & (RV3029_STATUS_VLOW1 | RV3029_STATUS_VLOW2)) { + if (sr & RV3029_STATUS_VLOW1) { dev_err(rv3029->dev, "Supply voltage is too low to safely access the EEPROM.\n"); return -ENODEV; @@ -306,9 +307,17 @@ static irqreturn_t rv3029_handle_irq(int irq, void *dev_id) static int rv3029_read_time(struct device *dev, struct rtc_time *tm) { struct rv3029_data *rv3029 = dev_get_drvdata(dev); + unsigned int sr; int ret; u8 regs[RV3029_WATCH_SECTION_LEN] = { 0, }; + ret = regmap_read(rv3029->regmap, RV3029_STATUS, &sr); + if (ret < 0) + return ret; + + if (sr & (RV3029_STATUS_VLOW2 | RV3029_STATUS_PON)) + return -EINVAL; + ret = regmap_bulk_read(rv3029->regmap, RV3029_W_SEC, regs, RV3029_WATCH_SECTION_LEN); if (ret < 0) { @@ -454,9 +463,9 @@ static int rv3029_set_time(struct device *dev, struct rtc_time *tm) if (ret < 0) return ret; - /* clear PON bit */ + /* clear PON and VLOW2 bits */ return regmap_update_bits(rv3029->regmap, RV3029_STATUS, - RV3029_STATUS_PON, 0); + RV3029_STATUS_PON | RV3029_STATUS_VLOW2, 0); } static int rv3029_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) -- 2.7.4