diff options
| author | Baruch Siach <baruch@tkos.co.il> | 2018-12-05 18:00:09 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2019-06-19 09:21:00 +0300 |
| commit | 3177ab541ba8b875d0cdb85e9813f5402e59714d (patch) | |
| tree | fa353c3724df3f32ee97bf324d7f8d42ce712e5c /drivers/rtc/rtc-pcf8523.c | |
| parent | 488beeebddaf563aed96c27aa78c520a00f1a30f (diff) | |
| download | linux-3177ab541ba8b875d0cdb85e9813f5402e59714d.tar.xz | |
rtc: pcf8523: don't return invalid date when battery is low
commit ecb4a353d3afd45b9bb30c85d03ee113a0589079 upstream.
The RTC_VL_READ ioctl reports the low battery condition. Still,
pcf8523_rtc_read_time() happily returns invalid dates in this case.
Check the battery health on pcf8523_rtc_read_time() to avoid that.
Reported-by: Erik Čuk <erik.cuk@domel.com>
Signed-off-by: Baruch Siach <baruch@tkos.co.il>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/rtc/rtc-pcf8523.c')
| -rw-r--r-- | drivers/rtc/rtc-pcf8523.c | 32 |
1 files changed, 24 insertions, 8 deletions
diff --git a/drivers/rtc/rtc-pcf8523.c b/drivers/rtc/rtc-pcf8523.c index 28c48b3c1946..3c8c6f942e67 100644 --- a/drivers/rtc/rtc-pcf8523.c +++ b/drivers/rtc/rtc-pcf8523.c @@ -82,6 +82,18 @@ static int pcf8523_write(struct i2c_client *client, u8 reg, u8 value) return 0; } +static int pcf8523_voltage_low(struct i2c_client *client) +{ + u8 value; + int err; + + err = pcf8523_read(client, REG_CONTROL3, &value); + if (err < 0) + return err; + + return !!(value & REG_CONTROL3_BLF); +} + static int pcf8523_select_capacitance(struct i2c_client *client, bool high) { u8 value; @@ -164,6 +176,14 @@ static int pcf8523_rtc_read_time(struct device *dev, struct rtc_time *tm) struct i2c_msg msgs[2]; int err; + err = pcf8523_voltage_low(client); + if (err < 0) { + return err; + } else if (err > 0) { + dev_err(dev, "low voltage detected, time is unreliable\n"); + return -EINVAL; + } + msgs[0].addr = client->addr; msgs[0].flags = 0; msgs[0].len = 1; @@ -248,17 +268,13 @@ static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd, unsigned long arg) { struct i2c_client *client = to_i2c_client(dev); - u8 value; - int ret = 0, err; + int ret; switch (cmd) { case RTC_VL_READ: - err = pcf8523_read(client, REG_CONTROL3, &value); - if (err < 0) - return err; - - if (value & REG_CONTROL3_BLF) - ret = 1; + ret = pcf8523_voltage_low(client); + if (ret < 0) + return ret; if (copy_to_user((void __user *)arg, &ret, sizeof(int))) return -EFAULT; |