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authorBaruch Siach <baruch@tkos.co.il>2018-12-05 17:00:09 +0200
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2019-06-19 08:18:07 +0200
commit90fc261d509ea9a0314a2b4973d3e9622b34db2b (patch)
treed303a393879d2cebe73d3824e8928c7b2c5e7c0b
parent04757d0e37897cdfa59050157b9083d661bd099e (diff)
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>
-rw-r--r--drivers/rtc/rtc-pcf8523.c32
1 files changed, 24 insertions, 8 deletions
diff --git a/drivers/rtc/rtc-pcf8523.c b/drivers/rtc/rtc-pcf8523.c
index 453615f8ac9a..3fcd2cbafc84 100644
--- a/drivers/rtc/rtc-pcf8523.c
+++ b/drivers/rtc/rtc-pcf8523.c
@@ -85,6 +85,18 @@ 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;
@@ -167,6 +179,14 @@ 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;
@@ -251,17 +271,13 @@ 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;