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rtc: rv3029: remove race condition when update STATUS

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There is no lock preventing concurrent access to the status register from
bth the rtc subsystem and the hwmon subsystem. Use regmap_update_bits to
ensure updating RV3029_STATUS is properly locked.

Link: https://lore.kernel.org/r/20191214221022.622482-5-alexandre.belloni@bootlin.com
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
This commit is contained in:
Alexandre Belloni 2019-12-14 23:10:10 +01:00
parent 609e97fe31
commit 54c5970df4
1 changed files with 6 additions and 28 deletions
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34
drivers/rtc/rtc-rv3029c2.c
View file

@ -147,19 +147,6 @@ static int rv3029_get_sr(struct device *dev, u8 *buf)
return 0;
}
static int rv3029_set_sr(struct device *dev, u8 val)
{
u8 buf[1];
int sr;
buf[0] = val;
sr = rv3029_write_regs(dev, RV3029_STATUS, buf, 1);
dev_dbg(dev, "status = 0x%.2x (%d)\n", buf[0], buf[0]);
if (sr < 0)
return -EIO;
return 0;
}
static int rv3029_eeprom_busywait(struct device *dev)
{
int i, ret;
@ -205,9 +192,9 @@ static int rv3029_eeprom_enter(struct device *dev)
/* We clear the bits and retry once just in case
* we had a brown out in early startup.
*/
sr &= ~RV3029_STATUS_VLOW1;
sr &= ~RV3029_STATUS_VLOW2;
ret = rv3029_set_sr(dev, sr);
ret = regmap_update_bits(rv3029->regmap, RV3029_STATUS,
RV3029_STATUS_VLOW1 |
RV3029_STATUS_VLOW2, 0);
if (ret < 0)
return ret;
usleep_range(1000, 10000);
@ -515,6 +502,7 @@ static int rv3029_set_alarm(struct device *dev, struct rtc_wkalrm *alarm)
static int rv3029_set_time(struct device *dev, struct rtc_time *tm)
{
struct rv3029_data *rv3029 = dev_get_drvdata(dev);
u8 regs[8];
int ret;
@ -539,19 +527,9 @@ static int rv3029_set_time(struct device *dev, struct rtc_time *tm)
if (ret < 0)
return ret;
ret = rv3029_get_sr(dev, regs);
if (ret < 0) {
dev_err(dev, "%s: reading SR failed\n", __func__);
return ret;
}
/* clear PON bit */
ret = rv3029_set_sr(dev, (regs[0] & ~RV3029_STATUS_PON));
if (ret < 0) {
dev_err(dev, "%s: reading SR failed\n", __func__);
return ret;
}
return 0;
return regmap_update_bits(rv3029->regmap, RV3029_STATUS,
RV3029_STATUS_PON, 0);
}
static const struct rv3029_trickle_tab_elem {