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authorAlexandre Belloni <alexandre.belloni@bootlin.com>2019-10-07 15:47:22 +0200
committerAlexandre Belloni <alexandre.belloni@bootlin.com>2019-10-07 15:49:35 +0200
commitd9dcfa5f7084a0c648d9f0946994f4320a411a40 (patch)
tree083aece3ba798a1b885ad57e97babb304a01a0f7 /drivers/rtc/rtc-ds1347.c
parent3ce20a23e2199bd98eb85fbaa524104931cd14dd (diff)
rtc: ds1347: properly handle oscillator failures
The comment in the probe function stating that it disables oscillator stop detection and glitch filtering is incorrect as it sets bits 3 and 4 while it should be setting 5 and 6 to achieve that. Then, it is safe to assume that the oscillator failure detection is actually enabled. Properly handle oscillator failures by returning -EINVAL when the time and date are know to be incorrect and reset the flag when the time is set. Link: https://lore.kernel.org/r/20191007134724.15505-8-alexandre.belloni@bootlin.com Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Diffstat (limited to 'drivers/rtc/rtc-ds1347.c')
-rw-r--r--drivers/rtc/rtc-ds1347.c30
1 files changed, 23 insertions, 7 deletions
diff --git a/drivers/rtc/rtc-ds1347.c b/drivers/rtc/rtc-ds1347.c
index 22a75b01f1ac..eeaf43586bce 100644
--- a/drivers/rtc/rtc-ds1347.c
+++ b/drivers/rtc/rtc-ds1347.c
@@ -29,6 +29,9 @@
#define DS1347_STATUS_REG 0x17
#define DS1347_CLOCK_BURST 0x3F
+#define DS1347_NEOSC_BIT BIT(7)
+#define DS1347_OSF_BIT BIT(2)
+
static const struct regmap_range ds1347_ranges[] = {
{
.range_min = DS1347_SECONDS_REG,
@@ -44,9 +47,17 @@ static const struct regmap_access_table ds1347_access_table = {
static int ds1347_read_time(struct device *dev, struct rtc_time *dt)
{
struct regmap *map = dev_get_drvdata(dev);
+ unsigned int status;
int err;
unsigned char buf[8];
+ err = regmap_read(map, DS1347_STATUS_REG, &status);
+ if (err)
+ return err;
+
+ if (status & DS1347_OSF_BIT)
+ return -EINVAL;
+
err = regmap_bulk_read(map, DS1347_CLOCK_BURST, buf, 8);
if (err)
return err;
@@ -66,6 +77,12 @@ static int ds1347_set_time(struct device *dev, struct rtc_time *dt)
{
struct regmap *map = dev_get_drvdata(dev);
unsigned char buf[8];
+ int err;
+
+ err = regmap_update_bits(map, DS1347_STATUS_REG,
+ DS1347_NEOSC_BIT, DS1347_NEOSC_BIT);
+ if (err)
+ return err;
buf[0] = bin2bcd(dt->tm_sec);
buf[1] = bin2bcd(dt->tm_min);
@@ -82,7 +99,12 @@ static int ds1347_set_time(struct device *dev, struct rtc_time *dt)
buf[7] = bin2bcd(0x00);
/* write the rtc settings */
- return regmap_bulk_write(map, DS1347_CLOCK_BURST, buf, 8);
+ err = regmap_bulk_write(map, DS1347_CLOCK_BURST, buf, 8);
+ if (err)
+ return err;
+
+ return regmap_update_bits(map, DS1347_STATUS_REG,
+ DS1347_NEOSC_BIT | DS1347_OSF_BIT, 0);
}
static const struct rtc_class_ops ds1347_rtc_ops = {
@@ -123,12 +145,6 @@ static int ds1347_probe(struct spi_device *spi)
data = data & ~(1<<7);
regmap_write(map, DS1347_CONTROL_REG, data);
- /* Enable the oscillator , disable the oscillator stop flag,
- and glitch filter to reduce current consumption */
- regmap_read(map, DS1347_STATUS_REG, &data);
- data = data & 0x1B;
- regmap_write(map, DS1347_STATUS_REG, data);
-
rtc = devm_rtc_allocate_device(&spi->dev);
if (IS_ERR(rtc))
return PTR_ERR(rtc);