Factor out checking and fixing the weekday.
In addition fix two issues with the old implementation:
- For variable timestamp use correct type time64_t instead of
unsigned long which may be just 32bit long.
- Updating the weekday register only may be racy, therefore write all
timekeeping registers.
Signed-off-by: Heiner Kallweit <hkallweit1@xxxxxxxxx>
---
drivers/rtc/rtc-ds1307.c | 42 +++++++++++++++++++++++++-----------------
1 file changed, 25 insertions(+), 17 deletions(-)
diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index ea88e4b3..69f514b6 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -1368,6 +1368,29 @@ static void ds1307_trickle_init(struct ds1307 *ds1307)
}
}
+static void ds1307_fix_weekday(struct ds1307 *ds1307)
+{
+ struct rtc_time tm;
+ time64_t timestamp;
+ int wday;
+
+ if (ds1307_get_time(ds1307->dev, &tm))
+ return;
+
+ wday = tm.tm_wday;
+ timestamp = rtc_tm_to_time64(&tm);
+ rtc_time64_to_tm(timestamp, &tm);
+
+ /*
+ * Check if reset wday is different from the computed wday
+ * If different then set the wday which we computed using
+ * timestamp
+ * Set not only wday but complete date to avoid potential races.
+ */
+ if (wday != tm.tm_wday)
+ ds1307_set_time(ds1307->dev, &tm);
+}
+
static const struct regmap_config regmap_config = {
.reg_bits = 8,
.val_bits = 8,
@@ -1378,13 +1401,11 @@ static int ds1307_probe(struct i2c_client *client,
{
struct ds1307 *ds1307;
int err = -ENODEV;
- int tmp, wday;
+ int tmp;
const struct chip_desc *chip;
bool want_irq;
bool ds1307_can_wakeup_device = false;
unsigned char *buf;
- struct rtc_time tm;
- unsigned long timestamp;
ds1307 = devm_kzalloc(&client->dev, sizeof(struct ds1307), GFP_KERNEL);
if (!ds1307)
@@ -1642,20 +1663,7 @@ static int ds1307_probe(struct i2c_client *client,
* Some IPs have weekday reset value = 0x1 which might not correct
* hence compute the wday using the current date/month/year values
*/
- ds1307_get_time(ds1307->dev, &tm);
- wday = tm.tm_wday;
- timestamp = rtc_tm_to_time64(&tm);
- rtc_time64_to_tm(timestamp, &tm);
-
- /*
- * Check if reset wday is different from the computed wday
- * If different then set the wday which we computed using
- * timestamp
- */
- if (wday != tm.tm_wday)
- regmap_update_bits(ds1307->regmap, MCP794XX_REG_WEEKDAY,
- MCP794XX_REG_WEEKDAY_WDAY_MASK,
- tm.tm_wday + 1);
+ ds1307_fix_weekday(ds1307);
if (want_irq || ds1307_can_wakeup_device) {
device_set_wakeup_capable(ds1307->dev, true);
--
2.14.1
