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authorPaul Kocialkowski <paul.kocialkowski@bootlin.com>2019-12-12 16:31:11 +0100
committerAlexandre Belloni <alexandre.belloni@bootlin.com>2019-12-23 11:18:06 +0100
commite2ed7507ae89b92b67025f221448b543e2333b21 (patch)
tree525ea891e51431438de58b95a7198efa81fac5f2 /drivers/rtc
parentf236a2a2ebabad0848ad0995af7ad1dc7029e895 (diff)
downloadlinux-e2ed7507ae89b92b67025f221448b543e2333b21.tar.bz2
rtc: hym8563: Read the valid flag directly instead of caching it
The RTC has a valid bit in the seconds register that indicates whether power was lost since the pevious time set. This bit is currently read once at probe time, cached and updated with set_time. Howeever, caching the bit may prevent detecting power loss at runtime (which can happen if the RTC's supply is distinct from the the platform's). Writing the seconds register when setting time will clear the bit, so there should be no downside in reading the bit directly instead of caching it. Signed-off-by: Paul Kocialkowski <paul.kocialkowski@bootlin.com> Link: https://lore.kernel.org/r/20191212153111.966923-2-paul.kocialkowski@bootlin.com Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Diffstat (limited to 'drivers/rtc')
-rw-r--r--drivers/rtc/rtc-hym8563.c19
1 files changed, 7 insertions, 12 deletions
diff --git a/drivers/rtc/rtc-hym8563.c b/drivers/rtc/rtc-hym8563.c
index fb6d7967ec00..0fb79c4afb46 100644
--- a/drivers/rtc/rtc-hym8563.c
+++ b/drivers/rtc/rtc-hym8563.c
@@ -78,7 +78,6 @@
struct hym8563 {
struct i2c_client *client;
struct rtc_device *rtc;
- bool valid;
#ifdef CONFIG_COMMON_CLK
struct clk_hw clkout_hw;
#endif
@@ -91,19 +90,19 @@ struct hym8563 {
static int hym8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
{
struct i2c_client *client = to_i2c_client(dev);
- struct hym8563 *hym8563 = i2c_get_clientdata(client);
u8 buf[7];
int ret;
- if (!hym8563->valid) {
- dev_warn(&client->dev, "no valid clock/calendar values available\n");
- return -EINVAL;
- }
-
ret = i2c_smbus_read_i2c_block_data(client, HYM8563_SEC, 7, buf);
if (ret < 0)
return ret;
+ if (buf[0] & HYM8563_SEC_VL) {
+ dev_warn(&client->dev,
+ "no valid clock/calendar values available\n");
+ return -EINVAL;
+ }
+
tm->tm_sec = bcd2bin(buf[0] & HYM8563_SEC_MASK);
tm->tm_min = bcd2bin(buf[1] & HYM8563_MIN_MASK);
tm->tm_hour = bcd2bin(buf[2] & HYM8563_HOUR_MASK);
@@ -118,7 +117,6 @@ static int hym8563_rtc_read_time(struct device *dev, struct rtc_time *tm)
static int hym8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
{
struct i2c_client *client = to_i2c_client(dev);
- struct hym8563 *hym8563 = i2c_get_clientdata(client);
u8 buf[7];
int ret;
@@ -157,8 +155,6 @@ static int hym8563_rtc_set_time(struct device *dev, struct rtc_time *tm)
if (ret < 0)
return ret;
- hym8563->valid = true;
-
return 0;
}
@@ -556,9 +552,8 @@ static int hym8563_probe(struct i2c_client *client,
if (ret < 0)
return ret;
- hym8563->valid = !(ret & HYM8563_SEC_VL);
dev_dbg(&client->dev, "rtc information is %s\n",
- hym8563->valid ? "valid" : "invalid");
+ (ret & HYM8563_SEC_VL) ? "invalid" : "valid");
hym8563->rtc = devm_rtc_device_register(&client->dev, client->name,
&hym8563_rtc_ops, THIS_MODULE);