linux-kernel - [PATCH 3/3] rtc: pcf8523: report oscillator failures

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Date:   Sun, 18 Apr 2021 02:20:23 +0200
From:   Alexandre Belloni <alexandre.belloni@...tlin.com>
To:     Alessandro Zummo <a.zummo@...ertech.it>,
        Alexandre Belloni <alexandre.belloni@...tlin.com>
Cc:     linux-rtc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 3/3] rtc: pcf8523: report oscillator failures

Report oscillator failures and invalid date/time on RTC_VL_READ.

Signed-off-by: Alexandre Belloni <alexandre.belloni@...tlin.com>
---
 drivers/rtc/rtc-pcf8523.c | 13 +++++++++++--
 1 file changed, 11 insertions(+), 2 deletions(-)

diff --git a/drivers/rtc/rtc-pcf8523.c b/drivers/rtc/rtc-pcf8523.c
index feadab8e3bd3..bb23379bbfc7 100644
--- a/drivers/rtc/rtc-pcf8523.c
+++ b/drivers/rtc/rtc-pcf8523.c
@@ -406,6 +406,8 @@ static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
 			     unsigned long arg)
 {
 	struct i2c_client *client = to_i2c_client(dev);
+	unsigned int flags = 0;
+	u8 value;
 	int ret;
 
 	switch (cmd) {
@@ -414,9 +416,16 @@ static int pcf8523_rtc_ioctl(struct device *dev, unsigned int cmd,
 		if (ret < 0)
 			return ret;
 		if (ret)
-			ret = RTC_VL_BACKUP_LOW;
+			flags |= RTC_VL_BACKUP_LOW;
+
+		ret = pcf8523_read(client, REG_SECONDS, &value);
+		if (ret < 0)
+			return ret;
+
+		if (value & REG_SECONDS_OS)
+			flags |= RTC_VL_DATA_INVALID;
 
-		return put_user(ret, (unsigned int __user *)arg);
+		return put_user(flags, (unsigned int __user *)arg);
 
 	default:
 		return -ENOIOCTLCMD;
-- 
2.30.2