From: Chris Packham <chris.packham@alliedtelesis.co.nz>
Date: Mon, 27 Jul 2020 15:46:14 +1200
Subject: rtc: ds1307: provide an indication that the watchdog has fired

Git-commit: 9bf1306257589b3a5ad46175538af9922d94e26f
Patch-mainline: v5.9-rc1
References: jsc#SLE-12251

There's not much feedback when the ds1388 watchdog fires. Generally it
yanks on the reset line and the board reboots. Capture the fact that the
watchdog has fired in the past so that userspace can retrieve it via
WDIOC_GETBOOTSTATUS. This should help distinguish a watchdog triggered
reset from a power interruption.

Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20200727034615.19755-1-chris.packham@alliedtelesis.co.nz
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@suse.com>
---
 drivers/rtc/rtc-ds1307.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/drivers/rtc/rtc-ds1307.c b/drivers/rtc/rtc-ds1307.c
index 49702942bb08..54c85cdd019d 100644
--- a/drivers/rtc/rtc-ds1307.c
+++ b/drivers/rtc/rtc-ds1307.c
@@ -1668,6 +1668,8 @@ static const struct watchdog_ops ds1388_wdt_ops = {
 static void ds1307_wdt_register(struct ds1307 *ds1307)
 {
 	struct watchdog_device	*wdt;
+	int err;
+	int val;
 
 	if (ds1307->type != ds_1388)
 		return;
@@ -1676,6 +1678,10 @@ static void ds1307_wdt_register(struct ds1307 *ds1307)
 	if (!wdt)
 		return;
 
+	err = regmap_read(ds1307->regmap, DS1388_REG_FLAG, &val);
+	if (!err && val & DS1388_BIT_WF)
+		wdt->bootstatus = WDIOF_CARDRESET;
+
 	wdt->info = &ds1388_wdt_info;
 	wdt->ops = &ds1388_wdt_ops;
 	wdt->timeout = 99;
-- 
2.26.2