[PATCH] rtc: pcf2127: handle boot-enabled watchdog feature

["Martin Hundebøll" <martin@geanix.com>]

Linux should handle when the pcf2127 watchdog feature is enabled by the
bootloader. This is done by checking the watchdog timer value during
init, and set the WDOG_HW_RUNNING flag if the value differs from zero.

Signed-off-by: Martin Hundebøll <martin@geanix.com>
---
 drivers/rtc/rtc-pcf2127.c | 14 +++++++++++++-
 1 file changed, 13 insertions(+), 1 deletion(-)

diff --git a/drivers/rtc/rtc-pcf2127.c b/drivers/rtc/rtc-pcf2127.c
index cb3472f..0fd3f3e 100644
--- a/drivers/rtc/rtc-pcf2127.c
+++ b/drivers/rtc/rtc-pcf2127.c
@@ -290,6 +290,8 @@ static int pcf2127_wdt_active_ping(struct watchdog_device *wdd)
 
 static int pcf2127_wdt_start(struct watchdog_device *wdd)
 {
+	set_bit(WDOG_HW_RUNNING, &wdd->status);
+
 	return pcf2127_wdt_ping(wdd);
 }
 
@@ -420,6 +422,7 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
 			const char *name, bool has_nvmem)
 {
 	struct pcf2127 *pcf2127;
+	u32 wdd_timeout;
 	int ret = 0;
 
 	dev_dbg(dev, "%s\n", __func__);
@@ -462,7 +465,6 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
 	/*
 	 * Watchdog timer enabled and reset pin /RST activated when timed out.
 	 * Select 1Hz clock source for watchdog timer.
-	 * Timer is not started until WD_VAL is loaded with a valid value.
 	 * Note: Countdown timer disabled and not available.
 	 */
 	ret = regmap_update_bits(pcf2127->regmap, PCF2127_REG_WD_CTL,
@@ -478,6 +480,16 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
 		return ret;
 	}
 
+	/* Test if watchdog timer is started by bootloader */
+	ret = regmap_read(pcf2127->regmap, PCF2127_REG_WD_VAL, &wdd_timeout);
+	if (ret) {
+		dev_err(dev, "%s: watchdog value (wd_wal) failed\n", __func__);
+		return ret;
+	}
+
+	if (wdd_timeout)
+		set_bit(WDOG_HW_RUNNING, &pcf2127->wdd.status);
+
 	ret = devm_watchdog_register_device(dev, &pcf2127->wdd);
 	if (ret)
 		return ret;
-- 
2.7.4