rtc: pcf2127: move watchdog initialisation to a separate function

The obvious advantages are:

 - The linker can drop the watchdog functions if CONFIG_WATCHDOG is off.
 - All watchdog stuff grouped together with only a single function call
   left in generic code.
 - Watchdog register is only read when it is actually used.
 - Less #ifdefery
Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Alexandre Belloni <alexandre.belloni@bootlin.com>
Link: https://lore.kernel.org/r/20200924105256.18162-2-u.kleine-koenig@pengutronix.de

drivers/rtc/rtc-pcf2127.c

@@ -335,6 +335,36 @@ static const struct watchdog_ops pcf2127_watchdog_ops = {
 	.set_timeout = pcf2127_wdt_set_timeout,
 };
 
+static int pcf2127_watchdog_init(struct device *dev, struct pcf2127 *pcf2127)
+{
+	u32 wdd_timeout;
+	int ret;
+
+	if (!IS_ENABLED(CONFIG_WATCHDOG))
+		return 0;
+
+	pcf2127->wdd.parent = dev;
+	pcf2127->wdd.info = &pcf2127_wdt_info;
+	pcf2127->wdd.ops = &pcf2127_watchdog_ops;
+	pcf2127->wdd.min_timeout = PCF2127_WD_VAL_MIN;
+	pcf2127->wdd.max_timeout = PCF2127_WD_VAL_MAX;
+	pcf2127->wdd.timeout = PCF2127_WD_VAL_DEFAULT;
+	pcf2127->wdd.min_hw_heartbeat_ms = 500;
+	pcf2127->wdd.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
+
+	watchdog_set_drvdata(&pcf2127->wdd, pcf2127);
+
+	/* Test if watchdog timer is started by bootloader */
+	ret = regmap_read(pcf2127->regmap, PCF2127_REG_WD_VAL, &wdd_timeout);
+	if (ret)
+		return ret;
+
+	if (wdd_timeout)
+		set_bit(WDOG_HW_RUNNING, &pcf2127->wdd.status);
+
+	return devm_watchdog_register_device(dev, &pcf2127->wdd);
+}
+
 /* Alarm */
 static int pcf2127_rtc_read_alarm(struct device *dev, struct rtc_wkalrm *alrm)
 {
@@ -536,7 +566,6 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
 			 int alarm_irq, const char *name, bool has_nvmem)
 {
 	struct pcf2127 *pcf2127;
-	u32 wdd_timeout;
 	int ret = 0;
 
 	dev_dbg(dev, "%s\n", __func__);
@@ -575,17 +604,6 @@ static int pcf2127_probe(struct device *dev, struct regmap *regmap,
 		pcf2127->rtc->ops = &pcf2127_rtc_alrm_ops;
 	}
 
-	pcf2127->wdd.parent = dev;
-	pcf2127->wdd.info = &pcf2127_wdt_info;
-	pcf2127->wdd.ops = &pcf2127_watchdog_ops;
-	pcf2127->wdd.min_timeout = PCF2127_WD_VAL_MIN;
-	pcf2127->wdd.max_timeout = PCF2127_WD_VAL_MAX;
-	pcf2127->wdd.timeout = PCF2127_WD_VAL_DEFAULT;
-	pcf2127->wdd.min_hw_heartbeat_ms = 500;
-	pcf2127->wdd.status = WATCHDOG_NOWAYOUT_INIT_STATUS;
-
-	watchdog_set_drvdata(&pcf2127->wdd, pcf2127);
-
 	if (has_nvmem) {
 		struct nvmem_config nvmem_cfg = {
 			.priv = pcf2127,
@@ -615,19 +633,7 @@ 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)
-		return ret;
-
-	if (wdd_timeout)
-		set_bit(WDOG_HW_RUNNING, &pcf2127->wdd.status);
-
-#ifdef CONFIG_WATCHDOG
-	ret = devm_watchdog_register_device(dev, &pcf2127->wdd);
-	if (ret)
-		return ret;
-#endif /* CONFIG_WATCHDOG */
+	pcf2127_watchdog_init(dev, pcf2127);
 
 	/*
 	 * Disable battery low/switch-over timestamp and interrupts.