watchdog: sama5d4: Cache MR instead of a partial config

.config is used to cache a part of WDT_MR at probe time and is not used
afterwards. Instead of doing that, actually cache MR and avoid reading it
every time it is modified.
Signed-off-by: Alexandre Belloni <alexandre.belloni@free-electrons.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

drivers/watchdog/sama5d4_wdt.c

@@ -28,7 +28,7 @@
 struct sama5d4_wdt {
 	struct watchdog_device	wdd;
 	void __iomem		*reg_base;
-	u32	config;
+	u32			mr;
 };
 
 static int wdt_timeout = WDT_DEFAULT_TIMEOUT;
@@ -53,11 +53,9 @@ MODULE_PARM_DESC(nowayout,
 static int sama5d4_wdt_start(struct watchdog_device *wdd)
 {
 	struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
-	u32 reg;
 
-	reg = wdt_read(wdt, AT91_WDT_MR);
-	reg &= ~AT91_WDT_WDDIS;
-	wdt_write(wdt, AT91_WDT_MR, reg);
+	wdt->mr &= ~AT91_WDT_WDDIS;
+	wdt_write(wdt, AT91_WDT_MR, wdt->mr);
 
 	return 0;
 }
@@ -65,11 +63,9 @@ static int sama5d4_wdt_start(struct watchdog_device *wdd)
 static int sama5d4_wdt_stop(struct watchdog_device *wdd)
 {
 	struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
-	u32 reg;
 
-	reg = wdt_read(wdt, AT91_WDT_MR);
-	reg |= AT91_WDT_WDDIS;
-	wdt_write(wdt, AT91_WDT_MR, reg);
+	wdt->mr |= AT91_WDT_WDDIS;
+	wdt_write(wdt, AT91_WDT_MR, wdt->mr);
 
 	return 0;
 }
@@ -88,14 +84,12 @@ static int sama5d4_wdt_set_timeout(struct watchdog_device *wdd,
 {
 	struct sama5d4_wdt *wdt = watchdog_get_drvdata(wdd);
 	u32 value = WDT_SEC2TICKS(timeout);
-	u32 reg;
 
-	reg = wdt_read(wdt, AT91_WDT_MR);
-	reg &= ~AT91_WDT_WDV;
-	reg &= ~AT91_WDT_WDD;
-	reg |= AT91_WDT_SET_WDV(value);
-	reg |= AT91_WDT_SET_WDD(value);
-	wdt_write(wdt, AT91_WDT_MR, reg);
+	wdt->mr &= ~AT91_WDT_WDV;
+	wdt->mr &= ~AT91_WDT_WDD;
+	wdt->mr |= AT91_WDT_SET_WDV(value);
+	wdt->mr |= AT91_WDT_SET_WDD(value);
+	wdt_write(wdt, AT91_WDT_MR, wdt->mr);
 
 	wdd->timeout = timeout;
 
@@ -132,19 +126,19 @@ static int of_sama5d4_wdt_init(struct device_node *np, struct sama5d4_wdt *wdt)
 {
 	const char *tmp;
 
-	wdt->config = AT91_WDT_WDDIS;
+	wdt->mr = AT91_WDT_WDDIS;
 
 	if (!of_property_read_string(np, "atmel,watchdog-type", &tmp) &&
 	    !strcmp(tmp, "software"))
-		wdt->config |= AT91_WDT_WDFIEN;
+		wdt->mr |= AT91_WDT_WDFIEN;
 	else
-		wdt->config |= AT91_WDT_WDRSTEN;
+		wdt->mr |= AT91_WDT_WDRSTEN;
 
 	if (of_property_read_bool(np, "atmel,idle-halt"))
-		wdt->config |= AT91_WDT_WDIDLEHLT;
+		wdt->mr |= AT91_WDT_WDIDLEHLT;
 
 	if (of_property_read_bool(np, "atmel,dbg-halt"))
-		wdt->config |= AT91_WDT_WDDBGHLT;
+		wdt->mr |= AT91_WDT_WDDBGHLT;
 
 	return 0;
 }
@@ -163,11 +157,10 @@ static int sama5d4_wdt_init(struct sama5d4_wdt *wdt)
 	reg &= ~AT91_WDT_WDDIS;
 	wdt_write(wdt, AT91_WDT_MR, reg);
 
-	reg = wdt->config;
-	reg |= AT91_WDT_SET_WDD(value);
-	reg |= AT91_WDT_SET_WDV(value);
+	wdt->mr |= AT91_WDT_SET_WDD(value);
+	wdt->mr |= AT91_WDT_SET_WDV(value);
 
-	wdt_write(wdt, AT91_WDT_MR, reg);
+	wdt_write(wdt, AT91_WDT_MR, wdt->mr);
 
 	return 0;
 }
@@ -211,7 +204,7 @@ static int sama5d4_wdt_probe(struct platform_device *pdev)
 			return ret;
 	}
 
-	if ((wdt->config & AT91_WDT_WDFIEN) && irq) {
+	if ((wdt->mr & AT91_WDT_WDFIEN) && irq) {
 		ret = devm_request_irq(&pdev->dev, irq, sama5d4_wdt_irq_handler,
 				       IRQF_SHARED | IRQF_IRQPOLL |
 				       IRQF_NO_SUSPEND, pdev->name, pdev);