watchdog: rzg2l_wdt: Add rzv2m support

The WDT on RZ/V2M devices is basically the same as RZ/G2L, but without
the parity error registers. This means the driver has to reset the
hardware plus set the minimum timeout in order to do a restart and has
a single interrupt.

Signed-off-by: Phil Edworthy <phil.edworthy@renesas.com>
Reviewed-by: Biju Das <biju.das.jz@bp.renesas.com>
Reviewed-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Link: https://lore.kernel.org/r/20220823093233.8577-3-phil.edworthy@renesas.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Wim Van Sebroeck <wim@linux-watchdog.org>

drivers/watchdog/rzg2l_wdt.c

@@ -10,7 +10,7 @@
 #include <linux/io.h>
 #include <linux/kernel.h>
 #include <linux/module.h>
-#include <linux/of.h>
+#include <linux/of_device.h>
 #include <linux/platform_device.h>
 #include <linux/pm_runtime.h>
 #include <linux/reset.h>
@@ -40,6 +40,11 @@ module_param(nowayout, bool, 0);
 MODULE_PARM_DESC(nowayout, "Watchdog cannot be stopped once started (default="
 				__MODULE_STRING(WATCHDOG_NOWAYOUT) ")");
 
+enum rz_wdt_type {
+	WDT_RZG2L,
+	WDT_RZV2M,
+};
+
 struct rzg2l_wdt_priv {
 	void __iomem *base;
 	struct watchdog_device wdev;
@@ -48,6 +53,7 @@ struct rzg2l_wdt_priv {
 	unsigned long delay;
 	struct clk *pclk;
 	struct clk *osc_clk;
+	enum rz_wdt_type devtype;
 };
 
 static void rzg2l_wdt_wait_delay(struct rzg2l_wdt_priv *priv)
@@ -142,11 +148,29 @@ static int rzg2l_wdt_restart(struct watchdog_device *wdev,
 	clk_prepare_enable(priv->pclk);
 	clk_prepare_enable(priv->osc_clk);
 
-	/* Generate Reset (WDTRSTB) Signal on parity error */
-	rzg2l_wdt_write(priv, 0, PECR);
+	if (priv->devtype == WDT_RZG2L) {
+		/* Generate Reset (WDTRSTB) Signal on parity error */
+		rzg2l_wdt_write(priv, 0, PECR);
+
+		/* Force parity error */
+		rzg2l_wdt_write(priv, PEEN_FORCE, PEEN);
+	} else {
+		/* RZ/V2M doesn't have parity error registers */
+
+		wdev->timeout = 0;
+
+		/* Initialize time out */
+		rzg2l_wdt_init_timeout(wdev);
 
-	/* Force parity error */
-	rzg2l_wdt_write(priv, PEEN_FORCE, PEEN);
+		/* Initialize watchdog counter register */
+		rzg2l_wdt_write(priv, 0, WDTTIM);
+
+		/* Enable watchdog timer*/
+		rzg2l_wdt_write(priv, WDTCNT_WDTEN, WDTCNT);
+
+		/* Wait 2 consecutive overflow cycles for reset */
+		mdelay(DIV_ROUND_UP(2 * 0xFFFFF * 1000, priv->osc_clk_rate));
+	}
 
 	return 0;
 }
@@ -227,6 +251,8 @@ static int rzg2l_wdt_probe(struct platform_device *pdev)
 	if (ret)
 		return dev_err_probe(dev, ret, "failed to deassert");
 
+	priv->devtype = (uintptr_t)of_device_get_match_data(dev);
+
 	pm_runtime_enable(&pdev->dev);
 
 	priv->wdev.info = &rzg2l_wdt_ident;
@@ -255,7 +281,8 @@ static int rzg2l_wdt_probe(struct platform_device *pdev)
 }
 
 static const struct of_device_id rzg2l_wdt_ids[] = {
-	{ .compatible = "renesas,rzg2l-wdt", },
+	{ .compatible = "renesas,rzg2l-wdt", .data = (void *)WDT_RZG2L },
+	{ .compatible = "renesas,rzv2m-wdt", .data = (void *)WDT_RZV2M },
 	{ /* sentinel */ }
 };
 MODULE_DEVICE_TABLE(of, rzg2l_wdt_ids);