linux-kernel - [PATCH] watchdog: imx_sc_wdt: Don't disable WDT in suspend

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Message-ID: <20240801121845.1465765-1-jonas.blixt@actia.se>
Date: Thu, 1 Aug 2024 14:18:45 +0200
From: Jonas Blixt <jonas.blixt@...ia.se>
To: <wim@...ux-watchdog.org>, <linux@...ck-us.net>, <shawnguo@...nel.org>,
	<s.hauer@...gutronix.de>, <kernel@...gutronix.de>, <festevam@...il.com>,
	<linux-watchdog@...r.kernel.org>, <imx@...ts.linux.dev>,
	<linux-arm-kernel@...ts.infradead.org>, <linux-kernel@...r.kernel.org>
CC: <john.ernberg@...ia.se>, Jonas Blixt <jonas.blixt@...ia.se>, Anson Huang
	<anson.huang@....com>
Subject: [PATCH] watchdog: imx_sc_wdt: Don't disable WDT in suspend

Parts of the suspend and resume chain is left unprotected if we disable
the WDT here.

>From experiments we can see that the SCU disables and re-enables the WDT
when we enter and leave suspend to ram. By not touching the WDT here we
are protected by the WDT all the way to the SCU.

CC: Anson Huang <anson.huang@....com>
Fixes: 986857acbc9a ("watchdog: imx_sc: Add i.MX system controller watchdog support")
Signed-off-by: Jonas Blixt <jonas.blixt@...ia.se>
---
 drivers/watchdog/imx_sc_wdt.c | 24 ------------------------
 1 file changed, 24 deletions(-)

diff --git a/drivers/watchdog/imx_sc_wdt.c b/drivers/watchdog/imx_sc_wdt.c
index e51fe1b78518..d73076b686d8 100644
--- a/drivers/watchdog/imx_sc_wdt.c
+++ b/drivers/watchdog/imx_sc_wdt.c
@@ -216,29 +216,6 @@ static int imx_sc_wdt_probe(struct platform_device *pdev)
 	return devm_watchdog_register_device(dev, wdog);
 }
 
-static int __maybe_unused imx_sc_wdt_suspend(struct device *dev)
-{
-	struct imx_sc_wdt_device *imx_sc_wdd = dev_get_drvdata(dev);
-
-	if (watchdog_active(&imx_sc_wdd->wdd))
-		imx_sc_wdt_stop(&imx_sc_wdd->wdd);
-
-	return 0;
-}
-
-static int __maybe_unused imx_sc_wdt_resume(struct device *dev)
-{
-	struct imx_sc_wdt_device *imx_sc_wdd = dev_get_drvdata(dev);
-
-	if (watchdog_active(&imx_sc_wdd->wdd))
-		imx_sc_wdt_start(&imx_sc_wdd->wdd);
-
-	return 0;
-}
-
-static SIMPLE_DEV_PM_OPS(imx_sc_wdt_pm_ops,
-			 imx_sc_wdt_suspend, imx_sc_wdt_resume);
-
 static const struct of_device_id imx_sc_wdt_dt_ids[] = {
 	{ .compatible = "fsl,imx-sc-wdt", },
 	{ /* sentinel */ }
@@ -250,7 +227,6 @@ static struct platform_driver imx_sc_wdt_driver = {
 	.driver		= {
 		.name	= "imx-sc-wdt",
 		.of_match_table = imx_sc_wdt_dt_ids,
-		.pm	= &imx_sc_wdt_pm_ops,
 	},
 };
 module_platform_driver(imx_sc_wdt_driver);
-- 
2.34.1