linux-kernel - [PATCH v3 2/4] watchdog: da9062: reset board on watchdog timeout

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Message-Id: <20211201081512.3580837-2-andrej.picej@norik.com>
Date:   Wed,  1 Dec 2021 09:15:10 +0100
From:   Andrej Picej <andrej.picej@...ik.com>
To:     support.opensource@...semi.com, linux@...ck-us.net,
        linux-watchdog@...r.kernel.org
Cc:     andrej.picej@...ik.com, wim@...ux-watchdog.org,
        linux-kernel@...r.kernel.org, robh+dt@...nel.org,
        devicetree@...r.kernel.org, shawnguo@...nel.org,
        s.hauer@...gutronix.de, kernel@...gutronix.de, festevam@...il.com,
        linux-imx@....com, linux-arm-kernel@...ts.infradead.org
Subject: [PATCH v3 2/4] watchdog: da9062: reset board on watchdog timeout

Implement a method to change watchdog timeout configuration based on DT
binding ("dlg,wdt-sd"). There is a possibility to change the bahaviour
of watchdog reset. Setting WATCHDOG_SD bit enables SHUTDOWN mode, and
clearing it enables POWERDOWN mode on watchdog timeout.

If no DT binding is specified the WATCHDOG_SD bit stays in default
configuration, not breaking behaviour of devices which might depend on
default fuse configuration.

Note: This patch requires that the config register CONFIG_I is
configured as writable in the da9062 multi function device.

Signed-off-by: Andrej Picej <andrej.picej@...ik.com>
---
Changes in v3:
 - no changes

Changes in v2:
 - don't force the "reset" for all da9062-watchdog users, instead add DT
   binding where the behavior can be selected
---
 drivers/watchdog/da9062_wdt.c | 25 +++++++++++++++++++++++++
 1 file changed, 25 insertions(+)

diff --git a/drivers/watchdog/da9062_wdt.c b/drivers/watchdog/da9062_wdt.c
index f02cbd530538..e342e9e50cb1 100644
--- a/drivers/watchdog/da9062_wdt.c
+++ b/drivers/watchdog/da9062_wdt.c
@@ -85,8 +85,33 @@ static int da9062_wdt_start(struct watchdog_device *wdd)
 {
 	struct da9062_watchdog *wdt = watchdog_get_drvdata(wdd);
 	unsigned int selector;
+	unsigned int mask;
+	u32 val;
 	int ret;
 
+	/* Configure what happens on watchdog timeout. Can be specified with
+	 * "dlg,wdt-sd" dt-binding (0 -> POWERDOWN, 1 -> SHUTDOWN).
+	 * If "dlg,wdt-sd" dt-binding is NOT set use the default.
+	 */
+	ret = device_property_read_u32(wdd->parent, "dlg,wdt-sd", &val);
+	if (!ret) {
+		if (val)
+			/* Use da9062's SHUTDOWN mode */
+			mask = DA9062AA_WATCHDOG_SD_MASK;
+		else
+			/* Use da9062's POWERDOWN mode. */
+			mask = 0x0;
+
+		ret = regmap_update_bits(wdt->hw->regmap,
+						DA9062AA_CONFIG_I,
+						DA9062AA_WATCHDOG_SD_MASK,
+						mask);
+
+		if (ret)
+			dev_err(wdt->hw->dev, "failed to set wdt reset mode: %d\n",
+				ret);
+	}
+
 	selector = da9062_wdt_timeout_to_sel(wdt->wdtdev.timeout);
 	ret = da9062_wdt_update_timeout_register(wdt, selector);
 	if (ret)
-- 
2.25.1