linux-kernel - [PATCH v1] watchdog: meson: keep running if already active

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Date:   Tue,  5 Jul 2022 16:24:44 +0200
From:   Philippe Boos <pboos@...libre.com>
To:     Wim Van Sebroeck <wim@...ux-watchdog.org>,
        Guenter Roeck <linux@...ck-us.net>,
        Neil Armstrong <narmstrong@...libre.com>
Cc:     Philippe Boos <pboos@...libre.com>,
        Kevin Hilman <khilman@...libre.com>,
        Jerome Brunet <jbrunet@...libre.com>,
        Martin Blumenstingl <martin.blumenstingl@...glemail.com>,
        linux-watchdog@...r.kernel.org,
        linux-arm-kernel@...ts.infradead.org,
        linux-amlogic@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [PATCH v1] watchdog: meson: keep running if already active

If the watchdog is already running (e.g.: started by bootloader) then
the kernel driver should keep the watchdog active but the amlogic driver
turns it off.

Let the driver fix the clock rate then restart the watchdog if it was
previously active.

Reviewed-by: Jerome Brunet <jbrunet@...libre.com>
Signed-off-by: Philippe Boos <pboos@...libre.com>
---
 drivers/watchdog/meson_gxbb_wdt.c | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/drivers/watchdog/meson_gxbb_wdt.c b/drivers/watchdog/meson_gxbb_wdt.c
index 5a9ca10fbcfa..8c2c6f7f3bb5 100644
--- a/drivers/watchdog/meson_gxbb_wdt.c
+++ b/drivers/watchdog/meson_gxbb_wdt.c
@@ -146,6 +146,7 @@ static int meson_gxbb_wdt_probe(struct platform_device *pdev)
 	struct device *dev = &pdev->dev;
 	struct meson_gxbb_wdt *data;
 	int ret;
+	u32 regval;
 
 	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
 	if (!data)
@@ -177,6 +178,8 @@ static int meson_gxbb_wdt_probe(struct platform_device *pdev)
 	data->wdt_dev.timeout = DEFAULT_TIMEOUT;
 	watchdog_set_drvdata(&data->wdt_dev, data);
 
+	regval = readl(data->reg_base + GXBB_WDT_CTRL_REG);
+
 	/* Setup with 1ms timebase */
 	writel(((clk_get_rate(data->clk) / 1000) & GXBB_WDT_CTRL_DIV_MASK) |
 		GXBB_WDT_CTRL_EE_RESET |
@@ -186,6 +189,13 @@ static int meson_gxbb_wdt_probe(struct platform_device *pdev)
 
 	meson_gxbb_wdt_set_timeout(&data->wdt_dev, data->wdt_dev.timeout);
 
+	if ((regval & GXBB_WDT_CTRL_EN) != 0) {
+		ret = meson_gxbb_wdt_start(&data->wdt_dev);
+		if (ret)
+			return ret;
+		set_bit(WDOG_HW_RUNNING, &data->wdt_dev.status);
+	}
+
 	watchdog_stop_on_reboot(&data->wdt_dev);
 	return devm_watchdog_register_device(dev, &data->wdt_dev);
 }
-- 
2.20.1