[PATCH v4 2/3] watchdog: dw_wdt: get reset lines from dt

[Steffen Trumtrar]

The dw_wdt has an external reset line, that can keep the device in reset
and therefore rendering it useless and also is the only way of stopping
the watchdog once it was started.

Get the reset lines for this core from the devicetree. As these lines are
optional, use devm_reset_control_get_optional_shared. If the reset line
is not specified in the devicetree, the reset framework will just skip
deasserting and continue.
This way all users of the driver will continue to function without
any harm, even if the reset line is not specified in the devicetree.

Signed-off-by: Steffen Trumtrar <s.trumtrar at pengutronix.de>
Cc: Wim Van Sebroeck <wim at iguana.be>
Cc: Guenter Roeck <linux at roeck-us.net>
Cc: linux-watchdog at vger.kernel.org
Reviewed-by: Philipp Zabel <p.zabel at pengutronix.de>
---
 drivers/watchdog/dw_wdt.c | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
index 914da3a4d334..36be987ff9ef 100644
--- a/drivers/watchdog/dw_wdt.c
+++ b/drivers/watchdog/dw_wdt.c
@@ -29,6 +29,7 @@
 #include <linux/of.h>
 #include <linux/pm.h>
 #include <linux/platform_device.h>
+#include <linux/reset.h>
 #include <linux/watchdog.h>
 
 #define WDOG_CONTROL_REG_OFFSET		    0x00
@@ -54,6 +55,7 @@ struct dw_wdt {
 	struct clk		*clk;
 	unsigned long		rate;
 	struct watchdog_device	wdd;
+	struct reset_control	*rst;
 };
 
 #define to_dw_wdt(wdd)	container_of(wdd, struct dw_wdt, wdd)
@@ -234,6 +236,14 @@ static int dw_wdt_drv_probe(struct platform_device *pdev)
 		goto out_disable_clk;
 	}
 
+	dw_wdt->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
+	if (IS_ERR(dw_wdt->rst)) {
+		ret = PTR_ERR(dw_wdt->rst);
+		goto out_disable_clk;
+	}
+
+	reset_control_deassert(dw_wdt->rst);
+
 	wdd = &dw_wdt->wdd;
 	wdd->info = &dw_wdt_ident;
 	wdd->ops = &dw_wdt_ops;
@@ -279,6 +289,7 @@ static int dw_wdt_drv_remove(struct platform_device *pdev)
 	struct dw_wdt *dw_wdt = platform_get_drvdata(pdev);
 
 	watchdog_unregister_device(&dw_wdt->wdd);
+	reset_control_assert(dw_wdt->rst);
 	clk_disable_unprepare(dw_wdt->clk);
 
 	return 0;
-- 
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