[PATCH v3 0/3] watchdog: dw_wdt: add reset lines

[PATCH v3 0/3] watchdog: dw_wdt: add reset lines

[Steffen Trumtrar]

Hi!

This series adds support for the reset line that is (potentially) holding
the watchdog in reset.

As the watchdog is useless if this happens, it needs to be deasserted in
the probe function.

Tested on a Socrates board.

Regards,
Steffen

Changes since v2:

  - use optional reset functions
  - add Acked-by to devicetree bindings

Changes since v1:

  - remove reset-names property
  - remove warning if reset property is missing

Steffen Trumtrar (3):
  watchdog: bindings: dw_wdt: add reset lines
  watchdog: dw_wdt: get reset lines from dt
  ARM: socfpga: dtsi: add dw-wdt reset lines

 Documentation/devicetree/bindings/watchdog/dw_wdt.txt |  3 +++
 arch/arm/boot/dts/socfpga.dtsi                        |  2 ++
 drivers/watchdog/dw_wdt.c                             |  9 +++++++++
 3 files changed, 14 insertions(+)

base-commit: 2ea659a9ef488125eb46da6eb571de5eae5c43f6
-- 
git-series 0.9.1

[PATCH v3 1/3] watchdog: bindings: dw_wdt: add reset lines

[Steffen Trumtrar]

Document the reset lines holding the watchdog core in reset.

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Rob Herring <robh+dt@kernel.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: linux-watchdog at vger.kernel.org
Cc: devicetree at vger.kernel.org
Acked-by: Rob Herring <robh@kernel.org>
---
 Documentation/devicetree/bindings/watchdog/dw_wdt.txt | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/Documentation/devicetree/bindings/watchdog/dw_wdt.txt b/Documentation/devicetree/bindings/watchdog/dw_wdt.txt
index 08e16f684f2d..eb0914420c7c 100644
--- a/Documentation/devicetree/bindings/watchdog/dw_wdt.txt
+++ b/Documentation/devicetree/bindings/watchdog/dw_wdt.txt
@@ -10,6 +10,8 @@ Required Properties:
 Optional Properties:
 
 - interrupts	: The interrupt used for the watchdog timeout warning.
+- resets	: phandle pointing to the system reset controller with
+		line index for the watchdog.
 
 Example:
 
@@ -18,4 +20,5 @@ Example:
 		reg = <0xffd02000 0x1000>;
 		interrupts = <0 171 4>;
 		clocks = <&per_base_clk>;
+		resets = <&rst WDT0_RESET>;
 	};
-- 
git-series 0.9.1

[PATCH v3 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@pengutronix.de>
Cc: Wim Van Sebroeck <wim@iguana.be>
Cc: Guenter Roeck <linux@roeck-us.net>
Cc: linux-watchdog at vger.kernel.org
---
 drivers/watchdog/dw_wdt.c |  9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
index 914da3a4d334..61cbae3a9331 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 +236,12 @@ 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))
+		return PTR_ERR(dw_wdt->rst);
+
+	reset_control_deassert(dw_wdt->rst);
+
 	wdd = &dw_wdt->wdd;
 	wdd->info = &dw_wdt_ident;
 	wdd->ops = &dw_wdt_ops;
@@ -278,6 +286,7 @@ static int dw_wdt_drv_remove(struct platform_device *pdev)
 {
 	struct dw_wdt *dw_wdt = platform_get_drvdata(pdev);
 
+	reset_control_assert(dw_wdt->rst);
 	watchdog_unregister_device(&dw_wdt->wdd);
 	clk_disable_unprepare(dw_wdt->clk);
 
-- 
git-series 0.9.1

[PATCH v3 2/3] watchdog: dw_wdt: get reset lines from dt

[Philipp Zabel]

On Thu, 2017-05-18 at 10:42 +0200, Steffen Trumtrar wrote:
> 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@pengutronix.de>
> Cc: Wim Van Sebroeck <wim@iguana.be>
> Cc: Guenter Roeck <linux@roeck-us.net>
> Cc: linux-watchdog at vger.kernel.org
> ---
>  drivers/watchdog/dw_wdt.c |  9 +++++++++
>  1 file changed, 9 insertions(+)
> 
> diff --git a/drivers/watchdog/dw_wdt.c b/drivers/watchdog/dw_wdt.c
> index 914da3a4d334..61cbae3a9331 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 +236,12 @@ static int dw_wdt_drv_probe(struct platform_device *pdev)
>  		goto out_disable_clk;

Sorry, I didn't notice this before.

>  	}
>  
> +	dw_wdt->rst = devm_reset_control_get_optional_shared(&pdev->dev, NULL);
> +	if (IS_ERR(dw_wdt->rst))
> +		return PTR_ERR(dw_wdt->rst);

This should either goto out_disable_clk, or the reset_control could be
acquired a bit earlier before enabling the clock.

> +
> +	reset_control_deassert(dw_wdt->rst);
> +
>  	wdd = &dw_wdt->wdd;
>  	wdd->info = &dw_wdt_ident;
>  	wdd->ops = &dw_wdt_ops;
> @@ -278,6 +286,7 @@ static int dw_wdt_drv_remove(struct platform_device *pdev)
>  {
>  	struct dw_wdt *dw_wdt = platform_get_drvdata(pdev);
>  
> +	reset_control_assert(dw_wdt->rst);

And I'd move this ...

>  	watchdog_unregister_device(&dw_wdt->wdd);

... here for symmetry.

>  	clk_disable_unprepare(dw_wdt->clk);
>  

Otherwise,
Reviewed-by: Philipp Zabel <p.zabel@pengutronix.de>

regards
Philipp

[PATCH v3 3/3] ARM: socfpga: dtsi: add dw-wdt reset lines

[Steffen Trumtrar]

Add the reset lines to both watchdogs.

Signed-off-by: Steffen Trumtrar <s.trumtrar@pengutronix.de>
Cc: Dinh Nguyen <dinguyen@opensource.altera.com>
Cc: linux-arm-kernel at lists.infradead.org
---
 arch/arm/boot/dts/socfpga.dtsi | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/arch/arm/boot/dts/socfpga.dtsi b/arch/arm/boot/dts/socfpga.dtsi
index b2674bdb8e6a..547b2720abf5 100644
--- a/arch/arm/boot/dts/socfpga.dtsi
+++ b/arch/arm/boot/dts/socfpga.dtsi
@@ -924,6 +924,7 @@
 			reg = <0xffd02000 0x1000>;
 			interrupts = <0 171 4>;
 			clocks = <&osc1>;
+			resets = <&rst L4WD0_RESET>;
 			status = "disabled";
 		};
 
@@ -932,6 +933,7 @@
 			reg = <0xffd03000 0x1000>;
 			interrupts = <0 172 4>;
 			clocks = <&osc1>;
+			resets = <&rst L4WD1_RESET>;
 			status = "disabled";
 		};
 	};
-- 
git-series 0.9.1