[PATCH] AT91: DT: Watchdog, remove property idle halt by default

[PATCH] AT91: DT: Watchdog, remove property idle halt by default

[Sylvain Rochet]

The behavior changed when watchdog properties were added to DT, it makes
the watchdog not counting when CPU is in idle state, therefore the
watchdog reset time depend on mean CPU usage and will not reset at all
if the CPU stop working while it is in idle state, which is a very weird
behavior.

Apply principle of least surprise on at91sam9260-wdt by removing idle
halt flag by default.

Signed-off-by: Sylvain Rochet <sylvain.rochet@finsecur.com>
---
 arch/arm/boot/dts/at91sam9x5.dtsi | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/arm/boot/dts/at91sam9x5.dtsi b/arch/arm/boot/dts/at91sam9x5.dtsi
index bbb3ba6..ce61f91 100644
--- a/arch/arm/boot/dts/at91sam9x5.dtsi
+++ b/arch/arm/boot/dts/at91sam9x5.dtsi
@@ -1125,7 +1125,6 @@
 				atmel,watchdog-type = "hardware";
 				atmel,reset-type = "all";
 				atmel,dbg-halt;
-				atmel,idle-halt;
 				status = "disabled";
 			};
 
-- 
2.1.4

[PATCH] AT91: DT: Watchdog, remove property idle halt by default

[Sylvain Rochet]

The behavior changed when watchdog properties were added to DT, it makes
the watchdog not counting when CPU is in idle state, therefore the
watchdog reset time depend on mean CPU usage and will not reset at all
if the CPU stop working while it is in idle state, which is a very weird
behavior.

Apply principle of least surprise on at91sam9260-wdt by removing idle
halt flag by default.

Signed-off-by: Sylvain Rochet <sylvain.rochet@finsecur.com>
---
 arch/arm/boot/dts/at91sam9x5.dtsi | 1 -
 1 file changed, 1 deletion(-)

diff --git a/arch/arm/boot/dts/at91sam9x5.dtsi b/arch/arm/boot/dts/at91sam9x5.dtsi
index bbb3ba6..ce61f91 100644
--- a/arch/arm/boot/dts/at91sam9x5.dtsi
+++ b/arch/arm/boot/dts/at91sam9x5.dtsi
@@ -1125,7 +1125,6 @@
 				atmel,watchdog-type = "hardware";
 				atmel,reset-type = "all";
 				atmel,dbg-halt;
-				atmel,idle-halt;
 				status = "disabled";
 			};
 
-- 
2.1.4

Re: [PATCH] AT91: DT: Watchdog, remove property idle halt by default

[Boris Brezillon]

Hi Sylvain,

On Sat, 17 Jan 2015 22:49:56 +0100
Sylvain Rochet <sylvain.rochet-ETtyaVkrhkNWk0Htik3J/w@public.gmane.org> wrote:

> The behavior changed when watchdog properties were added to DT, it makes
> the watchdog not counting when CPU is in idle state, therefore the
> watchdog reset time depend on mean CPU usage and will not reset at all
> if the CPU stop working while it is in idle state, which is a very weird
> behavior.
> 
> Apply principle of least surprise on at91sam9260-wdt by removing idle
> halt flag by default.
> 
> Signed-off-by: Sylvain Rochet <sylvain.rochet-ETtyaVkrhkNWk0Htik3J/w@public.gmane.org>

Can you do this change for all impacted SoCs (here is a patch
doing it [1]) ?

Apart from that you can add my:

Acked-by: Boris Brezillon <boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>

Best Regards,

Boris

[1]http://code.bulix.org/weg3zv-87745

> ---
>  arch/arm/boot/dts/at91sam9x5.dtsi | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/arch/arm/boot/dts/at91sam9x5.dtsi b/arch/arm/boot/dts/at91sam9x5.dtsi
> index bbb3ba6..ce61f91 100644
> --- a/arch/arm/boot/dts/at91sam9x5.dtsi
> +++ b/arch/arm/boot/dts/at91sam9x5.dtsi
> @@ -1125,7 +1125,6 @@
>  				atmel,watchdog-type = "hardware";
>  				atmel,reset-type = "all";
>  				atmel,dbg-halt;
> -				atmel,idle-halt;
>  				status = "disabled";
>  			};
>  



-- 
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Embedded Linux and Kernel engineering
http://free-electrons.com
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[PATCH] AT91: DT: Watchdog, remove property idle halt by default

[Boris Brezillon]

Hi Sylvain,

On Sat, 17 Jan 2015 22:49:56 +0100
Sylvain Rochet <sylvain.rochet@finsecur.com> wrote:

> The behavior changed when watchdog properties were added to DT, it makes
> the watchdog not counting when CPU is in idle state, therefore the
> watchdog reset time depend on mean CPU usage and will not reset at all
> if the CPU stop working while it is in idle state, which is a very weird
> behavior.
> 
> Apply principle of least surprise on at91sam9260-wdt by removing idle
> halt flag by default.
> 
> Signed-off-by: Sylvain Rochet <sylvain.rochet@finsecur.com>

Can you do this change for all impacted SoCs (here is a patch
doing it [1]) ?

Apart from that you can add my:

Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>

Best Regards,

Boris

[1]http://code.bulix.org/weg3zv-87745

> ---
>  arch/arm/boot/dts/at91sam9x5.dtsi | 1 -
>  1 file changed, 1 deletion(-)
> 
> diff --git a/arch/arm/boot/dts/at91sam9x5.dtsi b/arch/arm/boot/dts/at91sam9x5.dtsi
> index bbb3ba6..ce61f91 100644
> --- a/arch/arm/boot/dts/at91sam9x5.dtsi
> +++ b/arch/arm/boot/dts/at91sam9x5.dtsi
> @@ -1125,7 +1125,6 @@
>  				atmel,watchdog-type = "hardware";
>  				atmel,reset-type = "all";
>  				atmel,dbg-halt;
> -				atmel,idle-halt;
>  				status = "disabled";
>  			};
>  



-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com

[PATCHv2 0/2] dts: AT91 Watchdog, remove property idle halt by default

[Sylvain Rochet]

Change since v1:
  * Apply this change for all impacted SoCs
  * Improved DTS documentation about this property

Sylvain Rochet (2):
  dts: Documentation: AT91 Watchdog, explain what atmel,idle-halt
    property really do
  dts: AT91 Watchdog, remove property idle halt by default

 Documentation/devicetree/bindings/watchdog/atmel-wdt.txt | 5 +++++
 arch/arm/boot/dts/at91sam9260.dtsi                       | 1 -
 arch/arm/boot/dts/at91sam9263.dtsi                       | 1 -
 arch/arm/boot/dts/at91sam9g45.dtsi                       | 1 -
 arch/arm/boot/dts/at91sam9n12.dtsi                       | 1 -
 arch/arm/boot/dts/at91sam9x5.dtsi                        | 1 -
 arch/arm/boot/dts/sama5d3.dtsi                           | 1 -
 7 files changed, 5 insertions(+), 6 deletions(-)

-- 
2.1.4

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[PATCHv2 0/2] dts: AT91 Watchdog, remove property idle halt by default

[Sylvain Rochet]

Change since v1:
  * Apply this change for all impacted SoCs
  * Improved DTS documentation about this property

Sylvain Rochet (2):
  dts: Documentation: AT91 Watchdog, explain what atmel,idle-halt
    property really do
  dts: AT91 Watchdog, remove property idle halt by default

 Documentation/devicetree/bindings/watchdog/atmel-wdt.txt | 5 +++++
 arch/arm/boot/dts/at91sam9260.dtsi                       | 1 -
 arch/arm/boot/dts/at91sam9263.dtsi                       | 1 -
 arch/arm/boot/dts/at91sam9g45.dtsi                       | 1 -
 arch/arm/boot/dts/at91sam9n12.dtsi                       | 1 -
 arch/arm/boot/dts/at91sam9x5.dtsi                        | 1 -
 arch/arm/boot/dts/sama5d3.dtsi                           | 1 -
 7 files changed, 5 insertions(+), 6 deletions(-)

-- 
2.1.4

[PATCHv2 1/2] dts: Documentation: AT91 Watchdog, explain what atmel,idle-halt property really do

[Sylvain Rochet]

atmel,idle-halt property should be used with care, it actually makes the
watchdog not counting when the CPU is in idle state, therefore the
watchdog reset time depends on mean CPU usage and will not reset at all
of the CPU stop working while it is in idle state, which is probably not
what you want.

Signed-off-by: Sylvain Rochet <sylvain.rochet-ETtyaVkrhkNWk0Htik3J/w@public.gmane.org>
---
 Documentation/devicetree/bindings/watchdog/atmel-wdt.txt | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt b/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt
index f90e294..a4d8697 100644
--- a/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt
+++ b/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt
@@ -26,6 +26,11 @@ Optional properties:
 - atmel,disable : Should be present if you want to disable the watchdog.
 - atmel,idle-halt : Should be present if you want to stop the watchdog when
 	entering idle state.
+	CAUTION: This property should be used with care, it actually makes the
+	watchdog not counting when the CPU is in idle state, therefore the
+	watchdog reset time depends on mean CPU usage and will not reset at all
+	if the CPU stop working while it is in idle state, which is probably
+	not what you want.
 - atmel,dbg-halt : Should be present if you want to stop the watchdog when
 	entering debug state.
 
-- 
2.1.4

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[PATCHv2 1/2] dts: Documentation: AT91 Watchdog, explain what atmel, idle-halt property really do

[Sylvain Rochet]

atmel,idle-halt property should be used with care, it actually makes the
watchdog not counting when the CPU is in idle state, therefore the
watchdog reset time depends on mean CPU usage and will not reset at all
of the CPU stop working while it is in idle state, which is probably not
what you want.

Signed-off-by: Sylvain Rochet <sylvain.rochet@finsecur.com>
---
 Documentation/devicetree/bindings/watchdog/atmel-wdt.txt | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt b/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt
index f90e294..a4d8697 100644
--- a/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt
+++ b/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt
@@ -26,6 +26,11 @@ Optional properties:
 - atmel,disable : Should be present if you want to disable the watchdog.
 - atmel,idle-halt : Should be present if you want to stop the watchdog when
 	entering idle state.
+	CAUTION: This property should be used with care, it actually makes the
+	watchdog not counting when the CPU is in idle state, therefore the
+	watchdog reset time depends on mean CPU usage and will not reset at all
+	if the CPU stop working while it is in idle state, which is probably
+	not what you want.
 - atmel,dbg-halt : Should be present if you want to stop the watchdog when
 	entering debug state.
 
-- 
2.1.4

[PATCHv2 2/2] dts: AT91 Watchdog, remove property idle halt by default

[Sylvain Rochet]

The behavior changed when watchdog properties were added to DT, it makes
the watchdog not counting when CPU is in idle state, therefore the
watchdog reset time depends on mean CPU usage and will not reset at all
if the CPU stop working while it is in idle state, which is a very weird
behavior.

Apply principle of least surprise on at91sam9260-wdt by removing idle
halt flag by default.

Signed-off-by: Sylvain Rochet <sylvain.rochet-ETtyaVkrhkNWk0Htik3J/w@public.gmane.org>
---
Acked-by: Boris Brezillon <boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>
 arch/arm/boot/dts/at91sam9260.dtsi | 1 -
 arch/arm/boot/dts/at91sam9263.dtsi | 1 -
 arch/arm/boot/dts/at91sam9g45.dtsi | 1 -
 arch/arm/boot/dts/at91sam9n12.dtsi | 1 -
 arch/arm/boot/dts/at91sam9x5.dtsi  | 1 -
 arch/arm/boot/dts/sama5d3.dtsi     | 1 -
 6 files changed, 6 deletions(-)

diff --git a/arch/arm/boot/dts/at91sam9260.dtsi b/arch/arm/boot/dts/at91sam9260.dtsi
index dd1313c..184e1d1 100644
--- a/arch/arm/boot/dts/at91sam9260.dtsi
+++ b/arch/arm/boot/dts/at91sam9260.dtsi
@@ -971,7 +971,6 @@
 				atmel,watchdog-type = "hardware";
 				atmel,reset-type = "all";
 				atmel,dbg-halt;
-				atmel,idle-halt;
 				status = "disabled";
 			};
 
diff --git a/arch/arm/boot/dts/at91sam9263.dtsi b/arch/arm/boot/dts/at91sam9263.dtsi
index 1467750..c39556b 100644
--- a/arch/arm/boot/dts/at91sam9263.dtsi
+++ b/arch/arm/boot/dts/at91sam9263.dtsi
@@ -874,7 +874,6 @@
 				atmel,watchdog-type = "hardware";
 				atmel,reset-type = "all";
 				atmel,dbg-halt;
-				atmel,idle-halt;
 				status = "disabled";
 			};
 
diff --git a/arch/arm/boot/dts/at91sam9g45.dtsi b/arch/arm/boot/dts/at91sam9g45.dtsi
index 2a8da8a..b8d741d 100644
--- a/arch/arm/boot/dts/at91sam9g45.dtsi
+++ b/arch/arm/boot/dts/at91sam9g45.dtsi
@@ -1111,7 +1111,6 @@
 				atmel,watchdog-type = "hardware";
 				atmel,reset-type = "all";
 				atmel,dbg-halt;
-				atmel,idle-halt;
 				status = "disabled";
 			};
 
diff --git a/arch/arm/boot/dts/at91sam9n12.dtsi b/arch/arm/boot/dts/at91sam9n12.dtsi
index 68eb9ad..e0b5c24 100644
--- a/arch/arm/boot/dts/at91sam9n12.dtsi
+++ b/arch/arm/boot/dts/at91sam9n12.dtsi
@@ -889,7 +889,6 @@
 				atmel,watchdog-type = "hardware";
 				atmel,reset-type = "all";
 				atmel,dbg-halt;
-				atmel,idle-halt;
 				status = "disabled";
 			};
 
diff --git a/arch/arm/boot/dts/at91sam9x5.dtsi b/arch/arm/boot/dts/at91sam9x5.dtsi
index bbb3ba6..ce61f91 100644
--- a/arch/arm/boot/dts/at91sam9x5.dtsi
+++ b/arch/arm/boot/dts/at91sam9x5.dtsi
@@ -1125,7 +1125,6 @@
 				atmel,watchdog-type = "hardware";
 				atmel,reset-type = "all";
 				atmel,dbg-halt;
-				atmel,idle-halt;
 				status = "disabled";
 			};
 
diff --git a/arch/arm/boot/dts/sama5d3.dtsi b/arch/arm/boot/dts/sama5d3.dtsi
index 5f4144d..63d12ed 100644
--- a/arch/arm/boot/dts/sama5d3.dtsi
+++ b/arch/arm/boot/dts/sama5d3.dtsi
@@ -1224,7 +1224,6 @@
 				atmel,watchdog-type = "hardware";
 				atmel,reset-type = "all";
 				atmel,dbg-halt;
-				atmel,idle-halt;
 				status = "disabled";
 			};
 
-- 
2.1.4

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[PATCHv2 2/2] dts: AT91 Watchdog, remove property idle halt by default

[Sylvain Rochet]

The behavior changed when watchdog properties were added to DT, it makes
the watchdog not counting when CPU is in idle state, therefore the
watchdog reset time depends on mean CPU usage and will not reset at all
if the CPU stop working while it is in idle state, which is a very weird
behavior.

Apply principle of least surprise on at91sam9260-wdt by removing idle
halt flag by default.

Signed-off-by: Sylvain Rochet <sylvain.rochet@finsecur.com>
---
Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>
 arch/arm/boot/dts/at91sam9260.dtsi | 1 -
 arch/arm/boot/dts/at91sam9263.dtsi | 1 -
 arch/arm/boot/dts/at91sam9g45.dtsi | 1 -
 arch/arm/boot/dts/at91sam9n12.dtsi | 1 -
 arch/arm/boot/dts/at91sam9x5.dtsi  | 1 -
 arch/arm/boot/dts/sama5d3.dtsi     | 1 -
 6 files changed, 6 deletions(-)

diff --git a/arch/arm/boot/dts/at91sam9260.dtsi b/arch/arm/boot/dts/at91sam9260.dtsi
index dd1313c..184e1d1 100644
--- a/arch/arm/boot/dts/at91sam9260.dtsi
+++ b/arch/arm/boot/dts/at91sam9260.dtsi
@@ -971,7 +971,6 @@
 				atmel,watchdog-type = "hardware";
 				atmel,reset-type = "all";
 				atmel,dbg-halt;
-				atmel,idle-halt;
 				status = "disabled";
 			};
 
diff --git a/arch/arm/boot/dts/at91sam9263.dtsi b/arch/arm/boot/dts/at91sam9263.dtsi
index 1467750..c39556b 100644
--- a/arch/arm/boot/dts/at91sam9263.dtsi
+++ b/arch/arm/boot/dts/at91sam9263.dtsi
@@ -874,7 +874,6 @@
 				atmel,watchdog-type = "hardware";
 				atmel,reset-type = "all";
 				atmel,dbg-halt;
-				atmel,idle-halt;
 				status = "disabled";
 			};
 
diff --git a/arch/arm/boot/dts/at91sam9g45.dtsi b/arch/arm/boot/dts/at91sam9g45.dtsi
index 2a8da8a..b8d741d 100644
--- a/arch/arm/boot/dts/at91sam9g45.dtsi
+++ b/arch/arm/boot/dts/at91sam9g45.dtsi
@@ -1111,7 +1111,6 @@
 				atmel,watchdog-type = "hardware";
 				atmel,reset-type = "all";
 				atmel,dbg-halt;
-				atmel,idle-halt;
 				status = "disabled";
 			};
 
diff --git a/arch/arm/boot/dts/at91sam9n12.dtsi b/arch/arm/boot/dts/at91sam9n12.dtsi
index 68eb9ad..e0b5c24 100644
--- a/arch/arm/boot/dts/at91sam9n12.dtsi
+++ b/arch/arm/boot/dts/at91sam9n12.dtsi
@@ -889,7 +889,6 @@
 				atmel,watchdog-type = "hardware";
 				atmel,reset-type = "all";
 				atmel,dbg-halt;
-				atmel,idle-halt;
 				status = "disabled";
 			};
 
diff --git a/arch/arm/boot/dts/at91sam9x5.dtsi b/arch/arm/boot/dts/at91sam9x5.dtsi
index bbb3ba6..ce61f91 100644
--- a/arch/arm/boot/dts/at91sam9x5.dtsi
+++ b/arch/arm/boot/dts/at91sam9x5.dtsi
@@ -1125,7 +1125,6 @@
 				atmel,watchdog-type = "hardware";
 				atmel,reset-type = "all";
 				atmel,dbg-halt;
-				atmel,idle-halt;
 				status = "disabled";
 			};
 
diff --git a/arch/arm/boot/dts/sama5d3.dtsi b/arch/arm/boot/dts/sama5d3.dtsi
index 5f4144d..63d12ed 100644
--- a/arch/arm/boot/dts/sama5d3.dtsi
+++ b/arch/arm/boot/dts/sama5d3.dtsi
@@ -1224,7 +1224,6 @@
 				atmel,watchdog-type = "hardware";
 				atmel,reset-type = "all";
 				atmel,dbg-halt;
-				atmel,idle-halt;
 				status = "disabled";
 			};
 
-- 
2.1.4

Re: [PATCHv2 1/2] dts: Documentation: AT91 Watchdog, explain what atmel,idle-halt property really do

[Boris Brezillon]

On Sun, 18 Jan 2015 14:26:50 +0100
Sylvain Rochet <sylvain.rochet-ETtyaVkrhkNWk0Htik3J/w@public.gmane.org> wrote:

> atmel,idle-halt property should be used with care, it actually makes the
> watchdog not counting when the CPU is in idle state, therefore the
> watchdog reset time depends on mean CPU usage and will not reset at all
> of the CPU stop working while it is in idle state, which is probably not
> what you want.
> 
> Signed-off-by: Sylvain Rochet <sylvain.rochet-ETtyaVkrhkNWk0Htik3J/w@public.gmane.org>

Acked-by: Boris Brezillon <boris.brezillon-wi1+55ScJUtKEb57/3fJTNBPR1lH4CV8@public.gmane.org>

> ---
>  Documentation/devicetree/bindings/watchdog/atmel-wdt.txt | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt b/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt
> index f90e294..a4d8697 100644
> --- a/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt
> +++ b/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt
> @@ -26,6 +26,11 @@ Optional properties:
>  - atmel,disable : Should be present if you want to disable the watchdog.
>  - atmel,idle-halt : Should be present if you want to stop the watchdog when
>  	entering idle state.
> +	CAUTION: This property should be used with care, it actually makes the
> +	watchdog not counting when the CPU is in idle state, therefore the
> +	watchdog reset time depends on mean CPU usage and will not reset at all
> +	if the CPU stop working while it is in idle state, which is probably
> +	not what you want.
>  - atmel,dbg-halt : Should be present if you want to stop the watchdog when
>  	entering debug state.
>  



-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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To unsubscribe from this list: send the line "unsubscribe devicetree" in
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[PATCHv2 1/2] dts: Documentation: AT91 Watchdog, explain what atmel,idle-halt property really do

[Boris Brezillon]

On Sun, 18 Jan 2015 14:26:50 +0100
Sylvain Rochet <sylvain.rochet@finsecur.com> wrote:

> atmel,idle-halt property should be used with care, it actually makes the
> watchdog not counting when the CPU is in idle state, therefore the
> watchdog reset time depends on mean CPU usage and will not reset at all
> of the CPU stop working while it is in idle state, which is probably not
> what you want.
> 
> Signed-off-by: Sylvain Rochet <sylvain.rochet@finsecur.com>

Acked-by: Boris Brezillon <boris.brezillon@free-electrons.com>

> ---
>  Documentation/devicetree/bindings/watchdog/atmel-wdt.txt | 5 +++++
>  1 file changed, 5 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt b/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt
> index f90e294..a4d8697 100644
> --- a/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt
> +++ b/Documentation/devicetree/bindings/watchdog/atmel-wdt.txt
> @@ -26,6 +26,11 @@ Optional properties:
>  - atmel,disable : Should be present if you want to disable the watchdog.
>  - atmel,idle-halt : Should be present if you want to stop the watchdog when
>  	entering idle state.
> +	CAUTION: This property should be used with care, it actually makes the
> +	watchdog not counting when the CPU is in idle state, therefore the
> +	watchdog reset time depends on mean CPU usage and will not reset at all
> +	if the CPU stop working while it is in idle state, which is probably
> +	not what you want.
>  - atmel,dbg-halt : Should be present if you want to stop the watchdog when
>  	entering debug state.
>  



-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com