[PATCH v4 0/2] Add ASPEED watchdog device tree properties

[PATCH v4 0/2] Add ASPEED watchdog device tree properties

[Christopher Bostic]

Document device tree optional properties for ASPEED watchdog.
Reference properties in ASPEED watchdog driver and configure accordingly.

Christopher Bostic (2):
  drivers/watchdog: Add optional ASPEED device tree properties
  drivers/watchdog: ASPEED reference dev tree properties for config

 .../devicetree/bindings/watchdog/aspeed-wdt.txt    | 35 ++++++++++++++++++++++
 drivers/watchdog/aspeed_wdt.c                      | 27 +++++++++++++----
 2 files changed, 57 insertions(+), 5 deletions(-)

-- 
1.8.2.2

[PATCH v4 1/2] drivers/watchdog: Add optional ASPEED device tree properties

[Christopher Bostic]

Describe device tree optional properties:

  * aspeed,reset-type = "cpu|soc|system|none"
     One of three different, mutually exclusive, values

	"cpu" : ARM CPU reset on signal
	"soc" : 'System on chip' reset
	"system" : Full system reset

     The value can also be set to "none" which indicates that no
     reset of any kind is to be done via this watchdog.  This assumes
     another watchdog on the chip is to take care of resets.

  * aspeed,interrupt - Interrupt CPU on signal
  * aspeed,external-signal - Generate external signal (WDT1 and WDT2 only)
  * aspeed,alt-boot - Boot from alternate block on signal

Signed-off-by: Christopher Bostic <cbostic@linux.vnet.ibm.com>
---
v4 - Add aspeed-reset-type and assign one of four values,
     cpu, soc, system, none.
v3 - Invert soc and sys reset to 'no' to preserve backwards
     compatibility.  SOC and SYS reset will be set by default
     without any optional parameters set
v2 - Add 'aspeed,' prefix to all optional properties
   - Add arm-reset, soc-reset, interrupt, alt-boot properties
---
 .../devicetree/bindings/watchdog/aspeed-wdt.txt    | 35 ++++++++++++++++++++++
 1 file changed, 35 insertions(+)

diff --git a/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt b/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
index c5e74d7..f526b00 100644
--- a/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
+++ b/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
@@ -8,9 +8,44 @@ Required properties:
  - reg: physical base address of the controller and length of memory mapped
    region
 
+Optional properties:
+
+ - aspeed,reset-type = "cpu|soc|system|none"
+
+   Reset behavior - Whenever a timeout occurs the watchdog can be programmed
+   to generate one of three different, mutually exclusive, types of resets.
+
+   Type "none" can be specified to indicate that no resets are to be done.
+   This is useful in situations where another watchdog engine on chip is
+   to perform the reset.
+
+   If 'aspeed,reset-type=' is not specfied the default is to enable system
+   reset.
+
+   Reset types:
+
+        - cpu: Reset CPU on watchdog timeout
+
+        - soc: Reset 'System on Chip' on watchdog timeout
+
+        - system: Reset system on watchdog timeout
+
+        - none: No reset is performed on timeout. Assumes another watchdog
+                engine is responsible for this.
+
+ - aspeed,interrupt:	If property is present then interrupt CPU.
+			If not specified then don't interrupt CPU.
+
+ - aspeed,external-signal: If property is present then signal is sent to
+			external reset counter (only WDT1 and WDT2). If not
+			specified no external signal is sent.
+ - aspeed,alt-boot:    If property is present then boot from alternate block.
+
 Example:
 
 	wdt1: watchdog@1e785000 {
 		compatible = "aspeed,ast2400-wdt";
 		reg = <0x1e785000 0x1c>;
+		aspeed,reset-type = "system";
+		aspeed,external-signal;
 	};
-- 
1.8.2.2

[PATCH v4 2/2] drivers/watchdog: ASPEED reference dev tree properties for config

[Christopher Bostic]

Reference the system device tree when configuring the watchdog
engines. If property 'aspeed,reset_type' is present then set
reset behavior based on the specified value.  This can be one of
three different mutually exclusive values
  * cpu - Reset CPU only on watchdog timeout
  * soc - Reset System on Chip
  * system - Full system reset

No reset can also be specified by indicating:
  * none - No reset, assumes another watchdog is responsible for
           this.

Add optional property 'aspeed,external-signal'. If present then
configure to generate external signal on watchdog timeout.

Signed-off-by: Christopher Bostic <cbostic-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
---
v4 - Change the three reset type parameters to a new property
     'aspeed,reset_type' and check assignment for one of four
     different values, cpu, soc, system, none
v3 - Invert the logic for system reset dev tree property to
     preserve backwards compatibility. If not specified the
     default is to configure for system reset
   - Add check for 'aspeed,no-soc-reset' property and only if
     not present is SOC reset to be configured.  This preserves
     backwards compatibility.
v2 - Change of_get_property() to of_property_read_bool()
   - Remove redundant check for NULL struct device_node pointer
   - Optional property names now start with prefix 'aspeed,'
---
 drivers/watchdog/aspeed_wdt.c | 27 ++++++++++++++++++++++-----
 1 file changed, 22 insertions(+), 5 deletions(-)

diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
index 1c65258..3ca79565 100644
--- a/drivers/watchdog/aspeed_wdt.c
+++ b/drivers/watchdog/aspeed_wdt.c
@@ -36,6 +36,7 @@ struct aspeed_wdt {
 #define WDT_CTRL		0x0C
 #define   WDT_CTRL_RESET_MODE_SOC	(0x00 << 5)
 #define   WDT_CTRL_RESET_MODE_FULL_CHIP	(0x01 << 5)
+#define   WDT_CTRL_RESET_MODE_ARM_CPU	(0x10 << 5)
 #define   WDT_CTRL_1MHZ_CLK		BIT(4)
 #define   WDT_CTRL_WDT_EXT		BIT(3)
 #define   WDT_CTRL_WDT_INTR		BIT(2)
@@ -140,6 +141,8 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
 {
 	struct aspeed_wdt *wdt;
 	struct resource *res;
+	struct device_node *np;
+	const char *reset_type;
 	int ret;
 
 	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
@@ -164,14 +167,28 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
 	wdt->wdd.timeout = WDT_DEFAULT_TIMEOUT;
 	watchdog_init_timeout(&wdt->wdd, 0, &pdev->dev);
 
+	wdt->ctrl = WDT_CTRL_1MHZ_CLK;
+
 	/*
 	 * Control reset on a per-device basis to ensure the
-	 * host is not affected by a BMC reboot, so only reset
-	 * the SOC and not the full chip
+	 * host is not affected by a BMC reboot
 	 */
-	wdt->ctrl = WDT_CTRL_RESET_MODE_SOC |
-		WDT_CTRL_1MHZ_CLK |
-		WDT_CTRL_RESET_SYSTEM;
+	np = pdev->dev.of_node;
+	ret = of_property_read_string(np, "aspeed,reset-type", &reset_type);
+	if (ret) {
+		wdt->ctrl |= WDT_CTRL_RESET_SYSTEM;
+	} else {
+		if (!strcmp(reset_type, "cpu"))
+			wdt->ctrl |= WDT_CTRL_RESET_MODE_ARM_CPU;
+		else if (!strcmp(reset_type, "soc"))
+			wdt->ctrl |= WDT_CTRL_RESET_MODE_SOC;
+		else if (!strcmp(reset_type, "system"))
+			wdt->ctrl |= WDT_CTRL_RESET_SYSTEM;
+	}
+	if (of_property_read_bool(np, "aspeed,external-signal"))
+		wdt->ctrl |= WDT_CTRL_WDT_EXT;
+
+	writel(wdt->ctrl, wdt->base + WDT_CTRL);
 
 	if (readl(wdt->base + WDT_CTRL) & WDT_CTRL_ENABLE)  {
 		aspeed_wdt_start(&wdt->wdd);
-- 
1.8.2.2

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Re: [v4, 2/2] drivers/watchdog: ASPEED reference dev tree properties for config

[Guenter Roeck]

On Thu, Jul 06, 2017 at 07:49:00PM -0500, Christopher Bostic wrote:
> Reference the system device tree when configuring the watchdog
> engines. If property 'aspeed,reset_type' is present then set
> reset behavior based on the specified value.  This can be one of
> three different mutually exclusive values
>   * cpu - Reset CPU only on watchdog timeout
>   * soc - Reset System on Chip
>   * system - Full system reset
> 
> No reset can also be specified by indicating:
>   * none - No reset, assumes another watchdog is responsible for
>            this.
> 
> Add optional property 'aspeed,external-signal'. If present then
> configure to generate external signal on watchdog timeout.
> 
> Signed-off-by: Christopher Bostic <cbostic-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
> ---
> v4 - Change the three reset type parameters to a new property
>      'aspeed,reset_type' and check assignment for one of four
>      different values, cpu, soc, system, none
> v3 - Invert the logic for system reset dev tree property to
>      preserve backwards compatibility. If not specified the
>      default is to configure for system reset
>    - Add check for 'aspeed,no-soc-reset' property and only if
>      not present is SOC reset to be configured.  This preserves
>      backwards compatibility.
> v2 - Change of_get_property() to of_property_read_bool()
>    - Remove redundant check for NULL struct device_node pointer
>    - Optional property names now start with prefix 'aspeed,'
> ---
>  drivers/watchdog/aspeed_wdt.c | 27 ++++++++++++++++++++++-----
>  1 file changed, 22 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
> index 1c65258..3ca79565 100644
> --- a/drivers/watchdog/aspeed_wdt.c
> +++ b/drivers/watchdog/aspeed_wdt.c
> @@ -36,6 +36,7 @@ struct aspeed_wdt {
>  #define WDT_CTRL		0x0C
>  #define   WDT_CTRL_RESET_MODE_SOC	(0x00 << 5)
>  #define   WDT_CTRL_RESET_MODE_FULL_CHIP	(0x01 << 5)
> +#define   WDT_CTRL_RESET_MODE_ARM_CPU	(0x10 << 5)
>  #define   WDT_CTRL_1MHZ_CLK		BIT(4)
>  #define   WDT_CTRL_WDT_EXT		BIT(3)
>  #define   WDT_CTRL_WDT_INTR		BIT(2)
> @@ -140,6 +141,8 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
>  {
>  	struct aspeed_wdt *wdt;
>  	struct resource *res;
> +	struct device_node *np;
> +	const char *reset_type;
>  	int ret;
>  
>  	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
> @@ -164,14 +167,28 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
>  	wdt->wdd.timeout = WDT_DEFAULT_TIMEOUT;
>  	watchdog_init_timeout(&wdt->wdd, 0, &pdev->dev);
>  
> +	wdt->ctrl = WDT_CTRL_1MHZ_CLK;
> +
>  	/*
>  	 * Control reset on a per-device basis to ensure the
> -	 * host is not affected by a BMC reboot, so only reset
> -	 * the SOC and not the full chip
> +	 * host is not affected by a BMC reboot
>  	 */
> -	wdt->ctrl = WDT_CTRL_RESET_MODE_SOC |
> -		WDT_CTRL_1MHZ_CLK |
> -		WDT_CTRL_RESET_SYSTEM;
> +	np = pdev->dev.of_node;
> +	ret = of_property_read_string(np, "aspeed,reset-type", &reset_type);
> +	if (ret) {
> +		wdt->ctrl |= WDT_CTRL_RESET_SYSTEM;
> +	} else {
> +		if (!strcmp(reset_type, "cpu"))
> +			wdt->ctrl |= WDT_CTRL_RESET_MODE_ARM_CPU;
> +		else if (!strcmp(reset_type, "soc"))
> +			wdt->ctrl |= WDT_CTRL_RESET_MODE_SOC; 
> +		else if (!strcmp(reset_type, "system"))
> +			wdt->ctrl |= WDT_CTRL_RESET_SYSTEM;

This silently accepts 'aspeed,reset-type="junk"' as "none".
I think it would be better to explicitly check for "none".

Also, if I remember the datasheet correctly, bit 1 (WDT_CTRL_RESET_SYSTEM)
enables the reset in general, and bit 5/6 specify the reset type.
With that in mind, I don't think the above will work as expected.
I think it would have to be

	WDT_CTRL_RESET_MODE_FULL_CHIP | WDT_CTRL_RESET_SYSTEM
	WDT_CTRL_RESET_MODE_SOC | WDT_CTRL_RESET_SYSTEM
	WDT_CTRL_RESET_MODE_ARM_CPU | WDT_CTRL_RESET_SYSTEM

To match the original code, the default should be

	WDT_CTRL_RESET_MODE_SOC | WDT_CTRL_RESET_SYSTEM

> +	}
> +	if (of_property_read_bool(np, "aspeed,external-signal"))
> +		wdt->ctrl |= WDT_CTRL_WDT_EXT;
> +
No plan to support the other new configuration flags ?

> +	writel(wdt->ctrl, wdt->base + WDT_CTRL);
>  
>  	if (readl(wdt->base + WDT_CTRL) & WDT_CTRL_ENABLE)  {
>  		aspeed_wdt_start(&wdt->wdd);
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Re: [v4, 1/2] drivers/watchdog: Add optional ASPEED device tree properties

[Guenter Roeck]

On Thu, Jul 06, 2017 at 07:48:59PM -0500, Christopher Bostic wrote:
> Describe device tree optional properties:
> 
>   * aspeed,reset-type = "cpu|soc|system|none"
>      One of three different, mutually exclusive, values
> 
> 	"cpu" : ARM CPU reset on signal
> 	"soc" : 'System on chip' reset
> 	"system" : Full system reset
> 
>      The value can also be set to "none" which indicates that no
>      reset of any kind is to be done via this watchdog.  This assumes
>      another watchdog on the chip is to take care of resets.
> 
>   * aspeed,interrupt - Interrupt CPU on signal

After thinking about that, I wonder if this is necessary. It could be
implied by providing an interrupt to the driver. The driver could then
set the interrupt configuration bit automatically.

[ And the bit by itself doesn't really make sense if the driver doesn't
  also register an interrupt handler ]

>   * aspeed,external-signal - Generate external signal (WDT1 and WDT2 only)
>   * aspeed,alt-boot - Boot from alternate block on signal
> 
> Signed-off-by: Christopher Bostic <cbostic-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
> ---
> v4 - Add aspeed-reset-type and assign one of four values,
>      cpu, soc, system, none.
> v3 - Invert soc and sys reset to 'no' to preserve backwards
>      compatibility.  SOC and SYS reset will be set by default
>      without any optional parameters set
> v2 - Add 'aspeed,' prefix to all optional properties
>    - Add arm-reset, soc-reset, interrupt, alt-boot properties
> ---
>  .../devicetree/bindings/watchdog/aspeed-wdt.txt    | 35 ++++++++++++++++++++++
>  1 file changed, 35 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt b/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
> index c5e74d7..f526b00 100644
> --- a/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
> +++ b/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
> @@ -8,9 +8,44 @@ Required properties:
>   - reg: physical base address of the controller and length of memory mapped
>     region
>  
> +Optional properties:
> +
> + - aspeed,reset-type = "cpu|soc|system|none"
> +
> +   Reset behavior - Whenever a timeout occurs the watchdog can be programmed
> +   to generate one of three different, mutually exclusive, types of resets.
> +
> +   Type "none" can be specified to indicate that no resets are to be done.
> +   This is useful in situations where another watchdog engine on chip is
> +   to perform the reset.
> +
> +   If 'aspeed,reset-type=' is not specfied the default is to enable system
> +   reset.
> +
> +   Reset types:
> +
> +        - cpu: Reset CPU on watchdog timeout
> +
> +        - soc: Reset 'System on Chip' on watchdog timeout
> +
> +        - system: Reset system on watchdog timeout
> +
> +        - none: No reset is performed on timeout. Assumes another watchdog
> +                engine is responsible for this.
> +
> + - aspeed,interrupt:	If property is present then interrupt CPU.
> +			If not specified then don't interrupt CPU.
> +
> + - aspeed,external-signal: If property is present then signal is sent to
> +			external reset counter (only WDT1 and WDT2). If not
> +			specified no external signal is sent.
> + - aspeed,alt-boot:    If property is present then boot from alternate block.
> +
>  Example:
>  
>  	wdt1: watchdog@1e785000 {
>  		compatible = "aspeed,ast2400-wdt";
>  		reg = <0x1e785000 0x1c>;
> +		aspeed,reset-type = "system";
> +		aspeed,external-signal;
>  	};
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Re: [v4, 2/2] drivers/watchdog: ASPEED reference dev tree properties for config

[Christopher Bostic]

On 7/8/17 9:55 AM, Guenter Roeck wrote:
> On Thu, Jul 06, 2017 at 07:49:00PM -0500, Christopher Bostic wrote:
>> Reference the system device tree when configuring the watchdog
>> engines. If property 'aspeed,reset_type' is present then set
>> reset behavior based on the specified value.  This can be one of
>> three different mutually exclusive values
>>    * cpu - Reset CPU only on watchdog timeout
>>    * soc - Reset System on Chip
>>    * system - Full system reset
>>
>> No reset can also be specified by indicating:
>>    * none - No reset, assumes another watchdog is responsible for
>>             this.
>>
>> Add optional property 'aspeed,external-signal'. If present then
>> configure to generate external signal on watchdog timeout.
>>
>> Signed-off-by: Christopher Bostic <cbostic-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
>> ---
>> v4 - Change the three reset type parameters to a new property
>>       'aspeed,reset_type' and check assignment for one of four
>>       different values, cpu, soc, system, none
>> v3 - Invert the logic for system reset dev tree property to
>>       preserve backwards compatibility. If not specified the
>>       default is to configure for system reset
>>     - Add check for 'aspeed,no-soc-reset' property and only if
>>       not present is SOC reset to be configured.  This preserves
>>       backwards compatibility.
>> v2 - Change of_get_property() to of_property_read_bool()
>>     - Remove redundant check for NULL struct device_node pointer
>>     - Optional property names now start with prefix 'aspeed,'
>> ---
>>   drivers/watchdog/aspeed_wdt.c | 27 ++++++++++++++++++++++-----
>>   1 file changed, 22 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/watchdog/aspeed_wdt.c b/drivers/watchdog/aspeed_wdt.c
>> index 1c65258..3ca79565 100644
>> --- a/drivers/watchdog/aspeed_wdt.c
>> +++ b/drivers/watchdog/aspeed_wdt.c
>> @@ -36,6 +36,7 @@ struct aspeed_wdt {
>>   #define WDT_CTRL		0x0C
>>   #define   WDT_CTRL_RESET_MODE_SOC	(0x00 << 5)
>>   #define   WDT_CTRL_RESET_MODE_FULL_CHIP	(0x01 << 5)
>> +#define   WDT_CTRL_RESET_MODE_ARM_CPU	(0x10 << 5)
>>   #define   WDT_CTRL_1MHZ_CLK		BIT(4)
>>   #define   WDT_CTRL_WDT_EXT		BIT(3)
>>   #define   WDT_CTRL_WDT_INTR		BIT(2)
>> @@ -140,6 +141,8 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
>>   {
>>   	struct aspeed_wdt *wdt;
>>   	struct resource *res;
>> +	struct device_node *np;
>> +	const char *reset_type;
>>   	int ret;
>>   
>>   	wdt = devm_kzalloc(&pdev->dev, sizeof(*wdt), GFP_KERNEL);
>> @@ -164,14 +167,28 @@ static int aspeed_wdt_probe(struct platform_device *pdev)
>>   	wdt->wdd.timeout = WDT_DEFAULT_TIMEOUT;
>>   	watchdog_init_timeout(&wdt->wdd, 0, &pdev->dev);
>>   
>> +	wdt->ctrl = WDT_CTRL_1MHZ_CLK;
>> +
>>   	/*
>>   	 * Control reset on a per-device basis to ensure the
>> -	 * host is not affected by a BMC reboot, so only reset
>> -	 * the SOC and not the full chip
>> +	 * host is not affected by a BMC reboot
>>   	 */
>> -	wdt->ctrl = WDT_CTRL_RESET_MODE_SOC |
>> -		WDT_CTRL_1MHZ_CLK |
>> -		WDT_CTRL_RESET_SYSTEM;
>> +	np = pdev->dev.of_node;
>> +	ret = of_property_read_string(np, "aspeed,reset-type", &reset_type);
>> +	if (ret) {
>> +		wdt->ctrl |= WDT_CTRL_RESET_SYSTEM;
>> +	} else {
>> +		if (!strcmp(reset_type, "cpu"))
>> +			wdt->ctrl |= WDT_CTRL_RESET_MODE_ARM_CPU;
>> +		else if (!strcmp(reset_type, "soc"))
>> +			wdt->ctrl |= WDT_CTRL_RESET_MODE_SOC;
>> +		else if (!strcmp(reset_type, "system"))
>> +			wdt->ctrl |= WDT_CTRL_RESET_SYSTEM;
> This silently accepts 'aspeed,reset-type="junk"' as "none".
> I think it would be better to explicitly check for "none".

Will add that check.
> Also, if I remember the datasheet correctly, bit 1 (WDT_CTRL_RESET_SYSTEM)
> enables the reset in general, and bit 5/6 specify the reset type.
> With that in mind, I don't think the above will work as expected.
> I think it would have to be
>
> 	WDT_CTRL_RESET_MODE_FULL_CHIP | WDT_CTRL_RESET_SYSTEM
> 	WDT_CTRL_RESET_MODE_SOC | WDT_CTRL_RESET_SYSTEM
> 	WDT_CTRL_RESET_MODE_ARM_CPU | WDT_CTRL_RESET_SYSTEM
>
> To match the original code, the default should be
>
> 	WDT_CTRL_RESET_MODE_SOC | WDT_CTRL_RESET_SYSTEM

Yes, true.  Will make the change in line above to match original code.

>> +	}
>> +	if (of_property_read_bool(np, "aspeed,external-signal"))
>> +		wdt->ctrl |= WDT_CTRL_WDT_EXT;
>> +
> No plan to support the other new configuration flags ?

No plan to support the other config flags at this time.

Thanks,
Chris
>
>> +	writel(wdt->ctrl, wdt->base + WDT_CTRL);
>>   
>>   	if (readl(wdt->base + WDT_CTRL) & WDT_CTRL_ENABLE)  {
>>   		aspeed_wdt_start(&wdt->wdd);

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Re: [v4, 1/2] drivers/watchdog: Add optional ASPEED device tree properties

[Christopher Bostic]

On 7/8/17 9:59 AM, Guenter Roeck wrote:
> On Thu, Jul 06, 2017 at 07:48:59PM -0500, Christopher Bostic wrote:
>> Describe device tree optional properties:
>>
>>    * aspeed,reset-type = "cpu|soc|system|none"
>>       One of three different, mutually exclusive, values
>>
>> 	"cpu" : ARM CPU reset on signal
>> 	"soc" : 'System on chip' reset
>> 	"system" : Full system reset
>>
>>       The value can also be set to "none" which indicates that no
>>       reset of any kind is to be done via this watchdog.  This assumes
>>       another watchdog on the chip is to take care of resets.
>>
>>    * aspeed,interrupt - Interrupt CPU on signal
> After thinking about that, I wonder if this is necessary. It could be
> implied by providing an interrupt to the driver. The driver could then
> set the interrupt configuration bit automatically.
>
> [ And the bit by itself doesn't really make sense if the driver doesn't
>    also register an interrupt handler ]

The 'aspeed,interrupt' property was added for the sake of documenting 
all potential hardware configurations.  There is no plan as of now to 
enable this so I'm inclined to just remove this part from the 
documentation.  When and if this function is ever used the optional 
property can be documented at that time.

Thanks,
Chris

>>    * aspeed,external-signal - Generate external signal (WDT1 and WDT2 only)
>>    * aspeed,alt-boot - Boot from alternate block on signal
>>
>> Signed-off-by: Christopher Bostic <cbostic-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
>> ---
>> v4 - Add aspeed-reset-type and assign one of four values,
>>       cpu, soc, system, none.
>> v3 - Invert soc and sys reset to 'no' to preserve backwards
>>       compatibility.  SOC and SYS reset will be set by default
>>       without any optional parameters set
>> v2 - Add 'aspeed,' prefix to all optional properties
>>     - Add arm-reset, soc-reset, interrupt, alt-boot properties
>> ---
>>   .../devicetree/bindings/watchdog/aspeed-wdt.txt    | 35 ++++++++++++++++++++++
>>   1 file changed, 35 insertions(+)
>>
>> diff --git a/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt b/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
>> index c5e74d7..f526b00 100644
>> --- a/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
>> +++ b/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
>> @@ -8,9 +8,44 @@ Required properties:
>>    - reg: physical base address of the controller and length of memory mapped
>>      region
>>   
>> +Optional properties:
>> +
>> + - aspeed,reset-type = "cpu|soc|system|none"
>> +
>> +   Reset behavior - Whenever a timeout occurs the watchdog can be programmed
>> +   to generate one of three different, mutually exclusive, types of resets.
>> +
>> +   Type "none" can be specified to indicate that no resets are to be done.
>> +   This is useful in situations where another watchdog engine on chip is
>> +   to perform the reset.
>> +
>> +   If 'aspeed,reset-type=' is not specfied the default is to enable system
>> +   reset.
>> +
>> +   Reset types:
>> +
>> +        - cpu: Reset CPU on watchdog timeout
>> +
>> +        - soc: Reset 'System on Chip' on watchdog timeout
>> +
>> +        - system: Reset system on watchdog timeout
>> +
>> +        - none: No reset is performed on timeout. Assumes another watchdog
>> +                engine is responsible for this.
>> +
>> + - aspeed,interrupt:	If property is present then interrupt CPU.
>> +			If not specified then don't interrupt CPU.
>> +
>> + - aspeed,external-signal: If property is present then signal is sent to
>> +			external reset counter (only WDT1 and WDT2). If not
>> +			specified no external signal is sent.
>> + - aspeed,alt-boot:    If property is present then boot from alternate block.
>> +
>>   Example:
>>   
>>   	wdt1: watchdog@1e785000 {
>>   		compatible = "aspeed,ast2400-wdt";
>>   		reg = <0x1e785000 0x1c>;
>> +		aspeed,reset-type = "system";
>> +		aspeed,external-signal;
>>   	};

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Re: [v4, 1/2] drivers/watchdog: Add optional ASPEED device tree properties

[Guenter Roeck]

On Mon, Jul 10, 2017 at 10:07:40AM -0500, Christopher Bostic wrote:
> 
> 
> On 7/8/17 9:59 AM, Guenter Roeck wrote:
> >On Thu, Jul 06, 2017 at 07:48:59PM -0500, Christopher Bostic wrote:
> >>Describe device tree optional properties:
> >>
> >>   * aspeed,reset-type = "cpu|soc|system|none"
> >>      One of three different, mutually exclusive, values
> >>
> >>	"cpu" : ARM CPU reset on signal
> >>	"soc" : 'System on chip' reset
> >>	"system" : Full system reset
> >>
> >>      The value can also be set to "none" which indicates that no
> >>      reset of any kind is to be done via this watchdog.  This assumes
> >>      another watchdog on the chip is to take care of resets.
> >>
> >>   * aspeed,interrupt - Interrupt CPU on signal
> >After thinking about that, I wonder if this is necessary. It could be
> >implied by providing an interrupt to the driver. The driver could then
> >set the interrupt configuration bit automatically.
> >
> >[ And the bit by itself doesn't really make sense if the driver doesn't
> >   also register an interrupt handler ]
> 
> The 'aspeed,interrupt' property was added for the sake of documenting all
> potential hardware configurations.  There is no plan as of now to enable
> this so I'm inclined to just remove this part from the documentation.  When
> and if this function is ever used the optional property can be documented at
> that time.
> 
Ok.

Thanks,
Guenter

> Thanks,
> Chris
> 
> >>   * aspeed,external-signal - Generate external signal (WDT1 and WDT2 only)
> >>   * aspeed,alt-boot - Boot from alternate block on signal
> >>
> >>Signed-off-by: Christopher Bostic <cbostic-23VcF4HTsmIX0ybBhKVfKdBPR1lH4CV8@public.gmane.org>
> >>---
> >>v4 - Add aspeed-reset-type and assign one of four values,
> >>      cpu, soc, system, none.
> >>v3 - Invert soc and sys reset to 'no' to preserve backwards
> >>      compatibility.  SOC and SYS reset will be set by default
> >>      without any optional parameters set
> >>v2 - Add 'aspeed,' prefix to all optional properties
> >>    - Add arm-reset, soc-reset, interrupt, alt-boot properties
> >>---
> >>  .../devicetree/bindings/watchdog/aspeed-wdt.txt    | 35 ++++++++++++++++++++++
> >>  1 file changed, 35 insertions(+)
> >>
> >>diff --git a/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt b/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
> >>index c5e74d7..f526b00 100644
> >>--- a/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
> >>+++ b/Documentation/devicetree/bindings/watchdog/aspeed-wdt.txt
> >>@@ -8,9 +8,44 @@ Required properties:
> >>   - reg: physical base address of the controller and length of memory mapped
> >>     region
> >>+Optional properties:
> >>+
> >>+ - aspeed,reset-type = "cpu|soc|system|none"
> >>+
> >>+   Reset behavior - Whenever a timeout occurs the watchdog can be programmed
> >>+   to generate one of three different, mutually exclusive, types of resets.
> >>+
> >>+   Type "none" can be specified to indicate that no resets are to be done.
> >>+   This is useful in situations where another watchdog engine on chip is
> >>+   to perform the reset.
> >>+
> >>+   If 'aspeed,reset-type=' is not specfied the default is to enable system
> >>+   reset.
> >>+
> >>+   Reset types:
> >>+
> >>+        - cpu: Reset CPU on watchdog timeout
> >>+
> >>+        - soc: Reset 'System on Chip' on watchdog timeout
> >>+
> >>+        - system: Reset system on watchdog timeout
> >>+
> >>+        - none: No reset is performed on timeout. Assumes another watchdog
> >>+                engine is responsible for this.
> >>+
> >>+ - aspeed,interrupt:	If property is present then interrupt CPU.
> >>+			If not specified then don't interrupt CPU.
> >>+
> >>+ - aspeed,external-signal: If property is present then signal is sent to
> >>+			external reset counter (only WDT1 and WDT2). If not
> >>+			specified no external signal is sent.
> >>+ - aspeed,alt-boot:    If property is present then boot from alternate block.
> >>+
> >>  Example:
> >>  	wdt1: watchdog@1e785000 {
> >>  		compatible = "aspeed,ast2400-wdt";
> >>  		reg = <0x1e785000 0x1c>;
> >>+		aspeed,reset-type = "system";
> >>+		aspeed,external-signal;
> >>  	};
> 
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