[v2,1/2] dt-bindings: watchdog: Add Apple Watchdog

Apple SoCs come with a simple embedded watchdog. This watchdog is also
required in order to reset the SoC.

Reviewed-by: Mark Kettenis <kettenis@openbsd.org>
Reviewed-by: Rob Herring <robh@kernel.org>
Signed-off-by: Sven Peter <sven@svenpeter.dev>
---
v1 --> v2:
  - add Mark's and Rob's r-b tags

 .../bindings/watchdog/apple,wdt.yaml          | 52 +++++++++++++++++++
 MAINTAINERS                                   |  1 +
 2 files changed, 53 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/watchdog/apple,wdt.yaml

Hej,

On 2021-11-30 17:18:09 +0100, Sven Peter wrote:
> Add support for the watchdog timer found in Apple SoCs. This driver is
> also required to reboot these machines.
> 
> Signed-off-by: Sven Peter <sven@svenpeter.dev>
> ---
> v1 -> v2:
>  - set the default timeout to 30s and call watchdog_init_timeout
>    to allow the device tree to override it
>  - set WDOG_HW_RUNNING if the watchdog is enabled at boot
>  - check that the clock rate is not zero
>  - use unsigned long instead of u32 for clk_rate
>  - use devm_add_action_or_reset instead of manually calling
>    clk_disable_unprepare
>  - explain the magic number in apple_wdt_restart
> 
>  MAINTAINERS                  |   1 +
>  drivers/watchdog/Kconfig     |  12 ++
>  drivers/watchdog/Makefile    |   1 +
>  drivers/watchdog/apple_wdt.c | 226 +++++++++++++++++++++++++++++++++++
>  4 files changed, 240 insertions(+)
>  create mode 100644 drivers/watchdog/apple_wdt.c

Tested on M1 and M1 Max. Feel free to add
Tested-by: Janne Grunau <j@jannau.net>

best
Janne

On Tue, Nov 30, 2021 at 05:18:08PM +0100, Sven Peter wrote:
> Apple SoCs come with a simple embedded watchdog. This watchdog is also
> required in order to reset the SoC.
> 
> Reviewed-by: Mark Kettenis <kettenis@openbsd.org>
> Reviewed-by: Rob Herring <robh@kernel.org>
> Signed-off-by: Sven Peter <sven@svenpeter.dev>

Reviewed-by: Guenter Roeck <linux@roeck-us.net>

> ---
> v1 --> v2:
>   - add Mark's and Rob's r-b tags
> 
>  .../bindings/watchdog/apple,wdt.yaml          | 52 +++++++++++++++++++
>  MAINTAINERS                                   |  1 +
>  2 files changed, 53 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/watchdog/apple,wdt.yaml
> 
> diff --git a/Documentation/devicetree/bindings/watchdog/apple,wdt.yaml b/Documentation/devicetree/bindings/watchdog/apple,wdt.yaml
> new file mode 100644
> index 000000000000..e58c56a6fdf6
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/watchdog/apple,wdt.yaml
> @@ -0,0 +1,52 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/watchdog/apple,wdt.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Apple SoC Watchdog
> +
> +allOf:
> +  - $ref: "watchdog.yaml#"
> +
> +maintainers:
> +  - Sven Peter <sven@svenpeter.dev>
> +
> +properties:
> +  compatible:
> +    items:
> +      - enum:
> +          - apple,t8103-wdt
> +          - apple,t6000-wdt
> +      - const: apple,wdt
> +
> +  reg:
> +    maxItems: 1
> +
> +  clocks:
> +    maxItems: 1
> +
> +  interrupts:
> +    maxItems: 1
> +
> +required:
> +  - compatible
> +  - reg
> +  - clocks
> +  - interrupts
> +
> +unevaluatedProperties: false
> +
> +examples:
> +  - |
> +    #include <dt-bindings/interrupt-controller/apple-aic.h>
> +    #include <dt-bindings/interrupt-controller/irq.h>
> +
> +    wdt: watchdog@50000000 {
> +        compatible = "apple,t8103-wdt", "apple,wdt";
> +        reg = <0x50000000 0x4000>;
> +        clocks = <&clk>;
> +        interrupts = <AIC_IRQ 123 IRQ_TYPE_LEVEL_HIGH>;
> +    };
> +
> +...
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 360e9aa0205d..859201bbd4e8 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1750,6 +1750,7 @@ F:	Documentation/devicetree/bindings/interrupt-controller/apple,aic.yaml
>  F:	Documentation/devicetree/bindings/mailbox/apple,mailbox.yaml
>  F:	Documentation/devicetree/bindings/pci/apple,pcie.yaml
>  F:	Documentation/devicetree/bindings/pinctrl/apple,pinctrl.yaml
> +F:	Documentation/devicetree/bindings/watchdog/apple,wdt.yaml
>  F:	arch/arm64/boot/dts/apple/
>  F:	drivers/i2c/busses/i2c-pasemi-core.c
>  F:	drivers/i2c/busses/i2c-pasemi-platform.c
> -- 
> 2.25.1
>

On 02/12/2021 23.43, Guenter Roeck wrote:
> On Tue, Nov 30, 2021 at 05:18:08PM +0100, Sven Peter wrote:
>> Apple SoCs come with a simple embedded watchdog. This watchdog is also
>> required in order to reset the SoC.
>>
>> Reviewed-by: Mark Kettenis <kettenis@openbsd.org>
>> Reviewed-by: Rob Herring <robh@kernel.org>
>> Signed-off-by: Sven Peter <sven@svenpeter.dev>
> 
> Reviewed-by: Guenter Roeck <linux@roeck-us.net>
> 
>> ---
>> v1 --> v2:
>>    - add Mark's and Rob's r-b tags
>>
>>   .../bindings/watchdog/apple,wdt.yaml          | 52 +++++++++++++++++++
>>   MAINTAINERS                                   |  1 +
>>   2 files changed, 53 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/watchdog/apple,wdt.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/watchdog/apple,wdt.yaml b/Documentation/devicetree/bindings/watchdog/apple,wdt.yaml
>> new file mode 100644
>> index 000000000000..e58c56a6fdf6
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/watchdog/apple,wdt.yaml
>> @@ -0,0 +1,52 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: http://devicetree.org/schemas/watchdog/apple,wdt.yaml#
>> +$schema: http://devicetree.org/meta-schemas/core.yaml#
>> +
>> +title: Apple SoC Watchdog
>> +
>> +allOf:
>> +  - $ref: "watchdog.yaml#"
>> +
>> +maintainers:
>> +  - Sven Peter <sven@svenpeter.dev>
>> +
>> +properties:
>> +  compatible:
>> +    items:
>> +      - enum:
>> +          - apple,t8103-wdt
>> +          - apple,t6000-wdt
>> +      - const: apple,wdt
>> +
>> +  reg:
>> +    maxItems: 1
>> +
>> +  clocks:
>> +    maxItems: 1
>> +
>> +  interrupts:
>> +    maxItems: 1
>> +
>> +required:
>> +  - compatible
>> +  - reg
>> +  - clocks
>> +  - interrupts
>> +
>> +unevaluatedProperties: false
>> +
>> +examples:
>> +  - |
>> +    #include <dt-bindings/interrupt-controller/apple-aic.h>
>> +    #include <dt-bindings/interrupt-controller/irq.h>
>> +
>> +    wdt: watchdog@50000000 {
>> +        compatible = "apple,t8103-wdt", "apple,wdt";
>> +        reg = <0x50000000 0x4000>;
>> +        clocks = <&clk>;
>> +        interrupts = <AIC_IRQ 123 IRQ_TYPE_LEVEL_HIGH>;
>> +    };
>> +
>> +...
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index 360e9aa0205d..859201bbd4e8 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -1750,6 +1750,7 @@ F:	Documentation/devicetree/bindings/interrupt-controller/apple,aic.yaml
>>   F:	Documentation/devicetree/bindings/mailbox/apple,mailbox.yaml
>>   F:	Documentation/devicetree/bindings/pci/apple,pcie.yaml
>>   F:	Documentation/devicetree/bindings/pinctrl/apple,pinctrl.yaml
>> +F:	Documentation/devicetree/bindings/watchdog/apple,wdt.yaml
>>   F:	arch/arm64/boot/dts/apple/
>>   F:	drivers/i2c/busses/i2c-pasemi-core.c
>>   F:	drivers/i2c/busses/i2c-pasemi-platform.c
>> -- 
>> 2.25.1
>>
> 

I've gone ahead and applied this patch to the asahi-soc/dt tree, so we 
can build off of that to add the DT nodes.

Sven, can you spin a v3 with the MAINTAINERS split and just the driver 
itself, without this patch? I imagine Guenter will want to take the 
driver itself through the linux-watchdog tree.