diff mbox series

[06/13] dt-bindings: rng: add bindings for microchip mpfs rng

Message ID 20211108150554.4457-7-conor.dooley@microchip.com (mailing list archive)
State New, archived
Headers show
Series Update the icicle kit device tree | expand

Commit Message

Conor Dooley Nov. 8, 2021, 3:05 p.m. UTC
From: Conor Dooley <conor.dooley@microchip.com>

Add device tree bindings for the hardware rng device accessed via
the system services on the Microchip PolarFire SoC.

Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
---
 .../bindings/rng/microchip,mpfs-rng.yaml      | 31 +++++++++++++++++++
 1 file changed, 31 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml

Comments

Krzysztof Kozlowski Nov. 8, 2021, 9:16 p.m. UTC | #1
On 08/11/2021 16:05, conor.dooley@microchip.com wrote:
> From: Conor Dooley <conor.dooley@microchip.com>
> 
> Add device tree bindings for the hardware rng device accessed via
> the system services on the Microchip PolarFire SoC.
> 
> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
> ---
>  .../bindings/rng/microchip,mpfs-rng.yaml      | 31 +++++++++++++++++++
>  1 file changed, 31 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
> 
> diff --git a/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml b/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
> new file mode 100644
> index 000000000000..e8ecb3538a86
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
> @@ -0,0 +1,31 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: "http://devicetree.org/schemas/rng/microchip,mpfs-rng.yaml#"
> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> +
> +title: Microchip MPFS random number generator
> +
> +maintainers:
> +  - Conor Dooley <conor.dooley@microchip.com>
> +
> +properties:
> +  compatible:
> +    const: microchip,polarfire-soc-rng
> +
> +  syscontroller:
> +    maxItems: 1
> +    description: name of the system controller device node

There are several issues with this:
1. You need to describe the type.
2. Description is not helpful (just copying the name of property) and
actually misleading because you do not put there the name of device node.
3. What is it? Looks like syscon (or sometimes called sysreg). If yes,
please use existing syscon bindings.

> +
> +required:
> +  - compatible
> +  - "syscontroller"

No need for quotes.

> +
> +additionalProperties: false
> +
> +examples:
> +  - |
> +    hwrandom: hwrandom {
> +        compatible = "microchip,polarfire-soc-rng";
> +        syscontroller = <&syscontroller>;
> +    };
> 


Best regards,
Krzysztof
Geert Uytterhoeven Nov. 9, 2021, 8:37 a.m. UTC | #2
Hi Conor,

On Mon, Nov 8, 2021 at 4:07 PM <conor.dooley@microchip.com> wrote:
> From: Conor Dooley <conor.dooley@microchip.com>
>
> Add device tree bindings for the hardware rng device accessed via
> the system services on the Microchip PolarFire SoC.
>
> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>

Thanks for your patch!

> ---
>  .../bindings/rng/microchip,mpfs-rng.yaml      | 31 +++++++++++++++++++
>  1 file changed, 31 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
>
> diff --git a/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml b/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
> new file mode 100644
> index 000000000000..e8ecb3538a86
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
> @@ -0,0 +1,31 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: "http://devicetree.org/schemas/rng/microchip,mpfs-rng.yaml#"
> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> +
> +title: Microchip MPFS random number generator
> +
> +maintainers:
> +  - Conor Dooley <conor.dooley@microchip.com>
> +
> +properties:
> +  compatible:
> +    const: microchip,polarfire-soc-rng

"microchip,mpfs-rng", for consistency with other bindings?

Gr{oetje,eeting}s,

                        Geert

--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org

In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
                                -- Linus Torvalds
Conor Dooley Nov. 9, 2021, 11:55 a.m. UTC | #3
On 09/11/2021 08:37, Geert Uytterhoeven wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> Hi Conor,
> 
> On Mon, Nov 8, 2021 at 4:07 PM <conor.dooley@microchip.com> wrote:
>> From: Conor Dooley <conor.dooley@microchip.com>
>>
>> Add device tree bindings for the hardware rng device accessed via
>> the system services on the Microchip PolarFire SoC.
>>
>> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
> 
> Thanks for your patch!
> 
>> ---
>>   .../bindings/rng/microchip,mpfs-rng.yaml      | 31 +++++++++++++++++++
>>   1 file changed, 31 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml b/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
>> new file mode 100644
>> index 000000000000..e8ecb3538a86
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
>> @@ -0,0 +1,31 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: "http://devicetree.org/schemas/rng/microchip,mpfs-rng.yaml#"
>> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
>> +
>> +title: Microchip MPFS random number generator
>> +
>> +maintainers:
>> +  - Conor Dooley <conor.dooley@microchip.com>
>> +
>> +properties:
>> +  compatible:
>> +    const: microchip,polarfire-soc-rng
> 
> "microchip,mpfs-rng", for consistency with other bindings?
correct, dropped the wrong one while cleaning up since this doesnt match 
the device tree.
> 
> Gr{oetje,eeting}s,
> 
>                          Geert
> 
> --
> Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
> 
> In personal conversations with technical people, I call myself a hacker. But
> when I'm talking to journalists I just say "programmer" or something like that.
>                                  -- Linus Torvalds
>
Conor Dooley Nov. 9, 2021, 12:54 p.m. UTC | #4
On 08/11/2021 21:16, Krzysztof Kozlowski wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> On 08/11/2021 16:05, conor.dooley@microchip.com wrote:
>> From: Conor Dooley <conor.dooley@microchip.com>
>>
>> Add device tree bindings for the hardware rng device accessed via
>> the system services on the Microchip PolarFire SoC.
>>
>> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
>> ---
>>   .../bindings/rng/microchip,mpfs-rng.yaml      | 31 +++++++++++++++++++
>>   1 file changed, 31 insertions(+)
>>   create mode 100644 Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
>>
>> diff --git a/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml b/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
>> new file mode 100644
>> index 000000000000..e8ecb3538a86
>> --- /dev/null
>> +++ b/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
>> @@ -0,0 +1,31 @@
>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>> +%YAML 1.2
>> +---
>> +$id: "http://devicetree.org/schemas/rng/microchip,mpfs-rng.yaml#"
>> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
>> +
>> +title: Microchip MPFS random number generator
>> +
>> +maintainers:
>> +  - Conor Dooley <conor.dooley@microchip.com>
>> +
>> +properties:
>> +  compatible:
>> +    const: microchip,polarfire-soc-rng
>> +
>> +  syscontroller:
>> +    maxItems: 1
>> +    description: name of the system controller device node
> 
> There are several issues with this:
> 1. You need to describe the type.
> 2. Description is not helpful (just copying the name of property) and
> actually misleading because you do not put there the name of device node.
> 3. What is it? Looks like syscon (or sometimes called sysreg). If yes,
> please use existing syscon bindings.
1 & 2 - Correct, it is bad & I'll write a better description for it.
3 - Its a system controller implemented as a mailbox. The syscontroller 
is the mailbox client, which the rng and generic drivers both use.
> 
>> +
>> +required:
>> +  - compatible
>> +  - "syscontroller"
> 
> No need for quotes.
> 
>> +
>> +additionalProperties: false
>> +
>> +examples:
>> +  - |
>> +    hwrandom: hwrandom {
>> +        compatible = "microchip,polarfire-soc-rng";
>> +        syscontroller = <&syscontroller>;
>> +    };
>>
> 
> 
> Best regards,
> Krzysztof
>
Krzysztof Kozlowski Nov. 9, 2021, 12:56 p.m. UTC | #5
On 09/11/2021 13:54, Conor.Dooley@microchip.com wrote:
> On 08/11/2021 21:16, Krzysztof Kozlowski wrote:
>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>
>> On 08/11/2021 16:05, conor.dooley@microchip.com wrote:
>>> From: Conor Dooley <conor.dooley@microchip.com>
>>>
>>> Add device tree bindings for the hardware rng device accessed via
>>> the system services on the Microchip PolarFire SoC.
>>>
>>> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
>>> ---
>>>   .../bindings/rng/microchip,mpfs-rng.yaml      | 31 +++++++++++++++++++
>>>   1 file changed, 31 insertions(+)
>>>   create mode 100644 Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
>>>
>>> diff --git a/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml b/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
>>> new file mode 100644
>>> index 000000000000..e8ecb3538a86
>>> --- /dev/null
>>> +++ b/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
>>> @@ -0,0 +1,31 @@
>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>> +%YAML 1.2
>>> +---
>>> +$id: "http://devicetree.org/schemas/rng/microchip,mpfs-rng.yaml#"
>>> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
>>> +
>>> +title: Microchip MPFS random number generator
>>> +
>>> +maintainers:
>>> +  - Conor Dooley <conor.dooley@microchip.com>
>>> +
>>> +properties:
>>> +  compatible:
>>> +    const: microchip,polarfire-soc-rng
>>> +
>>> +  syscontroller:
>>> +    maxItems: 1
>>> +    description: name of the system controller device node
>>
>> There are several issues with this:
>> 1. You need to describe the type.
>> 2. Description is not helpful (just copying the name of property) and
>> actually misleading because you do not put there the name of device node.
>> 3. What is it? Looks like syscon (or sometimes called sysreg). If yes,
>> please use existing syscon bindings.
> 1 & 2 - Correct, it is bad & I'll write a better description for it.
> 3 - Its a system controller implemented as a mailbox. The syscontroller 
> is the mailbox client, which the rng and generic drivers both use.

I understood that pointed device node is a mailbox, not this node. But
here, what is it here? How do you use it here?

Best regards,
Krzysztof
Conor Dooley Nov. 9, 2021, 1:36 p.m. UTC | #6
On 09/11/2021 12:56, Krzysztof Kozlowski wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> On 09/11/2021 13:54, Conor.Dooley@microchip.com wrote:
>> On 08/11/2021 21:16, Krzysztof Kozlowski wrote:
>>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>>
>>> On 08/11/2021 16:05, conor.dooley@microchip.com wrote:
>>>> From: Conor Dooley <conor.dooley@microchip.com>
>>>>
>>>> Add device tree bindings for the hardware rng device accessed via
>>>> the system services on the Microchip PolarFire SoC.
>>>>
>>>> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
>>>> ---
>>>>    .../bindings/rng/microchip,mpfs-rng.yaml      | 31 +++++++++++++++++++
>>>>    1 file changed, 31 insertions(+)
>>>>    create mode 100644 Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
>>>>
>>>> diff --git a/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml b/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
>>>> new file mode 100644
>>>> index 000000000000..e8ecb3538a86
>>>> --- /dev/null
>>>> +++ b/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
>>>> @@ -0,0 +1,31 @@
>>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>>> +%YAML 1.2
>>>> +---
>>>> +$id: "http://devicetree.org/schemas/rng/microchip,mpfs-rng.yaml#"
>>>> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
>>>> +
>>>> +title: Microchip MPFS random number generator
>>>> +
>>>> +maintainers:
>>>> +  - Conor Dooley <conor.dooley@microchip.com>
>>>> +
>>>> +properties:
>>>> +  compatible:
>>>> +    const: microchip,polarfire-soc-rng
>>>> +
>>>> +  syscontroller:
>>>> +    maxItems: 1
>>>> +    description: name of the system controller device node
>>>
>>> There are several issues with this:
>>> 1. You need to describe the type.
>>> 2. Description is not helpful (just copying the name of property) and
>>> actually misleading because you do not put there the name of device node.
>>> 3. What is it? Looks like syscon (or sometimes called sysreg). If yes,
>>> please use existing syscon bindings.
>> 1 & 2 - Correct, it is bad & I'll write a better description for it.
>> 3 - Its a system controller implemented as a mailbox. The syscontroller
>> is the mailbox client, which the rng and generic drivers both use.
> 
> I understood that pointed device node is a mailbox, not this node. But
> here, what is it here? How do you use it here?
The system controller is the means of access to the random number 
generator. The phandle to the sys controller is provided here so that 
the rng driver can locate the mailbox client through which it requests 
random numbers.

I'm not quite sure that I am answering the question you are asking though.
> 
> Best regards,
> Krzysztof
>
Krzysztof Kozlowski Nov. 10, 2021, 7:43 a.m. UTC | #7
On 09/11/2021 14:36, Conor.Dooley@microchip.com wrote:
> On 09/11/2021 12:56, Krzysztof Kozlowski wrote:
>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>
>> On 09/11/2021 13:54, Conor.Dooley@microchip.com wrote:
>>> On 08/11/2021 21:16, Krzysztof Kozlowski wrote:
>>>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>>>
>>>> On 08/11/2021 16:05, conor.dooley@microchip.com wrote:
>>>>> From: Conor Dooley <conor.dooley@microchip.com>
>>>>>
>>>>> Add device tree bindings for the hardware rng device accessed via
>>>>> the system services on the Microchip PolarFire SoC.
>>>>>
>>>>> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
>>>>> ---
>>>>>    .../bindings/rng/microchip,mpfs-rng.yaml      | 31 +++++++++++++++++++
>>>>>    1 file changed, 31 insertions(+)
>>>>>    create mode 100644 Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
>>>>>
>>>>> diff --git a/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml b/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
>>>>> new file mode 100644
>>>>> index 000000000000..e8ecb3538a86
>>>>> --- /dev/null
>>>>> +++ b/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
>>>>> @@ -0,0 +1,31 @@
>>>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>>>> +%YAML 1.2
>>>>> +---
>>>>> +$id: "http://devicetree.org/schemas/rng/microchip,mpfs-rng.yaml#"
>>>>> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
>>>>> +
>>>>> +title: Microchip MPFS random number generator
>>>>> +
>>>>> +maintainers:
>>>>> +  - Conor Dooley <conor.dooley@microchip.com>
>>>>> +
>>>>> +properties:
>>>>> +  compatible:
>>>>> +    const: microchip,polarfire-soc-rng
>>>>> +
>>>>> +  syscontroller:
>>>>> +    maxItems: 1
>>>>> +    description: name of the system controller device node
>>>>
>>>> There are several issues with this:
>>>> 1. You need to describe the type.
>>>> 2. Description is not helpful (just copying the name of property) and
>>>> actually misleading because you do not put there the name of device node.
>>>> 3. What is it? Looks like syscon (or sometimes called sysreg). If yes,
>>>> please use existing syscon bindings.
>>> 1 & 2 - Correct, it is bad & I'll write a better description for it.
>>> 3 - Its a system controller implemented as a mailbox. The syscontroller
>>> is the mailbox client, which the rng and generic drivers both use.
>>
>> I understood that pointed device node is a mailbox, not this node. But
>> here, what is it here? How do you use it here?
> The system controller is the means of access to the random number 
> generator. The phandle to the sys controller is provided here so that 
> the rng driver can locate the mailbox client through which it requests 
> random numbers.

I am asking this to understand whether there is a generic or existing
property which should be used instead.

If I understand correctly, the rng driver needs a mailbox client?  If it
is mailbox client, then there is a property: "mboxes". Use this one
(look for existing bindings, e.g.
Documentation/devicetree/bindings/firmware/arm,scmi.yaml).


Best regards,
Krzysztof
Conor Dooley Nov. 10, 2021, 9:46 a.m. UTC | #8
On 10/11/2021 07:43, Krzysztof Kozlowski wrote:
> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> 
> On 09/11/2021 14:36, Conor.Dooley@microchip.com wrote:
>> On 09/11/2021 12:56, Krzysztof Kozlowski wrote:
>>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>>
>>> On 09/11/2021 13:54, Conor.Dooley@microchip.com wrote:
>>>> On 08/11/2021 21:16, Krzysztof Kozlowski wrote:
>>>>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
>>>>>
>>>>> On 08/11/2021 16:05, conor.dooley@microchip.com wrote:
>>>>>> From: Conor Dooley <conor.dooley@microchip.com>
>>>>>>
>>>>>> Add device tree bindings for the hardware rng device accessed via
>>>>>> the system services on the Microchip PolarFire SoC.
>>>>>>
>>>>>> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
>>>>>> ---
>>>>>>     .../bindings/rng/microchip,mpfs-rng.yaml      | 31 +++++++++++++++++++
>>>>>>     1 file changed, 31 insertions(+)
>>>>>>     create mode 100644 Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
>>>>>>
>>>>>> diff --git a/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml b/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
>>>>>> new file mode 100644
>>>>>> index 000000000000..e8ecb3538a86
>>>>>> --- /dev/null
>>>>>> +++ b/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
>>>>>> @@ -0,0 +1,31 @@
>>>>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
>>>>>> +%YAML 1.2
>>>>>> +---
>>>>>> +$id: "http://devicetree.org/schemas/rng/microchip,mpfs-rng.yaml#"
>>>>>> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
>>>>>> +
>>>>>> +title: Microchip MPFS random number generator
>>>>>> +
>>>>>> +maintainers:
>>>>>> +  - Conor Dooley <conor.dooley@microchip.com>
>>>>>> +
>>>>>> +properties:
>>>>>> +  compatible:
>>>>>> +    const: microchip,polarfire-soc-rng
>>>>>> +
>>>>>> +  syscontroller:
>>>>>> +    maxItems: 1
>>>>>> +    description: name of the system controller device node
>>>>>
>>>>> There are several issues with this:
>>>>> 1. You need to describe the type.
>>>>> 2. Description is not helpful (just copying the name of property) and
>>>>> actually misleading because you do not put there the name of device node.
>>>>> 3. What is it? Looks like syscon (or sometimes called sysreg). If yes,
>>>>> please use existing syscon bindings.
>>>> 1 & 2 - Correct, it is bad & I'll write a better description for it.
>>>> 3 - Its a system controller implemented as a mailbox. The syscontroller
>>>> is the mailbox client, which the rng and generic drivers both use.
>>>
>>> I understood that pointed device node is a mailbox, not this node. But
>>> here, what is it here? How do you use it here?
>> The system controller is the means of access to the random number
>> generator. The phandle to the sys controller is provided here so that
>> the rng driver can locate the mailbox client through which it requests
>> random numbers.
> 
> I am asking this to understand whether there is a generic or existing
> property which should be used instead.
> 
> If I understand correctly, the rng driver needs a mailbox client?
Correct, it needs one. Binding for that is here:
Documentation/devicetree/bindings/soc/microchip/microchip,polarfire-soc-sys-controller.yaml
> If it is a mailbox client, then there is a property: "mboxes". Use this one
> (look for existing bindings, e.g.
> Documentation/devicetree/bindings/firmware/arm,scmi.yaml).
> 
> 
> Best regards,
> Krzysztof
>
Rob Herring (Arm) Nov. 29, 2021, 8:08 p.m. UTC | #9
On Wed, Nov 10, 2021 at 09:46:23AM +0000, Conor.Dooley@microchip.com wrote:
> On 10/11/2021 07:43, Krzysztof Kozlowski wrote:
> > EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> > 
> > On 09/11/2021 14:36, Conor.Dooley@microchip.com wrote:
> >> On 09/11/2021 12:56, Krzysztof Kozlowski wrote:
> >>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> >>>
> >>> On 09/11/2021 13:54, Conor.Dooley@microchip.com wrote:
> >>>> On 08/11/2021 21:16, Krzysztof Kozlowski wrote:
> >>>>> EXTERNAL EMAIL: Do not click links or open attachments unless you know the content is safe
> >>>>>
> >>>>> On 08/11/2021 16:05, conor.dooley@microchip.com wrote:
> >>>>>> From: Conor Dooley <conor.dooley@microchip.com>
> >>>>>>
> >>>>>> Add device tree bindings for the hardware rng device accessed via
> >>>>>> the system services on the Microchip PolarFire SoC.
> >>>>>>
> >>>>>> Signed-off-by: Conor Dooley <conor.dooley@microchip.com>
> >>>>>> ---
> >>>>>>     .../bindings/rng/microchip,mpfs-rng.yaml      | 31 +++++++++++++++++++
> >>>>>>     1 file changed, 31 insertions(+)
> >>>>>>     create mode 100644 Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
> >>>>>>
> >>>>>> diff --git a/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml b/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
> >>>>>> new file mode 100644
> >>>>>> index 000000000000..e8ecb3538a86
> >>>>>> --- /dev/null
> >>>>>> +++ b/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
> >>>>>> @@ -0,0 +1,31 @@
> >>>>>> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> >>>>>> +%YAML 1.2
> >>>>>> +---
> >>>>>> +$id: "http://devicetree.org/schemas/rng/microchip,mpfs-rng.yaml#"
> >>>>>> +$schema: "http://devicetree.org/meta-schemas/core.yaml#"
> >>>>>> +
> >>>>>> +title: Microchip MPFS random number generator
> >>>>>> +
> >>>>>> +maintainers:
> >>>>>> +  - Conor Dooley <conor.dooley@microchip.com>
> >>>>>> +
> >>>>>> +properties:
> >>>>>> +  compatible:
> >>>>>> +    const: microchip,polarfire-soc-rng
> >>>>>> +
> >>>>>> +  syscontroller:
> >>>>>> +    maxItems: 1
> >>>>>> +    description: name of the system controller device node
> >>>>>
> >>>>> There are several issues with this:
> >>>>> 1. You need to describe the type.
> >>>>> 2. Description is not helpful (just copying the name of property) and
> >>>>> actually misleading because you do not put there the name of device node.
> >>>>> 3. What is it? Looks like syscon (or sometimes called sysreg). If yes,
> >>>>> please use existing syscon bindings.
> >>>> 1 & 2 - Correct, it is bad & I'll write a better description for it.
> >>>> 3 - Its a system controller implemented as a mailbox. The syscontroller
> >>>> is the mailbox client, which the rng and generic drivers both use.
> >>>
> >>> I understood that pointed device node is a mailbox, not this node. But
> >>> here, what is it here? How do you use it here?
> >> The system controller is the means of access to the random number
> >> generator. The phandle to the sys controller is provided here so that
> >> the rng driver can locate the mailbox client through which it requests
> >> random numbers.
> > 
> > I am asking this to understand whether there is a generic or existing
> > property which should be used instead.
> > 
> > If I understand correctly, the rng driver needs a mailbox client?
> Correct, it needs one. Binding for that is here:
> Documentation/devicetree/bindings/soc/microchip/microchip,polarfire-soc-sys-controller.yaml

The rng node and others should be a child of the sys controller node.

Rob
diff mbox series

Patch

diff --git a/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml b/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
new file mode 100644
index 000000000000..e8ecb3538a86
--- /dev/null
+++ b/Documentation/devicetree/bindings/rng/microchip,mpfs-rng.yaml
@@ -0,0 +1,31 @@ 
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/rng/microchip,mpfs-rng.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Microchip MPFS random number generator
+
+maintainers:
+  - Conor Dooley <conor.dooley@microchip.com>
+
+properties:
+  compatible:
+    const: microchip,polarfire-soc-rng
+
+  syscontroller:
+    maxItems: 1
+    description: name of the system controller device node
+
+required:
+  - compatible
+  - "syscontroller"
+
+additionalProperties: false
+
+examples:
+  - |
+    hwrandom: hwrandom {
+        compatible = "microchip,polarfire-soc-rng";
+        syscontroller = <&syscontroller>;
+    };