linux-kernel - Re: [PATCH v2 08/16] dt-bindings: nvmem: microchip-otpc: Add required clocks

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Message-ID: <8e9562c8-5c01-4b5c-b2b0-4dad3d16e7a8@kernel.org>
Date: Mon, 10 Feb 2025 17:59:52 +0100
From: Krzysztof Kozlowski <krzk@...nel.org>
To: Alexander Dahl <ada@...rsis.com>,
 Claudiu Beznea <claudiu.beznea@...on.dev>
Cc: Nicolas Ferre <nicolas.ferre@...rochip.com>,
 Ryan Wanner <ryan.wanner@...rochip.com>,
 linux-arm-kernel@...ts.infradead.org, devicetree@...r.kernel.org,
 linux-clk@...r.kernel.org, linux-kernel@...r.kernel.org,
 Srinivas Kandagatla <srinivas.kandagatla@...aro.org>,
 Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk+dt@...nel.org>,
 Conor Dooley <conor+dt@...nel.org>
Subject: Re: [PATCH v2 08/16] dt-bindings: nvmem: microchip-otpc: Add required
 clocks

On 10/02/2025 17:44, Alexander Dahl wrote:
> The OTPC requires both the peripheral clock through PMC and the main RC
> oscillator.  Seemed to work without explicitly enabling those clocks on
> sama7g5 before, but did not on sam9x60.
> 
> Older datasheets were not clear and explicit about this, but recent are,
> e.g. SAMA7G5 series datasheet (DS60001765B),
> section 30.4.1 Power Management:
> 
>> The OTPC is clocked through the Power Management Controller (PMC).
>> The user must power on the main RC oscillator and enable the
>> peripheral clock of the OTPC prior to reading or writing the OTP
>> memory.
> 
> Link: https://lore.kernel.org/linux-clk/ec34efc2-2051-4b8a-b5d8-6e2fd5e08c28@microchip.com/T/#u
> Signed-off-by: Alexander Dahl <ada@...rsis.com>
> ---
> 
> Notes:
>     v2:
>     - new patch, not present in v1
> 
>  .../nvmem/microchip,sama7g5-otpc.yaml         | 28 +++++++++++++++++++
>  1 file changed, 28 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/nvmem/microchip,sama7g5-otpc.yaml b/Documentation/devicetree/bindings/nvmem/microchip,sama7g5-otpc.yaml
> index 9a7aaf64eef32..1fa40610888f3 100644
> --- a/Documentation/devicetree/bindings/nvmem/microchip,sama7g5-otpc.yaml
> +++ b/Documentation/devicetree/bindings/nvmem/microchip,sama7g5-otpc.yaml
> @@ -29,6 +29,16 @@ properties:
>    reg:
>      maxItems: 1
>  
> +  clocks:
> +    items:
> +      - description: main rc oscillator
> +      - description: otpc peripheral clock
> +
> +  clock-names:
> +    items:
> +      - const: main_rc_osc

osc

> +      - const: otpc_clk

otpc or bus or whatever logically this is

> +
>  required:
>    - compatible
>    - reg
> @@ -37,6 +47,8 @@ unevaluatedProperties: false
>  
>  examples:
>    - |
> +    #include <dt-bindings/clock/at91.h>
> +    #include <dt-bindings/clock/microchip,sama7g5-pmc.h>
>      #include <dt-bindings/nvmem/microchip,sama7g5-otpc.h>
>  
>      otpc: efuse@...00000 {
> @@ -44,10 +56,26 @@ examples:
>          reg = <0xe8c00000 0xec>;
>          #address-cells = <1>;
>          #size-cells = <1>;
> +        clocks = <&pmc PMC_TYPE_CORE SAMA7G5_PMC_MAIN_RC>, <&pmc PMC_TYPE_PERIPHERAL 67>;
> +        clock-names = "main_rc_osc", "otpc_clk";
>  
>          temperature_calib: calib@1 {
>              reg = <OTP_PKT(1) 76>;
>          };
>      };
>  
> +  - |
> +    #include <dt-bindings/clock/at91.h>
> +    #include <dt-bindings/clock/microchip,sam9x60-pmc.h>
> +    #include <dt-bindings/nvmem/microchip,sama7g5-otpc.h>
> +
> +    efuse@...00000 {
> +        compatible = "microchip,sam9x60-otpc", "syscon";
> +        reg = <0xeff00000 0xec>;

No need for new example with difference in what exactly? Even compatible
was not added here...

> +        #address-cells = <1>;
> +        #size-cells = <1>;
> +        clocks = <&pmc PMC_TYPE_CORE SAM9X60_PMC_MAIN_RC>, <&pmc PMC_TYPE_PERIPHERAL 46>;
> +        clock-names = "main_rc_osc", "otpc_clk";
> +    };
> +
>  ...


Best regards,
Krzysztof