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Message-ID: <58d24ddc-4e8f-4932-ac37-c9a699d36425@linaro.org>
Date: Fri, 26 Jan 2024 10:03:51 +0100
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Subject: Re: [PATCH v2 4/8] dt-bindings: power: reset: add bindings for NVMEM
 hardware storing PSCR Data
Content-Language: en-US
To: Oleksij Rempel <o.rempel@pengutronix.de>
Cc: Sebastian Reichel <sre@kernel.org>, Rob Herring <robh+dt@kernel.org>,
 Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
 Conor Dooley <conor+dt@kernel.org>,
 Srinivas Kandagatla <srinivas.kandagatla@linaro.org>, kernel@pengutronix.de,
 linux-kernel@vger.kernel.org, Liam Girdwood <lgirdwood@gmail.com>,
 Mark Brown <broonie@kernel.org>, "Rafael J. Wysocki" <rafael@kernel.org>,
 Daniel Lezcano <daniel.lezcano@linaro.org>, Zhang Rui <rui.zhang@intel.com>,
 Lukasz Luba <lukasz.luba@arm.com>, linux-pm@vger.kernel.org,
 devicetree@vger.kernel.org, =?UTF-8?Q?S=C3=B8ren_Andersen?= <san@skov.dk>
References: <20240124122204.730370-1-o.rempel@pengutronix.de>
 <20240124122204.730370-5-o.rempel@pengutronix.de>
 <4e14b7c7-7f0a-437b-aa84-20fdc30a2361@linaro.org>
 <20240125171146.GC381737@pengutronix.de>
From: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
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In-Reply-To: <20240125171146.GC381737@pengutronix.de>
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On 25/01/2024 18:11, Oleksij Rempel wrote:
> On Thu, Jan 25, 2024 at 11:57:18AM +0100, Krzysztof Kozlowski wrote:
>> On 24/01/2024 13:22, Oleksij Rempel wrote:
>>> Add device tree bindings that describe hardware implementations of
>>> Non-Volatile Memory (NVMEM) used for storing Power State Change Reasons
>>> (PSCR).
>>> +  that stores Power State Change Reasons (PSCR).
>>> +
>>> +allOf:
>>> +  - $ref: pscrr.yaml#
>>> +
>>> +properties:
>>> +  compatible:
>>> +    const: pscrr-nvmem
>>> +
>>
>> So that's a driver :/. Maybe Rob will like it, but it's a no from me.
>> Please come up with something really suiting DEVICES, not DRIVERS.
> 
> If I understand your distinction between 'DEVICES' and 'DRIVERS'
> correctly, 'DEVICES' in the device tree context are meant to represent
> physical hardware components, while 'DRIVERS' refer to software

Yes.

> abstractions of these components. However, there are numerous device
> tree instances, like software-based implementations for SPI, I2C, or
> GPIO, which could also be interpreted as 'DRIVERS' in the context of

True. Yet they are still for physical interfaces. There is no DTS having
some virtual I2C for a board which does not have I2C.

> your email. Similarly, the binding for PSCRR represents functionality not
> fully implemented in hardware but supported by the hardware component of
> NVMEM, akin to how ramoops or other functionalities are represented.

You don't need a binding for your case. Instantiate it whatever you wish
- modprobe for example - and configure through approved kernel
interfaces - sysfs for example.

Best regards,
Krzysztof