linux-kernel - Re: [PATCH 1/4] firmware: arm_scmi: bus: Bypass setting fwnode for scmi cpufreq

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Message-ID: <Z7Z-ZnztmvUxWoQJ@NXL53680.wbi.nxp.com>
Date: Thu, 20 Feb 2025 08:59:18 +0800
From: Peng Fan <peng.fan@....nxp.com>
To: Sudeep Holla <sudeep.holla@....com>
Cc: Cristian Marussi <cristian.marussi@....com>,
	Saravana Kannan <saravanak@...gle.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Linus Walleij <linus.walleij@...aro.org>,
	Dong Aisheng <aisheng.dong@....com>,
	Fabio Estevam <festevam@...il.com>, Shawn Guo <shawnguo@...nel.org>,
	Jacky Bai <ping.bai@....com>,
	Pengutronix Kernel Team <kernel@...gutronix.de>,
	Sascha Hauer <s.hauer@...gutronix.de>, arm-scmi@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org,
	linux-gpio@...r.kernel.org, imx@...ts.linux.dev,
	Peng Fan <peng.fan@....com>
Subject: Re: [PATCH 1/4] firmware: arm_scmi: bus: Bypass setting fwnode for
 scmi cpufreq

On Wed, Feb 19, 2025 at 10:17:46AM +0000, Sudeep Holla wrote:
>On Tue, Feb 18, 2025 at 09:36:19PM +0800, Peng Fan wrote:
>> On Tue, Feb 18, 2025 at 10:24:52AM +0000, Sudeep Holla wrote:
>> >On Tue, Feb 18, 2025 at 09:09:49AM +0800, Peng Fan wrote:
>> >> A potential solution is not using reg in the protocol nodes. Define nodes
>> >> as below:
>> >> devperf {
>> >> 	compatible ="arm,scmi-devperf";
>> >> }
>> >>
>> >> cpuperf {
>> >> 	compatible ="arm,scmi-cpuperf";
>> >> }
>> >>
>> >> pinctrl {
>> >> 	compatible ="arm,scmi-pinctrl";
>> >> }
>> >>
>> >> The reg is coded in driver.
>> >>
>> >> But the upper requires restruction of scmi framework.
>> >>
>> >> Put the above away, could we first purse a simple way first to address
>> >> the current bug in kernel? Just as I prototyped here:
>> >> https://github.com/MrVan/linux/tree/b4/scmi-fwdevlink-v2
>> >>
>> >
>> >Good luck getting these bindings merged. I don't like it as it is pushing
>> >software policy or issues into to the devicetree. What we have as SCMI
>> >binding is more than required for a firmware interface IMO. So, you are
>>
>> Would you mind share more info on other cases that SCMI not as firmware
>> interface?
>>
>> >on your own to get these bindings approved as I am not on board with
>> >these but if you convince DT maintainers, I will have a look at it then
>> >to see if we can make that work really.
>>
>> The issues are common to SCMI, not i.MX specific.
>> I just propose potential solutions. You are the SCMI maintainer, there
>> is no chance to get bindings approved without you.
>>
>
>I am not blocking you. What I mentioned is I don't agree that DT can be used
>to resolve this issue, but I don't have time or alternate solution ATM. So
>if you propose DT based solution and the maintainers agree for the proposed
>bindings I will take a look and help you to make that work. But I will raise
>any objections I may have if the proposal has issues mainly around the
>compatibility and ease of maintenance.

Sorry, if I misunderstood.

I will give a look on this and propose a RFC.

DT maintainers may ask for a patchset including binding change and
driver changes to get a whole view on the compatible stuff.

BTW, Cristian, Saravana if you have any objections/ideas or would take on this
effort, please let me know.

Thanks,
Peng

>
>> No more ideas from me. Leave this to you in case you have better solution.
>>
>
>Unfortunately no, I don't have one. I haven't had time to sit and explore
>the issue and think of any solution yet.
>
>--
>Regards,
>Sudeep