linux-kernel - Re: [PATCH] clk: imx: imx93: introduce clk

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Message-ID: <7e585791-ed7b-80de-d1d7-7df54b7da442@pengutronix.de>
Date:   Thu, 4 May 2023 12:04:20 +0200
From:   Ahmad Fatoum <a.fatoum@...gutronix.de>
To:     Peng Fan <peng.fan@....com>,
        Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>,
        Greg KH <greg@...ah.com>,
        "Peng Fan (OSS)" <peng.fan@....nxp.com>,
        Rob Herring <robh+dt@...nel.org>,
        "krzysztof.kozlowski+dt@...aro.org" 
        <krzysztof.kozlowski+dt@...aro.org>
Cc:     "sboyd@...nel.org" <sboyd@...nel.org>,
        "festevam@...il.com" <festevam@...il.com>,
        "mturquette@...libre.com" <mturquette@...libre.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        "linux-clk@...r.kernel.org" <linux-clk@...r.kernel.org>,
        dl-linux-imx <linux-imx@....com>,
        "kernel@...gutronix.de" <kernel@...gutronix.de>,
        "shawnguo@...nel.org" <shawnguo@...nel.org>,
        "s.hauer@...gutronix.de" <s.hauer@...gutronix.de>,
        "linux-arm-kernel@...ts.infradead.org" 
        <linux-arm-kernel@...ts.infradead.org>,
        "abelvesa@...nel.org" <abelvesa@...nel.org>
Subject: Re: [PATCH] clk: imx: imx93: introduce clk_bypassed module parameter

Hello Peng,

On 04.05.23 11:34, Peng Fan wrote:
 >> -----Original Message-----
>> From: Krzysztof Kozlowski <krzysztof.kozlowski@...aro.org>
>> Sent: 2023年5月4日 17:31
>> To: Peng Fan <peng.fan@....com>; Greg KH <greg@...ah.com>; Peng Fan
>> (OSS) <peng.fan@....nxp.com>; Rob Herring <robh+dt@...nel.org>;
>> krzysztof.kozlowski+dt@...aro.org
>> Cc: abelvesa@...nel.org; mturquette@...libre.com; sboyd@...nel.org;
>> shawnguo@...nel.org; s.hauer@...gutronix.de; kernel@...gutronix.de;
>> festevam@...il.com; dl-linux-imx <linux-imx@....com>; linux-
>> clk@...r.kernel.org; linux-arm-kernel@...ts.infradead.org; linux-
>> kernel@...r.kernel.org
>> Subject: Re: [PATCH] clk: imx: imx93: introduce clk_bypassed module
>> parameter
>>
>> On 04/05/2023 11:17, Peng Fan wrote:
>>> + DT maintainers.
>>>
>>>> Subject: Re: [PATCH] clk: imx: imx93: introduce clk_bypassed module
>>>> parameter
>>>>
>>>> On Thu, May 04, 2023 at 04:55:06PM +0800, Peng Fan (OSS) wrote:
>>>>> From: Peng Fan <peng.fan@....com>
>>>>>
>>>>> With the clk names specified in clk_bypassed module parameter, give
>>>>> user an option to bypass the clk from managing them by Linux kernel.
>>>>
>>>> As I said on another email, no, please do not add new module
>>>> parameters for drivers, this is not the 1990s
>>>
>>> ok, but this is for boot, so only DT could be considered.
>>>
>>> But DT is to describe hardware, here I just wanna give user an option
>>> to bypass some clocks. Is it ok to add a DT property saying
>>> "fsl,imx93-bypass-clks = <IMX93_CLK_X>, <IMX93_CLK_Y>" ?
>>>
>>
>> I don't know what it is to "bypass some clocks". This does not look like
>> parameter for system at all.
> 
> Currently the linux clk driver registers all the clocks and manage them.
> But when M33 is running, M33 may not wanna linux to manage
> some clocks M33 is using. So I wanna linux not register those clocks
> that M33 will use.

Describe the M33 in the DT, assign it the clocks it depends on and have
a driver bind to it that just claims the clocks in question to ensure
nothing else messes with it?

Cheers,
Ahmad

> 
> Thanks,
> Peng.
> 
>>
>> Best regards,
>> Krzysztof
> 

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