linux-kernel - Re: [PATCH] Revert "firmware: arm_scmi: Add clock management to the SCMI power domain"

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Date:   Wed, 21 Sep 2022 16:56:34 +0100
From:   Sudeep Holla <sudeep.holla@....com>
To:     Ulf Hansson <ulf.hansson@...aro.org>,
        Dien Pham <dien.pham.ry@...esas.com>,
        Gaku Inami <gaku.inami.xh@...esas.com>
Cc:     Cristian Marussi <cristian.marussi@....com>,
        linux-arm-kernel@...ts.infradead.org, Peng Fan <peng.fan@....com>,
        Geert Uytterhoeven <geert@...ux-m68k.org>,
        Nicolas Pitre <npitre@...libre.com>,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org
Subject: Re: [PATCH] Revert "firmware: arm_scmi: Add clock management to the
 SCMI power domain"

Hi Dien, Gaku,

On Mon, Sep 19, 2022 at 02:20:33PM +0200, Ulf Hansson wrote:
> This reverts commit a3b884cef873 ("firmware: arm_scmi: Add clock management
> to the SCMI power domain").
> 
> Using the GENPD_FLAG_PM_CLK tells genpd to gate/ungate the consumer
> device's clock(s) during runtime suspend/resume through the PM clock API.
> More precisely, in genpd_runtime_resume() the clock(s) for the consumer
> device would become ungated prior to the driver-level ->runtime_resume()
> callbacks gets invoked.
> 
> This behaviour isn't a good fit for all platforms/drivers. For example, a
> driver may need to make some preparations of its device in its
> ->runtime_resume() callback, like calling clk_set_rate() before the
> clock(s) should be ungated. In these cases, it's easier to let the clock(s)
> to be managed solely by the driver, rather than at the PM domain level.
> 
> For these reasons, let's drop the use GENPD_FLAG_PM_CLK for the SCMI PM
> domain, as to enable it to be more easily adopted across ARM platforms.
> 
> Fixes: a3b884cef873 ("firmware: arm_scmi: Add clock management to the SCMI power domain")
> Cc: Nicolas Pitre <npitre@...libre.com>
> Cc: stable@...r.kernel.org
> Signed-off-by: Ulf Hansson <ulf.hansson@...aro.org>
> ---
> 
> To get some more background to $subject patch, please have a look at the
> lore-link below.
> 
> https://lore.kernel.org/all/DU0PR04MB94173B45A2CFEE3BF1BD313A88409@DU0PR04MB9417.eurprd04.prod.outlook.com/
>

If you have any objections, this is your last chance to speak up before
the original change gets reverted in the mainline with this patch.

Hi Ulf,

I don't have any other SCMI changes for v6.0 fixes or v6.1
I am fine if you are happy to take this via your tree or I can send it
to SoC team. Let me know. I will give final one or 2 days for Renesas
to get back if they really care much.

--
Regards,
Sudeep