linux-kernel - Re: [PATCH 03/18] reset: rzv2h-usb2phy: Simplify pm

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Message-ID: <aOS65YC8blClFPE-@tom-desktop>
Date: Tue, 7 Oct 2025 09:01:57 +0200
From: Tommaso Merciai <tommaso.merciai.xr@...renesas.com>
To: Philipp Zabel <p.zabel@...gutronix.de>
Cc: tomm.merciai@...il.com, linux-renesas-soc@...r.kernel.org,
	biju.das.jz@...renesas.com,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@...esas.com>,
	Vinod Koul <vkoul@...nel.org>,
	Kishon Vijay Abraham I <kishon@...nel.org>,
	Geert Uytterhoeven <geert+renesas@...der.be>,
	Magnus Damm <magnus.damm@...il.com>,
	Fabrizio Castro <fabrizio.castro.jz@...esas.com>,
	Lad Prabhakar <prabhakar.mahadev-lad.rj@...renesas.com>,
	linux-phy@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 03/18] reset: rzv2h-usb2phy: Simplify pm_runtime driver
 handling

Hi Philipp,
Thanks for your review.

On Mon, Oct 06, 2025 at 06:21:25PM +0200, Philipp Zabel wrote:
> Hi Tommaso,
> 
> On Mi, 2025-10-01 at 23:26 +0200, Tommaso Merciai wrote:
> > Remove redundant pm_runtime_resume_and_get() and pm_runtime_put() calls
> > from the reset assert, deassert, and status paths.
> 
> These calls are only made redundant by this patch.
> 
> > These paths do not require runtime PM handling, as power management is
> > already taken care of during probe and remove.
> 
> Only since you removed the pm_runtime_put() in
> rzv2h_usb2phy_reset_probe(). It feels like the important part of this
> patch is actually the side note:
> 
> > Additionally, the IP is active only when its clock is enabled.
> > Previously, the clock was being turned off immediately after register
> > configuration, which is incorrect. The code may have appeared to work
> > if another module had incremented the clock usage count, but this
> > behavior is unreliable.
> 
> So this is a reliability fix first and foremost?
> The IP must be active to reliably keep reset lines at the configured
> level?
> 
> If so, please make this clear in the commit subject and description.

The main purpose of this patch is to ensure the USB PHY controller
remain in a proper state by keeping the IP clock enabled and reset
deasserted for the normal operation.

I will make it clear in v2 also adding Fixes tag.

Thanks & Regards,
Tommaso



> 
> regards
> Philipp