Re: [PATCH 03/18] reset: rzv2h-usb2phy: Simplify pm_runtime driver handling

From: Tommaso Merciai <tommaso.merciai.xr@bp.renesas.com>
To: Philipp Zabel <p.zabel@pengutronix.de>
Cc: tomm.merciai@gmail.com, linux-renesas-soc@vger.kernel.org,
	biju.das.jz@bp.renesas.com,
	Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>,
	Vinod Koul <vkoul@kernel.org>,
	Kishon Vijay Abraham I <kishon@kernel.org>,
	Geert Uytterhoeven <geert+renesas@glider.be>,
	Magnus Damm <magnus.damm@gmail.com>,
	Fabrizio Castro <fabrizio.castro.jz@renesas.com>,
	Lad Prabhakar <prabhakar.mahadev-lad.rj@bp.renesas.com>,
	linux-phy@lists.infradead.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 03/18] reset: rzv2h-usb2phy: Simplify pm_runtime driver handling
Date: Tue, 7 Oct 2025 09:01:57 +0200	[thread overview]
Message-ID: <aOS65YC8blClFPE-@tom-desktop> (raw)
In-Reply-To: <c3e1e3da577de1370e7604560f0b42c0fcb7db44.camel@pengutronix.de>

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

-- 
linux-phy mailing list
linux-phy@lists.infradead.org
https://lists.infradead.org/mailman/listinfo/linux-phy