linux-kernel - Re: [PATCH v3 14/18] phy: cadence-torrent: add suspend and resume support

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Date: Wed, 21 Feb 2024 14:58:43 +0100
From: Philipp Zabel <p.zabel@...gutronix.de>
To: Thomas Richard <thomas.richard@...tlin.com>, Linus Walleij
 <linus.walleij@...aro.org>, Bartosz Golaszewski <brgl@...ev.pl>, Andy
 Shevchenko <andy@...nel.org>, Tony Lindgren <tony@...mide.com>, Haojian
 Zhuang <haojian.zhuang@...aro.org>,  Vignesh R <vigneshr@...com>, Aaro
 Koskinen <aaro.koskinen@....fi>, Janusz Krzysztofik <jmkrzyszt@...il.com>,
 Andi Shyti <andi.shyti@...nel.org>, Peter Rosin <peda@...ntia.se>, Vinod
 Koul <vkoul@...nel.org>, Kishon Vijay Abraham I <kishon@...nel.org>,
 Lorenzo Pieralisi <lpieralisi@...nel.org>, Krzysztof
 Wilczyński <kw@...ux.com>, Rob Herring <robh@...nel.org>,
 Bjorn Helgaas <bhelgaas@...gle.com>
Cc: linux-gpio@...r.kernel.org, linux-kernel@...r.kernel.org, 
 linux-arm-kernel@...ts.infradead.org, linux-omap@...r.kernel.org, 
 linux-i2c@...r.kernel.org, linux-phy@...ts.infradead.org, 
 linux-pci@...r.kernel.org, gregory.clement@...tlin.com,
 theo.lebrun@...tlin.com,  thomas.petazzoni@...tlin.com, u-kumar1@...com
Subject: Re: [PATCH v3 14/18] phy: cadence-torrent: add suspend and resume
 support

On Mi, 2024-02-21 at 14:41 +0100, Thomas Richard wrote:
> On 2/21/24 14:09, Philipp Zabel wrote:
> > On Do, 2024-02-15 at 16:17 +0100, Thomas Richard wrote:
> > > Add suspend and resume support.
> > > 
> > > The already_configured flag is cleared during the suspend stage to force
> > > the PHY initialization during the resume stage.
> > > 
> > > Based on the work of Théo Lebrun <theo.lebrun@...tlin.com>
> > > 
> > > Signed-off-by: Thomas Richard <thomas.richard@...tlin.com>
> > > ---
> > >  drivers/phy/cadence/phy-cadence-torrent.c | 54 +++++++++++++++++++++++++++++++
> > >  1 file changed, 54 insertions(+)
> > > 
> > > diff --git a/drivers/phy/cadence/phy-cadence-torrent.c b/drivers/phy/cadence/phy-cadence-torrent.c
> > > index 52cadca4c07b..f8945a11e7ca 100644
> > > --- a/drivers/phy/cadence/phy-cadence-torrent.c
> > > +++ b/drivers/phy/cadence/phy-cadence-torrent.c
> > > @@ -3005,6 +3005,59 @@ static void cdns_torrent_phy_remove(struct platform_device *pdev)
> > >  	cdns_torrent_clk_cleanup(cdns_phy);
> > >  }
> > >  
> > > +static int cdns_torrent_phy_suspend_noirq(struct device *dev)
> > > +{
> > > +	struct cdns_torrent_phy *cdns_phy = dev_get_drvdata(dev);
> > > +	int i;
> > > +
> > > +	reset_control_assert(cdns_phy->phy_rst);
> > > +	reset_control_assert(cdns_phy->apb_rst);
> > > +	for (i = 0; i < cdns_phy->nsubnodes; i++)
> > > +		reset_control_assert(cdns_phy->phys[i].lnk_rst);
> > > +
> > > +	if (cdns_phy->already_configured)
> > > +		cdns_phy->already_configured = 0;
> > > +	else
> > > +		clk_disable_unprepare(cdns_phy->clk);
> > > +
> > > +	return 0;
> > > +}
> > > +
> > > +static int cdns_torrent_phy_resume_noirq(struct device *dev)
> > > +{
> > > +	struct cdns_torrent_phy *cdns_phy = dev_get_drvdata(dev);
> > > +	int node = cdns_phy->nsubnodes;
> > > +	int ret, i;
> > > +
> > > +	ret = cdns_torrent_clk(cdns_phy);
> > > +	if (ret)
> > > +		goto clk_cleanup;
> > > +
> > > +	/* Enable APB */
> > > +	reset_control_deassert(cdns_phy->apb_rst);
> > > +
> > > +	if (cdns_phy->nsubnodes > 1) {
> > > +		ret = cdns_torrent_phy_configure_multilink(cdns_phy);
> > > +		if (ret)
> > > +			goto put_lnk_rst;
> > > +	}
> > > +
> > > +	return 0;
> > > +
> > > +put_lnk_rst:
> > > +	for (i = 0; i < node; i++)
> > > +		reset_control_assert(cdns_phy->phys[i].lnk_rst);
> > 
> > The same cleanup is found in probe. Would it be cleaner to move this
> > into cdns_torrent_phy_configure_multilink() instead of duplicating it
> > here?
> 
> Hello Philipp,
> 
> Yes I could, but from my point of view, it would not be cleaner.
> This cleanup is called from many places in the probe:
> -
> https://elixir.bootlin.com/linux/v6.8-rc5/source/drivers/phy/cadence/phy-cadence-torrent.c#L2948
> -
> https://elixir.bootlin.com/linux/v6.8-rc5/source/drivers/phy/cadence/phy-cadence-torrent.c#L2954
> -
> https://elixir.bootlin.com/linux/v6.8-rc5/source/drivers/phy/cadence/phy-cadence-torrent.c#L2960
>
> If I add this cleanup in cdns_torrent_phy_configure_multilink(), yes I
> could remove it from cdns_torrent_phy_resume_noirq(), but I should keep
> it in the probe. And I should modify the probe to jump to clk_cleanup if
> cdns_torrent_phy_configure_multilink() fails.

I see it now. If it can't be consolidated, it's not useful to move it
around.

> 
regards
Philipp