linux-kernel - Re: [PATCH v2 2/8] usb: phy: tegra: Support waking up from a low power mode

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Message-ID: <X9tzlWYKRS9FY9q3@ulmo>
Date:   Thu, 17 Dec 2020 16:04:53 +0100
From:   Thierry Reding <thierry.reding@...il.com>
To:     Dmitry Osipenko <digetx@...il.com>
Cc:     Jonathan Hunter <jonathanh@...dia.com>,
        Peter Chen <Peter.Chen@....com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        Alan Stern <stern@...land.harvard.edu>,
        Felipe Balbi <balbi@...nel.org>,
        Matt Merhar <mattmerhar@...tonmail.com>,
        Nicolas Chauvet <kwizart@...il.com>,
        Peter Geis <pgwipeout@...il.com>,
        Ion Agorria <ion@...rria.com>, linux-tegra@...r.kernel.org,
        linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2 2/8] usb: phy: tegra: Support waking up from a low
 power mode

On Thu, Dec 17, 2020 at 04:47:50PM +0300, Dmitry Osipenko wrote:
> 17.12.2020 16:33, Thierry Reding пишет:
> >> +	/* PHY won't resume if reset is asserted */
> >> +	if (phy->wakeup_enabled)
> >> +		goto chrg_cfg0;
> >>  
> >>  	val = readl_relaxed(base + USB_SUSP_CTRL);
> >>  	val |= UTMIP_RESET;
> >>  	writel_relaxed(val, base + USB_SUSP_CTRL);
> >>  
> >> +chrg_cfg0:
> > I found this diffcult to read until I realized that it was basically
> > just the equivalent of this:
> > 
> > 	if (!phy->wakeup_enabled) {
> > 		val = readl_relaxed(base + USB_SUSP_CTRL);
> > 		val |= UTMIP_RESET;
> > 		writel_relaxed(val, base + USB_SUSP_CTRL);
> > 	}
> > 
> >>  	val = readl_relaxed(base + UTMIP_BAT_CHRG_CFG0);
> >>  	val |= UTMIP_PD_CHRG;
> >>  	writel_relaxed(val, base + UTMIP_BAT_CHRG_CFG0);
> >>  
> >> +	if (phy->wakeup_enabled)
> >> +		goto xcvr_cfg1;
> >> +
> >>  	val = readl_relaxed(base + UTMIP_XCVR_CFG0);
> >>  	val |= UTMIP_FORCE_PD_POWERDOWN | UTMIP_FORCE_PD2_POWERDOWN |
> >>  	       UTMIP_FORCE_PDZI_POWERDOWN;
> >>  	writel_relaxed(val, base + UTMIP_XCVR_CFG0);
> >>  
> >> +xcvr_cfg1:
> > Similarly, I think this is more readable as:
> > 
> > 	if (!phy->wakeup_enabled) {
> > 		val = readl_relaxed(base + UTMIP_XCVR_CFG0);
> > 		val |= UTMIP_FORCE_PD_POWERDOWN | UTMIP_FORCE_PD2_POWERDOWN |
> > 		       UTMIP_FORCE_PDZI_POWERDOWN;
> > 		writel_relaxed(val, base + UTMIP_XCVR_CFG0);
> > 	}
> > 
> >>  	val = readl_relaxed(base + UTMIP_XCVR_CFG1);
> >>  	val |= UTMIP_FORCE_PDDISC_POWERDOWN | UTMIP_FORCE_PDCHRP_POWERDOWN |
> >>  	       UTMIP_FORCE_PDDR_POWERDOWN;
> >>  	writel_relaxed(val, base + UTMIP_XCVR_CFG1);
> >>  
> >> +	if (phy->wakeup_enabled) {
> > Which then also matches the style of this conditional here.
> 
> I'll change it in v3, thanks.

Given that my other comment about the WARN_ONCE seems to have been
resolved, with the above gotos replaced by conditionals as I suggested:

Acked-by: Thierry Reding <treding@...dia.com>

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