linux-kernel - Re: [PATCH] usb: chipidea: Grab the (legacy) USB PHY by phandle first

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Message-ID: <b42e37ab06ae3efa244a35df801e2126fd692bb7.camel@bootlin.com>
Date:   Wed, 16 Jan 2019 15:22:40 +0100
From:   Paul Kocialkowski <paul.kocialkowski@...tlin.com>
To:     Thomas Petazzoni <thomas.petazzoni@...tlin.com>
Cc:     linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org,
        Peter Chen <Peter.Chen@....com>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Subject: Re: [PATCH] usb: chipidea: Grab the (legacy) USB PHY by phandle
 first

Hi,

On Wed, 2019-01-16 at 14:44 +0100, Thomas Petazzoni wrote:
> Well prior to your code, there was already a possibility for both
> ci->phy and ci->usb_phy to be valid. I don't think it's really useful
> to avoid the fallback when a generic PHY has already been found, it's
> confusing. If really you want to clarify that, it should be:
> 
> 	/* Let's first try to find a generic PHY */
> 	ci->phy = devm_phy_get(dev->parent, "usb-phy");
> 	if (IS_ERR(ci->phy)) {
> 		/* Fall back to legacy USB PHY */
> 		ci->usb_phy = devm_usb_get_phy_by_phandle(dev->parent, "phys", 0);
> 		if (IS_ERR(ci->usb_phy))
> 			ci->usb_phy = devm_usb_get_phy(dev->parent, USB_PHY_TYPE_USB2);
> 	}
> 
> With that, you would only have either ci->phy or ci->usb_phy be valid,
> and never both. With  your change, you can have ci->phy and ci->usb_phy
> both be valid if the legacy USB PHY was found using
> devm_usb_get_phy_by_phandle(), but not if we fell back to
> devm_usb_get_phy().

Okay that makes sense, your suggestion is indeed more consistent with
the existing behavior. I'll go with that in the next revision!

Cheers,

Paul

-- 
Paul Kocialkowski, Bootlin
Embedded Linux and kernel engineering
https://bootlin.com