From mboxrd@z Thu Jan 1 00:00:00 1970 From: Chunfeng Yun Subject: Re: [PATCH 2/2] usb: core: phy: fix return value checking about devm_of_phy_get_by_index() Date: Mon, 25 Jun 2018 14:37:01 +0800 Message-ID: <1529908621.32173.27.camel@mhfsdcap03> References: <4c338a129ab14ab41949da5e3c21aed0d77dff8d.1529647619.git.chunfeng.yun@mediatek.com> <644d00edd2932c1a0d0a1bf368dd25427d1d9f64.1529647619.git.chunfeng.yun@mediatek.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=m.gmane.org@lists.infradead.org To: Martin Blumenstingl Cc: devicetree@vger.kernel.org, felipe.balbi@linux.intel.com, gregkh@linuxfoundation.org, linux-usb@vger.kernel.org, johan@kernel.org, linux-kernel@vger.kernel.org, linux-mediatek@lists.infradead.org, matthias.bgg@gmail.com, linux-arm-kernel@lists.infradead.org List-Id: devicetree@vger.kernel.org On Sun, 2018-06-24 at 20:00 +0200, Martin Blumenstingl wrote: > Hello Chunfeng, > > thank you for the patch! > > On Fri, Jun 22, 2018 at 8:33 AM Chunfeng Yun wrote: > > > > 1. use IS_ERR() but not IS_ERR_OR_NULL() because devm_of_phy_get_by_index() > > never return NULL value; > ACK - good catch! > > > 2. devm_of_phy_get_by_index() should not fail for a valid index > I have learned that the PHY framework can return -ENODEV if the PHY is: > 1. supposed to be handled by the legacy USB PHY framework > 2. the PHY node is disabled in devicetree A little confused, we can avoid this error by not using a disabled or "usb-nop-xceiv" phy in host node. If ignore error of -ENODEV, we will also skip an error case which we don't want it happen. > > see [0] for the code in the PHY framework and [1] for the discussion > with Johan (who informed me of case #1, I added him on this mail) > > > Signed-off-by: Chunfeng Yun > > --- > > drivers/usb/core/phy.c | 11 ++++------- > > 1 file changed, 4 insertions(+), 7 deletions(-) > > > > diff --git a/drivers/usb/core/phy.c b/drivers/usb/core/phy.c > > index 9879767..0f972e1 100644 > > --- a/drivers/usb/core/phy.c > > +++ b/drivers/usb/core/phy.c > > @@ -23,14 +23,11 @@ static int usb_phy_roothub_add_phy(struct device *dev, int index, > > struct list_head *list) > > { > > struct usb_phy_roothub *roothub_entry; > > - struct phy *phy = devm_of_phy_get_by_index(dev, dev->of_node, index); > > + struct phy *phy; > > > > - if (IS_ERR_OR_NULL(phy)) { > > - if (!phy || PTR_ERR(phy) == -ENODEV) > > - return 0; > > - else > > - return PTR_ERR(phy); > > - } > > + phy = devm_of_phy_get_by_index(dev, dev->of_node, index); > > + if (IS_ERR(phy)) > > + return PTR_ERR(phy); > @Johan can you please review this as well? maybe we need to keep the > -ENODEV check > > > Regards > Martin > > > [0] https://elixir.bootlin.com/linux/v4.18-rc2/source/drivers/phy/phy-core.c#L421 > [1] https://lkml.org/lkml/2018/4/19/88