From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 06110C3F2C6 for ; Tue, 3 Mar 2020 15:33:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id D4B4D2083E for ; Tue, 3 Mar 2020 15:33:47 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729872AbgCCPdr (ORCPT ); Tue, 3 Mar 2020 10:33:47 -0500 Received: from relay9-d.mail.gandi.net ([217.70.183.199]:36895 "EHLO relay9-d.mail.gandi.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729589AbgCCPdq (ORCPT ); Tue, 3 Mar 2020 10:33:46 -0500 X-Originating-IP: 90.89.41.158 Received: from localhost (lfbn-tou-1-1473-158.w90-89.abo.wanadoo.fr [90.89.41.158]) (Authenticated sender: antoine.tenart@bootlin.com) by relay9-d.mail.gandi.net (Postfix) with ESMTPSA id 8EBB2FF815; Tue, 3 Mar 2020 15:33:44 +0000 (UTC) Date: Tue, 3 Mar 2020 16:33:43 +0100 From: Antoine Tenart To: Russell King - ARM Linux admin Cc: Antoine Tenart , Andrew Lunn , Florian Fainelli , Heiner Kallweit , "David S. Miller" , netdev@vger.kernel.org Subject: Re: [PATCH net-next 2/3] net: phy: marvell10g: add energy detect power down tunable Message-ID: <20200303153343.GF3179@kwain> References: <20200303144259.GM25745@shell.armlinux.org.uk> <20200303150741.GC3179@kwain> <20200303151232.GO25745@shell.armlinux.org.uk> <20200303151958.GE3179@kwain> <20200303153013.GQ25745@shell.armlinux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20200303153013.GQ25745@shell.armlinux.org.uk> Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Tue, Mar 03, 2020 at 03:30:13PM +0000, Russell King - ARM Linux admin wrote: > On Tue, Mar 03, 2020 at 04:19:58PM +0100, Antoine Tenart wrote: > > On Tue, Mar 03, 2020 at 03:12:32PM +0000, Russell King - ARM Linux admin wrote: > > > On Tue, Mar 03, 2020 at 04:07:41PM +0100, Antoine Tenart wrote: > > > > On Tue, Mar 03, 2020 at 02:44:02PM +0000, Russell King wrote: > > > > > drivers/net/phy/marvell10g.c | 111 ++++++++++++++++++++++++++++++++++- > > > > > > > > > > +static int mv3310_maybe_reset(struct phy_device *phydev, u32 unit, bool reset) > > > > > +{ > > > > > + int retries, val, err; > > > > > + > > > > > + if (!reset) > > > > > + return 0; > > > > > > > > You could also call mv3310_maybe_reset after testing the 'reset' > > > > condition, that would make it easier to read the code. > > > > > > I'm not too convinced: > > > > > > diff --git a/drivers/net/phy/marvell10g.c b/drivers/net/phy/marvell10g.c > > > index ef1ed9415d9f..3daf73e61dff 100644 > > > --- a/drivers/net/phy/marvell10g.c > > > +++ b/drivers/net/phy/marvell10g.c > > > @@ -279,13 +279,10 @@ static int mv3310_power_up(struct phy_device *phydev) > > > MV_V2_PORT_CTRL_PWRDOWN); > > > } > > > > > > -static int mv3310_maybe_reset(struct phy_device *phydev, u32 unit, bool reset) > > > +static int mv3310_reset(struct phy_device *phydev, u32 unit) > > > { > > > int retries, val, err; > > > > > > - if (!reset) > > > - return 0; > > > - > > > err = phy_modify_mmd(phydev, MDIO_MMD_PCS, unit + MDIO_CTRL1, > > > MDIO_CTRL1_RESET, MDIO_CTRL1_RESET); > > > if (err < 0) > > > @@ -684,10 +681,10 @@ static int mv3310_config_mdix(struct phy_device *phydev) > > > > > > err = phy_modify_mmd_changed(phydev, MDIO_MMD_PCS, MV_PCS_CSCR1, > > > MV_PCS_CSCR1_MDIX_MASK, val); > > > - if (err < 0) > > > + if (err <= 0) > > > return err; > > > > > > - return mv3310_maybe_reset(phydev, MV_PCS_BASE_T, err > 0); > > > + return mv3310_reset(phydev, MV_PCS_BASE_T); > > > } > > > > > > static int mv3310_config_aneg(struct phy_device *phydev) > > > > > > The change from: > > > > > > if (err < 0) > > > > > > to: > > > > > > if (err <= 0) > > > > > > could easily be mistaken as a bug, and someone may decide to try to > > > "fix" that back to being the former instead. The way I have the code > > > makes the intention explicit. > > > > Using a single line to test both the error and the 'return 0' > > conditions, yes, I agree. Another solution would be to do something of > > the like: > > > > phy_modify_mmd_changed() > > if (err < 0) > > return err; > > > > if (err) > > mv3310_reset(); > > > > return 0; > > > > I find it more readable, but this kind of thing is also a matter of > > personal taste. > > Well, it either becomes: > > err = phy_modify_mmd_changed(phydev, MDIO_MMD_PCS, MV_PCS_CSCR1, > MV_PCS_CSCR1_MDIX_MASK, val); > if (err < 0) > return err; > > if (err > 0) > return mv3310_reset(phydev, MV_PCS_BASE_T); > > return 0; > > or: > > err = phy_modify_mmd_changed(phydev, MDIO_MMD_PCS, MV_PCS_CSCR1, > MV_PCS_CSCR1_MDIX_MASK, val); > if (err > 0) > err = mv3310_reset(phydev, MV_PCS_BASE_T); > > return err; > > In the former case, we have two success-exit paths - one via a successful > mv3310_reset() and one by dropping through to the final return statement. > > The latter case looks a bit better, at least to me. I do agree, the latter looks good. Thanks, Antoine -- Antoine Ténart, Bootlin Embedded Linux and Kernel engineering https://bootlin.com