From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pandora.armlinux.org.uk (pandora.armlinux.org.uk [78.32.30.218]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 854CE7E1; Mon, 29 Jul 2024 23:39:30 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=78.32.30.218 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722296373; cv=none; b=ZJO+PyxB8ZN0kbN+ZmP1ArajhKUW14ngsW6Lmh9CSNzeOhfGl6CIlBTiVJdqGUmt3JE0NezhW2pCujdw28UE2IHm3jgBfi7/ZqOworQfArcqKxf5g69WExovtSq0/T5u80hahwSXMULqNW9sdhIKm5xfwbd3+DT9t8QpFMvhnh0= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1722296373; c=relaxed/simple; bh=oWZ3IYgzKT6CnlOSYJcLs3DHWI2QuVDBZuog8IoRvSk=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=rKQec8xhXKL5owo0Po/qsWrh7YK7kKio2tn7M7C+1xYX+XIhh68H4xol0fBaGy4WiZN7Vku78UOLi+jXkRqE9B1C+FmvldEzI19fLhxmrib675aGBm8P1gxpEut9so24l8tcCBKLrULTIYJO1HfJCYOcSqE5NCLlf7v6T42QWb4= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk; spf=none smtp.mailfrom=armlinux.org.uk; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b=vZoE0vtI; arc=none smtp.client-ip=78.32.30.218 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=armlinux.org.uk Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=armlinux.org.uk header.i=@armlinux.org.uk header.b="vZoE0vtI" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=armlinux.org.uk; s=pandora-2019; h=Sender:In-Reply-To:Content-Type: MIME-Version:References:Message-ID:Subject:Cc:To:From:Date:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Id: List-Help:List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=LMjXLw4I49235k9Hi/bPaVIFeEwbQQwxpJC/Qsvb5RM=; b=vZoE0vtIZ8SERB9oJeOXQG8egc LH5Zwd5UEAcgcRE3dQCoDuiC1Ibj3eiPsORN/wGhtWQVaoNH/kNtpkb5ULWuJnF48XyON1nyUopMp 9EABDD38l4GxZWwq/Xs9WletZO6og7dmJHA5PS/6VQOcxdgbLQHUiPRFkli4MjrJP9mGe2OfiezYk f5oYeSU/Xm9uz6Vy5cbxumOuIij9nD65roF2aeT6gSDVfg0lWf7Dt5/qNGc7mM1U9UKP03YZ0dOgb fNIt9J9+E1ImiMlReaIsDIEQ4h6kZsBPP/PbQSJu9QsWnZL/A19cnZtXqWl0+f7PBsu2KZXK4RLZc wwZTTR9A==; Received: from shell.armlinux.org.uk ([fd8f:7570:feb6:1:5054:ff:fe00:4ec]:55872) by pandora.armlinux.org.uk with esmtpsa (TLS1.3) tls TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384 (Exim 4.96) (envelope-from ) id 1sYZxY-0005c5-2d; Tue, 30 Jul 2024 00:39:20 +0100 Received: from linux by shell.armlinux.org.uk with local (Exim 4.94.2) (envelope-from ) id 1sYZxc-0004jq-Bs; Tue, 30 Jul 2024 00:39:24 +0100 Date: Tue, 30 Jul 2024 00:39:24 +0100 From: "Russell King (Oracle)" To: Pawel Dembicki Cc: netdev@vger.kernel.org, Andrew Lunn , Florian Fainelli , Vladimir Oltean , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Heiner Kallweit , Linus Walleij , linux-kernel@vger.kernel.org Subject: Re: [PATCH net-next 9/9] net: phy: vitesse: implement downshift in vsc73xx phys Message-ID: References: <20240729210615.279952-1-paweldembicki@gmail.com> <20240729210615.279952-10-paweldembicki@gmail.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20240729210615.279952-10-paweldembicki@gmail.com> Sender: Russell King (Oracle) On Mon, Jul 29, 2024 at 11:06:15PM +0200, Pawel Dembicki wrote: > +static int vsc73xx_get_downshift(struct phy_device *phydev, u8 *data) > +{ > + int page, val, cnt, enable; > + > + page = phy_select_page(phydev, MII_VSC73XX_EXT_PAGE_1E); > + if (page < 0) > + return page; > + > + val = __phy_read(phydev, MII_VSC73XX_PHY_CTRL_EXT3); > + if (val < 0) > + goto restore_page; > + > + enable = FIELD_GET(MII_VSC73XX_PHY_CTRL_EXT3_DOWNSHIFT_EN, val); > + cnt = FIELD_GET(MII_VSC73XX_PHY_CTRL_EXT3_DOWNSHIFT_CNT, val) + 2; > + > + *data = enable ? cnt : DOWNSHIFT_DEV_DISABLE; > + > +restore_page: > + phy_restore_page(phydev, page, val); > + return 0; If you're going to use phy_select_page()..phy_restore_page(), please read the documentation. If the __phy_read() fails, then you're returning zero from this function, but leaving *data uninitialised. Surely not what you want. In any case, this complexity is unnecessary. static int vsc73xx_get_downshift(struct phy_device *phydev, u8 *data) { int val, enable, cnt; val = phy_read_paged(phydev, MII_VSC73XX_EXT_PAGE_1E, MII_VSC73XX_PHY_CTRL_EXT3); if (val < 0) return val; enable = FIELD_GET(MII_VSC73XX_PHY_CTRL_EXT3_DOWNSHIFT_EN, val); cnt = FIELD_GET(MII_VSC73XX_PHY_CTRL_EXT3_DOWNSHIFT_CNT, val) + 2; *data = enable ? cnt : DOWNSHIFT_DEV_DISABLE; return 0; } is all that it needs. > +} > + > +static int vsc73xx_set_downshift(struct phy_device *phydev, u8 cnt) > +{ > + int page, ret, val; > + > + if (cnt > MII_VSC73XX_DOWNSHIFT_MAX) > + return -E2BIG; > + else if (cnt == MII_VSC73XX_DOWNSHIFT_INVAL) > + return -EINVAL; > + > + page = phy_select_page(phydev, MII_VSC73XX_EXT_PAGE_1E); > + if (page < 0) > + return page; > + > + if (!cnt) { > + ret = __phy_clear_bits(phydev, MII_VSC73XX_PHY_CTRL_EXT3, > + MII_VSC73XX_PHY_CTRL_EXT3_DOWNSHIFT_EN); > + } else { > + val = MII_VSC73XX_PHY_CTRL_EXT3_DOWNSHIFT_EN | > + FIELD_PREP(MII_VSC73XX_PHY_CTRL_EXT3_DOWNSHIFT_CNT, > + cnt - 2); > + > + ret = __phy_modify(phydev, MII_VSC73XX_PHY_CTRL_EXT3, > + MII_VSC73XX_PHY_CTRL_EXT3_DOWNSHIFT_EN | > + MII_VSC73XX_PHY_CTRL_EXT3_DOWNSHIFT_CNT, > + val); > + } > + > + ret = phy_restore_page(phydev, page, ret); > + if (ret < 0) > + return ret; This is also needlessly over-complex. u16 mask, val; ... mask = MII_VSC73XX_PHY_CTRL_EXT3_DOWNSHIFT_EN; if (!cnt) { val = 0; } else { mask |= MII_VSC73XX_PHY_CTRL_EXT3_DOWNSHIFT_CNT; val = MII_VSC73XX_PHY_CTRL_EXT3_DOWNSHIFT_EN | FIELD_PREP(MII_VSC73XX_PHY_CTRL_EXT3_DOWNSHIFT_CNT, cnt - 2); } ret = phy_modify_paged(phydev, MII_VSC73XX_EXT_PAGE_1E, MII_VSC73XX_PHY_CTRL_EXT3, mask, val); if (ret < 0) return ret; Would be equivalent to your code above, only simpler. -- RMK's Patch system: https://www.armlinux.org.uk/developer/patches/ FTTP is here! 80Mbps down 10Mbps up. Decent connectivity at last!