Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753028AbdLEN0n (ORCPT ); Tue, 5 Dec 2017 08:26:43 -0500 Received: from relay03.alfahosting-server.de ([109.237.142.239]:52709 "EHLO relay03.alfahosting-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752693AbdLEN0g (ORCPT ); Tue, 5 Dec 2017 08:26:36 -0500 X-Spam-DCC: : From: Richard Leitner To: robh+dt@kernel.org, mark.rutland@arm.com, fugang.duan@nxp.com, andrew@lunn.ch, f.fainelli@gmail.com, frowand.list@gmail.com Cc: davem@davemloft.net, geert+renesas@glider.be, sergei.shtylyov@cogentembedded.com, baruch@tkos.co.il, david.wu@rock-chips.com, lukma@denx.de, netdev@vger.kernel.org, devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, richard.leitner@skidata.com Subject: [PATCH net-next v3 2/4] phylib: add reset after clk enable support Date: Tue, 5 Dec 2017 14:25:58 +0100 Message-Id: <20171205132600.13796-3-dev@g0hl1n.net> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20171205132600.13796-1-dev@g0hl1n.net> References: <20171205132600.13796-1-dev@g0hl1n.net> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2821 Lines: 82 From: Richard Leitner Some PHYs need the refclk to be a continuous clock. Therefore they don't allow turning it off and on again during operation. Nonetheless such a clock switching is performed by some ETH drivers (namely FEC [1]) for power saving reasons. An example for an affected PHY is the SMSC/Microchip LAN8720 in "REF_CLK In Mode". In order to provide a uniform method to overcome this problem this patch adds a new phy_driver flag (PHY_RST_AFTER_CLK_EN) and corresponding function phy_reset_after_clk_enable() to the phylib. These should be used to trigger reset of the PHY after the refclk is switched on again. This patch depends on the "phylib: Add device reset GPIO support" patch submitted by Geert Uytterhoeven/Sergei Shtylyov [2]. [1] commit e8fcfcd5684a ("net: fec: optimize the clock management to save power") [2] https://patchwork.kernel.org/patch/10090149/ Signed-off-by: Richard Leitner --- drivers/net/phy/phy_device.c | 24 ++++++++++++++++++++++++ include/linux/phy.h | 2 ++ 2 files changed, 26 insertions(+) diff --git a/drivers/net/phy/phy_device.c b/drivers/net/phy/phy_device.c index 1de5e242b8b4..462c17ed87b8 100644 --- a/drivers/net/phy/phy_device.c +++ b/drivers/net/phy/phy_device.c @@ -1218,6 +1218,30 @@ int phy_loopback(struct phy_device *phydev, bool enable) } EXPORT_SYMBOL(phy_loopback); +/** + * phy_reset_after_clk_enable - perform a PHY reset if needed + * @phydev: target phy_device struct + * + * Description: Some PHYs are known to need a reset after their refclk was + * enabled. This function evaluates the flags and perform the reset if it's + * needed. Returns < 0 on error, 0 if the phy wasn't reset and 1 if the phy + * was reset. + */ +int phy_reset_after_clk_enable(struct phy_device *phydev) +{ + if (!phydev || !phydev->drv) + return -ENODEV; + + if (phydev->drv->flags & PHY_RST_AFTER_CLK_EN) { + phy_device_reset(phydev, 1); + phy_device_reset(phydev, 0); + return 1; + } + + return 0; +} +EXPORT_SYMBOL(phy_reset_after_clk_enable); + /* Generic PHY support and helper functions */ /** diff --git a/include/linux/phy.h b/include/linux/phy.h index 2bcbe894eb10..5c05fc73af70 100644 --- a/include/linux/phy.h +++ b/include/linux/phy.h @@ -59,6 +59,7 @@ #define PHY_HAS_INTERRUPT 0x00000001 #define PHY_IS_INTERNAL 0x00000002 +#define PHY_RST_AFTER_CLK_EN 0x00000004 #define MDIO_DEVICE_IS_PHY 0x80000000 /* Interface Mode definitions */ @@ -839,6 +840,7 @@ int phy_aneg_done(struct phy_device *phydev); int phy_stop_interrupts(struct phy_device *phydev); int phy_restart_aneg(struct phy_device *phydev); +int phy_reset_after_clk_enable(struct phy_device *phydev); static inline void phy_device_reset(struct phy_device *phydev, int value) { -- 2.11.0