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=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, UNPARSEABLE_RELAY,USER_AGENT_SANE_2 autolearn=unavailable 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 9102AC47404 for ; Fri, 11 Oct 2019 08:21:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 73A1221D7A for ; Fri, 11 Oct 2019 08:21:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727520AbfJKIV1 (ORCPT ); Fri, 11 Oct 2019 04:21:27 -0400 Received: from Mailgw01.mediatek.com ([1.203.163.78]:41245 "EHLO mailgw01.mediatek.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1726983AbfJKIVZ (ORCPT ); Fri, 11 Oct 2019 04:21:25 -0400 X-UUID: 683957e80d3f4b828ae9e3cf2535bbf0-20191011 X-UUID: 683957e80d3f4b828ae9e3cf2535bbf0-20191011 Received: from mtkcas32.mediatek.inc [(172.27.4.253)] by mailgw01.mediatek.com (envelope-from ) (mailgw01.mediatek.com ESMTP with TLS) with ESMTP id 1514359459; Fri, 11 Oct 2019 16:21:11 +0800 Received: from MTKCAS32.mediatek.inc (172.27.4.184) by MTKMBS31DR.mediatek.inc (172.27.6.102) with Microsoft SMTP Server (TLS) id 15.0.1395.4; Fri, 11 Oct 2019 16:21:07 +0800 Received: from [10.17.3.153] (172.27.4.253) by MTKCAS32.mediatek.inc (172.27.4.170) with Microsoft SMTP Server id 15.0.1395.4 via Frontend Transport; Fri, 11 Oct 2019 16:21:07 +0800 Message-ID: <1570782069.5044.12.camel@mhfsdcap03> Subject: Re: [PATCH] net: stmmac: disable/enable ptp_ref_clk in suspend/resume flow From: biao huang To: Jakub Kicinski CC: , Jose Abreu , , Giuseppe Cavallaro , Alexandre Torgue , Maxime Coquelin , Matthias Brugger , , , , , , , , , Date: Fri, 11 Oct 2019 16:21:09 +0800 In-Reply-To: <20191010160103.63c3c0ed@cakuba.netronome.com> References: <20191009085649.6736-1-biao.huang@mediatek.com> <20191010160103.63c3c0ed@cakuba.netronome.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.10.4-0ubuntu2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-TM-SNTS-SMTP: 830FACAF2A292503757689C34417C3AFCD74A88CD9AC4330D44496E1DBE6BC492000:8 X-MTK: N Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Appreciate your comments! On Thu, 2019-10-10 at 16:01 -0700, Jakub Kicinski wrote: > On Wed, 9 Oct 2019 16:56:49 +0800, Biao Huang wrote: > > disable ptp_ref_clk in suspend flow, and enable it in resume flow. > > > > Signed-off-by: Biao Huang > > --- > > drivers/net/ethernet/stmicro/stmmac/stmmac_main.c | 4 ++++ > > 1 file changed, 4 insertions(+) > > > > diff --git a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > > index c7c9e5f162e6..b592aeecc3dd 100644 > > --- a/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > > +++ b/drivers/net/ethernet/stmicro/stmmac/stmmac_main.c > > @@ -4469,6 +4469,8 @@ int stmmac_suspend(struct device *dev) > > stmmac_mac_set(priv, priv->ioaddr, false); > > pinctrl_pm_select_sleep_state(priv->device); > > /* Disable clock in case of PWM is off */ > > + if (priv->plat->clk_ptp_ref) > > + clk_disable_unprepare(priv->plat->clk_ptp_ref); > > I don't know much embedded, but it seems like this should perhaps just > be clk_disable() without the unprepare? stmmac_hw_teardown() is called > when driver is removed so it needs to unprepare as well. > > Please feel free to explain to me why this needs to be > clk_disable_unprepare(), as I said - not an expert. > As our clock owner's advice, there are prepare/unprepare clk_ops for pll, but no enable/disable clk_ops for it, and pll will be off only when the prepare reference count decrease to 0. so for the sake of power saving, we'd better call clk_disable_unprepare to turn the parent pll off. > Also - if this is a bug fix and you'd like to have it backported to > older releases you need to add a Fixes tag. > Thanks for the reminder, I'll add the fixes tag in the next version. > Thanks! > > > clk_disable(priv->plat->pclk); > > clk_disable(priv->plat->stmmac_clk); maybe it should be clk_disable_unprepare(priv->plat->pclk); clk_disable_unprepare(priv->plat->stmmac_clk); > > } > > @@ -4535,6 +4537,8 @@ int stmmac_resume(struct device *dev) > > /* enable the clk previously disabled */ > > clk_enable(priv->plat->stmmac_clk); > > clk_enable(priv->plat->pclk); > > + if (priv->plat->clk_ptp_ref) > > + clk_prepare_enable(priv->plat->clk_ptp_ref); > > /* reset the phy so that it's ready */ > > if (priv->mii) > > stmmac_mdio_reset(priv->mii); >