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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 6B0F4C4332F for ; Thu, 17 Mar 2022 12:20:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233490AbiCQMVr (ORCPT ); Thu, 17 Mar 2022 08:21:47 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41400 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229509AbiCQMVo (ORCPT ); Thu, 17 Mar 2022 08:21:44 -0400 Received: from mailgw01.mediatek.com (unknown [60.244.123.138]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2092A1AA4B1 for ; Thu, 17 Mar 2022 05:20:23 -0700 (PDT) X-UUID: ca9f5fc0992e48a1b96ea7664a771e60-20220317 X-UUID: ca9f5fc0992e48a1b96ea7664a771e60-20220317 Received: from mtkcas11.mediatek.inc [(172.21.101.40)] by mailgw01.mediatek.com (envelope-from ) (Generic MTA with TLSv1.2 ECDHE-RSA-AES256-SHA384 256/256) with ESMTP id 1558619466; Thu, 17 Mar 2022 20:20:18 +0800 Received: from mtkexhb02.mediatek.inc (172.21.101.103) by mtkmbs10n1.mediatek.inc (172.21.101.34) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA384) id 15.2.792.15; Thu, 17 Mar 2022 20:20:17 +0800 Received: from mtkcas11.mediatek.inc (172.21.101.40) by mtkexhb02.mediatek.inc (172.21.101.103) with Microsoft SMTP Server (TLS) id 15.0.1497.2; Thu, 17 Mar 2022 20:20:16 +0800 Received: from mtksdccf07 (172.21.84.99) by mtkcas11.mediatek.inc (172.21.101.73) with Microsoft SMTP Server id 15.0.1497.2 via Frontend Transport; Thu, 17 Mar 2022 20:20:16 +0800 Message-ID: Subject: Re: [PATCH v3,4/4] drm/mediatek: Add pull-down MIPI operation in mtk_dsi_poweroff function From: Rex-BC Chen To: , , , , , CC: , , , , , Date: Thu, 17 Mar 2022 20:20:16 +0800 In-Reply-To: <1647503611-13144-5-git-send-email-xinlei.lee@mediatek.com> References: <1647503611-13144-1-git-send-email-xinlei.lee@mediatek.com> <1647503611-13144-5-git-send-email-xinlei.lee@mediatek.com> Content-Type: text/plain; charset="UTF-8" X-Mailer: Evolution 3.28.5-0ubuntu0.18.04.2 MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-MTK: N Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hello Xinlei, On Thu, 2022-03-17 at 15:53 +0800, xinlei.lee@mediatek.com wrote: > From: Xinlei Lee > > In the dsi_enable function, mtk_dsi_rxtx_control is to > pull up the MIPI signal operation. Before dsi_disable, > MIPI should also be pulled down by writing a register instead of > disabling dsi. > What will happen if you do not pulled down the mipi before disable dsi? What's differnet for this two setting? > Signed-off-by: Jitao Shi > Signed-off-by: Xinlei Lee > --- > drivers/gpu/drm/mediatek/mtk_dsi.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/drivers/gpu/drm/mediatek/mtk_dsi.c > b/drivers/gpu/drm/mediatek/mtk_dsi.c > index b509d59235e2..1c6a75a46b67 100644 > --- a/drivers/gpu/drm/mediatek/mtk_dsi.c > +++ b/drivers/gpu/drm/mediatek/mtk_dsi.c > @@ -676,6 +676,8 @@ static void mtk_dsi_poweroff(struct mtk_dsi *dsi) > mtk_dsi_reset_engine(dsi); > mtk_dsi_lane0_ulp_mode_enter(dsi); > mtk_dsi_clk_ulp_mode_enter(dsi); > + /* set the lane number as 0 */ > + writel(0, dsi->regs + DSI_TXRX_CTRL); So set lane num to 0 means pull down mipi? BRs, Rex > > mtk_dsi_disable(dsi); >