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=-8.6 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED,USER_AGENT_MUTT autolearn=ham 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 7DE7FC43381 for ; Mon, 4 Mar 2019 12:31:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 4A2052070B for ; Mon, 4 Mar 2019 12:31:02 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=ideasonboard.com header.i=@ideasonboard.com header.b="v8ZV2+Te" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726439AbfCDMbA (ORCPT ); Mon, 4 Mar 2019 07:31:00 -0500 Received: from perceval.ideasonboard.com ([213.167.242.64]:36336 "EHLO perceval.ideasonboard.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726095AbfCDMbA (ORCPT ); Mon, 4 Mar 2019 07:31:00 -0500 Received: from pendragon.ideasonboard.com (dfj612yhrgyx302h3jwwy-3.rev.dnainternet.fi [IPv6:2001:14ba:21f5:5b00:ce28:277f:58d7:3ca4]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 019FF322; Mon, 4 Mar 2019 13:30:57 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1551702658; bh=9xEi0WezvKlK4ejlIY7sMBrrIicoJR8kBKwDzClZIJ0=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=v8ZV2+Te/0DyqeuyXhfiYJCmEwB0oJ/pBkRWLNoHbFcQoYRsBYpj8jIFJgGUAcZsw P6HpNS3QCK4rSIMvnEq96f7mmsH8cNdNQKz8GNpqtcpc63+orwgedgu7vIIlnnRQoj D2E6Nfe2POatzk8CWx5HxCJke1CuZFQMW12qWvZ4= Date: Mon, 4 Mar 2019 14:30:52 +0200 From: Laurent Pinchart To: Andrey Smirnov Cc: dri-devel@lists.freedesktop.org, Archit Taneja , Andrzej Hajda , Chris Healy , Lucas Stach , linux-kernel@vger.kernel.org Subject: Re: [PATCH 5/9] drm/bridge: tc358767: Simplify polling in tc_link_training() Message-ID: <20190304123052.GG6325@pendragon.ideasonboard.com> References: <20190226193609.9862-1-andrew.smirnov@gmail.com> <20190226193609.9862-6-andrew.smirnov@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20190226193609.9862-6-andrew.smirnov@gmail.com> User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Andrey, Thank you for the patch. On Tue, Feb 26, 2019 at 11:36:05AM -0800, Andrey Smirnov wrote: > Replace explicit polling in tc_link_training() with equivalent call to > regmap_read_poll_timeout() for simplicity. No functional change > intended (not including slightly altered debug output). > > Signed-off-by: Andrey Smirnov > Cc: Archit Taneja > Cc: Andrzej Hajda > Cc: Laurent Pinchart > Cc: Chris Healy > Cc: Lucas Stach > Cc: dri-devel@lists.freedesktop.org > Cc: linux-kernel@vger.kernel.org > --- > drivers/gpu/drm/bridge/tc358767.c | 14 +++++--------- > 1 file changed, 5 insertions(+), 9 deletions(-) > > diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c > index 6455e6484722..ea30cec4a0c3 100644 > --- a/drivers/gpu/drm/bridge/tc358767.c > +++ b/drivers/gpu/drm/bridge/tc358767.c > @@ -735,7 +735,6 @@ static int tc_link_training(struct tc_data *tc, int pattern) > const char * const *errors; > u32 srcctrl = tc_srcctrl(tc) | DP0_SRCCTRL_SCRMBLDIS | > DP0_SRCCTRL_AUTOCORRECT; > - int timeout; > int retry; > u32 value; > int ret; > @@ -765,20 +764,17 @@ static int tc_link_training(struct tc_data *tc, int pattern) > tc_write(DP0CTL, DP_EN); > > /* wait */ > - timeout = 1000; > - do { > - tc_read(DP0_LTSTAT, &value); > - udelay(1); > - } while ((!(value & LT_LOOPDONE)) && (--timeout)); > - if (timeout == 0) { > + ret = regmap_read_poll_timeout(tc->regmap, DP0_LTSTAT, value, > + value & LT_LOOPDONE, 1, 1000); > + if (ret) { > dev_err(tc->dev, "Link training timeout!\n"); > } else { > int pattern = (value >> 11) & 0x3; > int error = (value >> 8) & 0x7; > > dev_dbg(tc->dev, > - "Link training phase %d done after %d uS: %s\n", > - pattern, 1000 - timeout, errors[error]); > + "Link training phase %d done: %s\n", > + pattern, errors[error]); It's probably not a big deal in this specific case, but in general it can be useful to know how long the poll took. Any hope to enhance regmap_read_poll_timeout() to return either the elapsed time or the remaining timeout instead of 0 on success ? > if (pattern == DP_TRAINING_PATTERN_1 && error == 0) > break; > if (pattern == DP_TRAINING_PATTERN_2) { -- Regards, Laurent Pinchart