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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_PASS 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 AE3E4C28CF8 for ; Fri, 12 Oct 2018 00:55:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 5B1A220644 for ; Fri, 12 Oct 2018 00:55:30 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="iXeahS7N"; dkim=fail reason="key not found in DNS" (0-bit key) header.d=codeaurora.org header.i=@codeaurora.org header.b="B20uJHTT" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 5B1A220644 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=codeaurora.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727061AbeJLIZR (ORCPT ); Fri, 12 Oct 2018 04:25:17 -0400 Received: from smtp.codeaurora.org ([198.145.29.96]:54528 "EHLO smtp.codeaurora.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725850AbeJLIZQ (ORCPT ); Fri, 12 Oct 2018 04:25:16 -0400 Received: by smtp.codeaurora.org (Postfix, from userid 1000) id ABCB660C60; Fri, 12 Oct 2018 00:55:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1539305726; bh=NBlomhmy8pJqwpVilnH8sLnIQGcR7aWMCSAPqJXMne0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=iXeahS7N9RS88Ua8JP2zF/kkwSQQ5+P+kSOy6nTV2NosJmkIublLCpSyUwKz9H3rh gb0l4rWmg8q3k0hSc8PbFzuvpdHJSCOME0HJ8pr+DqmQ2iw0LVuKfChBaSq6Z0kEly swuBkMi1Ca2+3x/wdvXjEEouSGHg/+uqJQalnnDo= Received: from mail.codeaurora.org (localhost.localdomain [127.0.0.1]) by smtp.codeaurora.org (Postfix) with ESMTP id ADB4F60866; Fri, 12 Oct 2018 00:55:25 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=codeaurora.org; s=default; t=1539305725; bh=NBlomhmy8pJqwpVilnH8sLnIQGcR7aWMCSAPqJXMne0=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=B20uJHTTvUeFIMIMVkhNxSmmWzasg+EAi8IMdf9jttd8tJRhWZ5adyn7CxQnUVer4 us7XUb3MySe8hIsN5TRvHp2l2QJdRCZ5DINCkjOzYJdvsl4TJLyWYToUAlSXgmk4o3 j1RezeaMidLOTLWGuYtIJemGYowmJVCXaPxwpXt0= MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Date: Fri, 12 Oct 2018 08:55:25 +0800 From: cang@codeaurora.org To: Doug Anderson Cc: subhashj@codeaurora.org, Asutosh Das , Vivek Gautam , Evan Green , Rajendra Nayak , Vinayak Holikatti , jejb@linux.vnet.ibm.com, "Martin K. Petersen" , linux-scsi@vger.kernel.org, linux-arm-msm , venkatg@codeaurora.org, LKML Subject: Re: [PATCH v2 1/1] scsi: ufs: make UFS Tx lane1 clock optional for QCOM platforms In-Reply-To: References: <1539261196-14550-1-git-send-email-cang@codeaurora.org> Message-ID: <0f371e5e2cd1fe47834560a5072c0581@codeaurora.org> X-Sender: cang@codeaurora.org User-Agent: Roundcube Webmail/1.2.5 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Doug, On 2018-10-12 04:21, Doug Anderson wrote: > Hi, > > On Thu, Oct 11, 2018 at 5:33 AM Can Guo wrote: >> static int ufs_qcom_host_clk_get(struct device *dev, >> - const char *name, struct clk **clk_out) >> + const char *name, struct clk **clk_out, bool optional) >> { >> struct clk *clk; >> int err = 0; >> >> clk = devm_clk_get(dev, name); >> - if (IS_ERR(clk)) { >> + if (clk == ERR_PTR(-EPROBE_DEFER)) { >> + err = -EPROBE_DEFER; >> + dev_warn(dev, "required clock %s hasn't probed yet, >> err %d\n", >> + name, err); >> + } else if (IS_ERR(clk)) { >> + if (optional) >> + return 0; > > Change this function to: > > static int ufs_qcom_host_clk_get(struct device *dev, > const char *name, struct clk **clk_out, bool optional) > { > struct clk *clk; > int err; > > clk = devm_clk_get(dev, name); > if (!IS_ERR(clk)) { > *clk_out = clk; > return 0; > } > > err = PTR_ERR(clk); > > if (optional && err == -ENOENT) { > *clk_out = NULL; > return 0; > } > > if (err != -EPROBE_DEFER) > dev_err(dev, "failed to get %s err %d", > name, err); > > return err; > } > > Specifically: > > * Typically it just spams the log to print something when you see an > -EPROBE_DEFER. > > * If a clock is optional you should only consider things a success > only if "-ENOENT" was returned. All other errors should be considered > fatal. > > * If a clock is optional it's slightly cleaner to set *clk_out to > NULL. I know you're initting global data that happened to already be > NULL by default, but it still feels nice for the abstraction of the > function to do this. > > * Please don't pass __func__ to your error messages. > > Thank you for the detailed instructions. Shall make the change like so. >> err = PTR_ERR(clk); >> dev_err(dev, "%s: failed to get %s err %d", >> __func__, name, err); >> @@ -113,10 +119,10 @@ static void ufs_qcom_disable_lane_clks(struct >> ufs_qcom_host *host) >> if (!host->is_lane_clks_enabled) >> return; >> >> - if (host->hba->lanes_per_direction > 1) >> + if (host->tx_l1_sync_clk) > > Remove this "if". Always call clk_disable_unprepare() which will be a > no-op if "host->tx_l1_sync_clk" is NULL. clk_disable_unprepare() is a > no-op for NULL clocks by design specifically to make code like this > cleaner. > > Shall do. >> clk_disable_unprepare(host->tx_l1_sync_clk); >> clk_disable_unprepare(host->tx_l0_sync_clk); >> - if (host->hba->lanes_per_direction > 1) >> + if (host->rx_l1_sync_clk) > > Remove this "if". Always call clk_disable_unprepare() which will be a > no-op if "host->rx_l1_sync_clk" is NULL. clk_disable_unprepare() is a > no-op for NULL clocks by design specifically to make code like this > cleaner. > > Shall do. >> clk_disable_unprepare(host->rx_l1_sync_clk); >> clk_disable_unprepare(host->rx_l0_sync_clk); >> >> @@ -141,12 +147,14 @@ static int ufs_qcom_enable_lane_clks(struct >> ufs_qcom_host *host) >> if (err) >> goto disable_rx_l0; >> >> - if (host->hba->lanes_per_direction > 1) { >> + if (host->rx_l1_sync_clk) { > > Remove this "if". Always call ufs_qcom_host_clk_enable(). The > clk_prepare_enable() inside ufs_qcom_host_clk_enable() will be a no-op > if "host->rx_l1_sync_clk" is NULL and will return 0 (no error). > > Shall do so. >> err = ufs_qcom_host_clk_enable(dev, >> "rx_lane1_sync_clk", >> host->rx_l1_sync_clk); >> if (err) >> goto disable_tx_l0; >> + } >> >> + if (host->tx_l1_sync_clk) { > > Remove this "if". Always call ufs_qcom_host_clk_enable(). The > clk_prepare_enable() inside ufs_qcom_host_clk_enable() will be a no-op > if "host->tx_l1_sync_clk" is NULL and will return 0 (no error). > > > -Doug Shall do so. Thank you. -Can Guo