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 3B0D4C43334 for ; Thu, 14 Jul 2022 10:46:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238461AbiGNKq2 (ORCPT ); Thu, 14 Jul 2022 06:46:28 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55390 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S238459AbiGNKq1 (ORCPT ); Thu, 14 Jul 2022 06:46:27 -0400 Received: from mail-ed1-f41.google.com (mail-ed1-f41.google.com [209.85.208.41]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 7DD3354CAD; Thu, 14 Jul 2022 03:46:26 -0700 (PDT) Received: by mail-ed1-f41.google.com with SMTP id x91so1883018ede.1; Thu, 14 Jul 2022 03:46:26 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:in-reply-to :content-transfer-encoding; bh=mdZHN68nnDMwF7tgjBDSWcIdnt+cELpwBZVJBAjefvQ=; b=hxsg9NKfPHtAJXlsaBjbZYm+d6y3jnGqhVjhwZfbyFu37+r4Ik+rX6+5YdkCTj1j6q Zvnvt0lvbKCGIa9KjKmz8bNMBAwthXU3ZzIIsYWOJazQwZDazvGiEIR/yCFd1sDdh70d Cf9DXLtcEhx6dBQRBS+hTkVAjnS/lbvmAIQym4kfonSVAfqegB2MmbG7JHMSo/l4KRNx gyrHdg/Tl30y2VQOLeAM9ruxYvL8Ch/Aqgj8Pg1ZrZzA4gFKax1ODEVW8TDYVZ+mWDPy wCusAEYDSJS5LIC4UgtPcNcrTjTzBTrRLpGxgPydZVxtA7HB+g28mzY85YTL2QDFAs9x 2W+w== X-Gm-Message-State: AJIora96mc7UNIwd977YyQYlAGt4dLzmMamOgmLjfxBX+YArWcPvR4lm 5aSobQrYQaFVL/J488kgRyw6oFJcXLVz0Q== X-Google-Smtp-Source: AGRyM1syDuPlSQ3J3FJoTOFBJyVnDbl1sd0yL1SHmEfTsGCfRY7Ir7La5x85AMDOtIgmhPVSfr1Y4Q== X-Received: by 2002:a05:6402:2997:b0:43b:247b:89cb with SMTP id eq23-20020a056402299700b0043b247b89cbmr2879714edb.91.1657795584887; Thu, 14 Jul 2022 03:46:24 -0700 (PDT) Received: from ?IPV6:2a0b:e7c0:0:107::70f? ([2a0b:e7c0:0:107::70f]) by smtp.gmail.com with ESMTPSA id 18-20020a170906329200b0072b2eab813fsm343840ejw.75.2022.07.14.03.46.23 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 14 Jul 2022 03:46:24 -0700 (PDT) Message-ID: Date: Thu, 14 Jul 2022 12:46:23 +0200 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.10.0 Subject: Re: [V5] tty: serial: qcom-geni-serial: Fix get_clk_div_rate() which otherwise could return a sub-optimal clock rate. Content-Language: en-US To: Vijaya Krishna Nivarthi , agross@kernel.org, bjorn.andersson@linaro.org, konrad.dybcio@somainline.org, gregkh@linuxfoundation.org, linux-arm-msm@vger.kernel.org, linux-serial@vger.kernel.org, linux-kernel@vger.kernel.org Cc: quic_msavaliy@quicinc.com, dianders@chromium.org, mka@chromium.org, swboyd@chromium.org References: <1657629905-24685-1-git-send-email-quic_vnivarth@quicinc.com> From: Jiri Slaby In-Reply-To: <1657629905-24685-1-git-send-email-quic_vnivarth@quicinc.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-arm-msm@vger.kernel.org On 12. 07. 22, 14:45, Vijaya Krishna Nivarthi wrote: ... > +static unsigned long get_clk_div_rate(struct clk *clk, struct device *dev, > + unsigned int baud, unsigned int sampling_rate, unsigned int *clk_div) > +{ > + unsigned long ser_clk; > + unsigned long desired_clk; > + > + desired_clk = baud * sampling_rate; > + if (!desired_clk) { > + dev_dbg(dev, "Invalid frequency\n"); > + return 0; > } > > - *clk_div = ser_clk / desired_clk; > - if (!(*clk_div)) > - *clk_div = 1; > + /* > + * try to find a clock rate within 2% tolerance, then within "then within" ... "5" is missing, perhaps? > + */ > + ser_clk = find_clk_rate_in_tol(clk, desired_clk, clk_div, 2); > + if (!ser_clk) > + ser_clk = find_clk_rate_in_tol(clk, desired_clk, clk_div, 5); > + > + if (!ser_clk) > + dev_err(dev, "Couldn't find suitable clock rate for %lu\n", desired_clk); > + else > + dev_dbg(dev, "desired_clk-%lu, ser_clk-%lu, clk_div-%u\n", > + desired_clk, ser_clk, *clk_div); > > return ser_clk; > } > @@ -1021,8 +1040,8 @@ static void qcom_geni_serial_set_termios(struct uart_port *uport, > if (ver >= QUP_SE_VERSION_2_5) > sampling_rate /= 2; > > - clk_rate = get_clk_div_rate(port->se.clk, baud, > - sampling_rate, &clk_div); > + clk_rate = get_clk_div_rate(port->se.clk, port->se.dev, baud, Maybe worth passing whole geni_se (port->se) then? > + sampling_rate, &clk_div); > if (!clk_rate) > goto out_restart_rx; > thanks, -- js suse labs