From patchwork Mon May 16 10:38:30 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vijaya Krishna Nivarthi X-Patchwork-Id: 573213 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 BD9CAC433FE for ; Mon, 16 May 2022 10:38:55 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242602AbiEPKiy (ORCPT ); Mon, 16 May 2022 06:38:54 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41002 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231665AbiEPKix (ORCPT ); Mon, 16 May 2022 06:38:53 -0400 Received: from alexa-out.qualcomm.com (alexa-out.qualcomm.com [129.46.98.28]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BEB7D237DC; Mon, 16 May 2022 03:38:52 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=quicinc.com; i=@quicinc.com; q=dns/txt; s=qcdkim; t=1652697532; x=1684233532; h=from:to:cc:subject:date:message-id; bh=uv3hpvVLaKZAIJnN9FauPkILRYjjAJhkGFBGer0v5m4=; b=IbOqfwIXGkmuJkqPk6bynuT0XWe8Vo9FsoeX39BsWji+2FOLT7cshGEZ rhYvCPSKtAJjniOrVoyfGqAXQZV177f/ys02BmfNuQUQNuv8xqnejiRL2 keRXQ9YdvuREfJ1qa5hCr8hxonDAM5kUO2fw0/R1Lsjl4+BM3cplu1D4N s=; Received: from ironmsg09-lv.qualcomm.com ([10.47.202.153]) by alexa-out.qualcomm.com with ESMTP; 16 May 2022 03:38:52 -0700 X-QCInternal: smtphost Received: from ironmsg02-blr.qualcomm.com ([10.86.208.131]) by ironmsg09-lv.qualcomm.com with ESMTP/TLS/AES256-SHA; 16 May 2022 03:38:50 -0700 X-QCInternal: smtphost Received: from hu-vnivarth-hyd.qualcomm.com (HELO hu-sgudaval-hyd.qualcomm.com) ([10.213.111.166]) by ironmsg02-blr.qualcomm.com with ESMTP; 16 May 2022 16:08:34 +0530 Received: by hu-sgudaval-hyd.qualcomm.com (Postfix, from userid 3994820) id D1B523E6D; Mon, 16 May 2022 16:08:32 +0530 (+0530) From: Vijaya Krishna Nivarthi To: agross@kernel.org, bjorn.andersson@linaro.org, gregkh@linuxfoundation.org, jirislaby@kernel.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, quic_c_skakit@quicinc.com, Vijaya Krishna Nivarthi Subject: [V2] tty: serial: qcom-geni-serial: Remove uart frequency table. Instead, find suitable frequency with call to clk_round_rate. Date: Mon, 16 May 2022 16:08:30 +0530 Message-Id: <1652697510-30543-1-git-send-email-quic_vnivarth@quicinc.com> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: linux-serial@vger.kernel.org Replace the UART frequency table 'root_freq[]' with logic around clk_round_rate() so that SoC details like the available clk frequencies can change and this driver still works. This reduces tight coupling between this UART driver and the SoC clk driver because we no longer have to update the 'root_freq[]' array for new SoCs. Instead the driver determines the available frequencies at runtime. Signed-off-by: Vijaya Krishna Nivarthi --- v2: loops through clk dividers to zero-in quickly v1: intial patch looped through available clk frequencies --- drivers/tty/serial/qcom_geni_serial.c | 56 ++++++++++++++++++++++------------- 1 file changed, 36 insertions(+), 20 deletions(-) diff --git a/drivers/tty/serial/qcom_geni_serial.c b/drivers/tty/serial/qcom_geni_serial.c index f496102..4733a23 100644 --- a/drivers/tty/serial/qcom_geni_serial.c +++ b/drivers/tty/serial/qcom_geni_serial.c @@ -149,12 +149,6 @@ static unsigned int qcom_geni_serial_tx_empty(struct uart_port *port); static void qcom_geni_serial_stop_rx(struct uart_port *uport); static void qcom_geni_serial_handle_rx(struct uart_port *uport, bool drop); -static const unsigned long root_freq[] = {7372800, 14745600, 19200000, 29491200, - 32000000, 48000000, 51200000, 64000000, - 80000000, 96000000, 100000000, - 102400000, 112000000, 120000000, - 128000000}; - #define to_dev_port(ptr, member) \ container_of(ptr, struct qcom_geni_serial_port, member) @@ -946,25 +940,43 @@ static int qcom_geni_serial_startup(struct uart_port *uport) return 0; } -static unsigned long get_clk_cfg(unsigned long clk_freq) -{ - int i; - - for (i = 0; i < ARRAY_SIZE(root_freq); i++) { - if (!(root_freq[i] % clk_freq)) - return root_freq[i]; - } - return 0; -} - -static unsigned long get_clk_div_rate(unsigned int baud, +static unsigned long get_clk_div_rate(struct clk *clk, unsigned int baud, unsigned int sampling_rate, unsigned int *clk_div) { unsigned long ser_clk; unsigned long desired_clk; + unsigned long freq, prev; + unsigned long div, maxdiv; + int64_t mult; desired_clk = baud * sampling_rate; - ser_clk = get_clk_cfg(desired_clk); + if (!desired_clk) { + pr_err("%s: Invalid frequency\n", __func__); + return 0; + } + + maxdiv = CLK_DIV_MSK >> CLK_DIV_SHFT; + prev = 0; + + for (div = 1; div <= maxdiv; div++) { + mult = div * desired_clk; + if (mult > ULONG_MAX) + break; + + freq = clk_round_rate(clk, (unsigned long)mult); + if (!(freq % desired_clk)) { + ser_clk = freq; + break; + } + + if (!prev) + ser_clk = freq; + else if (prev == freq) + break; + + prev = freq; + } + if (!ser_clk) { pr_err("%s: Can't find matching DFS entry for baud %d\n", __func__, baud); @@ -972,6 +984,9 @@ static unsigned long get_clk_div_rate(unsigned int baud, } *clk_div = ser_clk / desired_clk; + if (!(*clk_div)) + *clk_div = 1; + return ser_clk; } @@ -1003,7 +1018,8 @@ 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(baud, sampling_rate, &clk_div); + clk_rate = get_clk_div_rate(port->se.clk, baud, + sampling_rate, &clk_div); if (!clk_rate) goto out_restart_rx;