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=-4.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=no 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 DED45C433E4 for ; Tue, 21 Jul 2020 21:50:15 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B2BF0206E3 for ; Tue, 21 Jul 2020 21:50:15 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="oVgXcOyg" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731287AbgGUVuP (ORCPT ); Tue, 21 Jul 2020 17:50:15 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38678 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727113AbgGUVuO (ORCPT ); Tue, 21 Jul 2020 17:50:14 -0400 Received: from mail-pl1-x62a.google.com (mail-pl1-x62a.google.com [IPv6:2607:f8b0:4864:20::62a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 19875C061794 for ; Tue, 21 Jul 2020 14:50:14 -0700 (PDT) Received: by mail-pl1-x62a.google.com with SMTP id o1so10846380plk.1 for ; Tue, 21 Jul 2020 14:50:14 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc:content-transfer-encoding; bh=rLFvuK+kzarLWaTzGm5PbHM5taHdTY+muXHU6FdT6q8=; b=oVgXcOyghOpASzJt7LbZZoUOY16Q3hh0/O/tSaE/WKs1B1R8D7/QA3FWYyUjC844lR wGMwLShNKPNYfjhWkJEzJHR8Z+HHgOVHdbAIIoKM8IcEA2zBXpXG22l+GJRCKLc3YXn1 04GCdMEBqrRHmRK5Ynv2eYR+9qS2WPxlPNDdwtBC6//aF8SmKjncRbqL7vlMYwZTzOM6 w8+5LvIjbM+mOcAzpmEFxxaj4cgISHysMoZwF8QoeGZZnkdvFUealAGw5yWFtayIB2BK 7vMVbQhFnItuHeYocmngnlzamnhd1h0vSDQM9aC6bP6rnqB+SOrIBhabOxu6aWAgS2X/ eP9A== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc:content-transfer-encoding; bh=rLFvuK+kzarLWaTzGm5PbHM5taHdTY+muXHU6FdT6q8=; b=cdEKZ1FRTcGyQrEZ4ljFXX3dAm6xOB+vw4b/x7n1x8ZtZKmUSEnjNwKso8lMoa55xP Qn4UT4+5ZIlaV0ezNrGXX+tGVCCUJtv9SKRVsssnaqycugN1KyA6ADGf0aW2nDYnCoQ3 IHbQvB4RR5yMuxp5KN1M0JleCfHn2X8+IBVCsyg4ENPi+IZq/g26KPiQYAjp6ZCuTQxt JqHXvM42d4IAzPxl2G+mvAaMBIG+sRn6aIWofp0RjxTZsmizVPA30rfmxfReEIYi+psV vW8hEvJX5zkJLh9MQBEdxoeH8tce/iUYE6IsD9lHJl1Jda7cuL3CLPqzG6Kv1pmBVIOG d11A== X-Gm-Message-State: AOAM532kqn42bM5ufXQjui7aK4yGvc/9Reit0ttgxSTojcvg0f2ohBPz ZsPLel4r8jdpEQvTFwUweYfymlOqIVXTpoPqfvA= X-Google-Smtp-Source: ABdhPJyZjaTDJ/I+coTbcNv0105/svblqBvtbeSIewdiZUHz6O48iKVQnLeh8QIqvaLaeWWBVyw47d+wrCAss7kWtV0= X-Received: by 2002:a17:90a:a393:: with SMTP id x19mr7032563pjp.228.1595368213628; Tue, 21 Jul 2020 14:50:13 -0700 (PDT) MIME-Version: 1.0 References: <20200519163353.20c03286@windsurf.home> <4c5c972b-c8b8-4326-a1f9-438d88217a4a@cesnet.cz> <20200721155139.40fdb835@windsurf.home> <070e2fa9-bacf-4d6e-a62a-63b3db55c25e@cesnet.cz> In-Reply-To: <070e2fa9-bacf-4d6e-a62a-63b3db55c25e@cesnet.cz> From: Andy Shevchenko Date: Wed, 22 Jul 2020 00:49:57 +0300 Message-ID: Subject: Re: High CPU load when using MAX14830 SPI UART controller To: =?UTF-8?B?SmFuIEt1bmRyw6F0?= Cc: Thomas Petazzoni , linux-spi , Mark Brown Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable Sender: linux-spi-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-spi@vger.kernel.org On Tue, Jul 21, 2020 at 5:32 PM Jan Kundr=C3=A1t wr= ote: > I have no code, but according to the datasheet, it's the "RTimeout" bit > (Line Status Register, bit 0). If properly configured (RxTimeOut set and > the interrupt routing enabled via LSRIntEn[0], the "RTimeoutIEn" bit), > we're supposed to get ISR[0] set upon this timeout. And usually timeout condition means no data for the time equal to receive 4 more words at given baudrate and bits. (For 8-bit words on 115200 it will be time as 10*4 / 115200 ~=3D 360us) --=20 With Best Regards, Andy Shevchenko