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=-18.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 3E0DAC433E0 for ; Thu, 28 Jan 2021 11:46:30 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id BD3CA64DE0 for ; Thu, 28 Jan 2021 11:46:29 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BD3CA64DE0 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linaro.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:42868 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1l55kq-0006Yp-4b for qemu-devel@archiver.kernel.org; Thu, 28 Jan 2021 06:46:28 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:33458) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1l55gT-00018l-Ie for qemu-devel@nongnu.org; Thu, 28 Jan 2021 06:41:59 -0500 Received: from mail-wr1-x436.google.com ([2a00:1450:4864:20::436]:33203) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_128_GCM_SHA256:128) (Exim 4.90_1) (envelope-from ) id 1l55gO-000659-Fv for qemu-devel@nongnu.org; Thu, 28 Jan 2021 06:41:57 -0500 Received: by mail-wr1-x436.google.com with SMTP id 7so5082485wrz.0 for ; Thu, 28 Jan 2021 03:41:51 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=p7OK2Ltq3LcHT8jmiWMB0NuP9bP3FPom3Sa8lyw278I=; b=gCGquRP0Tq7iLV2+thH/SHMnbU0DmXPsCQFJBliQwiegVnuo+8SgdBKCRXffaVjgUz fguVSICbaKxF8x9apRR8SalcuuPmJGz1+mXPpyptKYSbKDx1IfNVghD1Yadia5WuM+6Q qzbRex3U8lZCMrU53+eeRKP+NpL2IrxVznCYpKsQE4a/pV97wVhU2MFbWS8RWGaPN/6K 4cuQOaGiVgadLm+z+y7BN51sV87w0Ok5ggMNdWZNRSpz7Cdvmd2ROGGmFkH8dI+m255a 9zs0/Wg6gu2EdT2qDW4hVwVpW+cHWU+hERhlwl85nlxJ7CGP2ptsJ/IhnRh2WacIFCPB kP7Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=p7OK2Ltq3LcHT8jmiWMB0NuP9bP3FPom3Sa8lyw278I=; b=PNy0QSfFd8b9o6jEuoQHSbc/8MbhXrzxjAHhSJx+m2prIeGz07T5/llojqpVx1xycM f1fR3MTY3T5Zua0npmwE/H8FXUpDNEQ+wUuNCG6Nah+0Ul8BjumFO1fG9tXeWSwmamp5 NJV+0LoAWduhspKVVRim1qB1FHto1Tzga6cq0CXUP82QG/ZYewMacqAYP8VQ7RVw6psw nc4aelXzeG9ITekM/437eBhJmTBFh8AfNZlugNL1olj9xSVR1netwzwwd3/KOu+EoNQM qYIssc0eysTGqw8vZhCkYoFIiZBnO8vPuozLotlAJ9Vt/uL8TXYNyshWsNp/fxwVHar9 30BQ== X-Gm-Message-State: AOAM533RQ2QAQ8OAZufGYIGSVA/dI8YTeYQQSQYuiVfPsorZOVl0ya7P uXwbUev9uf6XHJuMrDLzCbFhnA== X-Google-Smtp-Source: ABdhPJy6oNQQQxS14IMy81JnTrzMLx0/UDgWLRdLNX/PGAsU1++7AzHVtmObWtn1mrQkQvatsgf06A== X-Received: by 2002:a05:6000:1547:: with SMTP id 7mr15910116wry.301.1611834110398; Thu, 28 Jan 2021 03:41:50 -0800 (PST) Received: from orth.archaic.org.uk (orth.archaic.org.uk. [81.2.115.148]) by smtp.gmail.com with ESMTPSA id q9sm6431033wme.18.2021.01.28.03.41.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 28 Jan 2021 03:41:49 -0800 (PST) From: Peter Maydell To: qemu-arm@nongnu.org, qemu-devel@nongnu.org Subject: [PATCH v2 02/25] clock: Add new clock_has_source() function Date: Thu, 28 Jan 2021 11:41:22 +0000 Message-Id: <20210128114145.20536-3-peter.maydell@linaro.org> X-Mailer: git-send-email 2.20.1 In-Reply-To: <20210128114145.20536-1-peter.maydell@linaro.org> References: <20210128114145.20536-1-peter.maydell@linaro.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=2a00:1450:4864:20::436; envelope-from=peter.maydell@linaro.org; helo=mail-wr1-x436.google.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Luc Michel , =?UTF-8?q?Philippe=20Mathieu-Daud=C3=A9?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Add a function for checking whether a clock has a source. This is useful for devices which have input clocks that must be wired up by the board as it allows them to fail in realize rather than ploughing on with a zero-period clock. Signed-off-by: Peter Maydell Reviewed-by: Luc Michel Reviewed-by: Philippe Mathieu-Daudé Message-id: 20210121190622.22000-3-peter.maydell@linaro.org --- docs/devel/clocks.rst | 16 ++++++++++++++++ include/hw/clock.h | 15 +++++++++++++++ 2 files changed, 31 insertions(+) diff --git a/docs/devel/clocks.rst b/docs/devel/clocks.rst index 2548d842322..c54bbb82409 100644 --- a/docs/devel/clocks.rst +++ b/docs/devel/clocks.rst @@ -235,6 +235,22 @@ object during device instance init. For example: /* set initial value to 10ns / 100MHz */ clock_set_ns(clk, 10); +To enforce that the clock is wired up by the board code, you can +call ``clock_has_source()`` in your device's realize method: + +.. code-block:: c + + if (!clock_has_source(s->clk)) { + error_setg(errp, "MyDevice: clk input must be connected"); + return; + } + +Note that this only checks that the clock has been wired up; it is +still possible that the output clock connected to it is disabled +or has not yet been configured, in which case the period will be +zero. You should use the clock callback to find out when the clock +period changes. + Fetching clock frequency/period ------------------------------- diff --git a/include/hw/clock.h b/include/hw/clock.h index 6382f346569..e5f45e2626d 100644 --- a/include/hw/clock.h +++ b/include/hw/clock.h @@ -139,6 +139,21 @@ void clock_clear_callback(Clock *clk); */ void clock_set_source(Clock *clk, Clock *src); +/** + * clock_has_source: + * @clk: the clock + * + * Returns true if the clock has a source clock connected to it. + * This is useful for devices which have input clocks which must + * be connected by the board/SoC code which creates them. The + * device code can use this to check in its realize method that + * the clock has been connected. + */ +static inline bool clock_has_source(const Clock *clk) +{ + return clk->source != NULL; +} + /** * clock_set: * @clk: the clock to initialize. -- 2.20.1