From patchwork Wed Mar 16 12:30:33 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Marek Vasut X-Patchwork-Id: 12782589 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 68DF3C433F5 for ; Wed, 16 Mar 2022 12:31:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237563AbiCPMcO (ORCPT ); Wed, 16 Mar 2022 08:32:14 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38348 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230190AbiCPMcN (ORCPT ); Wed, 16 Mar 2022 08:32:13 -0400 Received: from phobos.denx.de (phobos.denx.de [85.214.62.61]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 21895BF78; Wed, 16 Mar 2022 05:30:58 -0700 (PDT) Received: from tr.lan (ip-89-176-112-137.net.upcbroadband.cz [89.176.112.137]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) (Authenticated sender: marex@denx.de) by phobos.denx.de (Postfix) with ESMTPSA id 4835782155; Wed, 16 Mar 2022 13:30:56 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=denx.de; s=phobos-20191101; t=1647433856; bh=8DLiq12+R+1W1A2dvx8Ymm+lSe/Df51pPYgzhPcT6nI=; h=From:To:Cc:Subject:Date:From; b=rgCtfRkUFuYOwdkX9/dEFkFcgmDn+WHfghlXYodnZ8SrFSMY1jx7C/V3fC7Bweptx NKuFMqGI+VCoskIGVLy/0ybj/B6r+QPInYOt6PTqoALxWLQw/HzWC+o1R29Tzj/Ve7 j2GTSoXn30vGj9jww5NaK5bmJKX9oHIRzQqAlcR4kb2Ia6gKkvfgOswbD9WYIp40YU spXgDCVLuDpu+O0xTybMOgthWXA/tbwq1WHOk1/dWDZ5j706RxZ4GkRIJA3RxKyEse WT8KRHcF5p68sITpyeJmBu4jg3bZRxc8rpG1D0/0Hy9zLev9Ona2A9knoaJX8QuIkp FCvtATsoYnkGA== From: Marek Vasut To: linux-clk@vger.kernel.org Cc: Marek Vasut , Michael Turquette , Rob Herring , Stephen Boyd , devicetree@vger.kernel.org Subject: [PATCH v2 1/2] dt-bindings: clk: Introduce 'critical-clocks' property Date: Wed, 16 Mar 2022 13:30:33 +0100 Message-Id: <20220316123034.13465-1-marex@denx.de> X-Mailer: git-send-email 2.35.1 MIME-Version: 1.0 X-Virus-Scanned: clamav-milter 0.103.5 at phobos.denx.de X-Virus-Status: Clean Precedence: bulk List-ID: X-Mailing-List: linux-clk@vger.kernel.org Some platforms require select clock to be always running, e.g. because those clock supply vital devices which are not otherwise attached to the system and thus do not have a matching DT node and clock consumer. An example is a system where the SoC serves as a crystal oscillator replacement for a programmable logic device. The "critical-clocks" property of a clock controller allows listing clock which must never be turned off. Clock listed in the "critical-clocks" property may have other consumers in DT, listing the clock in "critical-clocks" only assures those clock are never turned off, and none of these optional additional consumers can turn the clock off either. The implementation is modeled after "protected-clocks". Signed-off-by: Marek Vasut Cc: Michael Turquette Cc: Rob Herring Cc: Stephen Boyd Cc: devicetree@vger.kernel.org To: linux-clk@vger.kernel.org --- V2: Update the commit message to clarify the behavior --- .../devicetree/bindings/clock/clock-bindings.txt | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) diff --git a/Documentation/devicetree/bindings/clock/clock-bindings.txt b/Documentation/devicetree/bindings/clock/clock-bindings.txt index f2ea53832ac63..975230e603d12 100644 --- a/Documentation/devicetree/bindings/clock/clock-bindings.txt +++ b/Documentation/devicetree/bindings/clock/clock-bindings.txt @@ -169,6 +169,22 @@ a shared clock is forbidden. Configuration of common clocks, which affect multiple consumer devices can be similarly specified in the clock provider node. +==Critical clocks== + +Some platforms require clock to be always running, e.g. because those clock +supply devices which are not otherwise attached to the system. One example +is a system where the SoC serves as a crystal oscillator replacement for a +programmable logic device. The critical-clocks property of a clock controller +allows listing clock which must never be turned off. + + clock-controller@a000f000 { + compatible = "vendor,clk95; + reg = <0xa000f000 0x1000> + #clocks-cells = <1>; + ... + critical-clocks = , ; + }; + ==Protected clocks== Some platforms or firmwares may not fully expose all the clocks to the OS, such