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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 89E81C47082 for ; Mon, 31 May 2021 19:50:12 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 6FE3C61057 for ; Mon, 31 May 2021 19:50:12 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232237AbhEaTvs (ORCPT ); Mon, 31 May 2021 15:51:48 -0400 Received: from mga11.intel.com ([192.55.52.93]:32368 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231418AbhEaTvS (ORCPT ); Mon, 31 May 2021 15:51:18 -0400 IronPort-SDR: FwF/s4PBsTufMwmPP8C3JKsKh27fNOun/vVBJ4ztz0s6/DtSiwQk363B+U28EngKyDYjG9+C7Z E5Q66H05+Jdg== X-IronPort-AV: E=McAfee;i="6200,9189,10001"; a="200396761" X-IronPort-AV: E=Sophos;i="5.83,238,1616482800"; d="scan'208";a="200396761" Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 31 May 2021 12:49:30 -0700 IronPort-SDR: tr++MuEQ1FbwlylOLS9zb64sl8VUaVMcrSnE/6dTPNGmaBGbVPW8w5SPq0ag1DsK9ymEYeWRHf fPUWwjnf2p+w== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.83,238,1616482800"; d="scan'208";a="482206806" Received: from black.fi.intel.com ([10.237.72.28]) by fmsmga002.fm.intel.com with ESMTP; 31 May 2021 12:49:28 -0700 Received: by black.fi.intel.com (Postfix, from userid 1003) id F326F11D; Mon, 31 May 2021 22:49:50 +0300 (EEST) From: Andy Shevchenko To: =?UTF-8?q?Uwe=20Kleine-K=C3=B6nig?= , Andy Shevchenko , Flavio Suligoi , Thierry Reding , linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-pwm@vger.kernel.org, linux-acpi@vger.kernel.org Cc: Jonathan Corbet , Lee Jones , "Rafael J. Wysocki" , Len Brown Subject: [PATCH v2 1/7] docs: firmware-guide: ACPI: Add a PWM example Date: Mon, 31 May 2021 22:49:41 +0300 Message-Id: <20210531194947.10770-1-andriy.shevchenko@linux.intel.com> X-Mailer: git-send-email 2.30.2 MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When PWM support for ACPI has been added into the kernel, it missed the documentation update. Hence update documentation here. Fixes: 4a6ef8e37c4d ("pwm: Add support referencing PWMs from ACPI") Signed-off-by: Andy Shevchenko --- v2: updated example to use 600 ms instead of 600 us (looks saner) .../firmware-guide/acpi/enumeration.rst | 32 +++++++++++++++++++ 1 file changed, 32 insertions(+) diff --git a/Documentation/firmware-guide/acpi/enumeration.rst b/Documentation/firmware-guide/acpi/enumeration.rst index 9f0d5c854fa4..f588663ba906 100644 --- a/Documentation/firmware-guide/acpi/enumeration.rst +++ b/Documentation/firmware-guide/acpi/enumeration.rst @@ -258,6 +258,38 @@ input driver:: .id_table = mpu3050_ids, }; +Reference to PWM device +======================= + +Sometimes a device can be a consumer of PWM channel. Obviously OS would like +to know which one. To provide this mapping the special property has been +introduced, i.e.:: + + Device (DEV) + { + Name (_DSD, Package () + { + ToUUID("daffd814-6eba-4d8c-8a91-bc9bbf4aa301"), + Package () { + Package () { "compatible", Package () { "pwm-leds" } }, + Package () { "label", "alarm-led" }, + Package () { "pwms", + Package () { + "\\_SB.PCI0.PWM", // + 0, // + 600000000, // + 0, // + } + } + } + + }) + ... + +In the above example the PWM-based LED driver references to the PWM channel 0 +of \_SB.PCI0.PWM device with initial period setting equal to 600 ms (note that +value is given in nanoseconds). + GPIO support ============ -- 2.30.2