From patchwork Thu May 4 07:57:13 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Matti Vaittinen X-Patchwork-Id: 13230851 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 7B7F7C7EE21 for ; Thu, 4 May 2023 07:57:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229723AbjEDH5a (ORCPT ); Thu, 4 May 2023 03:57:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40238 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229836AbjEDH52 (ORCPT ); Thu, 4 May 2023 03:57:28 -0400 Received: from mail-lj1-x235.google.com (mail-lj1-x235.google.com [IPv6:2a00:1450:4864:20::235]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E6D4B3C28; Thu, 4 May 2023 00:57:26 -0700 (PDT) Received: by mail-lj1-x235.google.com with SMTP id 38308e7fff4ca-2ac80ed7f26so1129701fa.1; Thu, 04 May 2023 00:57:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1683187045; x=1685779045; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:from:to:cc:subject:date:message-id:reply-to; bh=o9ZN5Kt7PzcLmeQSM4/6ILQKH7duKu8J3KsFC8gjMWY=; b=JPYlVAlb7y9k2cIrdQjpuO+2COC4kNkXF6Hx1ptRVANh/ZvtZFxr23P/He+hDFSkiH SOGXfClMVcDWrriuiucKMoEzuLEnggFDg6bpr9kjXCQe/NCIQzT+H0I926Y/hmju98/I 49jqxUOZjL5qMKXPFLZcbNQ5Czo8JOCXTOnNKG7IMKcpQezGeFzhzCeu3FsetjNDGJl6 MWM6LU+8+Q52j+FjAqpwkCdipVCPayn0shXvUeD8qLS2RV0JIvgAYkF2gFd2cIHrKF0e /IyQ/QQnHn0d3cVtJwyGxT/KU+KVW3Gd3YzjBSMeeod+zLyIs2q81AlqZG86OqrigTGW mMgA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1683187045; x=1685779045; h=in-reply-to:content-disposition:mime-version:references:message-id :subject:cc:to:from:date:x-gm-message-state:from:to:cc:subject:date :message-id:reply-to; bh=o9ZN5Kt7PzcLmeQSM4/6ILQKH7duKu8J3KsFC8gjMWY=; b=gZWqsAPnHRN5OntHaxoEcirI2NLRiRgSeeYnmIMmEgeoulzURXk84HS6Igc97tA6n+ 8wf69H+UhY9fhB0yWtu3t9h4cVek0iIF7BrB5yz5Ye4v6bMe/94EsOIEpREKKMruWwLP +U69/i1hHeXl50I/FpzJNdwv12QUIy14xWTAfaXWSeXvf/uQb0o7U7w2J0qniiXJqFpW xnucdLetHpmhfYSoao1jADnnmGs6xFe5nbXqVnqxfsKf0UwFpWf0e0LNx7MYiJIgKD10 e/VmvOnMoiY93Wpx42rkAQWT6ni68CKOEGwuSbG9P94NJAQCJVAZIHVRvLRnuTIoCm8O 5yYw== X-Gm-Message-State: AC+VfDygrPtSAf0GIbp6BT31sK+IqLgXQ++sKhhLZ5DmXYABys68PBd+ P7hXVqLt+KOwlpGTbtYlX3E= X-Google-Smtp-Source: ACHHUZ4Y+BZSjHFN5VwYPlnpB4sPH1TooqUzdhob7wA1xihalx4cRFlUUnZ/QCJykXjARr6+fJFnjg== X-Received: by 2002:a2e:7011:0:b0:2a8:c32d:1238 with SMTP id l17-20020a2e7011000000b002a8c32d1238mr699739ljc.15.1683187044986; Thu, 04 May 2023 00:57:24 -0700 (PDT) Received: from fedora (62-78-225-252.bb.dnainternet.fi. [62.78.225.252]) by smtp.gmail.com with ESMTPSA id u22-20020a2ea176000000b002ab1216de44sm5062166ljl.71.2023.05.04.00.57.24 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 04 May 2023 00:57:24 -0700 (PDT) Date: Thu, 4 May 2023 10:57:13 +0300 From: Matti Vaittinen To: Matti Vaittinen , Matti Vaittinen Cc: Matti Vaittinen , Jonathan Cameron , Lars-Peter Clausen , linux-iio@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [RFC PATCH 1/3] iio: bu27034: Probe asynchronously Message-ID: References: MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-iio@vger.kernel.org Devices which may take a while to initialize during probe and which have no strong reason to probe synchronously can request asynchronous probing as default probe strategy. This can speed-up start times on some platforms. The BU27034 gets probe delayed for at least two reasons. It enables the supply regulator, (which is likely to have ramp-up delay if it was disabled) and additionally it delays while the sensor itself is initializing. Changing to asynchronous probing may cause problems. Some of which are discussed in: https://lore.kernel.org/all/06db017f-e985-4434-8d1d-02ca2100cca0@sirena.org.uk/ Enabling async probing for the ROHM BU27034 should be fairly safe to try though as there is no in-tree users for it yet. If the async probing appears to be an issue we can switch easily back to synchronous (or better yet, fix the actual problem). Enable asynchronous probing for BU27034. Signed-off-by: Matti Vaittinen --- I am unsure if this change is 100% safe - but I don't immediately see the harm. Please let me know if some of you have more experience on problems when using asynchronous probing with IIO devices. --- drivers/iio/light/rohm-bu27034.c | 1 + 1 file changed, 1 insertion(+) diff --git a/drivers/iio/light/rohm-bu27034.c b/drivers/iio/light/rohm-bu27034.c index f85194fda6b0..183cf550af13 100644 --- a/drivers/iio/light/rohm-bu27034.c +++ b/drivers/iio/light/rohm-bu27034.c @@ -1500,6 +1500,7 @@ static struct i2c_driver bu27034_i2c_driver = { .driver = { .name = "bu27034-als", .of_match_table = bu27034_of_match, + .probe_type = PROBE_PREFER_ASYNCHRONOUS, }, .probe_new = bu27034_probe, };