Received: by 2002:a05:6a10:8c0a:0:0:0:0 with SMTP id go10csp2305391pxb; Mon, 8 Mar 2021 21:54:45 -0800 (PST) X-Google-Smtp-Source: ABdhPJweVxVQL1SdX3rQoXwvS8J5hLvgOBhLlWtZ9RATnF9+yZJwMwcNheY66VegZ2e6rj5xmLdM X-Received: by 2002:a17:906:c099:: with SMTP id f25mr18872266ejz.141.1615269285348; Mon, 08 Mar 2021 21:54:45 -0800 (PST) ARC-Seal: i=1; a=rsa-sha256; t=1615269285; cv=none; d=google.com; s=arc-20160816; b=Y4UE1DVouLI9YrDIMm87O3Nqos8WoFyM54l52UyNwEEm+3NQLU4XoEXOuwuUO8w/87 cXS2lU1RHkuedJiYRhq7aKeko86CJMonSamvFT6JTJKhpRF1hmVud1w+dueBX5SSPf1H tZq1g+v6GXkmW0Jsu27GdAXhm2/fljzBdOPUWmvhf2B5eRmmZlyJkHVR2BMB6xt47o87 AIQNULv77arItBNWo4Ke1ZtmTV+oOlntkyP3RnegWmeD22MMwmneB5QiVoCAa6CllsQK NKRzleE/+w7lwt0ymGsbQPAUWhdzF8XQqzPAOc1X7iuiv/uJXeAA9CWlRVJQj8LoO94l KdnA== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=arc-20160816; h=list-id:precedence:content-transfer-encoding:content-language :in-reply-to:mime-version:user-agent:date:message-id:autocrypt:from :references:cc:to:subject:sender:dkim-signature; bh=P8use5HznHVSTRQHEMf/PO2GeUcJ6pS+jo8eH21EzzA=; b=GK+aHbQD61R/EIX6mWJCSP8Ih8PyjfUgIc7aGS3sYSWlP1W7Wci6UphbPeXSD+PAdd P0/oY5p7yFZYFOgzUNtarUIuextgNU2rDtadZEi0hTtBLPtMJe86A7+9RpkfcM5fgbHm XF2nSB3rxCD6RYJCXDptk9QOlAOtRnOvP2alui/Lg3ziytl0ghnTtUuyA8Y0/znyjC1u Gp7ClWzdF+t7eFPy2yZ83YYU9gK/P5nIs6+DAtBC1EYg5D71sbeB+NGLJE2oTUjIx4YJ YTqiye4JmYQTSq3pNbEOMM6UftKzd+KWS2h1IRtcuHnju2CzmYQY5rKBhvIFpsKyoMhp PF/g== ARC-Authentication-Results: i=1; mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b="MFhEXsN/"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Return-Path: Received: from vger.kernel.org (vger.kernel.org. [23.128.96.18]) by mx.google.com with ESMTP id k9si8135392eje.398.2021.03.08.21.54.23; Mon, 08 Mar 2021 21:54:45 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18; Authentication-Results: mx.google.com; dkim=pass header.i=@gmail.com header.s=20161025 header.b="MFhEXsN/"; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229772AbhCIFwH (ORCPT + 99 others); Tue, 9 Mar 2021 00:52:07 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59430 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229829AbhCIFvz (ORCPT ); Tue, 9 Mar 2021 00:51:55 -0500 Received: from mail-ot1-x335.google.com (mail-ot1-x335.google.com [IPv6:2607:f8b0:4864:20::335]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 08897C06174A; Mon, 8 Mar 2021 21:51:55 -0800 (PST) Received: by mail-ot1-x335.google.com with SMTP id f8so6694621otp.8; Mon, 08 Mar 2021 21:51:55 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=sender:subject:to:cc:references:from:autocrypt:message-id:date :user-agent:mime-version:in-reply-to:content-language :content-transfer-encoding; bh=P8use5HznHVSTRQHEMf/PO2GeUcJ6pS+jo8eH21EzzA=; b=MFhEXsN/NqptaShWoDt2CvQgZ+3DpRXwRezMOCNCfjB31lf9RDZkGmT+WEoyr9jiD1 ROVQ1GdVvfOL7M7ULXPlUkqhSKdo+dJ8T/NZbApQquzaL590C3yNkOHPccu088QBBeMp pOB3rJD4e4yWsIgYPyKq8sJe36+tXOhyU5Hr2NosKvPyFgh5lwBM4HsfR6x4Ax1bGdGp 8uDzT2mO7D7zMDdsAjESAR/ZJcRjsrYe0o5jWPqqpX/wACiEj1vmeIapbfAOnT+svJ2j 8isQJhUhBg8enKvkiCbJoMxGHCeQwMvsCMktD1iU5DmpHXe1YQbBaQfGS/2+ALnSOU6y VWfw== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:sender:subject:to:cc:references:from:autocrypt :message-id:date:user-agent:mime-version:in-reply-to :content-language:content-transfer-encoding; bh=P8use5HznHVSTRQHEMf/PO2GeUcJ6pS+jo8eH21EzzA=; b=VyS+tt9clC00ypZdHLG8xNhVuzggSheqRQpVge42j4imFYT9rn2Iiifetm9AQ/VCse nyCq96xkE7IAYkX8cOuIhY1xdT2nOBuOpO+iToySRoabPvfmOSBf1dWW1PF+++lPWuwJ QOejexWx/Xa/lbtx6485g9JqLOyW2M/MSwzTyLtdd6exPymABDz6TTbba5kfKGneBdGj 9x+hcyYzJ3NmfLIyEOjRI81k+d2OuruVWf+Flq3rzI4y5U6HihuhaYS26YQiEVw6+BYx YiCbuC0/IcokkFmIiEIII5ul4HuQAESKRyexwaap3aigsiAHU0ggXFbqIFyjdTj9gHKU dT9w== X-Gm-Message-State: AOAM533NuOkxyy7k0wcvJIHVoZJMm+LCyWMNUPMS5xBOZupC+UhmP8FZ +picvHltLUBgXt3dRYzQVfTIjRXkCJI= X-Received: by 2002:a9d:6545:: with SMTP id q5mr22902859otl.179.1615269114081; Mon, 08 Mar 2021 21:51:54 -0800 (PST) Received: from server.roeck-us.net ([2600:1700:e321:62f0:329c:23ff:fee3:9d7c]) by smtp.gmail.com with ESMTPSA id 53sm1126323oti.77.2021.03.08.21.51.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 08 Mar 2021 21:51:53 -0800 (PST) Sender: Guenter Roeck Subject: Re: [PATCH v2 0/3] add "delay" clock support to gpio_wdt To: Rasmus Villemoes , Arnd Bergmann , Stephen Boyd Cc: Rob Herring , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, linux-clk@vger.kernel.org, linux-watchdog@vger.kernel.org References: <20210226141411.2517368-1-linux@rasmusvillemoes.dk> <20210304221247.488173-1-linux@rasmusvillemoes.dk> From: Guenter Roeck Autocrypt: addr=linux@roeck-us.net; keydata= xsFNBE6H1WcBEACu6jIcw5kZ5dGeJ7E7B2uweQR/4FGxH10/H1O1+ApmcQ9i87XdZQiB9cpN RYHA7RCEK2dh6dDccykQk3bC90xXMPg+O3R+C/SkwcnUak1UZaeK/SwQbq/t0tkMzYDRxfJ7 nyFiKxUehbNF3r9qlJgPqONwX5vJy4/GvDHdddSCxV41P/ejsZ8PykxyJs98UWhF54tGRWFl 7i1xvaDB9lN5WTLRKSO7wICuLiSz5WZHXMkyF4d+/O5ll7yz/o/JxK5vO/sduYDIlFTvBZDh gzaEtNf5tQjsjG4io8E0Yq0ViobLkS2RTNZT8ICq/Jmvl0SpbHRvYwa2DhNsK0YjHFQBB0FX IdhdUEzNefcNcYvqigJpdICoP2e4yJSyflHFO4dr0OrdnGLe1Zi/8Xo/2+M1dSSEt196rXaC kwu2KgIgmkRBb3cp2vIBBIIowU8W3qC1+w+RdMUrZxKGWJ3juwcgveJlzMpMZNyM1jobSXZ0 VHGMNJ3MwXlrEFPXaYJgibcg6brM6wGfX/LBvc/haWw4yO24lT5eitm4UBdIy9pKkKmHHh7s jfZJkB5fWKVdoCv/omy6UyH6ykLOPFugl+hVL2Prf8xrXuZe1CMS7ID9Lc8FaL1ROIN/W8Vk BIsJMaWOhks//7d92Uf3EArDlDShwR2+D+AMon8NULuLBHiEUQARAQABzTJHdWVudGVyIFJv ZWNrIChMaW51eCBhY2NvdW50KSA8bGludXhAcm9lY2stdXMubmV0PsLBgQQTAQIAKwIbAwYL CQgHAwIGFQgCCQoLBBYCAwECHgECF4ACGQEFAlVcphcFCRmg06EACgkQyx8mb86fmYFg0RAA nzXJzuPkLJaOmSIzPAqqnutACchT/meCOgMEpS5oLf6xn5ySZkl23OxuhpMZTVX+49c9pvBx hpvl5bCWFu5qC1jC2eWRYU+aZZE4sxMaAGeWenQJsiG9lP8wkfCJP3ockNu0ZXXAXwIbY1O1 c+l11zQkZw89zNgWgKobKzrDMBFOYtAh0pAInZ9TSn7oA4Ctejouo5wUugmk8MrDtUVXmEA9 7f9fgKYSwl/H7dfKKsS1bDOpyJlqhEAH94BHJdK/b1tzwJCFAXFhMlmlbYEk8kWjcxQgDWMu GAthQzSuAyhqyZwFcOlMCNbAcTSQawSo3B9yM9mHJne5RrAbVz4TWLnEaX8gA5xK3uCNCeyI sqYuzA4OzcMwnnTASvzsGZoYHTFP3DQwf2nzxD6yBGCfwNGIYfS0i8YN8XcBgEcDFMWpOQhT Pu3HeztMnF3HXrc0t7e5rDW9zCh3k2PA6D2NV4fews9KDFhLlTfCVzf0PS1dRVVWM+4jVl6l HRIAgWp+2/f8dx5vPc4Ycp4IsZN0l1h9uT7qm1KTwz+sSl1zOqKD/BpfGNZfLRRxrXthvvY8 BltcuZ4+PGFTcRkMytUbMDFMF9Cjd2W9dXD35PEtvj8wnEyzIos8bbgtLrGTv/SYhmPpahJA l8hPhYvmAvpOmusUUyB30StsHIU2LLccUPPOwU0ETofVZwEQALlLbQeBDTDbwQYrj0gbx3bq 7kpKABxN2MqeuqGr02DpS9883d/t7ontxasXoEz2GTioevvRmllJlPQERVxM8gQoNg22twF7 pB/zsrIjxkE9heE4wYfN1AyzT+AxgYN6f8hVQ7Nrc9XgZZe+8IkuW/Nf64KzNJXnSH4u6nJM J2+Dt274YoFcXR1nG76Q259mKwzbCukKbd6piL+VsT/qBrLhZe9Ivbjq5WMdkQKnP7gYKCAi pNVJC4enWfivZsYupMd9qn7Uv/oCZDYoBTdMSBUblaLMwlcjnPpOYK5rfHvC4opxl+P/Vzyz 6WC2TLkPtKvYvXmdsI6rnEI4Uucg0Au/Ulg7aqqKhzGPIbVaL+U0Wk82nz6hz+WP2ggTrY1w ZlPlRt8WM9w6WfLf2j+PuGklj37m+KvaOEfLsF1v464dSpy1tQVHhhp8LFTxh/6RWkRIR2uF I4v3Xu/k5D0LhaZHpQ4C+xKsQxpTGuYh2tnRaRL14YMW1dlI3HfeB2gj7Yc8XdHh9vkpPyuT nY/ZsFbnvBtiw7GchKKri2gDhRb2QNNDyBnQn5mRFw7CyuFclAksOdV/sdpQnYlYcRQWOUGY HhQ5eqTRZjm9z+qQe/T0HQpmiPTqQcIaG/edgKVTUjITfA7AJMKLQHgp04Vylb+G6jocnQQX JqvvP09whbqrABEBAAHCwWUEGAECAA8CGwwFAlVcpi8FCRmg08MACgkQyx8mb86fmYHNRQ/+ J0OZsBYP4leJvQF8lx9zif+v4ZY/6C9tTcUv/KNAE5leyrD4IKbnV4PnbrVhjq861it/zRQW cFpWQszZyWRwNPWUUz7ejmm9lAwPbr8xWT4qMSA43VKQ7ZCeTQJ4TC8kjqtcbw41SjkjrcTG wF52zFO4bOWyovVAPncvV9eGA/vtnd3xEZXQiSt91kBSqK28yjxAqK/c3G6i7IX2rg6pzgqh hiH3/1qM2M/LSuqAv0Rwrt/k+pZXE+B4Ud42hwmMr0TfhNxG+X7YKvjKC+SjPjqp0CaztQ0H nsDLSLElVROxCd9m8CAUuHplgmR3seYCOrT4jriMFBtKNPtj2EE4DNV4s7k0Zy+6iRQ8G8ng QjsSqYJx8iAR8JRB7Gm2rQOMv8lSRdjva++GT0VLXtHULdlzg8VjDnFZ3lfz5PWEOeIMk7Rj trjv82EZtrhLuLjHRCaG50OOm0hwPSk1J64R8O3HjSLdertmw7eyAYOo4RuWJguYMg5DRnBk WkRwrSuCn7UG+qVWZeKEsFKFOkynOs3pVbcbq1pxbhk3TRWCGRU5JolI4ohy/7JV1TVbjiDI HP/aVnm6NC8of26P40Pg8EdAhajZnHHjA7FrJXsy3cyIGqvg9os4rNkUWmrCfLLsZDHD8FnU mDW4+i+XlNFUPUYMrIKi9joBhu18ssf5i5Q= Message-ID: <1c0cd771-6067-69be-9838-9d3ab24a2503@roeck-us.net> Date: Mon, 8 Mar 2021 21:51:51 -0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20210304221247.488173-1-linux@rasmusvillemoes.dk> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/4/21 2:12 PM, Rasmus Villemoes wrote: > As Arnd and Guenther suggested, this adds support to the gpio_wdt > driver for being a consumer of the clock driving the ripple > counter. However, I don't think it should be merged as-is, see below. > > The first patch makes sense on its own, quick grepping suggests plenty > of places that could benefit from this, and I thought it would be odd > to have to re-introduce a .remove callback in the gpio_wdt driver. > This has zero chance to be accepted. As suggested in the patch, just use devm_add_action(), like many other watchdog drivers. > Unfortunately, this turns out to be a bit of an "operation succeeded, > patient (almost) died": We use CONFIG_GPIO_WATCHDOG_ARCH_INITCALL > because the watchdog has a rather short timeout (1.0-2.25s, 1.6s > typical according to data sheet). At first, I put the new code right > after the devm_gpiod_get(), but the problem is that this early, we get > -EPROBE_DEFER since the clock provider (the RTC which sits off i2c) > isn't probed yet. But then the board would reset because it takes way > too long for the rest of the machine to initialize. [The bootloader > makes sure to turn on the RTC's clock output so the watchdog is > actually functional, the task here is to figure out the proper way to > prevent clk_disable_unused() from disabling it.] > Is there a property indicating always-on for clocks, similar to regulator-always-on ? The idea seems to exist, but it looks like it is always explict (ie mentioned somewhere in the code that a clock is always on, or "safe"). It would help if the clock in question can be marked as always-on without explicit consumer. Thanks, Guenter > Moving the logic to after the first "is it always-running and if so > give it an initial ping" made the board survive, but unfortunately the > second, and succesful, probe happens a little more than a second > later, which happens to work on this particular board, but is > obviously not suitable for production given that it's already above > what the spec says, and other random changes in the future might make > the gap even wider. > > So I don't know. The hardware is obviously misdesigned, and I don't > know how far the mainline kernel should stretch to support this; OTOH > the kernel does contain lots of workarounds for quirks and hardware > bugs. > > > > > Rasmus Villemoes (3): > clk: add devm_clk_prepare_enable() helper > dt-bindings: watchdog: add optional "delay" clock to gpio-wdt binding > watchdog: gpio_wdt: implement support for optional "delay" clock > > .../devicetree/bindings/watchdog/gpio-wdt.txt | 6 ++++ > .../driver-api/driver-model/devres.rst | 1 + > drivers/clk/clk-devres.c | 29 +++++++++++++++++++ > drivers/watchdog/gpio_wdt.c | 9 ++++++ > include/linux/clk.h | 13 +++++++++ > 5 files changed, 58 insertions(+) >