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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C0309C43334 for ; Sat, 4 Jun 2022 08:11:35 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233498AbiFDILe (ORCPT ); Sat, 4 Jun 2022 04:11:34 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:59804 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231828AbiFDILa (ORCPT ); Sat, 4 Jun 2022 04:11:30 -0400 Received: from mail-yw1-x112c.google.com (mail-yw1-x112c.google.com [IPv6:2607:f8b0:4864:20::112c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2FCD438BC8 for ; Sat, 4 Jun 2022 01:11:29 -0700 (PDT) Received: by mail-yw1-x112c.google.com with SMTP id 00721157ae682-30c143c41e5so102154267b3.3 for ; Sat, 04 Jun 2022 01:11:29 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=I13xghRJZ9qk6cykz4w1fDYTb/H8Sm22vdjVHXo29TE=; b=VdmAmBHA6m7bm4C1XCyzAxo3GzpxdcMBRmGnlFBqYxTJLccgCZo4222kvHR9L/ZFqg yEtwitNUpVX8wc5cDxSYADo6KRiqOjnsk+d9+X/7i9Vn+eSkH6HDZulVWycy/dlcFVwS wrG3KhIFoyJwaaREbOCwu4cQtofeXqBu6gnXb4UQhKX8HOrxbZSGtkFs8+4NT9HiPRMV q/cLeEhaVBKcxN7iCP5p2vH5M37g3D4McCL7rERy4rzIRALiBL2UGUYbqWQNZiUeQvup PoDZS3uGmIdmVhAm4bCFoKhv7ykqZBoJOU6UJW2D6W4Lo+UAho8WEefF3qg5Oi0tQafL Z69g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=I13xghRJZ9qk6cykz4w1fDYTb/H8Sm22vdjVHXo29TE=; b=x048JgP5SDXg8evkzh2hBv/l4ppyQGQrK2l9iM3WNKPwK5gVK1eOSFfrG5fJME09cJ 0SXmIPd0mQASB3+xNs//E/cJMyvUZrISQQd/9LARRTm66LJBLS5j+Ig4MbTYPFHOpkfn xbYEnqDPNhyY2HUEW3EVbxwKHX1mOTUg25invsf8JZsG/22zbhbqUPE2rV9+2hyPcaaB a/Co68Tv0mN0nW1RMJz5zcbLyEY0eX/FeXG5k/xayp7PBqwBdnDsrVyeGY4+X0+o6KTT hQEN4fT+Pqj77+wrUfKUok1LvPNiL4dIN9ou8/tGTmItgtaPJ2ZWKV5r3MXpCNXpX1ox 30PA== X-Gm-Message-State: AOAM530UrU4MhcCc8M7zWkOMAZpZRM/qJd+2QPQh6i2aGnrviEH7KotX TdgdHufMO1U+FUJYX9G3+DcpK+6HcaXku6t+DtZ+9Q== X-Google-Smtp-Source: ABdhPJy4i6fQu4ekTJ5vsn5HDSlqWGJnhhSGVcuU4GviBejc544f0mPcEQt3SeSBlz0VlMOv4J5zkuoP9Z9mfbnG1sI= X-Received: by 2002:a81:1154:0:b0:2fe:d5a4:f26b with SMTP id 81-20020a811154000000b002fed5a4f26bmr15921192ywr.140.1654330288381; Sat, 04 Jun 2022 01:11:28 -0700 (PDT) MIME-Version: 1.0 References: <20220603113908.78777-1-thierry.reding@gmail.com> In-Reply-To: From: Linus Walleij Date: Sat, 4 Jun 2022 10:11:17 +0200 Message-ID: Subject: Re: [GIT PULL] hte: New subsystem for v5.19-rc1 To: Linus Torvalds , "D, Lakshmi Sowjanya" Cc: Thierry Reding , Dipen Patel , Bartosz Golaszewski , linux-tegra , Linux Kernel Mailing List , Mark Gross , Andy Shevchenko , "Saha, Tamal" , bala.senthil@intel.com Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Jun 4, 2022 at 6:38 AM Linus Torvalds wrote: > On Fri, Jun 3, 2022 at 4:39 AM Thierry Reding wrote: > > > > Note that this currently supports only one provider, but there seems to > > be enough interest in this functionality and we expect to see more > > drivers added once this is merged. > > So the "one provider" worries me, but the part that really doesn't > make me all warm and fuzzy is how this came in at the end of the merge > window. Another provider did come up, and were requested (by me) to work with Dipen on the subsystem in august last year, that was the Intel PMC in the Elkhart and Tiger Lake platforms and forward: https://patchwork.ozlabs.org/project/linux-gpio/cover/20210824164801.28896-1-lakshmi.sowjanya.d@intel.com/#2766453 [I added the other Intel people on that submission to CC] Intel wanted to put this into the GPIO subsystem and what I saw as maintainer was that this is a general problem and general purpose (binary) I/O just isn't going to be the only thing they timestamp. Other events will be for IIO and hwmon or whatever. They have been requested to contribute to Dipens work the recent 9 months ... so... well I understand people can get other priorities and stuff. Dipen did the right thing and created a separate subsystem that is a provider to GPIO and can be a provider to things like IIO as well, which is what it needs to be because for things like sensor fusion and industrial control systems in general precise timestamps are of uttermost importance. And IIO handle a lot of sensors. > The DT bindings got the comment "why call it 'hardware timestamp'" > when no other case seems sane. Intel is talking about "input timestamping", admittedly it is done in hardware but the point is to timestamp input I/O events. > So the DT bindings got renamed. So now part of the code calls it "hte" > (which nobody understands outside of the hte community that is > apparently one single device: Tegra) and part of the code calls it > "timestamp". HTE is "hardware timestamping engine", we have hwmon, hwspinlock, hwtracing so maybe hwstamping would be a more natural name then? Yours, Linus Walleij