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[2620:137:e000::1:20]) by mx.google.com with ESMTP id r7-20020aa7d147000000b004616aff8436si7446611edo.83.2022.11.20.14.50.04; Sun, 20 Nov 2022 14:50:30 -0800 (PST) Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20; Authentication-Results: mx.google.com; dkim=pass header.i=@linaro.org header.s=google header.b=KdYBUjtQ; spf=pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org; dmarc=pass (p=NONE sp=NONE dis=NONE) header.from=linaro.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229687AbiKTWd5 (ORCPT + 91 others); Sun, 20 Nov 2022 17:33:57 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34644 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229449AbiKTWd4 (ORCPT ); Sun, 20 Nov 2022 17:33:56 -0500 Received: from mail-yb1-xb34.google.com (mail-yb1-xb34.google.com [IPv6:2607:f8b0:4864:20::b34]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 927D015FFF for ; Sun, 20 Nov 2022 14:33:54 -0800 (PST) Received: by mail-yb1-xb34.google.com with SMTP id s18so11656552ybe.10 for ; Sun, 20 Nov 2022 14:33:54 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linaro.org; s=google; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:from:to:cc:subject:date:message-id:reply-to; bh=Nv+M9JLErYIuqpEJrx3jYZjNp1otlxlEOydAF6yu7ts=; b=KdYBUjtQ78WAwpkKFAdrq1i8V9OJyZkN2IVbP3L5yW8MqFJh9WXNDOGRT/nSldRjRo 1qabr363Bqlk/m98zXhxj96Eb+P9y6DbpZ+MjCWkMEZCMssBH999FBC8T3R3R3FNZREV gA8hNJJlpVqEY24acpDmrYIsRZQF3Aj7bxSH/nMSWJt/hmBeouyOUvwLcSTTiZkR8eSY jJG76WQlt/+gdOV6Bxg8y4jO2Eo6psooO+3OwGPhmcgs1HyU616i70hZLalwe4u9Xguy M4hR38VivS13Yj9Ut2uoyzf5ebtSD7PGHT5a0eZ6Ti1XogT1m5hOrp3sdWlQPqS17Ale 6uNg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=cc:to:subject:message-id:date:from:in-reply-to:references :mime-version:x-gm-message-state:from:to:cc:subject:date:message-id :reply-to; bh=Nv+M9JLErYIuqpEJrx3jYZjNp1otlxlEOydAF6yu7ts=; b=xZ4PUq8uRN9GjsLv4C3RC6msFO2bHS3e1pZFr8Ec6I0poAAE3nn3t8AoxsZd77ZipN NuxO/XH2Lr2PmfhOeUYX0JyneRHReuq+67XxwDX/JWFlN8MhFNzdMs9yer73vDK6qTW5 CQZ4ZNHSKSmyx3W5VlpSiLjQhi2ebTgB4fRNQqxmW8rl4ygEqDWgwN4NuvJTvcaVZBRj wCMExEydXoSLQKaSmp5MXNPbEdKHLFvnhcpXpAwNAP8pPJwHDXTnFQnf9jUXnBeTTZ/u G718ukDUZKDjXlcxjkTEELZsYJ4QQX3xznTn8dempy63aTfd1/01EIOFPZr1RwGadJZu kA0Q== X-Gm-Message-State: ANoB5pk4CDyIWjnkmlULsgxcO08nabXAIeo+/WEJIeicDmkKKWv+LCRl ikMpYVWP8ky5Kmyl3A1OK5dkuW2kCDRt6/jXoYB3vg== X-Received: by 2002:a05:6902:4e8:b0:6d1:16bf:1f8f with SMTP id w8-20020a05690204e800b006d116bf1f8fmr1609540ybs.206.1668983633802; Sun, 20 Nov 2022 14:33:53 -0800 (PST) MIME-Version: 1.0 References: <7de35859-97ab-8e88-f590-d5851b81773b@nvidia.com> In-Reply-To: <7de35859-97ab-8e88-f590-d5851b81773b@nvidia.com> From: Linus Walleij Date: Sun, 20 Nov 2022 23:33:41 +0100 Message-ID: Subject: Re: Intel timed i/o driver in HTE To: Dipen Patel Cc: "N, Pandith" , "linux-kernel@vger.kernel.org" , "Hall, Christopher S" , "Gross, Mark" , "Sangannavar, Mallikarjunappa" , "D, Lakshmi Sowjanya" , "T R, Thejesh Reddy" , "andriy.shevchenko@linux.intel.com" , timestamp@lists.linux.dev Content-Type: text/plain; charset="UTF-8" X-Spam-Status: No, score=-2.1 required=5.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,RCVD_IN_DNSWL_NONE, SPF_HELO_NONE,SPF_PASS autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on lindbergh.monkeyblade.net Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Nov 19, 2022 at 3:33 AM Dipen Patel wrote: > On 11/17/22 10:47 AM, N, Pandith wrote: > > To support Intel timed i/o driver, it was suggested by Linux community to enhance hte framework. > > However, we see some limitations to support complete Intel timed i/o device. (...) > > b. Timed output - single shot or periodic pulse train. > > Uses TSC(Timestamp counter) for timestamp or generate events, which could be translated to system time. (...) > For 1b, the timestamp part can be added as hte provider. I see opportunity to enhance hte framework to provide > translation facility between the domain, system time in this case. However programming interface to facilitate > timed IO output can not fit into HTE the way it is right now. May be one possible way is to enchance HTE with API something like > hte_configure_timestamp_periodic/timed could be possible in which case HTE does something more than just timestamping the event. > > I have to see how in GPIO case that proposed API works out, if it will bypass gpio framework etc... > > Adding Linus W into the discussion.... I think I already answered with some open ended questions in discussion with Christopher S. Hall: https://lore.kernel.org/linux-iio/CACRpkdbeQ_67V3jkw_-KfTwe54TxrK_LA7N8Nwj1qEpTELN9dQ@mail.gmail.com/ https://lore.kernel.org/linux-iio/CACRpkda63TNWLdTjY+_xxXb4df4qCZi1EaXL3pXK=+Hon-0RLQ@mail.gmail.com/ https://lore.kernel.org/linux-iio/CACRpkdYxverx-KsG9URrh5qkEFXDknZKCE6RM555mjOuC--vMg@mail.gmail.com/ I think Intel is in a bit of uncomfortable design space with this thing that isn't fitting properly anywhere. Dunno what to do about that :/ One thing I didn't get a clear answer for is what kind of use cases the timed GPIO is for. I was suspecting things like stepper motors. I was suspecting at one point some kind of sync pulse to something. But no clear answer. It is useful to know the usecase to be able to figure out the appropriate subsystem. It might be that GPIO with some custom ioctl()s for the gpiodev is the right answer to some of the question, as outlined above. and I see Dipen has some answers: Yours, Linus Walleij