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=-2.5 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_2 autolearn=no 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 EA63CC4360C for ; Sat, 12 Oct 2019 14:00:24 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id B653621929 for ; Sat, 12 Oct 2019 14:00:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="If13/OoV"; dkim=fail reason="signature verification failed" (1024-bit key) header.d=kernel.org header.i=@kernel.org header.b="bipuAx3K" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org B653621929 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=kernel.org Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Message-ID:Subject:To:From:Date:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=pXwL75fE42h6XsQldIb2OdiGryeU48SHLuHZbUBcIvc=; b=If13/OoV1zotxv 57BZ2GlRQecYg0fPSv0Vq8LL5QYgQFRSi0b/OJEKXpA9aLbQgWdRSBjFxtjihvV1eZckBv4XJl35J TxCtBhT58+BbTwVq6jVyzP6vtUS9tJlZ5rnhHKWs+FF95d72lf6zTIeSkjas63FNcurrFkyYVnGaQ hDNRijP1AsFHiOrNpsy1RPBWqzRQG32eyytiLTjtr+eM6lteDUZM0u9T7ahfAR34i7YfzQHAfqxFn +8SP7LKvcWVXz1S3aHtlEKbb/cgt/g1ovCQ8jtHvZeieVHGyH5L7YLzM869UIDNCV3ijvx+YHcwis 7ybtwQAo/7cQzkzkJQ1Q==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1iJHwS-0005AG-Fl; Sat, 12 Oct 2019 14:00:20 +0000 Received: from mail.kernel.org ([198.145.29.99]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1iJHwQ-00059j-AC for linux-arm-kernel@lists.infradead.org; Sat, 12 Oct 2019 14:00:19 +0000 Received: from archlinux (cpc149474-cmbg20-2-0-cust94.5-4.cable.virginm.net [82.4.196.95]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id C42602089C; Sat, 12 Oct 2019 14:00:15 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1570888817; bh=Mz0BL3/C+OrOXXcjjKTuqtWi5Ny6ZYS0L4vIH8ltkfE=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=bipuAx3KMl+7dalmmCW/eKNVAhz7kU3AXJhnZJBdnEjXNPfkwuz455QiBKVrPhfmd PfIJViUdRtB9otkEn2Fzk7E4EhojB23oxtPUci/AhSdup6Tbzg7/FBu9jwLdiMeABm ZedXiIlxroMXFMHZfbWTaPplcVGqZuxfUEmQ1JdI= Date: Sat, 12 Oct 2019 15:00:12 +0100 From: Jonathan Cameron To: William Breathitt Gray Subject: Re: [PATCH v5 0/3] Simplify count_read/count_write/signal_read Message-ID: <20191012150012.5e3399f1@archlinux> In-Reply-To: References: X-Mailer: Claws Mail 3.17.4 (GTK+ 2.24.32; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20191012_070018_402536_5AFA7DA4 X-CRM114-Status: GOOD ( 21.83 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: benjamin.gaignard@linaro.org, alexandre.torgue@st.com, linux-iio@vger.kernel.org, patrick.havelange@essensium.com, linux-kernel@vger.kernel.org, mcoquelin.stm32@gmail.com, fabrice.gasnier@st.com, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, david@lechnology.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org Hi William What's the status on these? If you are happy that reviews and testing is complete enough, do you want me to take them after I pick up the eqep driver (hopefully shortly dependent on the pull request Greg has from me being fine). Thanks, Jonathan On Sun, 6 Oct 2019 16:03:08 -0400 William Breathitt Gray wrote: > Changes in v5: > - Add changes and additions to generic-counter.rst to clarify theory > and use of the Generic Counter interface > - Fix typo in counter.h action_get description comment > > The changes in this patchset will not affect the userspace interface. > Rather, these changes are intended to simplify the kernelspace Counter > callbacks for counter device driver authors. > > The following main changes are proposed: > > * Retire the opaque counter_count_read_value/counter_count_write_value > structures and simply represent count data as an unsigned integer. > > * Retire the opaque counter_signal_read_value structure and represent > Signal data as a counter_signal_value enum. > > These changes should reduce some complexity and code in the use and > implementation of the count_read, count_write, and signal_read > callbacks. > > The opaque structures for Count data and Signal data were introduced > originally in anticipation of supporting various representations of > counter data (e.g. arbitrary-precision tallies, floating-point spherical > coordinate positions, etc). However, with the counter device drivers > that have appeared, it's become apparent that utilizing opaque > structures in kernelspace is not the best approach to take. > > I believe it is best to let userspace applications decide how to > interpret the count data they receive. There are a couple of reasons why > it would be good to do so: > > * Users use their devices in unexpected ways. > > For example, a quadrature encoder counter device is typically used to > keep track of the position of a motor, but a user could set the device > in a pulse-direction mode and instead use it to count sporadic rising > edges from an arbitrary signal line unrelated to positioning. Users > should have the freedom to decide what their data represents. > > * Most counter devices represent data as unsigned integers anyway. > > For example, whether the device is a tally counter or position > counter, the count data is represented to the user as an unsigned > integer value. So specifying that one device is representing tallies > while the other specifies positions does not provide much utility from > an interface perspective. > > For these reasons, the count_read and count_write callbacks have been > redefined to pass count data directly as unsigned long instead of passed > via opaque structures: > > count_read(struct counter_device *counter, > struct counter_count *count, unsigned long *val); > count_write(struct counter_device *counter, > struct counter_count *count, unsigned long val); > > Similarly, the signal_read is redefined to pass Signal data directly as > a counter_signal_value enum instead of via an opaque structure: > > signal_read(struct counter_device *counter, > struct counter_signal *signal, > enum counter_signal_value *val); > > The counter_signal_value enum is simply the counter_signal_level enum > redefined to remove the references to the Signal data "level" data type. > > William Breathitt Gray (3): > counter: Simplify the count_read and count_write callbacks > docs: driver-api: generic-counter: Update Count and Signal data types > counter: Fix typo in action_get description > > Documentation/driver-api/generic-counter.rst | 162 +++++++++++-------- > drivers/counter/104-quad-8.c | 33 ++-- > drivers/counter/counter.c | 101 ++---------- > drivers/counter/ftm-quaddec.c | 14 +- > drivers/counter/stm32-lptimer-cnt.c | 5 +- > drivers/counter/stm32-timer-cnt.c | 17 +- > drivers/counter/ti-eqep.c | 19 +-- > include/linux/counter.h | 76 ++------- > 8 files changed, 144 insertions(+), 283 deletions(-) > > > base-commit: 0c3aa63a842d84990bd02622f2fa50d2bd33c652 > prerequisite-patch-id: ebe284609b3db8d4130ea2915f7f7b185c743a70 > prerequisite-patch-id: cbe857759f10d875690df125d18bc04f585ac7c9 > prerequisite-patch-id: 21f2660dc88627387ee4666d08044c63dd961dae _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel