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=-8.2 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=unavailable 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 9EBA4C3A59E for ; Mon, 2 Sep 2019 14:23:12 +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 7199A21670 for ; Mon, 2 Sep 2019 14:23:12 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="LkNbC2Pn" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 7199A21670 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=bootlin.com 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:In-Reply-To:MIME-Version:References: 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=Iw2VNNXlzahmpCM/Lm2b14o/ynbdrV/0tirwYzxQXVM=; b=LkNbC2Pn/shvrw vH8SvgMalvs686uM2QqTYsvCjCPDN+BJgVFzi9a8H5GoPHYYbhgCd6MYAhdVB53C2FcZDvu04jI6D G5nwVSB5+A8yCv7vPSmcf8ljDZmUYb7kwMhnDOaExIFhSuEBnN0DHB8Ag6fP6X7FUvA7bKAvLDaLD zrQMbd7xCg5+ZkRNtZQuKVLdmGttqXK9Lx3ihXgMsedjhDt6wuUG0Ss7piDFIc3FHZNOqZfoD61LL wOOIuV1AhElZGdetizeKWkfpNTBNWBwu67cgtfz1VbaMj7WHsIuGHPVa29uvHxzrLdxbqU0lw8QGt XAYJHD27IWLS9Anfz/VA==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1i4nEa-00072s-8x; Mon, 02 Sep 2019 14:23:08 +0000 Received: from relay3-d.mail.gandi.net ([217.70.183.195]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1i4nEX-00072N-1G for linux-arm-kernel@lists.infradead.org; Mon, 02 Sep 2019 14:23:06 +0000 X-Originating-IP: 86.207.98.53 Received: from localhost (aclermont-ferrand-651-1-259-53.w86-207.abo.wanadoo.fr [86.207.98.53]) (Authenticated sender: alexandre.belloni@bootlin.com) by relay3-d.mail.gandi.net (Postfix) with ESMTPSA id 92B5A6000A; Mon, 2 Sep 2019 14:22:54 +0000 (UTC) Date: Mon, 2 Sep 2019 16:22:51 +0200 From: Alexandre Belloni To: Eugen.Hristev@microchip.com Subject: Re: [PATCH v4 2/9] dt-bindings: i2c: add bindings for i2c analog and digital filter Message-ID: <20190902142251.GC21922@piout.net> References: <1567418773-2427-1-git-send-email-eugen.hristev@microchip.com> <1567418773-2427-3-git-send-email-eugen.hristev@microchip.com> <9a9c209c-2fb8-0a4c-4e0a-b04fefda3360@axentia.se> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.12.1 (2019-06-15) X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190902_072305_229780_2353C75E X-CRM114-Status: GOOD ( 18.24 ) 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: mark.rutland@arm.com, devicetree@vger.kernel.org, wsa@the-dreams.de, linux-kernel@vger.kernel.org, pierre-yves.mordret@st.com, Ludovic.Desroches@microchip.com, robh+dt@kernel.org, linux-i2c@vger.kernel.org, peda@axentia.se, linux-arm-kernel@lists.infradead.org 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 Eugen, On 02/09/2019 14:15:14+0000, Eugen.Hristev@microchip.com wrote: > On 02.09.2019 13:49, Peter Rosin wrote: > > > On 2019-09-02 12:12, Eugen.Hristev@microchip.com wrote: > >> From: Eugen Hristev > >> > >> Some i2c controllers have a built-in digital or analog filter. > >> This is specifically required depending on the hardware PCB/board. > >> Some controllers also allow specifying the maximum width of the > >> spikes that can be filtered. The width length can be specified in nanoseconds. > >> > >> Signed-off-by: Eugen Hristev > >> --- > >> Documentation/devicetree/bindings/i2c/i2c.txt | 11 +++++++++++ > >> 1 file changed, 11 insertions(+) > >> > >> diff --git a/Documentation/devicetree/bindings/i2c/i2c.txt b/Documentation/devicetree/bindings/i2c/i2c.txt > >> index 44efafd..8dbff67 100644 > >> --- a/Documentation/devicetree/bindings/i2c/i2c.txt > >> +++ b/Documentation/devicetree/bindings/i2c/i2c.txt > >> @@ -55,6 +55,17 @@ wants to support one of the below features, it should adapt the bindings below. > >> Number of nanoseconds the SDA signal takes to fall; t(f) in the I2C > >> specification. > >> > >> +- i2c-analog-filter > >> + Enable analog filter for i2c lines. > >> + > >> +- i2c-digital-filter > >> + Enable digital filter for i2c lines. > >> + > >> +- i2c-filter-width-ns > >> + Width of spikes which can be filtered by either digital or analog > >> + filters (i2c-analog-filtr or i2c-digital-filtr). This width is specified > > > > filtr -> filter (two instances) > > > > What if you want/need to have different bandwidth for the digital and analog > > filters? After all, this is a generic binding... > > For our needs, this is enough: the purpose of the filters is to avoid > noise on the lines, the noise is as big as it is for the digital and for > the analog filters, since we use an absolute measurement for them. So I > do not know how useful it would be to make a difference. > You are adding generic properties so they have to be generic and not tied to your particular use case. -- Alexandre Belloni, Bootlin Embedded Linux and Kernel engineering https://bootlin.com _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel