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 642C1C433EF for ; Mon, 28 Mar 2022 13:11:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242920AbiC1NNV (ORCPT ); Mon, 28 Mar 2022 09:13:21 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:42492 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234382AbiC1NNT (ORCPT ); Mon, 28 Mar 2022 09:13:19 -0400 Received: from mx0b-001ae601.pphosted.com (mx0b-001ae601.pphosted.com [67.231.152.168]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3C3201001 for ; Mon, 28 Mar 2022 06:11:39 -0700 (PDT) Received: from pps.filterd (m0077474.ppops.net [127.0.0.1]) by mx0b-001ae601.pphosted.com (8.16.1.2/8.16.1.2) with ESMTP id 22S897pb025877; Mon, 28 Mar 2022 08:11:34 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=cirrus.com; h=date : from : to : cc : subject : message-id : references : mime-version : content-type : in-reply-to; s=PODMain02222019; bh=z2lM6O7vGhTvwrKdmAeXIfKrAC85LExsDuP6+CYz1kU=; b=M/+80Apj4BzVfxM54IgAVjzRX6c51VJa0gZfOwGpD11pqJVHOiDadYbJNek5ef1IsYMt XfXVQSxjfrQILZrkoBRKLIfKhXOzeLHtC4TdJi/LoMvT3+13VuEXNTBu2gYKAgBTCPV9 ImPSHj7dpAM/m271cnQSgSpvCIYV2lpeAUdh79q9Qm/9JsB/ApXs7aCu9IMUMGdgsESq PboWzvHoWXW38Qt6lLAbfUu4gOkhqYgSWD62ma5VaYXhit1ALmNdNprbiLa90+JSOqgg qsAq2AA+eL14rXPYXzZ2GQk9pgAFcAS3Aj3Q/Uj60UV6WzsfpukhDZjQMcZboTiSsutm ug== Received: from ediex02.ad.cirrus.com ([84.19.233.68]) by mx0b-001ae601.pphosted.com (PPS) with ESMTPS id 3f1y8pag9u-1 (version=TLSv1.2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128 verify=NOT); Mon, 28 Mar 2022 08:11:33 -0500 Received: from EDIEX01.ad.cirrus.com (198.61.84.80) by EDIEX02.ad.cirrus.com (198.61.84.81) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2375.24; Mon, 28 Mar 2022 14:11:32 +0100 Received: from ediswmail.ad.cirrus.com (198.61.86.93) by EDIEX01.ad.cirrus.com (198.61.84.80) with Microsoft SMTP Server id 15.1.2375.24 via Frontend Transport; Mon, 28 Mar 2022 14:11:32 +0100 Received: from ediswmail.ad.cirrus.com (ediswmail.ad.cirrus.com [198.61.86.93]) by ediswmail.ad.cirrus.com (Postfix) with ESMTP id 11E24B16; Mon, 28 Mar 2022 13:11:32 +0000 (UTC) Date: Mon, 28 Mar 2022 13:11:32 +0000 From: Charles Keepax To: Jonathan Bakker CC: Liam Girdwood , Mark Brown , , Subject: Re: [PATCH v2] regulator: wm8994: Add an off-on delay for WM8994 variant Message-ID: <20220328131132.GI38351@ediswmail.ad.cirrus.com> References: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.21 (2010-09-15) X-Proofpoint-GUID: Ww6RZjcNHMZfZmcPqvt_gjr_tkMgo-I0 X-Proofpoint-ORIG-GUID: Ww6RZjcNHMZfZmcPqvt_gjr_tkMgo-I0 X-Proofpoint-Spam-Reason: safe Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Mar 27, 2022 at 06:01:54PM -0700, Jonathan Bakker wrote: > As per Table 130 of the wm8994 datasheet at [1], there is an off-on > delay for LDO1 and LDO2. In the wm8958 datasheet [2], I could not > find any reference to it. I could not find a wm1811 datasheet to > double-check there, but as no one has complained presumably it works > without it. > > This solves the issue on Samsung Aries boards with a wm8994 where > register writes fail when the device is powered off and back-on > quickly. > > [1] https://statics.cirrus.com/pubs/proDatasheet/WM8994_Rev4.6.pdf > [2] https://statics.cirrus.com/pubs/proDatasheet/WM8958_v3.5.pdf > > Signed-off-by: Jonathan Bakker > --- I can confirm the 1811 also doesn't mention the cycle time in the datasheet. So that checks out. Acked-by: Charles Keepax Part of me wonders if we should just apply it to 1811 and 8958 anyway, I suspect they have the same IP for the LDO and its just the datasheets never got updated. I had a go chasing the apps guys here but we are a little short on people who remember details of these parts. So I guess we trust the datasheets for now, unless you have any strong feelings, Mark? Thanks, Charles