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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 0BE49C433F5 for ; Fri, 15 Oct 2021 15:03:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id DDF2F611C3 for ; Fri, 15 Oct 2021 15:03:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S240730AbhJOPFH (ORCPT ); Fri, 15 Oct 2021 11:05:07 -0400 Received: from mail.kernel.org ([198.145.29.99]:55074 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230116AbhJOPFG (ORCPT ); Fri, 15 Oct 2021 11:05:06 -0400 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3AA1D600D4; Fri, 15 Oct 2021 15:02:59 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1634310179; bh=HUZyhXVFtyd+kL3lwYCZY+Spl4v5On1I0ObzJOAiC4Q=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=q/wSIGWGEl2/OWZr20i72XN6klWiorQtf9EIvLFZweKKKNbFSFXn5nRWkvKnX+UMZ ltA+W5RJeRiqqhqwdjf9cLswODKBvnnWJQ/TIB46snpzjKbwMmpf3WjPGualypOyU3 k6CNNCI2Ts822EChd9rTV81avQxcmcE828glTZhIwv2yAbPTyfRn0rpACfMYF8RD0D v1uALX3gbGqsMcSHeHCXGLE1k9zZdfUGJLEpKxXPP7fsVlp8u/lTObGlrPO6m8+N3c tne9Kh4vZVcluhZ+s5R79D2sMEOZdfHZrj8XGbCQcqCYnKd6pPCTdvi3icoiEoOqcO NrlrTFQbz42Hw== Date: Fri, 15 Oct 2021 16:02:57 +0100 From: Mark Brown To: Richard Fitzgerald Cc: alsa-devel@alsa-project.org, linux-kernel@vger.kernel.org, patches@opensource.cirrus.com Subject: Re: [PATCH 07/16] ASoC: cs42l42: Correct power-up sequence to match datasheet Message-ID: References: <20211015133619.4698-1-rf@opensource.cirrus.com> <20211015133619.4698-8-rf@opensource.cirrus.com> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="RZ6HkpV1NsoM41ux" Content-Disposition: inline In-Reply-To: <20211015133619.4698-8-rf@opensource.cirrus.com> X-Cookie: I'm having an emotional outburst!! Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org --RZ6HkpV1NsoM41ux Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Fri, Oct 15, 2021 at 02:36:10PM +0100, Richard Fitzgerald wrote: > The power-up sequence mandated in the datasheet is: > - VP must turn on first > - VA, VCP, VL, in any order > - VD_FILT after VL > static const char *const cs42l42_supply_names[CS42L42_NUM_SUPPLIES] = { > - "VA", > "VP", > + "VA", > "VCP", > - "VD_FILT", > "VL", > + "VD_FILT", > }; If you need the regulators to be turned on in sequence you shouldn't rely on bulk enable doing it for you - the existing regulator code will initiate all the enables in parallel and then wait for them all to complete ramping up so if for example VD_FILT were to ramp more quickly than the earlier regulators the hardware might notice it getting to whatever voltage the hardware cares about before them. The only sequencing you're getting at the minute is when the enables for the regulators are toggled and you shouldn't even rely on that. To get the sequencing guaranteed you should pull VP and VD_FILT out of the bulk enable and do individual enables for them. --RZ6HkpV1NsoM41ux Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmFpmCAACgkQJNaLcl1U h9CEHAf+KR9IRwQTLAgF/4BGe7x+ICDnwwxyPG6OAI0gYOK3VLGyJdTrAl6pyCmC d9/V8fKK5GbXumortiyIEqsnUOkFFyjHpFwyoXDUSA8GR0En5BYLcEAf3jo/WZcx fIcm5LDQkB2ahkWs2p45x0D77i24pzABdYQXp9HjEqH3Rhkmeh5Uu93hkKn6MPQN X5Y8aXsHrMdnz6dEAlGtd+0+jmHAu5PYPNalRB6gM0XXCoc+2SEpE1sSanCFlbH3 0LnX2g4iT2yp3r+ABpzWseK5GV4Xvg3C+e3REgOD29pwsoPCzinwhLU/xptbeqeI Mf8m8gP0yqixU1d5+uz0w4VdcnDZSw== =Z1lk -----END PGP SIGNATURE----- --RZ6HkpV1NsoM41ux--