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=-2.6 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 D1D13C2BA19 for ; Tue, 14 Apr 2020 17:21:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id B026E2074D for ; Tue, 14 Apr 2020 17:21:38 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586884898; bh=hqDprYjabFxBscfVEG0+5dvJzqZCcHd1opdmPnhd2Ak=; h=Date:From:To:Cc:Subject:References:In-Reply-To:List-ID:From; b=qweL6j7wKN7bbG4sqV1nZGxMJ4rk9wA5W8Py19WdDLb5JqlzIfLO4s1l6dDWy2KcV OxLbNj4l0yHT+8qn9FnseZGrxuEnCEb7fzzbbF6RrWaytpyFiFJIb4t+KTl7DmlUtY AJFS3dr8LW5e8N61yEyiEz8qtv5LhzEbuDNteiLs= Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2407626AbgDNRVe (ORCPT ); Tue, 14 Apr 2020 13:21:34 -0400 Received: from mail.kernel.org ([198.145.29.99]:52880 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2407622AbgDNRVd (ORCPT ); Tue, 14 Apr 2020 13:21:33 -0400 Received: from localhost (fw-tnat.cambridge.arm.com [217.140.96.140]) (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 CE77120678; Tue, 14 Apr 2020 17:21:31 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=default; t=1586884892; bh=hqDprYjabFxBscfVEG0+5dvJzqZCcHd1opdmPnhd2Ak=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=h+nY5DfVYhJx8o/ujjNNyx0kjonVY+DPsN2UhfHMYXXuk8Og3wt4jhCpynBMBQsd2 p21D/wQE6MCWwIlH0ZmgjFqR0D+M4Je8cOa8cweBdHkm6ikP4EFafxr6YWy1ePAAbi 0NzuUD49CAh9h2IhLW6bGuhkMptucBaXFvPmYvhk= Date: Tue, 14 Apr 2020 18:21:29 +0100 From: Mark Brown To: Michael Walle Cc: Bartosz Golaszewski , linux-gpio , linux-devicetree , LKML , linux-hwmon@vger.kernel.org, linux-pwm@vger.kernel.org, LINUXWATCHDOG , arm-soc , Linus Walleij , Rob Herring , Jean Delvare , Guenter Roeck , Lee Jones , Thierry Reding , Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= , Wim Van Sebroeck , Shawn Guo , Li Yang , Thomas Gleixner , Jason Cooper , Marc Zyngier , Greg Kroah-Hartman Subject: Re: [PATCH v2 10/16] gpio: add a reusable generic gpio_chip using regmap Message-ID: <20200414172129.GJ5412@sirena.org.uk> References: <20200402203656.27047-1-michael@walle.cc> <20200402203656.27047-11-michael@walle.cc> <80bd8661ec8a1f5eda3f09a267846eaa@walle.cc> MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="LQAwcd5tHl0Qlnzi" Content-Disposition: inline In-Reply-To: X-Cookie: I've only got 12 cards. User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-hwmon-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-hwmon@vger.kernel.org --LQAwcd5tHl0Qlnzi Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Tue, Apr 14, 2020 at 12:07:01PM +0200, Michael Walle wrote: > Am 2020-04-14 11:50, schrieb Bartosz Golaszewski: > > Maybe setting the pointer to ERR_PTR(-ENOENT) which will result in > > IS_ERR() returning true? > Unfortunatly, its not a pointer, but only a regular unsigned int (ie > the type the regmap API has for its "reg" property). It could be a > pointer of course but then the user would have to allocate additional > memory. You could define REGMAP_INVALID_ADDR to be (unsigned int)(-1) or some other suitably implausible address and use that as a value. It's possible that there might be a collision with a real address on some device but it should be sufficiently unlikely to be useful, especially if it's not something regmap in general goes and evaluates. For extra safety we could have an API for allowing users to query the register validity information regmap has (or can be given) and gpiolib could then use that to figure out if the value was actually a dummy value but that's probably overdoing it. --LQAwcd5tHl0Qlnzi Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAl6V8RkACgkQJNaLcl1U h9AnZwf8CXCh0WrZ2WtwfdTJ1yX5W12AkMOk5xoWSFXC9PzRicdAquQGHN0U0Qan v2iy9fXKFP9/vjkpNOP0q8hzXFoFbxcDvTTPUcPJV9Xd/bJ/X2OTXn7qKKLxIA0q 8i5t5KXA1+3upDL3nzJvH/dZULUUz7vP7m1SrwkowgS4asnOJVMfa8vGJLbnxhT5 m9MjUO206PwDS/sUpsK36S+4ccbV5Nzdq50Ce9sWr4szpQnKtAFb0Z8Q9eriTl15 hJxwRBCZJLqzXLYIGVC0eJPv9YrbG3YLM+x+Hb6oxzOuHRWU5B/Kv8n01YeHW5A1 Zk21Hdv+mJcVD0qTQ1dNFzb4QzAp5Q== =mDDb -----END PGP SIGNATURE----- --LQAwcd5tHl0Qlnzi--