From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.1 (2015-04-28) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-5.8 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI autolearn=ham autolearn_force=no version=3.4.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 7C0A47D082 for ; Wed, 3 Oct 2018 19:06:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727030AbeJDBz4 (ORCPT ); Wed, 3 Oct 2018 21:55:56 -0400 Received: from mail.bootlin.com ([62.4.15.54]:47668 "EHLO mail.bootlin.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726964AbeJDBz4 (ORCPT ); Wed, 3 Oct 2018 21:55:56 -0400 Received: by mail.bootlin.com (Postfix, from userid 110) id 51961207C3; Wed, 3 Oct 2018 21:06:13 +0200 (CEST) Received: from bbrezillon (91-160-177-164.subs.proxad.net [91.160.177.164]) by mail.bootlin.com (Postfix) with ESMTPSA id 7E79420719; Wed, 3 Oct 2018 21:06:12 +0200 (CEST) Date: Wed, 3 Oct 2018 21:06:13 +0200 From: Boris Brezillon To: Joe Perches , Rob Herring Cc: Wolfram Sang , linux-i2c@vger.kernel.org, Jonathan Corbet , linux-doc@vger.kernel.org, Greg Kroah-Hartman , Arnd Bergmann , Przemyslaw Sroka , Arkadiusz Golec , Alan Douglas , Bartosz Folta , Damian Kos , Alicja Jurasik-Urbaniak , Cyprian Wronka , Suresh Punnoose , Rafal Ciepiela , Thomas Petazzoni , Nishanth Menon , Pawel Moll , Mark Rutland , Ian Campbell , Kumar Gala , devicetree@vger.kernel.org, linux-kernel@vger.kernel.org, Vitor Soares , Geert Uytterhoeven , Linus Walleij , Xiang Lin , linux-gpio@vger.kernel.org, Sekhar Nori , Przemyslaw Gaj , Peter Rosin , Mike Shettel , Stephen Boyd Subject: Re: [PATCH v8 05/10] dt-bindings: i3c: Add macros to help fill I3C/I2C device's reg property Message-ID: <20181003210613.27d180c7@bbrezillon> In-Reply-To: <20181003205953.426021bb@bbrezillon> References: <20181003132212.12619-1-boris.brezillon@bootlin.com> <20181003132212.12619-6-boris.brezillon@bootlin.com> <20181003205953.426021bb@bbrezillon> X-Mailer: Claws Mail 3.15.0-dirty (GTK+ 2.24.31; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org On Wed, 3 Oct 2018 20:59:53 +0200 Boris Brezillon wrote: > On Wed, 03 Oct 2018 11:37:17 -0700 > Joe Perches wrote: > > > On Wed, 2018-10-03 at 15:22 +0200, Boris Brezillon wrote: > > > The reg property of devices connected to an I3C bus have 3 cells, and > > > filling them manually is not trivial. Provides macros to help doing > > > that. > > > > This patch logic seems excessively fragile. > > Keep in mind that this header is meant to be include by .dts(i) files, > not regular .c files. > > > > > > Signed-off-by: Boris Brezillon > > > Reviewed-by: Rob Herring > > > --- > > > Changes in v8: > > > - None > > > > > > Changes in v5: > > > - none > > > --- > > > include/dt-bindings/i3c/i3c.h | 28 ++++++++++++++++++++++++++++ > > > 1 file changed, 28 insertions(+) > > > create mode 100644 include/dt-bindings/i3c/i3c.h > > > > > > diff --git a/include/dt-bindings/i3c/i3c.h b/include/dt-bindings/i3c/i3c.h > > > new file mode 100644 > > > index 000000000000..97448c546649 > > > --- /dev/null > > > +++ b/include/dt-bindings/i3c/i3c.h > > > @@ -0,0 +1,28 @@ > > > +/* SPDX-License-Identifier: GPL-2.0 */ > > > +/* > > > + * Copyright (C) 2017 Cadence Design Systems Inc. > > > + * > > > + * Author: Boris Brezillon > > > + */ > > > + > > > +#ifndef _DT_BINDINGS_I3C_I3C_H > > > +#define _DT_BINDINGS_I3C_I3C_H > > > + > > > +#define IS_I2C_DEV 0x80000000 > > > + > > > +#define I2C_DEV(addr, lvr) \ > > > + (addr) (IS_I2C_DEV | (lvr)) 0x0 > > > > This looks to be missing surrounding parentheses. > > Actually it's not. The macro is supposed to declare 3 u32 integers each > of them separated by a space: > > reg = ; > > is translated into > > reg = <0x34 0x80000001 0x0>; > > > > > > + > > > +#define I3C_PID(manufid, partid, instid, extrainfo) \ > > > + ((manufid) << 1) \ > > > + (((partid) << 16) | ((instid) << 12) | (extrainfo)) > > > > This macro doesn't make any sense. Missing a shift and an or? > > Same here, the PID is taking 2 32-bit entries. > > Now, I agree that this is far from obvious, and if Rob is okay, I'd > like to propose a different binding to avoid having to define these > macros: > > reg = ; > > If pid_msb and pid_lsb are 0, then the node is defining an I2C device Actually, I meant pid_msb == 0. This part of the PID is encoding the manufacturer, and I don't think 0 is a valid manufacturer (I hope it's not). So, we'd have something like: reg = ; > (AFAICT, 0 is not a valid PID), otherwise it's an I3C device. This way > we get rid of the IS_I2C_DEV flag, and we can get rid of those macros > without making I3C dev node definition too painful (the only part > developers will have to get right is the PID) > > > > > > + > > > +#define I3C_DEV_WITH_STATIC_ADDR(addr, manufid, partid, \ > > > + instid, extrainfo) \ > > > + (addr) I3C_PID(manufid, partid, instid, extrainfo) > > > + > > > +#define I3C_DEV(manufid, partid, instid, extrainfo) \ > > > + I3C_DEV_WITH_STATIC_ADDR(0x0, manufid, partid, \ > > > + instid, extrainfo) > > > + > > > +#endif > > >