linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Boris Brezillon <boris.brezillon@bootlin.com>
To: Joe Perches <joe@perches.com>, Rob Herring <robh+dt@kernel.org>
Cc: Wolfram Sang <wsa@the-dreams.de>,
	linux-i2c@vger.kernel.org, Jonathan Corbet <corbet@lwn.net>,
	linux-doc@vger.kernel.org,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Arnd Bergmann <arnd@arndb.de>,
	Przemyslaw Sroka <psroka@cadence.com>,
	Arkadiusz Golec <agolec@cadence.com>,
	Alan Douglas <adouglas@cadence.com>,
	Bartosz Folta <bfolta@cadence.com>, Damian Kos <dkos@cadence.com>,
	Alicja Jurasik-Urbaniak <alicja@cadence.com>,
	Cyprian Wronka <cwronka@cadence.com>,
	Suresh Punnoose <sureshp@cadence.com>,
	Rafal Ciepiela <rafalc@cadence.com>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	Nishanth Menon <nm@ti.com>, Pawel Moll <pawel.moll@arm.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Ian Campbell <ijc+devicetree@hellion.org.uk>,
	Kumar Gala <galak@codeaurora.org>,
	devicetree@vger.kernel.org, linux-kernel@vger.kernel.org,
	Vitor Soares <Vitor.Soares@synopsys.com>,
	Geert Uytterhoeven <geert@linux-m68k.org>,
	Linus Walleij <linus.walleij@linaro.org>,
	Xiang Lin <Xiang.Lin@synaptics.com>,
	linux-gpio@vger.kernel.org, Sekhar Nori <nsekhar@ti.com>,
	Przemyslaw Gaj <pgaj@cadence.com>, Peter Rosin <peda@axentia.se>,
	Mike Shettel <mshettel@codeaurora.org>,
	Stephen Boyd <swboyd@chromium.org>
Subject: Re: [PATCH v8 05/10] dt-bindings: i3c: Add macros to help fill I3C/I2C device's reg property
Date: Wed, 3 Oct 2018 20:59:53 +0200	[thread overview]
Message-ID: <20181003205953.426021bb@bbrezillon> (raw)
In-Reply-To: <c7b929a8c8ebaec7ce0f0e09f803e414e74f986b.camel@perches.com>

On Wed, 03 Oct 2018 11:37:17 -0700
Joe Perches <joe@perches.com> 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 <boris.brezillon@bootlin.com>
> > Reviewed-by: Rob Herring <robh@kernel.org>
> > ---
> > 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 <boris.brezillon@bootlin.com>
> > + */
> > +
> > +#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 = <I2C_DEV(0x34, 0x1)>;

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 = <i2c_addr_or_i3c_static_addr pid_msb pid_lsb>;

If pid_msb and pid_lsb are 0, then the node is defining an I2C device
(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  
> 


  parent reply	other threads:[~2018-10-03 18:59 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-10-03 13:22 [PATCH v8 00/10] Add the I3C subsystem Boris Brezillon
2018-10-03 13:22 ` [PATCH v8 01/10] i3c: Add core I3C infrastructure Boris Brezillon
2018-10-03 13:22 ` [PATCH v8 02/10] docs: driver-api: Add I3C documentation Boris Brezillon
2018-10-03 13:22 ` [PATCH v8 03/10] i3c: Add sysfs ABI spec Boris Brezillon
2018-10-03 13:22 ` [PATCH v8 04/10] dt-bindings: i3c: Document core bindings Boris Brezillon
2018-10-03 13:22 ` [PATCH v8 05/10] dt-bindings: i3c: Add macros to help fill I3C/I2C device's reg property Boris Brezillon
2018-10-03 18:37   ` Joe Perches
2018-10-03 18:45     ` Geert Uytterhoeven
2018-10-03 19:02       ` Joe Perches
2018-10-03 18:59     ` Boris Brezillon [this message]
2018-10-03 19:06       ` Boris Brezillon
2018-10-03 13:22 ` [PATCH v8 06/10] MAINTAINERS: Add myself as the I3C subsystem maintainer Boris Brezillon
2018-10-03 13:22 ` [PATCH v8 07/10] i3c: master: Add driver for Cadence IP Boris Brezillon
2018-10-08 10:06   ` Arnd Bergmann
2018-10-08 10:21     ` Boris Brezillon
2018-10-08 10:36       ` Arnd Bergmann
2018-10-08 12:05         ` Boris Brezillon
2018-10-03 13:22 ` [PATCH v8 08/10] dt-bindings: i3c: Document Cadence I3C master bindings Boris Brezillon
2018-10-03 13:22 ` [PATCH v8 09/10] gpio: Add a driver for Cadence I3C GPIO expander Boris Brezillon
2018-10-03 13:22 ` [PATCH v8 10/10] dt-bindings: gpio: Add bindings for Cadence I3C gpio expander Boris Brezillon
2018-10-04  8:35   ` Linus Walleij
2018-10-08 10:47 ` [PATCH v8 00/10] Add the I3C subsystem Arnd Bergmann
2018-10-17 13:18   ` Boris Brezillon

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20181003205953.426021bb@bbrezillon \
    --to=boris.brezillon@bootlin.com \
    --cc=Vitor.Soares@synopsys.com \
    --cc=Xiang.Lin@synaptics.com \
    --cc=adouglas@cadence.com \
    --cc=agolec@cadence.com \
    --cc=alicja@cadence.com \
    --cc=arnd@arndb.de \
    --cc=bfolta@cadence.com \
    --cc=corbet@lwn.net \
    --cc=cwronka@cadence.com \
    --cc=devicetree@vger.kernel.org \
    --cc=dkos@cadence.com \
    --cc=galak@codeaurora.org \
    --cc=geert@linux-m68k.org \
    --cc=gregkh@linuxfoundation.org \
    --cc=ijc+devicetree@hellion.org.uk \
    --cc=joe@perches.com \
    --cc=linus.walleij@linaro.org \
    --cc=linux-doc@vger.kernel.org \
    --cc=linux-gpio@vger.kernel.org \
    --cc=linux-i2c@vger.kernel.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mark.rutland@arm.com \
    --cc=mshettel@codeaurora.org \
    --cc=nm@ti.com \
    --cc=nsekhar@ti.com \
    --cc=pawel.moll@arm.com \
    --cc=peda@axentia.se \
    --cc=pgaj@cadence.com \
    --cc=psroka@cadence.com \
    --cc=rafalc@cadence.com \
    --cc=robh+dt@kernel.org \
    --cc=sureshp@cadence.com \
    --cc=swboyd@chromium.org \
    --cc=thomas.petazzoni@bootlin.com \
    --cc=wsa@the-dreams.de \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).