linux-kernel - Re: [PATCH v1 1/8] i2c: Introduce i2c_10bit_addr_from

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <Z6zwqbzd5evG0H2z@smile.fi.intel.com>
Date: Wed, 12 Feb 2025 21:04:09 +0200
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Geert Uytterhoeven <geert@...ux-m68k.org>
Cc: Andi Shyti <andi.shyti@...nel.org>,
	Wolfram Sang <wsa+renesas@...g-engineering.com>,
	linux-i2c@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-mediatek@...ts.infradead.org,
	linux-renesas-soc@...r.kernel.org,
	Krzysztof Adamski <krzysztof.adamski@...ia.com>,
	Florian Fainelli <florian.fainelli@...adcom.com>,
	Ray Jui <rjui@...adcom.com>, Scott Branden <sbranden@...adcom.com>,
	Broadcom internal kernel review list <bcm-kernel-feedback-list@...adcom.com>,
	Stefan Roese <sr@...x.de>,
	Matthias Brugger <matthias.bgg@...il.com>,
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
	Gregory CLEMENT <gregory.clement@...tlin.com>,
	Fabrizio Castro <fabrizio.castro.jz@...esas.com>
Subject: Re: [PATCH v1 1/8] i2c: Introduce i2c_10bit_addr_from_msg()

On Wed, Feb 12, 2025 at 07:36:46PM +0100, Geert Uytterhoeven wrote:
> On Wed, 12 Feb 2025 at 17:35, Andy Shevchenko
> <andriy.shevchenko@...ux.intel.com> wrote:
> > There are already a lot of drivers that have been using
> > i2c_8bit_addr_from_msg() for 7-bit addresses, now it's time
> > to have the similar for 10-bit addresses.

...

> > +static inline u8 i2c_10bit_addr_from_msg(const struct i2c_msg *msg)
> 
> Having never used 10-bit addressing myself, or even looked into it,
> it took me a while to understand what this helper really does...
> So this returns the high byte of the artificial 16-bit address that
> must be used to address a target that uses 10-bit addressing?
> Hence I think this should be renamed, to better match its purpose.

Since you are giving a constructive feedback, please, propose the name.

> > +{
> > +       /*
> > +        * 10-bit address
> > +        *   addr_1: 5'b11110 | addr[9:8] | (R/nW)
> > +        *   addr_2: addr[7:0]
> 
> I think the second comment line does not belong here, as this function
> doesn't care about that part.

I think the comment is okay to stay. It explains the full picture which is
helpful. It may be extended to say that the function returns only addr_1.

> > +        */
> > +       return 0xf0 | ((msg->addr & GENMASK(9, 8)) >> 7) | (msg->flags & I2C_M_RD);
> > +}
> 
> Probably you also want to add a similar but much simpler helper to
> return the low byte?

Wouldn't it be too much?

-- 
With Best Regards,
Andy Shevchenko