From mboxrd@z Thu Jan 1 00:00:00 1970 From: Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= Subject: Re: [RFC 0/4] i2c: slave support framework for Linux devices Date: Fri, 12 Sep 2014 10:58:36 +0200 Message-ID: <20140912085836.GS3755@pengutronix.de> References: <1410274470-12712-1-git-send-email-wsa@the-dreams.de> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Return-path: Content-Disposition: inline In-Reply-To: <1410274470-12712-1-git-send-email-wsa-z923LK4zBo2bacvFa/9K2g@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Wolfram Sang Cc: linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Jean Delvare , Magnus Damm , linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, linux-sh-u79uwXL29TY76Z2rM5mHXA@public.gmane.org List-Id: linux-i2c@vger.kernel.org Hello Wolfram, On Tue, Sep 09, 2014 at 04:54:26PM +0200, Wolfram Sang wrote: > Finally, here is my take on the often desired feature that Linux can = not only > be an I2C master, but also an I2C slave. Compared to my draft sent ou= t last > week, this RFC has been tested on hardware (Renesas Lager board) and = works \o/ >=20 > One big part still missing is documentation, so brave ones need to "u= se the > source". However, this approach turned out to be even less intrusive = than > expected, so that is hopefully a good sign. Some thoughts from reading through your patch set: - If I understand correctly you cannot register an i2c slave without also registering a master, right? I don't think this is troubling in practice, is it? For abstraction I would prefer to make these different concepts though. - The IMHO most (even only?) useful slave is "i2cslvdev", i.e. a userspace device. With that you wouldn't need device tree stuff, the driver would just offer the device if supported. Userspace then could care about the rest (slave address, functionality, ...). Best regards Uwe --=20 Pengutronix e.K. | Uwe Kleine-K=F6nig = | Industrial Linux Solutions | http://www.pengutronix.de/= |