From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guenter Roeck Subject: Re: PMBus support in Linux Date: Sat, 29 May 2010 08:33:12 -0700 Message-ID: <20100529153312.GA20814@ericsson.com> References: <1275063391.2631.137.camel@groeck-laptop> <20100529023401.GB12507@pengutronix.de> <20100529044239.GA19155@ericsson.com> <20100529085301.GA14982@pengutronix.de> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Return-path: Content-Disposition: inline In-Reply-To: <20100529085301.GA14982-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org> Sender: linux-i2c-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Wolfram Sang Cc: "linux-i2c-u79uwXL29TY76Z2rM5mHXA@public.gmane.org" , David Brownell , "lm-sensors-GZX6beZjE8VD60Wz+7aTrA@public.gmane.org" List-Id: linux-i2c@vger.kernel.org On Sat, May 29, 2010 at 04:53:01AM -0400, Wolfram Sang wrote: > > If there is no activity yet, question is if I should write individual drivers or > > if I should define a PMBus infrastructure on top of i2c/smbus first. > > Any thoughts on which approach would be more likely to be accepted into the kernel ? > > Did I get this correct: The plan is to support PMBus-devices and let them > report their data in a hwmon-compatible-way? > Yes. > (If so, did you already check how well PMBus data maps to the > hwmon-sysfs-interface?) > Yes. PMBus uses i2c as transport, so it can use the existing i2c/smbus infrastructure. Data reported is voltage, temperature, current, power, and fan data as available from the individual chip. Chips support a chip dependent number of channels. Values reported are typically in the form of X = Y * 2^N, ie there is a mantissa and an exponent. So I would say it maps pretty well; I don't really see a substantial difference to other HW monitoring chips in that respect. Key difference may be that PMBus devices typically also have a control component, but I don't have plans to implement that, at least not for now. Guenter