From mboxrd@z Thu Jan 1 00:00:00 1970 From: Guenter Roeck Date: Wed, 23 Nov 2011 20:51:49 +0000 Subject: Re: [lm-sensors] [PATCH 0/3] hwmon: More LM63 enhancements Message-Id: <20111123205149.GA26543@ericsson.com> List-Id: References: <1321994400-29295-1-git-send-email-guenter.roeck@ericsson.com> In-Reply-To: <1321994400-29295-1-git-send-email-guenter.roeck@ericsson.com> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: lm-sensors@vger.kernel.org On Wed, Nov 23, 2011 at 03:34:29PM -0500, Jean Delvare wrote: > Hi Guenter, > > On Tue, 22 Nov 2011 12:39:57 -0800, Guenter Roeck wrote: > > Add support for unsigned temperatures on LM96163 > > Add support for writing remote T_CRIT limit > > Add support for writing conversion rate register > > > > Question: > > Calculations are currently along the line of "/ 125 * 32", causing loss of accuracy. > > Ok to change to "* 32 / 125" ? > > I think this is on purpose. Multiplying last guarantees that we don't > try to set bits which do not exist to 1. As long as proper rounding is > done before dividing, I don't quite see how we could be losing > accuracy. Do you have an actual example? > You are right. I didn't realize that "/ 125" reduces accuracy to 1/8 degree C, which is exactly what the chips support, and that "* 32" simply shifts the value left by 5 bit to match the 11-bit registers. Sorry for the noise. Guenter _______________________________________________ lm-sensors mailing list lm-sensors@lm-sensors.org http://lists.lm-sensors.org/mailman/listinfo/lm-sensors