[lm-sensors] [PATCH 0/3] hwmon: More LM63 enhancements
guenter.roeck at ericsson.com
Wed Nov 23 21:51:49 CET 2011
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
Sorry for the noise.
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