Hi Jean,
On Sat, Jul 09, 2011 at 04:36:18PM -0400, Jean Delvare wrote:
> Hi Guenter,
>
> On Thu, 7 Jul 2011 13:42:44 -0700, Guenter Roeck wrote:
> > Negative temperatures were returned in degrees C instead of milli-Degrees C.
> > Also, negative temperatures were reported for remote temperature sensors even
> > if the chip was configured for positive-only results.
> >
> > Fix by detecting temperature modes, and by treating negative temperatures
> > similar to positive temperatures, with appropriate sign extension.
> >
> > Signed-off-by: Guenter Roeck <guenter.roeck@xxxxxxxxxxxx>
> > ---
> > Candidate for -stable.
> >
> > drivers/hwmon/lm95241.c | 20 ++++++++++++++------
> > 1 files changed, 14 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/hwmon/lm95241.c b/drivers/hwmon/lm95241.c
> > index 01c638e..ec02e30 100644
> > --- a/drivers/hwmon/lm95241.c
> > +++ b/drivers/hwmon/lm95241.c
> > @@ -98,11 +98,16 @@ struct lm95241_data {
> > };
> >
> > /* Conversions */
> > -static int TempFromReg(u8 val_h, u8 val_l)
> > +static int temp_from_reg_signed(u8 val_h, u8 val_l)
> > {
> > - if (val_h & 0x80)
> > - return val_h - 0x100;
> > - return val_h * 1000 + val_l * 1000 / 256;
> > + s16 val_hl = (val_h << 8) | val_l;
> > + return val_hl * 1000 / 256;
> > +}
> > +
> > +static int temp_from_reg_unsigned(u8 val_h, u8 val_l)
> > +{
> > + u16 val_hl = (val_h << 8) | val_l;
> > + return val_hl * 1000 / 256;
> > }
> >
> > static struct lm95241_data *lm95241_update_device(struct device *dev)
> > @@ -135,10 +140,13 @@ static ssize_t show_input(struct device *dev, struct device_attribute *attr,
> > char *buf)
> > {
> > struct lm95241_data *data = lm95241_update_device(dev);
> > + int index = to_sensor_dev_attr(attr)->index;
> >
> > return snprintf(buf, PAGE_SIZE - 1, "%d\n",
> > - TempFromReg(data->temp[to_sensor_dev_attr(attr)->index],
> > - data->temp[to_sensor_dev_attr(attr)->index + 1]));
> > + !index || (data->config & index) ?
>
> Hmm. This really should be:
>
> + !index || (data->config & (1 << (index / 2))) ?
>
> It just _happens_ that (1 << (index / 2)) == index for index values 2
> and 4, so your code works. But if we ever add support for a compatible
> device with an extra temperature channel, it'll break. Not sure if the
> rest of the driver code would properly cope with such a change anyway,
> though.
>
> Furthermore, I think that readability could be slightly improved by
> changing "!index" to "index == 0", as this is neither an error
> condition nor a boolean).
>
Makes sense. I changed it to
index == 0 || (data->config & (1 << (index / 2)))
> Readability could be improved even more with driver-wide changes but
> this is obviously out-of-scope for this patch.
>
Yes, I know. Another time, maybe.
Thanks,
Guenter
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