On Tue, Jun 02, 2020 at 07:07:46AM -0700, Guenter Roeck wrote:
> On Tue, Jun 02, 2020 at 12:12:19PM +0300, Serge Semin wrote:
> > Clang-based kernel building with W=1 warns that some static const
> > variables are unused:
> >
> > drivers/hwmon/bt1-pvt.c:67:30: warning: unused variable 'poly_temp_to_N' [-Wunused-const-variable]
> > static const struct pvt_poly poly_temp_to_N = {
> > ^
> > drivers/hwmon/bt1-pvt.c:99:30: warning: unused variable 'poly_volt_to_N' [-Wunused-const-variable]
> > static const struct pvt_poly poly_volt_to_N = {
> > ^
> >
> > Indeed these polynomials are utilized only when the PVT sensor alarms are
> > enabled. In that case they are used to convert the temperature and
> > voltage alarm limits from normal quantities (Volts and degree Celsius) to
> > the sensor data representation N = [0, 1023]. Otherwise when alarms are
> > disabled the driver only does the detected data conversion to the human
> > readable form and doesn't need that polynomials defined. So let's declare
> > the Temp-to-N and Volt-to-N polynomials only if the PVT alarms are
> > switched on at compile-time.
> >
> > Note gcc with W=1 doesn't notice the problem.
> >
> > Fixes: 87976ce2825d ("hwmon: Add Baikal-T1 PVT sensor driver")
> > Reported-by: kbuild test robot <lkp@xxxxxxxxx>
> > Signed-off-by: Serge Semin <Sergey.Semin@xxxxxxxxxxxxxxxxxxxx>
> > Cc: Maxim Kaurkin <Maxim.Kaurkin@xxxxxxxxxxxxxxxxxxxx>
> > Cc: Alexey Malahov <Alexey.Malahov@xxxxxxxxxxxxxxxxxxxx>
>
> I don't really like the added #if. Can you use __maybe_unused instead ?
Ok. __maybe_unused is much better. Thanks for suggestion.
-Sergey
>
> Thanks,
> Guenter
>
> > ---
> > drivers/hwmon/bt1-pvt.c | 4 ++++
> > 1 file changed, 4 insertions(+)
> >
> > diff --git a/drivers/hwmon/bt1-pvt.c b/drivers/hwmon/bt1-pvt.c
> > index 1a9772fb1f73..1a5212c04549 100644
> > --- a/drivers/hwmon/bt1-pvt.c
> > +++ b/drivers/hwmon/bt1-pvt.c
> > @@ -64,6 +64,7 @@ static const struct pvt_sensor_info pvt_info[] = {
> > * 48380,
> > * where T = [-48380, 147438] mC and N = [0, 1023].
> > */
> > +#if defined(CONFIG_SENSORS_BT1_PVT_ALARMS)
> > static const struct pvt_poly poly_temp_to_N = {
> > .total_divider = 10000,
> > .terms = {
> > @@ -74,6 +75,7 @@ static const struct pvt_poly poly_temp_to_N = {
> > {0, 1720400, 1, 1}
> > }
> > };
> > +#endif /* CONFIG_SENSORS_BT1_PVT_ALARMS */
> >
> > static const struct pvt_poly poly_N_to_temp = {
> > .total_divider = 1,
> > @@ -96,6 +98,7 @@ static const struct pvt_poly poly_N_to_temp = {
> > * N = (18658e-3*V - 11572) / 10,
> > * V = N * 10^5 / 18658 + 11572 * 10^4 / 18658.
> > */
> > +#if defined(CONFIG_SENSORS_BT1_PVT_ALARMS)
> > static const struct pvt_poly poly_volt_to_N = {
> > .total_divider = 10,
> > .terms = {
> > @@ -103,6 +106,7 @@ static const struct pvt_poly poly_volt_to_N = {
> > {0, -11572, 1, 1}
> > }
> > };
> > +#endif /* CONFIG_SENSORS_BT1_PVT_ALARMS */
> >
> > static const struct pvt_poly poly_N_to_volt = {
> > .total_divider = 10,
