On Friday, April 13, 2018 01:00:09 PM Daniel Lezcano wrote: > The latest driver cleanup introduced a compilation warning > > drivers/thermal/samsung/exynos_tmu.c: In function ‘exynos_get_temp’: > drivers/thermal/samsung/exynos_tmu.c:931:37: warning: ‘temp’ may be used > uninitialized in this function [-Wmaybe-uninitialized] > *temp = code_to_temp(data, value) * MCELSIUS; > ^ > > drivers/thermal/samsung/exynos_tmu.c: In function ‘temp_to_code’ > drivers/thermal/samsung/exynos_tmu.c:304:9: warning: ‘temp_code’ may be used > uninitialized in this function [-Wmaybe-uninitialized] > return temp_code; > ^~~~~~~~~ > > The compiler gives a warning because semantically speaking the > function has no default value. However the code path, were the > variable is never initialized is a dead branch because the switch > statement always choose one of the two cases as the data->cal_type is > initialized in the init function to one of both values. > > This is unclear as it adds a dependency on the initialization function > and it is prone to error. Make things clearer by converting the > functions with if ... return statements, thus showing we are expecting > the values to be correctly filled before calling this function. > > This change fixes the couple of function warnings. > > Signed-off-by: Daniel Lezcano <[email protected]>
Thanks Daniel, this is much better fix. Acked-by: Bartlomiej Zolnierkiewicz <[email protected]> > --- > drivers/thermal/samsung/exynos_tmu.c | 46 > ++++++++++-------------------------- > 1 file changed, 12 insertions(+), 34 deletions(-) > > diff --git a/drivers/thermal/samsung/exynos_tmu.c > b/drivers/thermal/samsung/exynos_tmu.c > index 2ec8548..197f267 100644 > --- a/drivers/thermal/samsung/exynos_tmu.c > +++ b/drivers/thermal/samsung/exynos_tmu.c > @@ -284,24 +284,13 @@ static void exynos_report_trigger(struct > exynos_tmu_data *p) > */ > static int temp_to_code(struct exynos_tmu_data *data, u8 temp) > { > - int temp_code; > - > - switch (data->cal_type) { > - case TYPE_TWO_POINT_TRIMMING: > - temp_code = (temp - EXYNOS_FIRST_POINT_TRIM) * > - (data->temp_error2 - data->temp_error1) / > - (EXYNOS_SECOND_POINT_TRIM - EXYNOS_FIRST_POINT_TRIM) + > - data->temp_error1; > - break; > - case TYPE_ONE_POINT_TRIMMING: > - temp_code = temp + data->temp_error1 - EXYNOS_FIRST_POINT_TRIM; > - break; > - default: > - WARN_ON(1); > - break; > - } > + if (data->cal_type == TYPE_ONE_POINT_TRIMMING) > + return temp + data->temp_error1 - EXYNOS_FIRST_POINT_TRIM; > > - return temp_code; > + return (temp - EXYNOS_FIRST_POINT_TRIM) * > + (data->temp_error2 - data->temp_error1) / > + (EXYNOS_SECOND_POINT_TRIM - EXYNOS_FIRST_POINT_TRIM) + > + data->temp_error1; > } > > /* > @@ -310,24 +299,13 @@ static int temp_to_code(struct exynos_tmu_data *data, > u8 temp) > */ > static int code_to_temp(struct exynos_tmu_data *data, u16 temp_code) > { > - int temp; > - > - switch (data->cal_type) { > - case TYPE_TWO_POINT_TRIMMING: > - temp = (temp_code - data->temp_error1) * > - (EXYNOS_SECOND_POINT_TRIM - EXYNOS_FIRST_POINT_TRIM) / > - (data->temp_error2 - data->temp_error1) + > - EXYNOS_FIRST_POINT_TRIM; > - break; > - case TYPE_ONE_POINT_TRIMMING: > - temp = temp_code - data->temp_error1 + EXYNOS_FIRST_POINT_TRIM; > - break; > - default: > - WARN_ON(1); > - break; > - } > + if (data->cal_type == TYPE_ONE_POINT_TRIMMING) > + return temp_code - data->temp_error1 + EXYNOS_FIRST_POINT_TRIM; > > - return temp; > + return (temp_code - data->temp_error1) * > + (EXYNOS_SECOND_POINT_TRIM - EXYNOS_FIRST_POINT_TRIM) / > + (data->temp_error2 - data->temp_error1) + > + EXYNOS_FIRST_POINT_TRIM; > } > > static void sanitize_temp_error(struct exynos_tmu_data *data, u32 trim_info) Best regards, -- Bartlomiej Zolnierkiewicz Samsung R&D Institute Poland Samsung Electronics
