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 <daniel.lezcano@xxxxxxxxxx>
Thanks Daniel, this is much better fix.
Acked-by: Bartlomiej Zolnierkiewicz <b.zolnierkie@xxxxxxxxxxx>
> ---
> 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
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