| Message ID | 20190613211228.34092-1-nhuck@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Eduardo Valentin |
| Headers | show |
| Series | thermal: rcar_gen3_thermal: Fix Wshift-negative-value | expand |
Hi Nathan, On 13/06/2019 23:12, Nathan Huckleberry wrote: > Clang produces the following warning > > vers/thermal/rcar_gen3_thermal.c:147:33: warning: shifting a negative > signed value is undefined [-Wshift-negative-value] / (ptat[0] - ptat[2])) + > FIXPT_INT(TJ_3); ^~~~~~~~~~~~~~~ drivers/thermal/rcar_gen3_thermal.c:126:29 > note: expanded from macro 'FIXPT_INT' #define FIXPT_INT(_x) ((_x) << > FIXPT_SHIFT) ~~~~ ^ drivers/thermal/rcar_gen3_thermal.c:150:18: warning: > shifting a negative signed value is undefined [-Wshift-negative-value] > tsc->tj_t - FIXPT_INT(TJ_3)); ~~~~~~~~~~~~^~~~~~~~~~~~~~~~ > > Upon further investigating it looks like there is no real reason for > TJ_3 to be -41. Usages subtract -41, code would be cleaner to just add. All the code seems broken regarding the negative value shifting as the macros pass an integer: eg. tsc->coef.a2 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]), tsc->tj_t - FIXPT_INT(ths_tj_1)); thcode[1] is always < than thcode[0], thcode[1] - thcode[0] < 0 FIXPT_INT(thcode[1] - thcode[0]) is undefined Is it done on purpose FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]) ? Try developing the macro with the coef.a2 computation ... The code quality of this driver could be better, it deserves a rework IMHO ... I suggest to revert: 4eb39f79ef443fa566d36bd43f1f578d5c140305 bdc4480a669d476814061b4da6bb006f7048c8e5 6a310f8f97bb8bc2e2bb9db6f49a1b8678c8d144 Rework the coefficient computation and re-introduce what was reverted in a nicer way. > Fixes: 4eb39f79ef44 ("thermal: rcar_gen3_thermal: Update value of Tj_1") > Cc: clang-built-linux@googlegroups.com > Link: https://github.com/ClangBuiltLinux/linux/issues/531 > Signed-off-by: Nathan Huckleberry <nhuck@google.com> > --- > drivers/thermal/rcar_gen3_thermal.c | 8 ++++---- > 1 file changed, 4 insertions(+), 4 deletions(-) > > diff --git a/drivers/thermal/rcar_gen3_thermal.c b/drivers/thermal/rcar_gen3_thermal.c > index a56463308694..f4b4558c08e9 100644 > --- a/drivers/thermal/rcar_gen3_thermal.c > +++ b/drivers/thermal/rcar_gen3_thermal.c > @@ -131,7 +131,7 @@ static inline void rcar_gen3_thermal_write(struct rcar_gen3_thermal_tsc *tsc, > #define RCAR3_THERMAL_GRAN 500 /* mili Celsius */ > > /* no idea where these constants come from */ > -#define TJ_3 -41 > +#define TJ_3 41 > > static void rcar_gen3_thermal_calc_coefs(struct rcar_gen3_thermal_tsc *tsc, > int *ptat, const int *thcode, > @@ -144,11 +144,11 @@ static void rcar_gen3_thermal_calc_coefs(struct rcar_gen3_thermal_tsc *tsc, > * the dividend (4095 * 4095 << 14 > INT_MAX) so keep it unscaled > */ > tsc->tj_t = (FIXPT_INT((ptat[1] - ptat[2]) * 157) > - / (ptat[0] - ptat[2])) + FIXPT_INT(TJ_3); > + / (ptat[0] - ptat[2])) - FIXPT_INT(TJ_3); > > tsc->coef.a1 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[2]), > - tsc->tj_t - FIXPT_INT(TJ_3)); > - tsc->coef.b1 = FIXPT_INT(thcode[2]) - tsc->coef.a1 * TJ_3; > + tsc->tj_t + FIXPT_INT(TJ_3)); > + tsc->coef.b1 = FIXPT_INT(thcode[2]) + tsc->coef.a1 * TJ_3; > > tsc->coef.a2 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]), > tsc->tj_t - FIXPT_INT(ths_tj_1)); >
I'm not familiar enough with the code to rewrite these parts of the driver. Silencing the warnings while maintaining the same functionality was the goal of this patch. On Fri, Jun 14, 2019 at 3:52 AM Daniel Lezcano <daniel.lezcano@linaro.org> wrote: > > > Hi Nathan, > > On 13/06/2019 23:12, Nathan Huckleberry wrote: > > Clang produces the following warning > > > > vers/thermal/rcar_gen3_thermal.c:147:33: warning: shifting a negative > > signed value is undefined [-Wshift-negative-value] / (ptat[0] - ptat[2])) + > > FIXPT_INT(TJ_3); ^~~~~~~~~~~~~~~ drivers/thermal/rcar_gen3_thermal.c:126:29 > > note: expanded from macro 'FIXPT_INT' #define FIXPT_INT(_x) ((_x) << > > FIXPT_SHIFT) ~~~~ ^ drivers/thermal/rcar_gen3_thermal.c:150:18: warning: > > shifting a negative signed value is undefined [-Wshift-negative-value] > > tsc->tj_t - FIXPT_INT(TJ_3)); ~~~~~~~~~~~~^~~~~~~~~~~~~~~~ > > > > Upon further investigating it looks like there is no real reason for > > TJ_3 to be -41. Usages subtract -41, code would be cleaner to just add. > > All the code seems broken regarding the negative value shifting as the > macros pass an integer: > > eg. > tsc->coef.a2 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]), > tsc->tj_t - FIXPT_INT(ths_tj_1)); > > thcode[1] is always < than thcode[0], > > thcode[1] - thcode[0] < 0 > > FIXPT_INT(thcode[1] - thcode[0]) is undefined > > > Is it done on purpose FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]) ? > > Try developing the macro with the coef.a2 computation ... > > The code quality of this driver could be better, it deserves a rework > IMHO ... > > I suggest to revert: > > 4eb39f79ef443fa566d36bd43f1f578d5c140305 > bdc4480a669d476814061b4da6bb006f7048c8e5 > 6a310f8f97bb8bc2e2bb9db6f49a1b8678c8d144 > > Rework the coefficient computation and re-introduce what was reverted in > a nicer way. > > > > Fixes: 4eb39f79ef44 ("thermal: rcar_gen3_thermal: Update value of Tj_1") > > Cc: clang-built-linux@googlegroups.com > > Link: https://github.com/ClangBuiltLinux/linux/issues/531 > > Signed-off-by: Nathan Huckleberry <nhuck@google.com> > > --- > > drivers/thermal/rcar_gen3_thermal.c | 8 ++++---- > > 1 file changed, 4 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/thermal/rcar_gen3_thermal.c b/drivers/thermal/rcar_gen3_thermal.c > > index a56463308694..f4b4558c08e9 100644 > > --- a/drivers/thermal/rcar_gen3_thermal.c > > +++ b/drivers/thermal/rcar_gen3_thermal.c > > @@ -131,7 +131,7 @@ static inline void rcar_gen3_thermal_write(struct rcar_gen3_thermal_tsc *tsc, > > #define RCAR3_THERMAL_GRAN 500 /* mili Celsius */ > > > > /* no idea where these constants come from */ > > -#define TJ_3 -41 > > +#define TJ_3 41 > > > > static void rcar_gen3_thermal_calc_coefs(struct rcar_gen3_thermal_tsc *tsc, > > int *ptat, const int *thcode, > > @@ -144,11 +144,11 @@ static void rcar_gen3_thermal_calc_coefs(struct rcar_gen3_thermal_tsc *tsc, > > * the dividend (4095 * 4095 << 14 > INT_MAX) so keep it unscaled > > */ > > tsc->tj_t = (FIXPT_INT((ptat[1] - ptat[2]) * 157) > > - / (ptat[0] - ptat[2])) + FIXPT_INT(TJ_3); > > + / (ptat[0] - ptat[2])) - FIXPT_INT(TJ_3); > > > > tsc->coef.a1 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[2]), > > - tsc->tj_t - FIXPT_INT(TJ_3)); > > - tsc->coef.b1 = FIXPT_INT(thcode[2]) - tsc->coef.a1 * TJ_3; > > + tsc->tj_t + FIXPT_INT(TJ_3)); > > + tsc->coef.b1 = FIXPT_INT(thcode[2]) + tsc->coef.a1 * TJ_3; > > > > tsc->coef.a2 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]), > > tsc->tj_t - FIXPT_INT(ths_tj_1)); > > > > > -- > <http://www.linaro.org/> Linaro.org │ Open source software for ARM SoCs > > Follow Linaro: <http://www.facebook.com/pages/Linaro> Facebook | > <http://twitter.com/#!/linaroorg> Twitter | > <http://www.linaro.org/linaro-blog/> Blog >
On Fri, 2019-06-14 at 12:52 +0200, Daniel Lezcano wrote: > Hi Nathan, > > On 13/06/2019 23:12, Nathan Huckleberry wrote: > > Clang produces the following warning > > > > vers/thermal/rcar_gen3_thermal.c:147:33: warning: shifting a > > negative > > signed value is undefined [-Wshift-negative-value] / (ptat[0] - > > ptat[2])) + > > FIXPT_INT(TJ_3); ^~~~~~~~~~~~~~~ > > drivers/thermal/rcar_gen3_thermal.c:126:29 > > note: expanded from macro 'FIXPT_INT' #define FIXPT_INT(_x) ((_x) > > << > > FIXPT_SHIFT) ~~~~ ^ drivers/thermal/rcar_gen3_thermal.c:150:18: > > warning: > > shifting a negative signed value is undefined [-Wshift-negative- > > value] > > tsc->tj_t - FIXPT_INT(TJ_3)); ~~~~~~~~~~~~^~~~~~~~~~~~~~~~ > > > > Upon further investigating it looks like there is no real reason > > for > > TJ_3 to be -41. Usages subtract -41, code would be cleaner to just > > add. > > All the code seems broken regarding the negative value shifting as > the > macros pass an integer: > > eg. > tsc->coef.a2 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]), > tsc->tj_t - FIXPT_INT(ths_tj_1)); > > thcode[1] is always < than thcode[0], > > thcode[1] - thcode[0] < 0 > > FIXPT_INT(thcode[1] - thcode[0]) is undefined > > > Is it done on purpose FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]) ? > > Try developing the macro with the coef.a2 computation ... > > The code quality of this driver could be better, it deserves a rework > IMHO ... > > I suggest to revert: > > 4eb39f79ef443fa566d36bd43f1f578d5c140305 > bdc4480a669d476814061b4da6bb006f7048c8e5 > 6a310f8f97bb8bc2e2bb9db6f49a1b8678c8d144 > > Rework the coefficient computation and re-introduce what was reverted > in > a nicer way. Sounds reasonable to me. Yoshihiro, can you please clarify on this? Or else I will revert the above commits first? Also CC Wolfram Sang, the driver author. thanks, rui > > > > Fixes: 4eb39f79ef44 ("thermal: rcar_gen3_thermal: Update value of > > Tj_1") > > Cc: clang-built-linux@googlegroups.com > > Link: https://github.com/ClangBuiltLinux/linux/issues/531 > > Signed-off-by: Nathan Huckleberry <nhuck@google.com> > > --- > > drivers/thermal/rcar_gen3_thermal.c | 8 ++++---- > > 1 file changed, 4 insertions(+), 4 deletions(-) > > > > diff --git a/drivers/thermal/rcar_gen3_thermal.c > > b/drivers/thermal/rcar_gen3_thermal.c > > index a56463308694..f4b4558c08e9 100644 > > --- a/drivers/thermal/rcar_gen3_thermal.c > > +++ b/drivers/thermal/rcar_gen3_thermal.c > > @@ -131,7 +131,7 @@ static inline void > > rcar_gen3_thermal_write(struct rcar_gen3_thermal_tsc *tsc, > > #define RCAR3_THERMAL_GRAN 500 /* mili Celsius */ > > > > /* no idea where these constants come from */ > > -#define TJ_3 -41 > > +#define TJ_3 41 > > > > static void rcar_gen3_thermal_calc_coefs(struct > > rcar_gen3_thermal_tsc *tsc, > > int *ptat, const int *thcode, > > @@ -144,11 +144,11 @@ static void > > rcar_gen3_thermal_calc_coefs(struct rcar_gen3_thermal_tsc *tsc, > > * the dividend (4095 * 4095 << 14 > INT_MAX) so keep it > > unscaled > > */ > > tsc->tj_t = (FIXPT_INT((ptat[1] - ptat[2]) * 157) > > - / (ptat[0] - ptat[2])) + FIXPT_INT(TJ_3); > > + / (ptat[0] - ptat[2])) - FIXPT_INT(TJ_3); > > > > tsc->coef.a1 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[2]), > > - tsc->tj_t - FIXPT_INT(TJ_3)); > > - tsc->coef.b1 = FIXPT_INT(thcode[2]) - tsc->coef.a1 * TJ_3; > > + tsc->tj_t + FIXPT_INT(TJ_3)); > > + tsc->coef.b1 = FIXPT_INT(thcode[2]) + tsc->coef.a1 * TJ_3; > > > > tsc->coef.a2 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]), > > tsc->tj_t - FIXPT_INT(ths_tj_1)); > > > >
On Wed, Aug 28, 2019 at 04:52:20PM +0800, Zhang Rui wrote: > On Fri, 2019-06-14 at 12:52 +0200, Daniel Lezcano wrote: > > Hi Nathan, > > > > On 13/06/2019 23:12, Nathan Huckleberry wrote: > > > Clang produces the following warning > > > > > > vers/thermal/rcar_gen3_thermal.c:147:33: warning: shifting a > > > negative > > > signed value is undefined [-Wshift-negative-value] / (ptat[0] - > > > ptat[2])) + > > > FIXPT_INT(TJ_3); ^~~~~~~~~~~~~~~ > > > drivers/thermal/rcar_gen3_thermal.c:126:29 > > > note: expanded from macro 'FIXPT_INT' #define FIXPT_INT(_x) ((_x) > > > << > > > FIXPT_SHIFT) ~~~~ ^ drivers/thermal/rcar_gen3_thermal.c:150:18: > > > warning: > > > shifting a negative signed value is undefined [-Wshift-negative- > > > value] > > > tsc->tj_t - FIXPT_INT(TJ_3)); ~~~~~~~~~~~~^~~~~~~~~~~~~~~~ > > > > > > Upon further investigating it looks like there is no real reason > > > for > > > TJ_3 to be -41. Usages subtract -41, code would be cleaner to just > > > add. > > > > All the code seems broken regarding the negative value shifting as > > the > > macros pass an integer: > > > > eg. > > tsc->coef.a2 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]), > > tsc->tj_t - FIXPT_INT(ths_tj_1)); > > > > thcode[1] is always < than thcode[0], > > > > thcode[1] - thcode[0] < 0 > > > > FIXPT_INT(thcode[1] - thcode[0]) is undefined > > > > > > Is it done on purpose FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]) ? > > > > Try developing the macro with the coef.a2 computation ... > > > > The code quality of this driver could be better, it deserves a rework > > IMHO ... > > > > I suggest to revert: > > > > 4eb39f79ef443fa566d36bd43f1f578d5c140305 > > bdc4480a669d476814061b4da6bb006f7048c8e5 > > 6a310f8f97bb8bc2e2bb9db6f49a1b8678c8d144 > > > > Rework the coefficient computation and re-introduce what was reverted > > in > > a nicer way. > > Sounds reasonable to me. > > Yoshihiro, > can you please clarify on this? Or else I will revert the above commits > first? > > Also CC Wolfram Sang, the driver author. CCing Simon Horman who worked with Kaneko-san on these changes. > thanks, > rui > > > > > > > Fixes: 4eb39f79ef44 ("thermal: rcar_gen3_thermal: Update value of > > > Tj_1") > > > Cc: clang-built-linux@googlegroups.com > > > Link: https://github.com/ClangBuiltLinux/linux/issues/531 > > > Signed-off-by: Nathan Huckleberry <nhuck@google.com> > > > --- > > > drivers/thermal/rcar_gen3_thermal.c | 8 ++++---- > > > 1 file changed, 4 insertions(+), 4 deletions(-) > > > > > > diff --git a/drivers/thermal/rcar_gen3_thermal.c > > > b/drivers/thermal/rcar_gen3_thermal.c > > > index a56463308694..f4b4558c08e9 100644 > > > --- a/drivers/thermal/rcar_gen3_thermal.c > > > +++ b/drivers/thermal/rcar_gen3_thermal.c > > > @@ -131,7 +131,7 @@ static inline void > > > rcar_gen3_thermal_write(struct rcar_gen3_thermal_tsc *tsc, > > > #define RCAR3_THERMAL_GRAN 500 /* mili Celsius */ > > > > > > /* no idea where these constants come from */ > > > -#define TJ_3 -41 > > > +#define TJ_3 41 > > > > > > static void rcar_gen3_thermal_calc_coefs(struct > > > rcar_gen3_thermal_tsc *tsc, > > > int *ptat, const int *thcode, > > > @@ -144,11 +144,11 @@ static void > > > rcar_gen3_thermal_calc_coefs(struct rcar_gen3_thermal_tsc *tsc, > > > * the dividend (4095 * 4095 << 14 > INT_MAX) so keep it > > > unscaled > > > */ > > > tsc->tj_t = (FIXPT_INT((ptat[1] - ptat[2]) * 157) > > > - / (ptat[0] - ptat[2])) + FIXPT_INT(TJ_3); > > > + / (ptat[0] - ptat[2])) - FIXPT_INT(TJ_3); > > > > > > tsc->coef.a1 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[2]), > > > - tsc->tj_t - FIXPT_INT(TJ_3)); > > > - tsc->coef.b1 = FIXPT_INT(thcode[2]) - tsc->coef.a1 * TJ_3; > > > + tsc->tj_t + FIXPT_INT(TJ_3)); > > > + tsc->coef.b1 = FIXPT_INT(thcode[2]) + tsc->coef.a1 * TJ_3; > > > > > > tsc->coef.a2 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]), > > > tsc->tj_t - FIXPT_INT(ths_tj_1)); > > > > > > > >
On Thu, Aug 29, 2019 at 03:11:24PM +0200, Wolfram Sang wrote: > On Wed, Aug 28, 2019 at 04:52:20PM +0800, Zhang Rui wrote: > > On Fri, 2019-06-14 at 12:52 +0200, Daniel Lezcano wrote: > > > Hi Nathan, > > > > > > On 13/06/2019 23:12, Nathan Huckleberry wrote: > > > > Clang produces the following warning > > > > > > > > vers/thermal/rcar_gen3_thermal.c:147:33: warning: shifting a > > > > negative > > > > signed value is undefined [-Wshift-negative-value] / (ptat[0] - > > > > ptat[2])) + > > > > FIXPT_INT(TJ_3); ^~~~~~~~~~~~~~~ > > > > drivers/thermal/rcar_gen3_thermal.c:126:29 > > > > note: expanded from macro 'FIXPT_INT' #define FIXPT_INT(_x) ((_x) > > > > << > > > > FIXPT_SHIFT) ~~~~ ^ drivers/thermal/rcar_gen3_thermal.c:150:18: > > > > warning: > > > > shifting a negative signed value is undefined [-Wshift-negative- > > > > value] > > > > tsc->tj_t - FIXPT_INT(TJ_3)); ~~~~~~~~~~~~^~~~~~~~~~~~~~~~ > > > > > > > > Upon further investigating it looks like there is no real reason > > > > for > > > > TJ_3 to be -41. Usages subtract -41, code would be cleaner to just > > > > add. > > > > > > All the code seems broken regarding the negative value shifting as > > > the > > > macros pass an integer: > > > > > > eg. > > > tsc->coef.a2 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]), > > > tsc->tj_t - FIXPT_INT(ths_tj_1)); > > > > > > thcode[1] is always < than thcode[0], > > > > > > thcode[1] - thcode[0] < 0 > > > > > > FIXPT_INT(thcode[1] - thcode[0]) is undefined > > > > > > > > > Is it done on purpose FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]) ? > > > > > > Try developing the macro with the coef.a2 computation ... > > > > > > The code quality of this driver could be better, it deserves a rework > > > IMHO ... > > > > > > I suggest to revert: > > > > > > 4eb39f79ef443fa566d36bd43f1f578d5c140305 > > > bdc4480a669d476814061b4da6bb006f7048c8e5 > > > 6a310f8f97bb8bc2e2bb9db6f49a1b8678c8d144 > > > > > > Rework the coefficient computation and re-introduce what was reverted > > > in > > > a nicer way. > > > > Sounds reasonable to me. > > > > Yoshihiro, > > can you please clarify on this? Or else I will revert the above commits > > first? > > > > Also CC Wolfram Sang, the driver author. > > CCing Simon Horman who worked with Kaneko-san on these changes. Hi, I think that what has happened here is that these patches and moreover the driver has been through quite a few hands and I agree that zooming out and cleaning things up would make a lot of sense. Personally I would take the approach of incrementally cleaning things up. But I don't feel strongly about this. As for the specific question about a negative constant, I don't know of a specific reason that approach was taken and I don't recall investigating it at the time. Kind regards, Simon > > > thanks, > > rui > > > > > > > > > > Fixes: 4eb39f79ef44 ("thermal: rcar_gen3_thermal: Update value of > > > > Tj_1") > > > > Cc: clang-built-linux@googlegroups.com > > > > Link: https://github.com/ClangBuiltLinux/linux/issues/531 > > > > Signed-off-by: Nathan Huckleberry <nhuck@google.com> > > > > --- > > > > drivers/thermal/rcar_gen3_thermal.c | 8 ++++---- > > > > 1 file changed, 4 insertions(+), 4 deletions(-) > > > > > > > > diff --git a/drivers/thermal/rcar_gen3_thermal.c > > > > b/drivers/thermal/rcar_gen3_thermal.c > > > > index a56463308694..f4b4558c08e9 100644 > > > > --- a/drivers/thermal/rcar_gen3_thermal.c > > > > +++ b/drivers/thermal/rcar_gen3_thermal.c > > > > @@ -131,7 +131,7 @@ static inline void > > > > rcar_gen3_thermal_write(struct rcar_gen3_thermal_tsc *tsc, > > > > #define RCAR3_THERMAL_GRAN 500 /* mili Celsius */ > > > > > > > > /* no idea where these constants come from */ Regarding the line above, I believe the constant comes from the documentation. > > > > -#define TJ_3 -41 > > > > +#define TJ_3 41 > > > > > > > > static void rcar_gen3_thermal_calc_coefs(struct > > > > rcar_gen3_thermal_tsc *tsc, > > > > int *ptat, const int *thcode, > > > > @@ -144,11 +144,11 @@ static void > > > > rcar_gen3_thermal_calc_coefs(struct rcar_gen3_thermal_tsc *tsc, > > > > * the dividend (4095 * 4095 << 14 > INT_MAX) so keep it > > > > unscaled > > > > */ > > > > tsc->tj_t = (FIXPT_INT((ptat[1] - ptat[2]) * 157) > > > > - / (ptat[0] - ptat[2])) + FIXPT_INT(TJ_3); > > > > + / (ptat[0] - ptat[2])) - FIXPT_INT(TJ_3); > > > > > > > > tsc->coef.a1 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[2]), > > > > - tsc->tj_t - FIXPT_INT(TJ_3)); > > > > - tsc->coef.b1 = FIXPT_INT(thcode[2]) - tsc->coef.a1 * TJ_3; > > > > + tsc->tj_t + FIXPT_INT(TJ_3)); > > > > + tsc->coef.b1 = FIXPT_INT(thcode[2]) + tsc->coef.a1 * TJ_3; > > > > > > > > tsc->coef.a2 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]), > > > > tsc->tj_t - FIXPT_INT(ths_tj_1)); > > > > > > > > > > > >
diff --git a/drivers/thermal/rcar_gen3_thermal.c b/drivers/thermal/rcar_gen3_thermal.c index a56463308694..f4b4558c08e9 100644 --- a/drivers/thermal/rcar_gen3_thermal.c +++ b/drivers/thermal/rcar_gen3_thermal.c @@ -131,7 +131,7 @@ static inline void rcar_gen3_thermal_write(struct rcar_gen3_thermal_tsc *tsc, #define RCAR3_THERMAL_GRAN 500 /* mili Celsius */ /* no idea where these constants come from */ -#define TJ_3 -41 +#define TJ_3 41 static void rcar_gen3_thermal_calc_coefs(struct rcar_gen3_thermal_tsc *tsc, int *ptat, const int *thcode, @@ -144,11 +144,11 @@ static void rcar_gen3_thermal_calc_coefs(struct rcar_gen3_thermal_tsc *tsc, * the dividend (4095 * 4095 << 14 > INT_MAX) so keep it unscaled */ tsc->tj_t = (FIXPT_INT((ptat[1] - ptat[2]) * 157) - / (ptat[0] - ptat[2])) + FIXPT_INT(TJ_3); + / (ptat[0] - ptat[2])) - FIXPT_INT(TJ_3); tsc->coef.a1 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[2]), - tsc->tj_t - FIXPT_INT(TJ_3)); - tsc->coef.b1 = FIXPT_INT(thcode[2]) - tsc->coef.a1 * TJ_3; + tsc->tj_t + FIXPT_INT(TJ_3)); + tsc->coef.b1 = FIXPT_INT(thcode[2]) + tsc->coef.a1 * TJ_3; tsc->coef.a2 = FIXPT_DIV(FIXPT_INT(thcode[1] - thcode[0]), tsc->tj_t - FIXPT_INT(ths_tj_1));
Clang produces the following warning vers/thermal/rcar_gen3_thermal.c:147:33: warning: shifting a negative signed value is undefined [-Wshift-negative-value] / (ptat[0] - ptat[2])) + FIXPT_INT(TJ_3); ^~~~~~~~~~~~~~~ drivers/thermal/rcar_gen3_thermal.c:126:29 note: expanded from macro 'FIXPT_INT' #define FIXPT_INT(_x) ((_x) << FIXPT_SHIFT) ~~~~ ^ drivers/thermal/rcar_gen3_thermal.c:150:18: warning: shifting a negative signed value is undefined [-Wshift-negative-value] tsc->tj_t - FIXPT_INT(TJ_3)); ~~~~~~~~~~~~^~~~~~~~~~~~~~~~ Upon further investigating it looks like there is no real reason for TJ_3 to be -41. Usages subtract -41, code would be cleaner to just add. Fixes: 4eb39f79ef44 ("thermal: rcar_gen3_thermal: Update value of Tj_1") Cc: clang-built-linux@googlegroups.com Link: https://github.com/ClangBuiltLinux/linux/issues/531 Signed-off-by: Nathan Huckleberry <nhuck@google.com> --- drivers/thermal/rcar_gen3_thermal.c | 8 ++++---- 1 file changed, 4 insertions(+), 4 deletions(-)