| Message ID | 20210214021718.2235342-1-giulio.benetti@benettiengineering.com |
|---|---|
| State | Accepted |
| Commit | 9e578f6340ba3f4324cd823872afe6eda39857d2 |
| Delegated to: | Lukasz Majewski |
| Headers | show |
| Series | [v2] clk: fix clk_get_rate() documentation | expand |
This looks good to me, and helps beginners like me. As for the function itself, i have 2 concerns: If it does return a negative value why is it unsigned, if it is in fact signed that a clock above 2.2Ghz is a negative number. As for the IS_ERR_VALUE macro there still is a chance that it will error if the clock just so happens to be 2^31 through 2^31 + number of err values. Just voicing my concerns i assume as i learn more about uboot, linux,rtos's and different programs there will be minor issues like this. On Sat, Feb 13, 2021 at 9:17 PM Giulio Benetti < giulio.benetti@benettiengineering.com> wrote: > Improve clk_get_rate() @return documentation that otherwise is a bit > ambiguous. At the moment I expect to return 0 as error since the return > type is 'ulong', instead the function really returns negative value in > case the corresponding function pointer is null and returns 0 if the clock > is invalid. > > Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com> > --- > V1->V2: > * previous comment was wrong, this function returns negative value, so > let's > improve it's @return documentation as suggested by Simon Glass > --- > include/clk.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/include/clk.h b/include/clk.h > index ca6b85fa6f..5a8c7244d0 100644 > --- a/include/clk.h > +++ b/include/clk.h > @@ -344,7 +344,8 @@ int clk_free(struct clk *clk); > * > * @clk: A clock struct that was previously successfully requested > by > * clk_request/get_by_*(). > - * @return clock rate in Hz, or -ve error code. > + * @return clock rate in Hz on success, 0 for invalid clock, or -ve error > code > + * for other errors. > */ > ulong clk_get_rate(struct clk *clk); > > -- > 2.25.1 > >
Hi Jesse, > Il giorno 14 feb 2021, alle ore 03:58, Jesse T <mr.bossman075@gmail.com> ha scritto: > > > This looks good to me, and helps beginners like me. As for the function itself, i have 2 concerns: If it does return a negative value why is it unsigned, if it is in fact signed that a clock above 2.2Ghz is a negative number. I was worried too at first sight but if you try to check negative numbers you see that -1 is 0xFFFFFFFF so in the worst case you only loose 4095 numbers from the maximum, try to check with hex calculator. And that is the trick. > As for the IS_ERR_VALUE macro there still is a chance that it will error if the clock just so happens to be 2^31 through 2^31 + number of err values. This is answered from above and IS_ERR_VALUE is a very contracted macro that basically let you to keep value NOT valid if (0 > value > 4095). > Just voicing my concerns i assume as i learn more about uboot, linux,rtos's and different programs there will be minor issues like this. Sure, no problem :-) Giulio > >> On Sat, Feb 13, 2021 at 9:17 PM Giulio Benetti <giulio.benetti@benettiengineering.com> wrote: >> Improve clk_get_rate() @return documentation that otherwise is a bit >> ambiguous. At the moment I expect to return 0 as error since the return >> type is 'ulong', instead the function really returns negative value in >> case the corresponding function pointer is null and returns 0 if the clock >> is invalid. >> >> Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com> >> --- >> V1->V2: >> * previous comment was wrong, this function returns negative value, so let's >> improve it's @return documentation as suggested by Simon Glass >> --- >> include/clk.h | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/include/clk.h b/include/clk.h >> index ca6b85fa6f..5a8c7244d0 100644 >> --- a/include/clk.h >> +++ b/include/clk.h >> @@ -344,7 +344,8 @@ int clk_free(struct clk *clk); >> * >> * @clk: A clock struct that was previously successfully requested by >> * clk_request/get_by_*(). >> - * @return clock rate in Hz, or -ve error code. >> + * @return clock rate in Hz on success, 0 for invalid clock, or -ve error code >> + * for other errors. >> */ >> ulong clk_get_rate(struct clk *clk); >> >> -- >> 2.25.1 >>
Awesome, thanks! I must have forgotten how twos complement works for a sec... On Sat, Feb 13, 2021 at 10:17 PM Giulio Benetti < giulio.benetti@benettiengineering.com> wrote: > Hi Jesse, > > Il giorno 14 feb 2021, alle ore 03:58, Jesse T <mr.bossman075@gmail.com> > ha scritto: > > > This looks good to me, and helps beginners like me. As for the function > itself, i have 2 concerns: If it does return a negative value why is it > unsigned, if it is in fact signed that a clock above 2.2Ghz is a negative > number. > > > I was worried too at first sight but if you try to check negative numbers > you see that -1 is 0xFFFFFFFF so in the worst case you only loose 4095 > numbers from the maximum, try to check with hex calculator. And that is the > trick. > > As for the IS_ERR_VALUE macro there still is a chance that it will error > if the clock just so happens to be 2^31 through 2^31 + number of err > values. > > > This is answered from above and IS_ERR_VALUE is a very contracted macro > that basically let you to keep value NOT valid if (0 > value > 4095). > > Just voicing my concerns i assume as i learn more about uboot, > linux,rtos's and different programs there will be minor issues like this. > > > Sure, no problem :-) > > Giulio > > > On Sat, Feb 13, 2021 at 9:17 PM Giulio Benetti < > giulio.benetti@benettiengineering.com> wrote: > >> Improve clk_get_rate() @return documentation that otherwise is a bit >> ambiguous. At the moment I expect to return 0 as error since the return >> type is 'ulong', instead the function really returns negative value in >> case the corresponding function pointer is null and returns 0 if the clock >> is invalid. >> >> Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com> >> --- >> V1->V2: >> * previous comment was wrong, this function returns negative value, so >> let's >> improve it's @return documentation as suggested by Simon Glass >> --- >> include/clk.h | 3 ++- >> 1 file changed, 2 insertions(+), 1 deletion(-) >> >> diff --git a/include/clk.h b/include/clk.h >> index ca6b85fa6f..5a8c7244d0 100644 >> --- a/include/clk.h >> +++ b/include/clk.h >> @@ -344,7 +344,8 @@ int clk_free(struct clk *clk); >> * >> * @clk: A clock struct that was previously successfully requested >> by >> * clk_request/get_by_*(). >> - * @return clock rate in Hz, or -ve error code. >> + * @return clock rate in Hz on success, 0 for invalid clock, or -ve >> error code >> + * for other errors. >> */ >> ulong clk_get_rate(struct clk *clk); >> >> -- >> 2.25.1 >> >>
On 2/14/21 4:49 AM, Jesse T wrote: > Awesome, thanks! I must have forgotten how twos complement works for a > sec... > > On Sat, Feb 13, 2021 at 10:17 PM Giulio Benetti < > giulio.benetti@benettiengineering.com> wrote: > >> Hi Jesse, >> >> Il giorno 14 feb 2021, alle ore 03:58, Jesse T <mr.bossman075@gmail.com> >> ha scritto: >> >> >> This looks good to me, and helps beginners like me. As for the function >> itself, i have 2 concerns: If it does return a negative value why is it >> unsigned, if it is in fact signed that a clock above 2.2Ghz is a negative >> number. >> >> >> I was worried too at first sight but if you try to check negative numbers >> you see that -1 is 0xFFFFFFFF so in the worst case you only loose 4095 >> numbers from the maximum, try to check with hex calculator. And that is the >> trick. >> >> As for the IS_ERR_VALUE macro there still is a chance that it will error >> if the clock just so happens to be 2^31 through 2^31 + number of err >> values. >> >> >> This is answered from above and IS_ERR_VALUE is a very contracted macro >> that basically let you to keep value NOT valid if (0 > value > 4095). >> >> Just voicing my concerns i assume as i learn more about uboot, >> linux,rtos's and different programs there will be minor issues like this. >> >> >> Sure, no problem :-) >> >> Giulio >> >> >> On Sat, Feb 13, 2021 at 9:17 PM Giulio Benetti < >> giulio.benetti@benettiengineering.com> wrote: >> >>> Improve clk_get_rate() @return documentation that otherwise is a bit >>> ambiguous. At the moment I expect to return 0 as error since the return >>> type is 'ulong', instead the function really returns negative value in >>> case the corresponding function pointer is null and returns 0 if the clock >>> is invalid. >>> >>> Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com> >>> --- >>> V1->V2: >>> * previous comment was wrong, this function returns negative value, so >>> let's >>> improve it's @return documentation as suggested by Simon Glass >>> --- >>> include/clk.h | 3 ++- >>> 1 file changed, 2 insertions(+), 1 deletion(-) >>> >>> diff --git a/include/clk.h b/include/clk.h >>> index ca6b85fa6f..5a8c7244d0 100644 >>> --- a/include/clk.h >>> +++ b/include/clk.h >>> @@ -344,7 +344,8 @@ int clk_free(struct clk *clk); >>> * >>> * @clk: A clock struct that was previously successfully requested >>> by >>> * clk_request/get_by_*(). >>> - * @return clock rate in Hz, or -ve error code. >>> + * @return clock rate in Hz on success, 0 for invalid clock, or -ve >>> error code >>> + * for other errors. >>> */ >>> ulong clk_get_rate(struct clk *clk); >>> >>> -- >>> 2.25.1 >>> >>> Cc: Lukasz Majewski <lukma@denx.de> Lukasz is maintainer for CLOCK.
On 2/22/21 8:13 PM, Heinrich Schuchardt wrote: > On 2/14/21 4:49 AM, Jesse T wrote: >> Awesome, thanks! I must have forgotten how twos complement works for a >> sec... >> >> On Sat, Feb 13, 2021 at 10:17 PM Giulio Benetti < >> giulio.benetti@benettiengineering.com> wrote: >> >>> Hi Jesse, >>> >>> Il giorno 14 feb 2021, alle ore 03:58, Jesse T <mr.bossman075@gmail.com> >>> ha scritto: >>> >>> >>> This looks good to me, and helps beginners like me. As for the function >>> itself, i have 2 concerns: If it does return a negative value why is it >>> unsigned, if it is in fact signed that a clock above 2.2Ghz is a negative >>> number. >>> >>> >>> I was worried too at first sight but if you try to check negative numbers >>> you see that -1 is 0xFFFFFFFF so in the worst case you only loose 4095 >>> numbers from the maximum, try to check with hex calculator. And that is the >>> trick. >>> >>> As for the IS_ERR_VALUE macro there still is a chance that it will error >>> if the clock just so happens to be 2^31 through 2^31 + number of err >>> values. >>> >>> >>> This is answered from above and IS_ERR_VALUE is a very contracted macro >>> that basically let you to keep value NOT valid if (0 > value > 4095). >>> >>> Just voicing my concerns i assume as i learn more about uboot, >>> linux,rtos's and different programs there will be minor issues like this. >>> >>> >>> Sure, no problem :-) >>> >>> Giulio >>> >>> >>> On Sat, Feb 13, 2021 at 9:17 PM Giulio Benetti < >>> giulio.benetti@benettiengineering.com> wrote: >>> >>>> Improve clk_get_rate() @return documentation that otherwise is a bit >>>> ambiguous. At the moment I expect to return 0 as error since the return >>>> type is 'ulong', instead the function really returns negative value in >>>> case the corresponding function pointer is null and returns 0 if the clock >>>> is invalid. >>>> >>>> Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com> >>>> --- >>>> V1->V2: >>>> * previous comment was wrong, this function returns negative value, so >>>> let's >>>> improve it's @return documentation as suggested by Simon Glass >>>> --- >>>> include/clk.h | 3 ++- >>>> 1 file changed, 2 insertions(+), 1 deletion(-) >>>> >>>> diff --git a/include/clk.h b/include/clk.h >>>> index ca6b85fa6f..5a8c7244d0 100644 >>>> --- a/include/clk.h >>>> +++ b/include/clk.h >>>> @@ -344,7 +344,8 @@ int clk_free(struct clk *clk); >>>> * >>>> * @clk: A clock struct that was previously successfully requested >>>> by >>>> * clk_request/get_by_*(). >>>> - * @return clock rate in Hz, or -ve error code. >>>> + * @return clock rate in Hz on success, 0 for invalid clock, or -ve >>>> error code >>>> + * for other errors. >>>> */ >>>> ulong clk_get_rate(struct clk *clk); >>>> >>>> -- >>>> 2.25.1 >>>> >>>> > > Cc: Lukasz Majewski <lukma@denx.de> > Lukasz is maintainer for CLOCK. Ah thank you that's right. I've missed it because ./scripts/get_maintainer.pl didn't list him.
Hi Lukasz, kindly ping Best regards
On 2/13/21 9:17 PM, Giulio Benetti wrote: > Improve clk_get_rate() @return documentation that otherwise is a bit > ambiguous. At the moment I expect to return 0 as error since the return > type is 'ulong', instead the function really returns negative value in > case the corresponding function pointer is null and returns 0 if the clock > is invalid. > > Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com> > --- > V1->V2: > * previous comment was wrong, this function returns negative value, so let's > improve it's @return documentation as suggested by Simon Glass > --- > include/clk.h | 3 ++- > 1 file changed, 2 insertions(+), 1 deletion(-) > > diff --git a/include/clk.h b/include/clk.h > index ca6b85fa6f..5a8c7244d0 100644 > --- a/include/clk.h > +++ b/include/clk.h > @@ -344,7 +344,8 @@ int clk_free(struct clk *clk); > * > * @clk: A clock struct that was previously successfully requested by > * clk_request/get_by_*(). > - * @return clock rate in Hz, or -ve error code. > + * @return clock rate in Hz on success, 0 for invalid clock, or -ve error code > + * for other errors. > */ > ulong clk_get_rate(struct clk *clk); > > Reviewed-by: Sean Anderson <seanga2@gmail.com>
On Sun, 14 Feb 2021 03:17:18 +0100, Giulio Benetti wrote: > Improve clk_get_rate() @return documentation that otherwise is a bit > ambiguous. At the moment I expect to return 0 as error since the return > type is 'ulong', instead the function really returns negative value in > case the corresponding function pointer is null and returns 0 if the clock > is invalid. > > > [...] Applied, thanks! [1/1] clk: fix clk_get_rate() documentation commit: 9e578f6340ba3f4324cd823872afe6eda39857d2 Best regards,
diff --git a/include/clk.h b/include/clk.h index ca6b85fa6f..5a8c7244d0 100644 --- a/include/clk.h +++ b/include/clk.h @@ -344,7 +344,8 @@ int clk_free(struct clk *clk); * * @clk: A clock struct that was previously successfully requested by * clk_request/get_by_*(). - * @return clock rate in Hz, or -ve error code. + * @return clock rate in Hz on success, 0 for invalid clock, or -ve error code + * for other errors. */ ulong clk_get_rate(struct clk *clk);
Improve clk_get_rate() @return documentation that otherwise is a bit ambiguous. At the moment I expect to return 0 as error since the return type is 'ulong', instead the function really returns negative value in case the corresponding function pointer is null and returns 0 if the clock is invalid. Signed-off-by: Giulio Benetti <giulio.benetti@benettiengineering.com> --- V1->V2: * previous comment was wrong, this function returns negative value, so let's improve it's @return documentation as suggested by Simon Glass --- include/clk.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)