| Message ID | 20210912184458.17995-5-digetx@gmail.com |
|---|---|
| State | Accepted |
| Commit | 4844bdbe9166bc3d194b1d20d13dc1f01d3c1bb7 |
| Headers | show |
| Series | Make probe() of Tegra devfreq driver completely resource-managed | expand |
Hi, On 21. 9. 13. 오전 3:44, Dmitry Osipenko wrote: > EMC clock is always-on and can't be zero. Check whether clk_round_rate() > returns zero rate and error out if it does. It can return zero if clock > tree isn't initialized properly. > > Signed-off-by: Dmitry Osipenko <digetx@gmail.com> > --- > drivers/devfreq/tegra30-devfreq.c | 4 ++-- > 1 file changed, 2 insertions(+), 2 deletions(-) > > diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c > index d83fdc2713ed..65ecf17a36f4 100644 > --- a/drivers/devfreq/tegra30-devfreq.c > +++ b/drivers/devfreq/tegra30-devfreq.c > @@ -891,9 +891,9 @@ static int tegra_devfreq_probe(struct platform_device *pdev) > return err; > > rate = clk_round_rate(tegra->emc_clock, ULONG_MAX); > - if (rate < 0) { > + if (rate <= 0) { > dev_err(&pdev->dev, "Failed to round clock rate: %ld\n", rate); > - return rate; > + return rate ?: -EINVAL; > } > > tegra->max_freq = rate / KHZ; > Acked-by: Chanwoo Choi <cw00.choi@samsung.com> -- Best Regards, Samsung Electronics Chanwoo Choi
On 21. 9. 15. 오후 12:51, Chanwoo Choi wrote: > Hi, > > On 21. 9. 13. 오전 3:44, Dmitry Osipenko wrote: >> EMC clock is always-on and can't be zero. Check whether clk_round_rate() >> returns zero rate and error out if it does. It can return zero if clock >> tree isn't initialized properly. >> >> Signed-off-by: Dmitry Osipenko <digetx@gmail.com> >> --- >> drivers/devfreq/tegra30-devfreq.c | 4 ++-- >> 1 file changed, 2 insertions(+), 2 deletions(-) >> >> diff --git a/drivers/devfreq/tegra30-devfreq.c >> b/drivers/devfreq/tegra30-devfreq.c >> index d83fdc2713ed..65ecf17a36f4 100644 >> --- a/drivers/devfreq/tegra30-devfreq.c >> +++ b/drivers/devfreq/tegra30-devfreq.c >> @@ -891,9 +891,9 @@ static int tegra_devfreq_probe(struct >> platform_device *pdev) >> return err; >> rate = clk_round_rate(tegra->emc_clock, ULONG_MAX); >> - if (rate < 0) { >> + if (rate <= 0) { >> dev_err(&pdev->dev, "Failed to round clock rate: %ld\n", rate); >> - return rate; >> + return rate ?: -EINVAL; If rate is 0, It doesn't return and fall-through? even if print the error message. 'return rate ?: -EINVAL;' style is strange for me because it doesn't specify the 'return value' when rate is true. -- Best Regards, Samsung Electronics Chanwoo Choi
15.09.2021 21:31, Chanwoo Choi пишет: > On 21. 9. 15. 오후 12:51, Chanwoo Choi wrote: >> Hi, >> >> On 21. 9. 13. 오전 3:44, Dmitry Osipenko wrote: >>> EMC clock is always-on and can't be zero. Check whether clk_round_rate() >>> returns zero rate and error out if it does. It can return zero if clock >>> tree isn't initialized properly. >>> >>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com> >>> --- >>> drivers/devfreq/tegra30-devfreq.c | 4 ++-- >>> 1 file changed, 2 insertions(+), 2 deletions(-) >>> >>> diff --git a/drivers/devfreq/tegra30-devfreq.c >>> b/drivers/devfreq/tegra30-devfreq.c >>> index d83fdc2713ed..65ecf17a36f4 100644 >>> --- a/drivers/devfreq/tegra30-devfreq.c >>> +++ b/drivers/devfreq/tegra30-devfreq.c >>> @@ -891,9 +891,9 @@ static int tegra_devfreq_probe(struct >>> platform_device *pdev) >>> return err; >>> rate = clk_round_rate(tegra->emc_clock, ULONG_MAX); >>> - if (rate < 0) { >>> + if (rate <= 0) { >>> dev_err(&pdev->dev, "Failed to round clock rate: %ld\n", >>> rate); >>> - return rate; >>> + return rate ?: -EINVAL; > > If rate is 0, It doesn't return and fall-through? even if print the > error message. 'return rate ?: -EINVAL;' style is strange for me > because it doesn't specify the 'return value' when rate is true. It's not clear to me what do you mean by "return and fall-through". It specifies the 'return value' when rate is true. It's a short form of "rate ? rate : -EINVAL". The final returned value will be printed by the driver's core. The value returned by clk_round_rate() is important here since it tells the reason of the error. https://elixir.bootlin.com/linux/v5.15-rc1/source/drivers/base/dd.c#L533
On 21. 9. 16. 오전 10:28, Dmitry Osipenko wrote: > 15.09.2021 21:31, Chanwoo Choi пишет: >> On 21. 9. 15. 오후 12:51, Chanwoo Choi wrote: >>> Hi, >>> >>> On 21. 9. 13. 오전 3:44, Dmitry Osipenko wrote: >>>> EMC clock is always-on and can't be zero. Check whether clk_round_rate() >>>> returns zero rate and error out if it does. It can return zero if clock >>>> tree isn't initialized properly. >>>> >>>> Signed-off-by: Dmitry Osipenko <digetx@gmail.com> >>>> --- >>>> drivers/devfreq/tegra30-devfreq.c | 4 ++-- >>>> 1 file changed, 2 insertions(+), 2 deletions(-) >>>> >>>> diff --git a/drivers/devfreq/tegra30-devfreq.c >>>> b/drivers/devfreq/tegra30-devfreq.c >>>> index d83fdc2713ed..65ecf17a36f4 100644 >>>> --- a/drivers/devfreq/tegra30-devfreq.c >>>> +++ b/drivers/devfreq/tegra30-devfreq.c >>>> @@ -891,9 +891,9 @@ static int tegra_devfreq_probe(struct >>>> platform_device *pdev) >>>> return err; >>>> rate = clk_round_rate(tegra->emc_clock, ULONG_MAX); >>>> - if (rate < 0) { >>>> + if (rate <= 0) { >>>> dev_err(&pdev->dev, "Failed to round clock rate: %ld\n", >>>> rate); >>>> - return rate; >>>> + return rate ?: -EINVAL; >> >> If rate is 0, It doesn't return and fall-through? even if print the >> error message. 'return rate ?: -EINVAL;' style is strange for me >> because it doesn't specify the 'return value' when rate is true. > > It's not clear to me what do you mean by "return and fall-through". > > It specifies the 'return value' when rate is true. It's a short form of > "rate ? rate : -EINVAL". I has not known this short form. Thanks for comment. I understand. -- Best Regards, Samsung Electronics Chanwoo Choi
diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c index d83fdc2713ed..65ecf17a36f4 100644 --- a/drivers/devfreq/tegra30-devfreq.c +++ b/drivers/devfreq/tegra30-devfreq.c @@ -891,9 +891,9 @@ static int tegra_devfreq_probe(struct platform_device *pdev) return err; rate = clk_round_rate(tegra->emc_clock, ULONG_MAX); - if (rate < 0) { + if (rate <= 0) { dev_err(&pdev->dev, "Failed to round clock rate: %ld\n", rate); - return rate; + return rate ?: -EINVAL; } tegra->max_freq = rate / KHZ;
EMC clock is always-on and can't be zero. Check whether clk_round_rate() returns zero rate and error out if it does. It can return zero if clock tree isn't initialized properly. Signed-off-by: Dmitry Osipenko <digetx@gmail.com> --- drivers/devfreq/tegra30-devfreq.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)