| Message ID | 20191023000906.14374-1-natechancellor@gmail.com (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | viresh kumar |
| Headers | show |
| Series | cpufreq: s3c64xx: Remove pointless NULL check in s3c64xx_cpufreq_driver_init | expand |
On 22-10-19, 17:09, Nathan Chancellor wrote: > When building with Clang + -Wtautological-pointer-compare: > > drivers/cpufreq/s3c64xx-cpufreq.c:152:6: warning: comparison of array > 's3c64xx_freq_table' equal to a null pointer is always false > [-Wtautological-pointer-compare] > if (s3c64xx_freq_table == NULL) { > ^~~~~~~~~~~~~~~~~~ ~~~~ > 1 warning generated. > > The definition of s3c64xx_freq_table is surrounded by an ifdef > directive for CONFIG_CPU_S3C6410, which is always true for this driver > because it depends on it in drivers/cpufreq/Kconfig.arm (and if it > weren't, there would be a build error because s3c64xx_freq_table would > not be a defined symbol). > > Resolve this warning by removing the unnecessary NULL check because it > is always false as Clang notes. While we are at it, remove the > unnecessary ifdef conditional because it is always true. > > Fixes: b3748ddd8056 ("[ARM] S3C64XX: Initial support for DVFS") +broonie, who wrote this patch to see his views on why he kept it like this. > Link: https://github.com/ClangBuiltLinux/linux/issues/748 > Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> > --- > drivers/cpufreq/s3c64xx-cpufreq.c | 7 ------- > 1 file changed, 7 deletions(-) > > diff --git a/drivers/cpufreq/s3c64xx-cpufreq.c b/drivers/cpufreq/s3c64xx-cpufreq.c > index af0c00dabb22..c6bdfc308e99 100644 > --- a/drivers/cpufreq/s3c64xx-cpufreq.c > +++ b/drivers/cpufreq/s3c64xx-cpufreq.c > @@ -19,7 +19,6 @@ > static struct regulator *vddarm; > static unsigned long regulator_latency; > > -#ifdef CONFIG_CPU_S3C6410 > struct s3c64xx_dvfs { > unsigned int vddarm_min; > unsigned int vddarm_max; > @@ -48,7 +47,6 @@ static struct cpufreq_frequency_table s3c64xx_freq_table[] = { > { 0, 4, 800000 }, > { 0, 0, CPUFREQ_TABLE_END }, > }; > -#endif > > static int s3c64xx_cpufreq_set_target(struct cpufreq_policy *policy, > unsigned int index) > @@ -149,11 +147,6 @@ static int s3c64xx_cpufreq_driver_init(struct cpufreq_policy *policy) > if (policy->cpu != 0) > return -EINVAL; > > - if (s3c64xx_freq_table == NULL) { > - pr_err("No frequency information for this CPU\n"); > - return -ENODEV; > - } > - > policy->clk = clk_get(NULL, "armclk"); > if (IS_ERR(policy->clk)) { > pr_err("Unable to obtain ARMCLK: %ld\n", > -- > 2.23.0
On Wed, Oct 23, 2019 at 08:53:02AM +0530, Viresh Kumar wrote: > On 22-10-19, 17:09, Nathan Chancellor wrote: > > When building with Clang + -Wtautological-pointer-compare: > > > > drivers/cpufreq/s3c64xx-cpufreq.c:152:6: warning: comparison of array > > 's3c64xx_freq_table' equal to a null pointer is always false > > [-Wtautological-pointer-compare] > > if (s3c64xx_freq_table == NULL) { > > ^~~~~~~~~~~~~~~~~~ ~~~~ > > 1 warning generated. > > > > The definition of s3c64xx_freq_table is surrounded by an ifdef > > directive for CONFIG_CPU_S3C6410, which is always true for this driver > > because it depends on it in drivers/cpufreq/Kconfig.arm (and if it > > weren't, there would be a build error because s3c64xx_freq_table would > > not be a defined symbol). > +broonie, who wrote this patch to see his views on why he kept it like > this. The driver should also have supported s3c6400 as well.
On Wed, Oct 23, 2019 at 11:43:04AM +0100, Mark Brown wrote: > On Wed, Oct 23, 2019 at 08:53:02AM +0530, Viresh Kumar wrote: > > On 22-10-19, 17:09, Nathan Chancellor wrote: > > > When building with Clang + -Wtautological-pointer-compare: > > > > > > drivers/cpufreq/s3c64xx-cpufreq.c:152:6: warning: comparison of array > > > 's3c64xx_freq_table' equal to a null pointer is always false > > > [-Wtautological-pointer-compare] > > > if (s3c64xx_freq_table == NULL) { > > > ^~~~~~~~~~~~~~~~~~ ~~~~ > > > 1 warning generated. > > > > > > The definition of s3c64xx_freq_table is surrounded by an ifdef > > > directive for CONFIG_CPU_S3C6410, which is always true for this driver > > > because it depends on it in drivers/cpufreq/Kconfig.arm (and if it > > > weren't, there would be a build error because s3c64xx_freq_table would > > > not be a defined symbol). > > > +broonie, who wrote this patch to see his views on why he kept it like > > this. > > The driver should also have supported s3c6400 as well. Kconfig says otherwise, unless I am missing something. config ARM_S3C64XX_CPUFREQ bool "Samsung S3C64XX" depends on CPU_S3C6410 default y help This adds the CPUFreq driver for Samsung S3C6410 SoC. If in doubt, say N. Cheers, Nathan
On Wed, Oct 23, 2019 at 09:26:28AM -0700, Nathan Chancellor wrote: > On Wed, Oct 23, 2019 at 11:43:04AM +0100, Mark Brown wrote: > > The driver should also have supported s3c6400 as well. > Kconfig says otherwise, unless I am missing something. > config ARM_S3C64XX_CPUFREQ > bool "Samsung S3C64XX" > depends on CPU_S3C6410 > default y > help > This adds the CPUFreq driver for Samsung S3C6410 SoC. > > If in doubt, say N. Note the XX in the config option.
On Wed, Oct 23, 2019 at 05:36:56PM +0100, Mark Brown wrote: > On Wed, Oct 23, 2019 at 09:26:28AM -0700, Nathan Chancellor wrote: > > On Wed, Oct 23, 2019 at 11:43:04AM +0100, Mark Brown wrote: > > > > The driver should also have supported s3c6400 as well. > > > Kconfig says otherwise, unless I am missing something. > > > config ARM_S3C64XX_CPUFREQ > > bool "Samsung S3C64XX" > > depends on CPU_S3C6410 > > default y > > help > > This adds the CPUFreq driver for Samsung S3C6410 SoC. > > > > If in doubt, say N. > > Note the XX in the config option. But what about the depends and the help text? If I just enable the following config options in multi_v7_defconfig and remove that depends, the driver will not build because the {dvfs,freq}_table definitions only get added to the final source file when CONFIG CPU_S3C6410 is set... CONFIG_ARCH_MULTI_V6=y CONFIG_ARCH_S3C64XX=y CONFIG_MACH_SMDK6400=y CC drivers/cpufreq/s3c64xx-cpufreq.o ../drivers/cpufreq/s3c64xx-cpufreq.c:61:13: error: use of undeclared identifier 's3c64xx_freq_table' new_freq = s3c64xx_freq_table[index].frequency; ^ ../drivers/cpufreq/s3c64xx-cpufreq.c:62:29: error: use of undeclared identifier 's3c64xx_freq_table' dvfs = &s3c64xx_dvfs_table[s3c64xx_freq_table[index].driver_data]; ^ ../drivers/cpufreq/s3c64xx-cpufreq.c:62:10: error: use of undeclared identifier 's3c64xx_dvfs_table' dvfs = &s3c64xx_dvfs_table[s3c64xx_freq_table[index].driver_data]; ^ ... 14 errors generated. So maybe it _should_ support s3c6400 but it does not appear to, which is why there is this clang warning that my patch is trying to address. If I am missing something critical, please let me know. Cheers, Nathan
On Wed, Oct 23, 2019 at 09:54:17AM -0700, Nathan Chancellor wrote: > On Wed, Oct 23, 2019 at 05:36:56PM +0100, Mark Brown wrote: > > On Wed, Oct 23, 2019 at 09:26:28AM -0700, Nathan Chancellor wrote: > > > On Wed, Oct 23, 2019 at 11:43:04AM +0100, Mark Brown wrote: > > > > The driver should also have supported s3c6400 as well. > > > Kconfig says otherwise, unless I am missing something. > > Note the XX in the config option. > But what about the depends and the help text? Viresh asked why the driver was written with s3c6410 support optional. I explained that the reason that it was written this way was to accomodate s3c6400 support.
On Wed, Oct 23, 2019 at 05:59:23PM +0100, Mark Brown wrote: > On Wed, Oct 23, 2019 at 09:54:17AM -0700, Nathan Chancellor wrote: > > On Wed, Oct 23, 2019 at 05:36:56PM +0100, Mark Brown wrote: > > > On Wed, Oct 23, 2019 at 09:26:28AM -0700, Nathan Chancellor wrote: > > > > On Wed, Oct 23, 2019 at 11:43:04AM +0100, Mark Brown wrote: > > > > > > The driver should also have supported s3c6400 as well. > > > > > Kconfig says otherwise, unless I am missing something. > > > > Note the XX in the config option. > > > But what about the depends and the help text? > > Viresh asked why the driver was written with s3c6410 support optional. > I explained that the reason that it was written this way was to > accomodate s3c6400 support. Ah understood, thanks for the clarification and sorry for the misunderstanding! Cheers, Nathan
On 22-10-19, 17:09, Nathan Chancellor wrote: > When building with Clang + -Wtautological-pointer-compare: > > drivers/cpufreq/s3c64xx-cpufreq.c:152:6: warning: comparison of array > 's3c64xx_freq_table' equal to a null pointer is always false > [-Wtautological-pointer-compare] > if (s3c64xx_freq_table == NULL) { > ^~~~~~~~~~~~~~~~~~ ~~~~ > 1 warning generated. > > The definition of s3c64xx_freq_table is surrounded by an ifdef > directive for CONFIG_CPU_S3C6410, which is always true for this driver > because it depends on it in drivers/cpufreq/Kconfig.arm (and if it > weren't, there would be a build error because s3c64xx_freq_table would > not be a defined symbol). > > Resolve this warning by removing the unnecessary NULL check because it > is always false as Clang notes. While we are at it, remove the > unnecessary ifdef conditional because it is always true. > > Fixes: b3748ddd8056 ("[ARM] S3C64XX: Initial support for DVFS") > Link: https://github.com/ClangBuiltLinux/linux/issues/748 > Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> > --- > drivers/cpufreq/s3c64xx-cpufreq.c | 7 ------- > 1 file changed, 7 deletions(-) Applied. Thanks.
diff --git a/drivers/cpufreq/s3c64xx-cpufreq.c b/drivers/cpufreq/s3c64xx-cpufreq.c index af0c00dabb22..c6bdfc308e99 100644 --- a/drivers/cpufreq/s3c64xx-cpufreq.c +++ b/drivers/cpufreq/s3c64xx-cpufreq.c @@ -19,7 +19,6 @@ static struct regulator *vddarm; static unsigned long regulator_latency; -#ifdef CONFIG_CPU_S3C6410 struct s3c64xx_dvfs { unsigned int vddarm_min; unsigned int vddarm_max; @@ -48,7 +47,6 @@ static struct cpufreq_frequency_table s3c64xx_freq_table[] = { { 0, 4, 800000 }, { 0, 0, CPUFREQ_TABLE_END }, }; -#endif static int s3c64xx_cpufreq_set_target(struct cpufreq_policy *policy, unsigned int index) @@ -149,11 +147,6 @@ static int s3c64xx_cpufreq_driver_init(struct cpufreq_policy *policy) if (policy->cpu != 0) return -EINVAL; - if (s3c64xx_freq_table == NULL) { - pr_err("No frequency information for this CPU\n"); - return -ENODEV; - } - policy->clk = clk_get(NULL, "armclk"); if (IS_ERR(policy->clk)) { pr_err("Unable to obtain ARMCLK: %ld\n",
When building with Clang + -Wtautological-pointer-compare: drivers/cpufreq/s3c64xx-cpufreq.c:152:6: warning: comparison of array 's3c64xx_freq_table' equal to a null pointer is always false [-Wtautological-pointer-compare] if (s3c64xx_freq_table == NULL) { ^~~~~~~~~~~~~~~~~~ ~~~~ 1 warning generated. The definition of s3c64xx_freq_table is surrounded by an ifdef directive for CONFIG_CPU_S3C6410, which is always true for this driver because it depends on it in drivers/cpufreq/Kconfig.arm (and if it weren't, there would be a build error because s3c64xx_freq_table would not be a defined symbol). Resolve this warning by removing the unnecessary NULL check because it is always false as Clang notes. While we are at it, remove the unnecessary ifdef conditional because it is always true. Fixes: b3748ddd8056 ("[ARM] S3C64XX: Initial support for DVFS") Link: https://github.com/ClangBuiltLinux/linux/issues/748 Signed-off-by: Nathan Chancellor <natechancellor@gmail.com> --- drivers/cpufreq/s3c64xx-cpufreq.c | 7 ------- 1 file changed, 7 deletions(-)