[PATCH] checkpatch: Make SI unit tolerance more lenient with 3-character units

[PATCH] checkpatch: Make SI unit tolerance more lenient with 3-character units

[Julius Werner]

Checkpatch flags CamelCase identifiers in strict mode, but it has a
feature to ignore parts with only two characters to allow for SI units
like mV or uA. Unfortunately, not all SI units fit in two characters,
and not all are lower case followed by upper case.

This patch changes the check from [a-z][A-Z] to [a-zA-Z]{1,3} (any
combination of up to three lower and upper case characters), so that it
will also allow units like MHz, As or KiB.

Signed-off-by: Julius Werner <jwerner@chromium.org>
---
 scripts/checkpatch.pl | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 374abf4..0bbd25a 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -4055,8 +4055,8 @@ sub process {
 			    $var =~ /[A-Z][a-z]|[a-z][A-Z]/ &&
 #Ignore Page<foo> variants
 			    $var !~ /^(?:Clear|Set|TestClear|TestSet|)Page[A-Z]/ &&
-#Ignore SI style variants like nS, mV and dB (ie: max_uV, regulator_min_uA_show)
-			    $var !~ /^(?:[a-z_]*?)_?[a-z][A-Z](?:_[a-z_]+)?$/) {
+#Ignore SI style variants like nS, mV, MHz and dB (ie: max_uV, regulator_min_uA_show)
+			    $var !~ /^(?:[a-z_]*?)_?[a-zA-Z]{1,3}(?:_[a-z_]+)?$/) {
 				while ($var =~ m{($Ident)}g) {
 					my $word = $1;
 					next if ($word !~ /[A-Z][a-z]|[a-z][A-Z]/);
-- 
1.8.3.2

Re: [PATCH] checkpatch: Make SI unit tolerance more lenient with 3-character units

[Joe Perches]

On Fri, 2014-11-07 at 16:18 -0800, Julius Werner wrote:
> Checkpatch flags CamelCase identifiers in strict mode, but it has a
> feature to ignore parts with only two characters to allow for SI units
> like mV or uA. Unfortunately, not all SI units fit in two characters,
> and not all are lower case followed by upper case.
> 
> This patch changes the check from [a-z][A-Z] to [a-zA-Z]{1,3} (any
> combination of up to three lower and upper case characters), so that it
> will also allow units like MHz, As or KiB.
[]
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
[]
> @@ -4055,8 +4055,8 @@ sub process {
>  			    $var =~ /[A-Z][a-z]|[a-z][A-Z]/ &&
>  #Ignore Page<foo> variants
>  			    $var !~ /^(?:Clear|Set|TestClear|TestSet|)Page[A-Z]/ &&
> -#Ignore SI style variants like nS, mV and dB (ie: max_uV, regulator_min_uA_show)
> -			    $var !~ /^(?:[a-z_]*?)_?[a-z][A-Z](?:_[a-z_]+)?$/) {
> +#Ignore SI style variants like nS, mV, MHz and dB (ie: max_uV, regulator_min_uA_show)
> +			    $var !~ /^(?:[a-z_]*?)_?[a-zA-Z]{1,3}(?:_[a-z_]+)?$/) {
>  				while ($var =~ m{($Ident)}g) {
>  					my $word = $1;
>  					next if ($word !~ /[A-Z][a-z]|[a-z][A-Z]/);

I think this may miss too many uses like pDB and
other variables used for hungarian notations.

It may be better to enumerate the specific character
sequences to exempt.

[PATCHv2] checkpatch: Allow certain SI units with three characters

[Julius Werner]

Checkpatch flags CamelCase identifiers in strict mode, but it has a
feature to ignore parts with only two characters to allow for SI units
like mV or uA. Unfortunately, not all SI units fit in two characters,
and not all are lower case followed by upper case.

This patch adds hardcoded detection for frequency and 1024-based size
units (Hz/KHz/MHz/GHz/THz and KiB/MiB/GiB/TiB), since allowing any three
character combinations might be too lenient. The list can later be
expanded as needed.

Signed-off-by: Julius Werner <jwerner@chromium.org>
---
 scripts/checkpatch.pl | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 374abf4..b947c75 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -4056,7 +4056,9 @@ sub process {
 #Ignore Page<foo> variants
 			    $var !~ /^(?:Clear|Set|TestClear|TestSet|)Page[A-Z]/ &&
 #Ignore SI style variants like nS, mV and dB (ie: max_uV, regulator_min_uA_show)
-			    $var !~ /^(?:[a-z_]*?)_?[a-z][A-Z](?:_[a-z_]+)?$/) {
+			    $var !~ /^(?:[a-z_]*?)_?[a-z][A-Z](?:_[a-z_]+)?$/ &&
+#Ignore some three character SI units explicitly, like MiB and KHz
+			    $var !~ /^(?:[a-z_]*?)_?(?:[KMGT]iB|[KMGT]?Hz)(?:_[a-z_]+)?$/) {
 				while ($var =~ m{($Ident)}g) {
 					my $word = $1;
 					next if ($word !~ /[A-Z][a-z]|[a-z][A-Z]/);
-- 
2.1.2

Re: [PATCHv2] checkpatch: Allow certain SI units with three characters

[Joe Perches]

On Mon, 2014-11-10 at 11:39 -0800, Julius Werner wrote:
> Checkpatch flags CamelCase identifiers in strict mode, but it has a
> feature to ignore parts with only two characters to allow for SI units
> like mV or uA. Unfortunately, not all SI units fit in two characters,
> and not all are lower case followed by upper case.
> 
> This patch adds hardcoded detection for frequency and 1024-based size
> units (Hz/KHz/MHz/GHz/THz and KiB/MiB/GiB/TiB), since allowing any three
> character combinations might be too lenient. The list can later be
> expanded as needed.

Seems sensible enough, thanks.

Acked-by: Joe Perches <joe@perches.com>

> Signed-off-by: Julius Werner <jwerner@chromium.org>
> ---
>  scripts/checkpatch.pl | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 374abf4..b947c75 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -4056,7 +4056,9 @@ sub process {
>  #Ignore Page<foo> variants
>  			    $var !~ /^(?:Clear|Set|TestClear|TestSet|)Page[A-Z]/ &&
>  #Ignore SI style variants like nS, mV and dB (ie: max_uV, regulator_min_uA_show)
> -			    $var !~ /^(?:[a-z_]*?)_?[a-z][A-Z](?:_[a-z_]+)?$/) {
> +			    $var !~ /^(?:[a-z_]*?)_?[a-z][A-Z](?:_[a-z_]+)?$/ &&
> +#Ignore some three character SI units explicitly, like MiB and KHz
> +			    $var !~ /^(?:[a-z_]*?)_?(?:[KMGT]iB|[KMGT]?Hz)(?:_[a-z_]+)?$/) {
>  				while ($var =~ m{($Ident)}g) {
>  					my $word = $1;
>  					next if ($word !~ /[A-Z][a-z]|[a-z][A-Z]/);