Re: [PATCH] checkpatch: recognize standard SI unit prefixes and symbols

[Joe Perches <joe@perches.com>]

On Fri, 2026-08-14 at 15:51 +0000, Ariel Yu wrote:
> ```
> The CAMELCASE check currently uses a broad [a-z][A-Z] pattern to
> skip SI-unit-style identifiers, which matches any lowercase-then-
> uppercase pair rather than actual SI units.
> 
> Replace it with an explicit list of standard SI prefixes
> (u, n, m, k, K, M, G, T) and units (V, A, Hz, Ohm, C, K, s, W),
> while retaining the binary byte units (KiB, MiB, GiB) and dB.

Why?  What does this complication do better?


> 
> Link: [https://lore.kernel.org/linux-iio/F9A182CC-62C0-445C-BAF0-9CDB7FFB3868@gmail.com/](https://lore.kernel.org/linux-iio/F9A182CC-62C0-445C-BAF0-9CDB7FFB3868@gmail.com/)
> Assisted-by: opencode:deepseek-v4-pro
> Signed-off-by: Ariel Yu <[ariel@ariels.xyz](mailto:ariel@ariels.xyz)>
> ---
>  scripts/checkpatch.pl | 18 ++++++++++++++----
>  1 file changed, 14 insertions(+), 4 deletions(-)
> 
> diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
> index 2b7a42bbdd..ba76beafc3 100755
> --- a/scripts/checkpatch.pl
> +++ b/scripts/checkpatch.pl
> @@ -5935,11 +5935,21 @@ sub process {
>  			    $var !~ /^(?:Clear|Set|TestClear|TestSet|)Page[A-Z]/ &&
>  #Ignore ETHTOOL_LINK_MODE_<foo> variants
>  			    $var !~ /^ETHTOOL_LINK_MODE_/ &&
> -#Ignore SI style variants like nS, mV and dB
> +#Ignore SI style variants like mV, uA, kHz, dB, MiB etc.
>  #(ie: max_uV, regulator_min_uA_show, RANGE_mA_VALUE)
> -			    $var !~ /^(?:[a-z0-9_]*|[A-Z0-9_]*)?_?[a-z][A-Z](?:_[a-z0-9_]+|_[A-Z0-9_]+)?$/ &&
> -#Ignore some three character SI units explicitly, like MiB and KHz
> -			    $var !~ /^(?:[a-z_]*?)_?(?:[KMGT]iB|[KMGT]?Hz)(?:_[a-z_]+)?$/) {
> +#
> +#Recognized standard SI unit prefixes (case sensitive):
> +#	u - micro (10^-6)	n - nano (10^-9)	m - milli (10^-3)
> +#	k - kilo (10^3)		K - kilo (10^3)		M - mega (10^6)
> +#	G - giga (10^9)		T - tera (10^12)
> +#
> +#Recognized units (optionally prefixed by the above):
> +#	V - volt		A - ampere		Hz - hertz
> +#	Ohm - ohm		C - coulomb		K - kelvin
> +#	s - second		W - watt
> +#Binary byte units: KiB, MiB, GiB (TiB)
> +#Decibel: dB
> +			    $var !~ /^(?:[a-z0-9_]*|[A-Z0-9_]*)?_?(?:[unmkKMGT]?(?:V|A|Hz|Ohm|C|K|s|W)|[KMG]iB|dB)(?:_[a-z0-9_]+|_[A-Z0-9_]+)?$/) {
>  				while ($var =~ m{\b($Ident)}g) {
>  					my $word = $1;
>  					next if ($word !~ /[A-Z][a-z]|[a-z][A-Z]/);
> 
> ---
> base-commit: d58772d8520c7ef247c4b95c9bd76d3a25da9ff5
> change-id: 20260814-ktodo-si-cad1bd45ca07
> 
> Best regards,
> --  
> Ariel Yu <[ariel@ariels.xyz](mailto:ariel@ariels.xyz)>
> 
> 
> ```