[PATCH] checkpatch: fix false positives for IIO_DEV_ATTR permission checks

[Angus Gardner <angusg778@gmail.com>]

The IIO_DEV_ATTR_[A-Z_]+ entry in @mode_permission_funcs used argument
position 1 for all IIO_DEV_ATTR_* macros, but this is incorrect for
several variants that take an extra numeric argument before the mode:

  IIO_DEV_ATTR_FREQ(channel, num, mode, ...)       - mode at position 3
  IIO_DEV_ATTR_PHASE(channel, num, mode, ...)      - mode at position 3
  IIO_DEV_ATTR_OUTY_ENABLE(channel, out, mode, ..) - mode at position 3

With position 1, checkpatch checked the channel argument (always 0)
or the numeric _num/_output argument (0, 1, 2, 3) instead of the actual
permission, producing spurious NON_OCTAL_PERMISSIONS errors.

IIO_DEV_ATTR_OUT_WAVETYPE has no permission argument at all (it is
hardcoded as 0200 inside the macro), so it should be excluded from
permission checking entirely.

Fix by splitting the single entry into two: one matching the three-
argument variants at position 3, using a negative lookahead to prevent
overlap with the second entry which matches the remaining IIO_DEV_ATTR_*
macros (including OUT_WAVETYPE exclusion) at the correct position 2.

Signed-off-by: Angus Gardner <angusg778@gmail.com>
---
 scripts/checkpatch.pl | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/scripts/checkpatch.pl b/scripts/checkpatch.pl
index 0492d6afc..fa2af8527 100755
--- a/scripts/checkpatch.pl
+++ b/scripts/checkpatch.pl
@@ -840,7 +840,8 @@ our @mode_permission_funcs = (
 	["debugfs_create_(?:file|u8|u16|u32|u64|x8|x16|x32|x64|size_t|atomic_t|bool|blob|regset32|u32_array)", 2],
 	["proc_create(?:_data|)", 2],
 	["(?:CLASS|DEVICE|SENSOR|SENSOR_DEVICE|IIO_DEVICE)_ATTR", 2],
-	["IIO_DEV_ATTR_[A-Z_]+", 1],
+	["IIO_DEV_ATTR_(?:FREQ|PHASE|OUTY_ENABLE)[A-Z_]*", 3],
+	["IIO_DEV_ATTR_(?!(?:FREQ|PHASE|OUTY_ENABLE|OUT_WAVETYPE))[A-Z_]+", 2],
 	["SENSOR_(?:DEVICE_|)ATTR_2", 2],
 	["SENSOR_TEMPLATE(?:_2|)", 3],
 	["__ATTR", 2],
-- 
2.51.0