bitfield: add explicit inclusions to the example

It's not obvious that bitfield.h doesn't guarantee the bits.h inclusion
and the example in the former is confusing.  Some developers think that
it's okay to just include bitfield.h to get it working.  Change example
to explicitly include necessary headers in order to avoid confusion.

Link: https://lkml.kernel.org/r/20220207123341.47533-1-andriy.shevchenko@linux.intel.com
Fixes: e8332df9b5e2 ("add basic register-field manipulation macros")
Depends-on: 0ad8be0919e5 ("locking/atomics, asm-generic: Move some macros from <linux/bitops.h> to a new <linux/bits.h> file")
Signed-off-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Reported-by: Jan Dąbroś <jsd@semihalf.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/bitfield.h b/include/linux/bitfield.h
index 6093fa6db2600b3246007b2236d7c0076b02343b..c9be1657f03d92ee6e5ad23362b09c379dbc9d50 100644 (file)
--- a/include/linux/bitfield.h
+++ b/include/linux/bitfield.h
@@ -19,6 +19,9 @@
  *
  * Example:
  *
+ *  #include <linux/bitfield.h>
+ *  #include <linux/bits.h>
+ *
  *  #define REG_FIELD_A  GENMASK(6, 0)
  *  #define REG_FIELD_B  BIT(7)
  *  #define REG_FIELD_C  GENMASK(15, 8)