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* [PATCH v9 0/9] Introduce the for_each_set_clump8 macro
@ 2019-03-03  7:44 William Breathitt Gray
  2019-03-03  7:47 ` William Breathitt Gray
                   ` (9 more replies)
  0 siblings, 10 replies; 28+ messages in thread
From: William Breathitt Gray @ 2019-03-03  7:44 UTC (permalink / raw)
  To: linus.walleij
  Cc: akpm, linux-gpio, linux-arch, linux-kernel, andriy.shevchenko,
	linux, yamada.masahiro, bgolaszewski, linux-arm-kernel,
	William Breathitt Gray

Changes in v9:
  - Return unsigned long for bitmap_get_value8 for consistency

While adding GPIO get_multiple/set_multiple callback support for various
drivers, I noticed a pattern of looping manifesting that would be useful
standardized as a macro.

This patchset introduces the for_each_set_clump8 macro and utilizes it
in several GPIO drivers. The for_each_set_clump macro8 facilitates a
for-loop syntax that iterates over a memory region entire groups of set
bits at a time.

For example, suppose you would like to iterate over a 32-bit integer 8
bits at a time, skipping over 8-bit groups with no set bit, where
XXXXXXXX represents the current 8-bit group:

    Example:        10111110 00000000 11111111 00110011
    First loop:     10111110 00000000 11111111 XXXXXXXX
    Second loop:    10111110 00000000 XXXXXXXX 00110011
    Third loop:     XXXXXXXX 00000000 11111111 00110011

Each iteration of the loop returns the next 8-bit group that has at
least one set bit.

The for_each_set_clump8 macro has four parameters:

    * start: set to the bit offset of the current clump
    * clump: set to the current clump value
    * bits: bitmap to search within
    * size: bitmap size in number of bits

In this version of the patchset, the for_each_set_clump macro has been
reimplemented and simplified based on the suggestions provided by Rasmus
Villemoes and Andy Shevchenko in the version 4 submission.

In particular, the function of the for_each_set_clump macro has been
restricted to handle only 8-bit clumps; the drivers that use the
for_each_set_clump macro only handle 8-bit ports so a generic
for_each_set_clump implementation is not necessary. Thus, a solution for
large clumps (i.e. those larger than the width of a bitmap word) can be
postponed until a driver appears that actually requires such a generic
for_each_set_clump implementation.

For what it's worth, a semi-generic for_each_set_clump (i.e. for clumps
smaller than the width of a bitmap word) can be implemented by simply
replacing the hardcoded '8' and '0xFF' instances with respective
variables. I have not yet had a need for such an implementation, and
since it falls short of a true generic for_each_set_clump function, I
have decided to forgo such an implementation for now.

In addition, the bitmap_get_value8 and bitmap_set_value8 functions are
introduced to get and set 8-bit values respectively. Their use is based
on the behavior suggested in the patchset version 4 review.

William Breathitt Gray (9):
  bitops: Introduce the for_each_set_clump8 macro
  lib/test_bitmap.c: Add for_each_set_clump8 test cases
  gpio: 104-dio-48e: Utilize for_each_set_clump8 macro
  gpio: 104-idi-48: Utilize for_each_set_clump8 macro
  gpio: gpio-mm: Utilize for_each_set_clump8 macro
  gpio: ws16c48: Utilize for_each_set_clump8 macro
  gpio: pci-idio-16: Utilize for_each_set_clump8 macro
  gpio: pcie-idio-24: Utilize for_each_set_clump8 macro
  gpio: uniphier: Utilize for_each_set_clump8 macro

 drivers/gpio/gpio-104-dio-48e.c   |  73 ++++++--------------
 drivers/gpio/gpio-104-idi-48.c    |  37 +++-------
 drivers/gpio/gpio-gpio-mm.c       |  73 ++++++--------------
 drivers/gpio/gpio-pci-idio-16.c   |  75 ++++++++------------
 drivers/gpio/gpio-pcie-idio-24.c  | 111 +++++++++++-------------------
 drivers/gpio/gpio-uniphier.c      |  16 ++---
 drivers/gpio/gpio-ws16c48.c       |  72 ++++++-------------
 include/asm-generic/bitops/find.h |  14 ++++
 include/linux/bitops.h            |   5 ++
 lib/find_bit.c                    |  81 ++++++++++++++++++++++
 lib/test_bitmap.c                 |  65 +++++++++++++++++
 11 files changed, 313 insertions(+), 309 deletions(-)

-- 
2.21.0


^ permalink raw reply	[flat|nested] 28+ messages in thread

end of thread, other threads:[~2019-03-12 14:54 UTC | newest]

Thread overview: 28+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2019-03-03  7:44 [PATCH v9 0/9] Introduce the for_each_set_clump8 macro William Breathitt Gray
2019-03-03  7:47 ` William Breathitt Gray
2019-03-03  7:48 ` [PATCH v9 1/9] bitops: " William Breathitt Gray
2019-03-08  8:31   ` Linus Walleij
2019-03-08  8:57     ` William Breathitt Gray
2019-03-08  9:19       ` Andy Shevchenko
2019-03-12  5:36       ` Masahiro Yamada
2019-03-12  7:22         ` William Breathitt Gray
2019-03-12 14:54           ` Andy Shevchenko
2019-03-12  1:01     ` Andrew Morton
2019-03-12 10:43       ` William Breathitt Gray
2019-03-12  3:52   ` Masahiro Yamada
2019-03-12  5:03   ` Masahiro Yamada
2019-03-12  7:14     ` Andy Shevchenko
2019-03-03  7:48 ` [PATCH v9 2/9] lib/test_bitmap.c: Add for_each_set_clump8 test cases William Breathitt Gray
2019-03-11  7:56   ` [LKP] [lib/test_bitmap.c] ecdc93614a: kernel_selftests.lib.bitmap.sh.fail kernel test robot
2019-03-03  7:49 ` [PATCH v9 3/9] gpio: 104-dio-48e: Utilize for_each_set_clump8 macro William Breathitt Gray
2019-03-03  7:49 ` [PATCH v9 4/9] gpio: 104-idi-48: " William Breathitt Gray
2019-03-03  7:50 ` [PATCH v9 5/9] gpio: gpio-mm: " William Breathitt Gray
2019-03-03  7:50 ` [PATCH v9 6/9] gpio: ws16c48: " William Breathitt Gray
2019-03-03  7:51 ` [PATCH v9 7/9] gpio: pci-idio-16: " William Breathitt Gray
2019-03-03  7:51 ` [PATCH v9 8/9] gpio: pcie-idio-24: " William Breathitt Gray
2019-03-03  7:51 ` [PATCH v9 9/9] gpio: uniphier: " William Breathitt Gray
2019-03-12  4:36   ` Masahiro Yamada
2019-03-12  7:17     ` Andy Shevchenko
2019-03-12  8:57       ` Masahiro Yamada
2019-03-12  9:09         ` Andy Shevchenko
2019-03-12  7:29     ` William Breathitt Gray

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