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* [PATCH v17 00/14] Introduce the for_each_set_clump8 macro
@ 2019-10-09 15:26 William Breathitt Gray
  2019-10-09 15:26 ` William Breathitt Gray
                   ` (14 more replies)
  0 siblings, 15 replies; 42+ messages in thread
From: William Breathitt Gray @ 2019-10-09 15:26 UTC (permalink / raw)
  To: linus.walleij, bgolaszewski, akpm
  Cc: linux-arch, preid, yamada.masahiro, linux-pm, linux,
	linux-kernel, morten.tiljeset, sean.nyekjaer, linux-gpio, lukas,
	geert, William Breathitt Gray, andriy.shevchenko,
	linux-arm-kernel

Changes in v17:
  - Move bitmap_get_value8/bitmap_set_value8 to include/linux/bitmap.h
  - add style changes suggested by Andy Shevchenko to intel_soc_dts_iosf

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 (14):
  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
  gpio: 74x164: Utilize the for_each_set_clump8 macro
  thermal: intel: intel_soc_dts_iosf: Utilize for_each_set_clump8 macro
  gpio: pisosr: Utilize the for_each_set_clump8 macro
  gpio: max3191x: Utilize the for_each_set_clump8 macro
  gpio: pca953x: Utilize the for_each_set_clump8 macro

 drivers/gpio/gpio-104-dio-48e.c            |  73 ++++----------
 drivers/gpio/gpio-104-idi-48.c             |  36 ++-----
 drivers/gpio/gpio-74x164.c                 |  19 ++--
 drivers/gpio/gpio-gpio-mm.c                |  73 ++++----------
 drivers/gpio/gpio-max3191x.c               |  19 ++--
 drivers/gpio/gpio-pca953x.c                |  17 ++--
 drivers/gpio/gpio-pci-idio-16.c            |  75 +++++---------
 drivers/gpio/gpio-pcie-idio-24.c           | 109 ++++++++-------------
 drivers/gpio/gpio-pisosr.c                 |  12 +--
 drivers/gpio/gpio-uniphier.c               |  16 ++-
 drivers/gpio/gpio-ws16c48.c                |  73 ++++----------
 drivers/thermal/intel/intel_soc_dts_iosf.c |  31 +++---
 drivers/thermal/intel/intel_soc_dts_iosf.h |   2 -
 include/asm-generic/bitops/find.h          |  17 ++++
 include/linux/bitmap.h                     |  35 +++++++
 include/linux/bitops.h                     |   5 +
 lib/find_bit.c                             |  14 +++
 lib/test_bitmap.c                          |  65 ++++++++++++
 18 files changed, 328 insertions(+), 363 deletions(-)


base-commit: 8c550e94b8835170593169a45b5ba30d3fc72a70
-- 
2.23.0


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-- links below jump to the message on this page --
2019-10-09 15:26 [PATCH v17 00/14] Introduce the for_each_set_clump8 macro William Breathitt Gray
2019-10-09 15:26 ` William Breathitt Gray
2019-10-09 15:26 ` [PATCH v17 01/14] bitops: " William Breathitt Gray
2019-10-09 15:26   ` William Breathitt Gray
2019-10-09 16:28   ` Masahiro Yamada
2019-10-09 16:28     ` Masahiro Yamada
2019-10-09 17:02     ` William Breathitt Gray
2019-10-09 17:09     ` Andy Shevchenko
2019-10-09 18:54       ` Geert Uytterhoeven
2019-10-10  2:28         ` Masahiro Yamada
2019-10-10  5:49           ` Andy Shevchenko
2019-10-10  6:29             ` Geert Uytterhoeven
2019-10-10  7:41               ` Andy Shevchenko
2019-10-10  7:49                 ` Geert Uytterhoeven
2019-10-10  8:07                   ` Andy Shevchenko
2019-10-10  8:21                     ` Geert Uytterhoeven
2019-10-10 13:12                       ` William Breathitt Gray
2019-10-09 15:27 ` [PATCH v17 02/14] lib/test_bitmap.c: Add for_each_set_clump8 test cases William Breathitt Gray
2019-10-09 15:27   ` William Breathitt Gray
2019-10-09 15:27 ` [PATCH v17 03/14] gpio: 104-dio-48e: Utilize for_each_set_clump8 macro William Breathitt Gray
2019-10-09 15:27 ` [PATCH v17 04/14] gpio: 104-idi-48: " William Breathitt Gray
2019-10-09 15:27   ` William Breathitt Gray
2019-10-09 15:27 ` [PATCH v17 05/14] gpio: gpio-mm: " William Breathitt Gray
2019-10-09 15:27 ` [PATCH v17 06/14] gpio: ws16c48: " William Breathitt Gray
2019-10-09 15:27 ` [PATCH v17 07/14] gpio: pci-idio-16: " William Breathitt Gray
2019-10-09 15:27   ` William Breathitt Gray
2019-10-09 15:27 ` [PATCH v17 08/14] gpio: pcie-idio-24: " William Breathitt Gray
2019-10-09 15:27   ` William Breathitt Gray
2019-10-09 15:27 ` [PATCH v17 09/14] gpio: uniphier: " William Breathitt Gray
2019-10-09 15:27   ` William Breathitt Gray
2019-10-09 16:33   ` Masahiro Yamada
2019-10-09 16:33     ` Masahiro Yamada
2019-10-09 17:05     ` William Breathitt Gray
2019-10-09 15:27 ` [PATCH v17 10/14] gpio: 74x164: Utilize the " William Breathitt Gray
2019-10-09 15:27   ` William Breathitt Gray
2019-10-09 15:27 ` [PATCH v17 11/14] thermal: intel: intel_soc_dts_iosf: Utilize " William Breathitt Gray
2019-10-09 15:27 ` [PATCH v17 12/14] gpio: pisosr: Utilize the " William Breathitt Gray
2019-10-09 15:27   ` William Breathitt Gray
2019-10-09 15:27 ` [PATCH v17 13/14] gpio: max3191x: " William Breathitt Gray
2019-10-09 15:27   ` William Breathitt Gray
2019-10-09 15:27 ` [PATCH v17 14/14] gpio: pca953x: " William Breathitt Gray
2019-10-09 15:27   ` William Breathitt Gray

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