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    Subject[PATCH v12 00/11] Introduce the for_each_set_clump8 macro
    Date
    Changes in v12:
    - Rebase changes (bitmap_set_value8 definition change in wrong commit)

    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 (11):
    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
    thermal: intel: intel_soc_dts_iosf: Utilize for_each_set_clump8 macro
    gpio: 74x164: Utilize the for_each_set_clump8 macro

    drivers/gpio/gpio-104-dio-48e.c | 73 ++++----------
    drivers/gpio/gpio-104-idi-48.c | 37 ++-----
    drivers/gpio/gpio-74x164.c | 20 ++--
    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 ++++---------
    drivers/thermal/intel/intel_soc_dts_iosf.c | 29 +++---
    drivers/thermal/intel/intel_soc_dts_iosf.h | 2 -
    include/asm-generic/bitops/find.h | 14 +++
    include/linux/bitops.h | 5 +
    lib/find_bit.c | 81 +++++++++++++++
    lib/test_bitmap.c | 65 ++++++++++++
    14 files changed, 340 insertions(+), 333 deletions(-)

    --
    2.21.0

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