On Sat, Oct 05, 2019 at 02:36:54PM -0400, William Breathitt Gray wrote: > Changes in v15: > - Move find_next_clump8 to lib/find_bit.c since it requires round_down > (I want this to be static inline like the others, but I need help) > - Utilize for_each_set_clump8 in pisosr, max3191x, and pca953x > > 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 | 29 +++--- > drivers/thermal/intel/intel_soc_dts_iosf.h | 2 - > include/asm-generic/bitops/find.h | 50 ++++++++++ > include/linux/bitops.h | 5 + > lib/find_bit.c | 14 +++ > lib/test_bitmap.c | 65 ++++++++++++ > 17 files changed, 325 insertions(+), 362 deletions(-) > > -- > 2.23.0 This patchset only implements for_each_set_clump8 which restricts the looping to 8 bits at a time. The drivers/gpio/gpio-thunderx.c file has a set_multiple callback that loops 64 bits at a time. That would be one case where a more general for_each_set_clump macro would be useful. However, we can focus on the simpler for_each_set_clump8 macro for now since looping by 8 bits at a time is the most common situation. William Breathitt Gray
