From mboxrd@z Thu Jan 1 00:00:00 1970 From: William Breathitt Gray Subject: [RESEND PATCH v4 0/8] Introduce the for_each_set_clump macro Date: Tue, 2 Oct 2018 10:12:39 +0900 Message-ID: Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Return-path: Sender: linux-kernel-owner@vger.kernel.org To: linus.walleij@linaro.org, akpm@linux-foundation.org Cc: linux-gpio@vger.kernel.org, linux-arch@vger.kernel.org, linux-kernel@vger.kernel.org, andriy.shevchenko@linux.intel.com, linux@rasmusvillemoes.dk, William Breathitt Gray List-Id: linux-gpio@vger.kernel.org This is a resend of v4 in hopes of getting some more ACKS and a few more eyes on this patchset. Changes in v4: - Fix bitmap_set arguments (last parameter is nbits not endbit) 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_clump macro and utilizes it in several GPIO drivers. The for_each_set_clump macro facilitates a for-loop syntax that iterates over entire groups of set bits at a time. For example, suppose you would like to iterate over a 16-bit integer 4 bits at a time, skipping over 4-bit groups with no set bit, where XXXX represents the current 4-bit group: Example: 1011 1110 0000 1111 First loop: 1011 1110 0000 XXXX Second loop: 1011 XXXX 0000 1111 Third loop: XXXX 1110 0000 1111 Each iteration of the loop returns the next 4-bit group that has at least one set bit. The for_each_set_clump macro has six parameters: * clump: set to current clump index for the iteration * index: set to current bitmap word index for the iteration * offset: bits offset of the found clump in the bitmap word * bits: bitmap to search within * size: bitmap size in number of clumps * clump_size: clump size in number of bits The clump_size argument can be an arbitrary number of bits and is not required to be a multiple of 2. This patchset was rebased on top of the following three commits: * commit aaf96e51de11 ("gpio: pci-idio-16: Fix port memory offset for get_multiple callback") * commit 304440aa96c6 ("gpio: pcie-idio-24: Fix port memory offset for get_multiple/set_multiple callbacks") * commit e026646c178d ("gpio: pcie-idio-24: Fix off-by-one error in get_multiple loop") When I implemented the test_for_each_set_clump function, I used bitmap_set to set the expected bitmap for the test. This method of setting bits only segments at a time was rather tedious and error-prone; is there a better way to accomplish what I did (set a bitmap after a DECLARE_BITMAP)? William Breathitt Gray William Breathitt Gray (8): bitops: Introduce the for_each_set_clump macro lib/test_bitmap.c: Add for_each_set_clump test cases gpio: 104-dio-48e: Utilize for_each_set_clump macro gpio: 104-idi-48: Utilize for_each_set_clump macro gpio: gpio-mm: Utilize for_each_set_clump macro gpio: ws16c48: Utilize for_each_set_clump macro gpio: pci-idio-16: Utilize for_each_set_clump macro gpio: pcie-idio-24: Utilize for_each_set_clump macro drivers/gpio/gpio-104-dio-48e.c | 67 +++++--------------- drivers/gpio/gpio-104-idi-48.c | 32 ++-------- drivers/gpio/gpio-gpio-mm.c | 67 +++++--------------- drivers/gpio/gpio-pci-idio-16.c | 67 ++++++-------------- drivers/gpio/gpio-pcie-idio-24.c | 102 +++++++++++------------------- drivers/gpio/gpio-ws16c48.c | 66 +++++-------------- include/asm-generic/bitops/find.h | 9 +++ include/linux/bitops.h | 7 ++ lib/find_bit.c | 40 ++++++++++++ lib/test_bitmap.c | 71 +++++++++++++++++++++ 10 files changed, 236 insertions(+), 292 deletions(-) -- 2.19.0