On 2018-10-02 03:14, William Breathitt Gray wrote: > /* clear bits array to a clean slate */ > bitmap_zero(bits, chip->ngpio); > > - /* get bits are evaluated a gpio port register at a time */ > - for (i = 0; i < ARRAY_SIZE(ports); i++) { > - /* gpio offset in bits array */ > - bits_offset = i * gpio_reg_size; > - > - /* word index for bits array */ > - word_index = BIT_WORD(bits_offset); > - > - /* gpio offset within current word of bits array */ > - word_offset = bits_offset % BITS_PER_LONG; > - > - /* mask of get bits for current gpio within current word */ > - word_mask = mask[word_index] & (port_mask << word_offset); > - if (!word_mask) { > - /* no get bits in this port so skip to next one */ > - continue; > - } > - > - /* read bits from current gpio port */ > + for_each_set_clump(i, word, offset, mask, ARRAY_SIZE(ports), 8) { > port_state = inb(dio48egpio->base + ports[i]); > - > - /* store acquired bits at respective bits array offset */ > - bits[word_index] |= port_state << word_offset; > + bits[word] |= port_state << offset;
Somewhat unrelated to this series, but is the existing code correct? I'd expect the RHS to be masked by word_mask; otherwise we might set bits in bits[] that were not requested? And if one does that, the !word_mask test is merely an optimization to avoid reading the gpios when the result would be ignored anyway. Perhaps no caller cares. Rasmus