Hi William, I love your patch! Perhaps something to improve: [auto build test WARNING on linus/master] [also build test WARNING on v4.16-rc5 next-20180313] [if your patch is applied to the wrong git tree, please drop us a note to help improve the system] url: https://github.com/0day-ci/linux/commits/William-Breathitt-Gray/Implement-get_multiple-for-ACCES-and-PC104-drivers/20180313-202244 config: x86_64-randconfig-x015-201810 (attached as .config) compiler: gcc-7 (Debian 7.3.0-1) 7.3.0 reproduce: # save the attached .config to linux build tree make ARCH=x86_64 Note: it may well be a FALSE warning. FWIW you are at least aware of it now. http://gcc.gnu.org/wiki/Better_Uninitialized_Warnings All warnings (new ones prefixed by >>): drivers//gpio/gpio-pci-idio-16.c: In function 'idio_16_gpio_get_multiple': >> drivers//gpio/gpio-pci-idio-16.c:147:35: warning: 'port_state' may be used uninitialized in this function [-Wmaybe-uninitialized] bits[BIT_WORD(i)] |= port_state << bit_word_offset; ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~ vim +/port_state +147 drivers//gpio/gpio-pci-idio-16.c 105 106 static int idio_16_gpio_get_multiple(struct gpio_chip *chip, 107 unsigned long *mask, unsigned long *bits) 108 { 109 struct idio_16_gpio *const idio16gpio = gpiochip_get_data(chip); 110 unsigned int i; 111 const unsigned int gpio_reg_size = 8; 112 unsigned int bit_word_offset; 113 unsigned int bits_mask; 114 const unsigned long reg_mask = GENMASK(gpio_reg_size, 0); 115 unsigned long port_state; 116 117 /* clear bits array to a clean slate */ 118 for (i = 0; i < chip->ngpio; i += BITS_PER_LONG) 119 bits[i / BITS_PER_LONG] = 0; 120 121 /* get bits are evaluated a gpio register size at a time */ 122 for (i = 0; i < chip->ngpio; i += gpio_reg_size) { 123 bit_word_offset = i % BITS_PER_LONG; 124 bits_mask = mask[BIT_WORD(i)] & (reg_mask << bit_word_offset); 125 if (!bits_mask) { 126 /* no get bits in this register so skip to next one */ 127 continue; 128 } 129 130 /* read bits from current gpio register */ 131 switch (i / gpio_reg_size) { 132 case 0: 133 port_state = ioread8(&idio16gpio->reg->out0_7); 134 break; 135 case 1: 136 port_state = ioread8(&idio16gpio->reg->out8_15); 137 break; 138 case 2: 139 port_state = ioread8(&idio16gpio->reg->in0_7); 140 break; 141 case 3: 142 port_state = ioread8(&idio16gpio->reg->in8_15); 143 break; 144 } 145 146 /* store acquired bits */ > 147 bits[BIT_WORD(i)] |= port_state << bit_word_offset; 148 } 149 150 return 0; 151 } 152 --- 0-DAY kernel test infrastructure Open Source Technology Center https://lists.01.org/pipermail/kbuild-all Intel Corporation
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