The ACCES I/O 104-DIO-48E series of devices contain two Programmable Peripheral Interface (PPI) chips of type 82C55, which each feature three 8-bit ports of I/O. Since eight input lines are acquired on a single port input read, the 104-DIO-48E GPIO driver may improve multiple input reads by utilizing a get_multiple callback. This patch implements the dio48e_gpio_get_multiple function which serves as the respective get_multiple callback. Signed-off-by: William Breathitt Gray <vilhelm.gray@xxxxxxxxx> --- drivers/gpio/gpio-104-dio-48e.c | 47 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) diff --git a/drivers/gpio/gpio-104-dio-48e.c b/drivers/gpio/gpio-104-dio-48e.c index bab3b94c5cbc..7d43c77364db 100644 --- a/drivers/gpio/gpio-104-dio-48e.c +++ b/drivers/gpio/gpio-104-dio-48e.c @@ -14,6 +14,7 @@ * This driver supports the following ACCES devices: 104-DIO-48E and * 104-DIO-24E. */ +#include <linux/bitmap.h> #include <linux/bitops.h> #include <linux/device.h> #include <linux/errno.h> @@ -182,6 +183,51 @@ static int dio48e_gpio_get(struct gpio_chip *chip, unsigned offset) return !!(port_state & mask); } +static int dio48e_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask, + unsigned long *bits) +{ + struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip); + size_t i; + const size_t ports[] = { 0, 1, 2, 4, 5, 6 }; + const unsigned int gpio_reg_size = 8; + unsigned int bits_offset; + size_t word_index; + unsigned int word_offset; + unsigned long word_mask; + const unsigned long port_mask = GENMASK(gpio_reg_size, 0); + unsigned long port_state; + + /* 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 */ + port_state = inb(dio48egpio->base + ports[i]); + + /* store acquired bits at respective bits array offset */ + bits[word_index] |= port_state << word_offset; + } + + return 0; +} + static void dio48e_gpio_set(struct gpio_chip *chip, unsigned offset, int value) { struct dio48e_gpio *const dio48egpio = gpiochip_get_data(chip); @@ -384,6 +430,7 @@ static int dio48e_probe(struct device *dev, unsigned int id) dio48egpio->chip.direction_input = dio48e_gpio_direction_input; dio48egpio->chip.direction_output = dio48e_gpio_direction_output; dio48egpio->chip.get = dio48e_gpio_get; + dio48egpio->chip.get_multiple = dio48e_gpio_get_multiple; dio48egpio->chip.set = dio48e_gpio_set; dio48egpio->chip.set_multiple = dio48e_gpio_set_multiple; dio48egpio->base = base[id]; -- 2.16.2 -- To unsubscribe from this list: send the line "unsubscribe linux-gpio" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html