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 <[email protected]> --- drivers/gpio/gpio-104-dio-48e.c | 41 +++++++++++++++++++++++++++++++++++++++++ 1 file changed, 41 insertions(+) diff --git a/drivers/gpio/gpio-104-dio-48e.c b/drivers/gpio/gpio-104-dio-48e.c index bab3b94c5cbc..35ae2357d2ba 100644 --- a/drivers/gpio/gpio-104-dio-48e.c +++ b/drivers/gpio/gpio-104-dio-48e.c @@ -182,6 +182,46 @@ 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); + unsigned int i; + const unsigned int gpio_reg_size = 8; + unsigned int bit_word_offset; + unsigned int bits_mask; + const unsigned long reg_mask = GENMASK(gpio_reg_size, 0); + unsigned int port; + unsigned int in_port; + unsigned long port_state; + + /* clear bits array to a clean slate */ + for (i = 0; i < chip->ngpio; i += BITS_PER_LONG) + bits[i / BITS_PER_LONG] = 0; + + /* get bits are evaluated a gpio register size at a time */ + for (i = 0; i < chip->ngpio; i += gpio_reg_size) { + bit_word_offset = i % BITS_PER_LONG; + bits_mask = mask[BIT_WORD(i)] & (reg_mask << bit_word_offset); + if (!bits_mask) { + /* no get bits in this register so skip to next one */ + continue; + } + + /* compute input port offset */ + port = i / gpio_reg_size; + in_port = (port > 2) ? port + 1 : port; + + /* get input bits */ + port_state = inb(dio48egpio->base + in_port); + + /* store acquired bits */ + bits[BIT_WORD(i)] |= port_state << bit_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 +424,7 @@ 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
