From 41b251318a6359848eef98b630ed578fad2cfbe6 Mon Sep 17 00:00:00 2001 From: William Breathitt Gray Date: Thu, 22 Mar 2018 09:00:42 -0400 Subject: gpio: gpio-mm: Implement get_multiple callback The Diamond Systems GPIO-MM series of devices contain two 82C55A devices, which each feature three 8-bit ports of I/O. Since eight input lines are acquired on a single port input read, the GPIO-MM GPIO driver may improve multiple input reads by utilizing a get_multiple callback. This patch implements the gpiomm_gpio_get_multiple function which serves as the respective get_multiple callback. Signed-off-by: William Breathitt Gray Signed-off-by: Linus Walleij --- drivers/gpio/gpio-gpio-mm.c | 47 +++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 47 insertions(+) (limited to 'drivers/gpio/gpio-gpio-mm.c') diff --git a/drivers/gpio/gpio-gpio-mm.c b/drivers/gpio/gpio-gpio-mm.c index 11ade5b..d496cc56 100644 --- a/drivers/gpio/gpio-gpio-mm.c +++ b/drivers/gpio/gpio-gpio-mm.c @@ -14,6 +14,7 @@ * This driver supports the following Diamond Systems devices: GPIO-MM and * GPIO-MM-12. */ +#include #include #include #include @@ -171,6 +172,51 @@ static int gpiomm_gpio_get(struct gpio_chip *chip, unsigned int offset) return !!(port_state & mask); } +static int gpiomm_gpio_get_multiple(struct gpio_chip *chip, unsigned long *mask, + unsigned long *bits) +{ + struct gpiomm_gpio *const gpiommgpio = 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 - 1, 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(gpiommgpio->base + ports[i]); + + /* store acquired bits at respective bits array offset */ + bits[word_index] |= port_state << word_offset; + } + + return 0; +} + static void gpiomm_gpio_set(struct gpio_chip *chip, unsigned int offset, int value) { @@ -268,6 +314,7 @@ static int gpiomm_probe(struct device *dev, unsigned int id) gpiommgpio->chip.direction_input = gpiomm_gpio_direction_input; gpiommgpio->chip.direction_output = gpiomm_gpio_direction_output; gpiommgpio->chip.get = gpiomm_gpio_get; + gpiommgpio->chip.get_multiple = gpiomm_gpio_get_multiple; gpiommgpio->chip.set = gpiomm_gpio_set; gpiommgpio->chip.set_multiple = gpiomm_gpio_set_multiple; gpiommgpio->base = base[id]; -- cgit v1.1