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Commit 41b25131 authored by William Breathitt Gray's avatar William Breathitt Gray Committed by Linus Walleij
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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: default avatarWilliam Breathitt Gray <vilhelm.gray@gmail.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent f72b1071

drivers/gpio/gpio-gpio-mm.c

+47 −0
Original line number Diff line number Diff line
@@ -14,6 +14,7 @@ 
 * This driver supports the following Diamond Systems devices: GPIO-MM and

 * GPIO-MM-12.

 */

#include <linux/bitmap.h>

#include <linux/bitops.h>

#include <linux/device.h>

#include <linux/errno.h>
@@ -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];