Commit 96d7c7b3 authored by Paul Thomas's avatar Paul Thomas Committed by Bartosz Golaszewski
Browse files

gpio: gpio-pca953x, Add get_multiple function 



Implement a get_multiple function for gpio-pca953x. If a driver
leaves get_multiple unimplemented then gpio_chip_get_multiple()
in gpiolib.c takes care of it by calling chip->get() as needed.
For i2c chips this is very inefficient. For example if you do an
8-bit read then instead of a single i2c transaction there are
8 transactions reading the same byte!

Signed-off-by: default avatarPaul Thomas <pthomas8589@gmail.com>
Acked-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarBartosz Golaszewski <bgolaszewski@baylibre.com>
parent ea06a482

drivers/gpio/gpio-pca953x.c

+37 −0
Original line number Diff line number Diff line
@@ -115,6 +115,7 @@ MODULE_DEVICE_TABLE(acpi, pca953x_acpi_ids); 


#define MAX_BANK 5

#define BANK_SZ 8

#define BANK_SFT 3 /* ilog2(BANK_SZ) */

#define MAX_LINE	(MAX_BANK * BANK_SZ)



#define NBANK(chip) DIV_ROUND_UP(chip->gpio_chip.ngpio, BANK_SZ)
@@ -466,6 +467,41 @@ static int pca953x_gpio_get_direction(struct gpio_chip *gc, unsigned off) 
	return GPIO_LINE_DIRECTION_OUT;

}



static int pca953x_gpio_get_multiple(struct gpio_chip *gc,

				      unsigned long *mask, unsigned long *bits)

{

	struct pca953x_chip *chip = gpiochip_get_data(gc);

	unsigned int reg_val;

	int offset, value, i, ret = 0;

	u8 inreg;



	/* Force offset outside the range of i so that

	 * at least the first relevant register is read

	 */

	offset = gc->ngpio;

	for_each_set_bit(i, mask, gc->ngpio) {

		/* whenever i goes into a new bank update inreg

		 * and read the register

		 */

		if ((offset >> BANK_SFT) != (i >> BANK_SFT)) {

			offset = i;

			inreg = pca953x_recalc_addr(chip, chip->regs->input,

						    offset, true, false);

			mutex_lock(&chip->i2c_lock);

			ret = regmap_read(chip->regmap, inreg, &reg_val);

			mutex_unlock(&chip->i2c_lock);

			if (ret < 0)

				return ret;

		}

		/* reg_val is relative to the last read byte,

		 * so only shift the relative bits

		 */

		value = (reg_val >> (i % 8)) & 0x01;

		__assign_bit(i, bits, value);

	}

	return ret;

}



static void pca953x_gpio_set_multiple(struct gpio_chip *gc,

				      unsigned long *mask, unsigned long *bits)

{
@@ -551,6 +587,7 @@ static void pca953x_setup_gpio(struct pca953x_chip *chip, int gpios) 
	gc->get = pca953x_gpio_get_value;

	gc->set = pca953x_gpio_set_value;

	gc->get_direction = pca953x_gpio_get_direction;

	gc->get_multiple = pca953x_gpio_get_multiple;

	gc->set_multiple = pca953x_gpio_set_multiple;

	gc->set_config = pca953x_gpio_set_config;

	gc->can_sleep = true;

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