Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 25553ff0 authored by Laxman Dewangan's avatar Laxman Dewangan Committed by Grant Likely
Browse files

gpio: gpiolib: Support for open source/emitter gpios 



Adding support for the open source gpio on which client
can specify the open source property through GPIO flag
GPIOF_OPEN_SOURCE at the time of gpio request.
The open source pins are normally pulled low and it
cannot be driven to output with value of 0 and so
when client request for setting the pin to LOW, the
gpio will be set to input direction to make pin in tristate
and hence PULL-DOWN on pins will make the state to LOW.
The open source pin can be driven to HIGH by setting output
with value of 1.

Signed-off-by: default avatarLaxman Dewangan <ldewangan@nvidia.com>
Reviwed-by: default avatarMark Brown <broonie@opensource.wolfsonmicro.com>
Acked-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
parent aca5ce14

drivers/gpio/gpiolib.c

+39 −0
Original line number Diff line number Diff line
@@ -59,6 +59,7 @@ struct gpio_desc { 
#define FLAG_TRIG_RISE	6	/* trigger on rising edge */

#define FLAG_ACTIVE_LOW	7	/* sysfs value has active low */

#define FLAG_OPEN_DRAIN	8	/* Gpio is open drain type */

#define FLAG_OPEN_SOURCE 9	/* Gpio is open source type */



#define ID_SHIFT	16	/* add new flags before this one */
@@ -1266,6 +1267,7 @@ void gpio_free(unsigned gpio) 
		clear_bit(FLAG_ACTIVE_LOW, &desc->flags);

		clear_bit(FLAG_REQUESTED, &desc->flags);

		clear_bit(FLAG_OPEN_DRAIN, &desc->flags);

		clear_bit(FLAG_OPEN_SOURCE, &desc->flags);

	} else

		WARN_ON(extra_checks);
@@ -1290,6 +1292,9 @@ int gpio_request_one(unsigned gpio, unsigned long flags, const char *label) 
	if (flags & GPIOF_OPEN_DRAIN)

		set_bit(FLAG_OPEN_DRAIN, &gpio_desc[gpio].flags);



	if (flags & GPIOF_OPEN_SOURCE)

		set_bit(FLAG_OPEN_SOURCE, &gpio_desc[gpio].flags);



	if (flags & GPIOF_DIR_IN)

		err = gpio_direction_input(gpio);

	else
@@ -1443,6 +1448,10 @@ int gpio_direction_output(unsigned gpio, int value) 
	if (value && test_bit(FLAG_OPEN_DRAIN,  &desc->flags))

		return gpio_direction_input(gpio);



	/* Open source pin should not be driven to 0 */

	if (!value && test_bit(FLAG_OPEN_SOURCE,  &desc->flags))

		return gpio_direction_input(gpio);



	spin_lock_irqsave(&gpio_lock, flags);



	if (!gpio_is_valid(gpio))
@@ -1604,6 +1613,32 @@ static void _gpio_set_open_drain_value(unsigned gpio, 
					__func__, gpio, err);

}



/*

 *  _gpio_set_open_source() - Set the open source gpio's value.

 * @gpio: Gpio whose state need to be set.

 * @chip: Gpio chip.

 * @value: Non-zero for setting it HIGH otherise it will set to LOW.

 */

static void _gpio_set_open_source_value(unsigned gpio,

			struct gpio_chip *chip, int value)

{

	int err = 0;

	if (value) {

		err = chip->direction_output(chip, gpio - chip->base, 1);

		if (!err)

			set_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags);

	} else {

		err = chip->direction_input(chip, gpio - chip->base);

		if (!err)

			clear_bit(FLAG_IS_OUT, &gpio_desc[gpio].flags);

	}

	trace_gpio_direction(gpio, !value, err);

	if (err < 0)

		pr_err("%s: Error in set_value for open source gpio%d err %d\n",

					__func__, gpio, err);

}





/**

 * __gpio_set_value() - assign a gpio's value

 * @gpio: gpio whose value will be assigned
@@ -1622,6 +1657,8 @@ void __gpio_set_value(unsigned gpio, int value) 
	trace_gpio_value(gpio, 0, value);

	if (test_bit(FLAG_OPEN_DRAIN,  &gpio_desc[gpio].flags))

		_gpio_set_open_drain_value(gpio, chip, value);

	else if (test_bit(FLAG_OPEN_SOURCE,  &gpio_desc[gpio].flags))

		_gpio_set_open_source_value(gpio, chip, value);

	else

		chip->set(chip, gpio - chip->base, value);

}
@@ -1692,6 +1729,8 @@ void gpio_set_value_cansleep(unsigned gpio, int value) 
	trace_gpio_value(gpio, 0, value);

	if (test_bit(FLAG_OPEN_DRAIN,  &gpio_desc[gpio].flags))

		_gpio_set_open_drain_value(gpio, chip, value);

	else if (test_bit(FLAG_OPEN_SOURCE,  &gpio_desc[gpio].flags))

		_gpio_set_open_source_value(gpio, chip, value);

	else

		chip->set(chip, gpio - chip->base, value);

}

include/linux/gpio.h

+3 −0
Original line number Diff line number Diff line
@@ -17,6 +17,9 @@ 
/* Gpio pin is open drain */

#define GPIOF_OPEN_DRAIN	(1 << 2)



/* Gpio pin is open source */

#define GPIOF_OPEN_SOURCE	(1 << 3)



/**

 * struct gpio - a structure describing a GPIO with configuration

 * @gpio:	the GPIO number