barebox/drivers/gpio/gpio.c

#include <common.h>
#include <command.h>
#include <complete.h>
#include <gpio.h>
#include <errno.h>
#include <malloc.h>

static LIST_HEAD(chip_list);

struct gpio_info {
	struct gpio_chip *chip;
	bool requested;
	char *label;
};

static struct gpio_info gpio_desc[ARCH_NR_GPIOS];

static int gpio_ensure_requested(struct gpio_info *gi, int gpio)
{
	if (gi->requested)
		return 0;

	return gpio_request(gpio, "gpio");
}

int gpio_request(unsigned gpio, const char *label)
{
	struct gpio_info *gi = &gpio_desc[gpio];
	struct gpio_chip *chip = gi->chip;
	int ret;

	if (!gpio_is_valid(gpio))
		return -EINVAL;
	if (!chip)
		return -EINVAL;
	if (gi->requested)
		return -EBUSY;
	if (chip->ops->request) {
		ret = chip->ops->request(chip, gpio - chip->base);
		if (ret)
			return ret;
	}

	gi->requested = true;
	gi->label = xstrdup(label);

	return 0;
}

void gpio_free(unsigned gpio)
{
	struct gpio_info *gi = &gpio_desc[gpio];
	struct gpio_chip *chip = gi->chip;

	if (!gpio_is_valid(gpio))
		return;
	if (!chip)
		return;
	if (!gi->requested)
		return;
	if (chip->ops->free)
		chip->ops->free(chip, gpio - chip->base);

	gi->requested = false;
	free(gi->label);
}

void gpio_set_value(unsigned gpio, int value)
{
	struct gpio_info *gi = &gpio_desc[gpio];
	struct gpio_chip *chip = gi->chip;

	if (!gpio_is_valid(gpio))
		return;
	if (!chip)
		return;
	if (gpio_ensure_requested(gi, gpio))
		return;
	if (!chip->ops->set)
		return;
	chip->ops->set(chip, gpio - chip->base, value);
}
EXPORT_SYMBOL(gpio_set_value);

int gpio_get_value(unsigned gpio)
{
	struct gpio_info *gi = &gpio_desc[gpio];
	struct gpio_chip *chip = gi->chip;
	int ret;

	if (!gpio_is_valid(gpio))
		return -EINVAL;
	if (!chip)
		return -ENODEV;
	ret = gpio_ensure_requested(gi, gpio);
	if (ret)
		return ret;
	if (!chip->ops->get)
		return -ENOSYS;
	return chip->ops->get(chip, gpio - chip->base);
}
EXPORT_SYMBOL(gpio_get_value);

int gpio_direction_output(unsigned gpio, int value)
{
	struct gpio_info *gi = &gpio_desc[gpio];
	struct gpio_chip *chip = gi->chip;
	int ret;

	if (!gpio_is_valid(gpio))
		return -EINVAL;
	if (!chip)
		return -ENODEV;
	ret = gpio_ensure_requested(gi, gpio);
	if (ret)
		return ret;
	if (!chip->ops->direction_output)
		return -ENOSYS;
	return chip->ops->direction_output(chip, gpio - chip->base, value);
}
EXPORT_SYMBOL(gpio_direction_output);

int gpio_direction_input(unsigned gpio)
{
	struct gpio_info *gi = &gpio_desc[gpio];
	struct gpio_chip *chip = gi->chip;
	int ret;

	if (!gpio_is_valid(gpio))
		return -EINVAL;
	if (!chip)
		return -ENODEV;
	ret = gpio_ensure_requested(gi, gpio);
	if (ret)
		return ret;
	if (!chip->ops->direction_input)
		return -ENOSYS;
	return chip->ops->direction_input(chip, gpio - chip->base);
}
EXPORT_SYMBOL(gpio_direction_input);

static int gpiochip_find_base(int start, int ngpio)
{
	int i;
	int spare = 0;
	int base = -ENOSPC;

	if (start < 0)
		start = 0;

	for (i = start; i < ARCH_NR_GPIOS; i++) {
		struct gpio_chip *chip = gpio_desc[i].chip;

		if (!chip) {
			spare++;
			if (spare == ngpio) {
				base = i + 1 - ngpio;
				break;
			}
		} else {
			spare = 0;
			i += chip->ngpio - 1;
		}
	}

	if (gpio_is_valid(base))
		debug("%s: found new base at %d\n", __func__, base);
	return base;
}

int gpiochip_add(struct gpio_chip *chip)
{
	int base, i;

	base = gpiochip_find_base(chip->base, chip->ngpio);
	if (base < 0)
		return base;

	if (chip->base >= 0 && chip->base != base)
		return -EBUSY;

	chip->base = base;

	list_add_tail(&chip->list, &chip_list);

	for (i = chip->base; i < chip->base + chip->ngpio; i++)
		gpio_desc[i].chip = chip;

	return 0;
}

void gpiochip_remove(struct gpio_chip *chip)
{
	list_del(&chip->list);
}

int gpio_get_num(struct device_d *dev, int gpio)
{
	struct gpio_chip *chip;

	list_for_each_entry(chip, &chip_list, list) {
		if (chip->dev == dev)
			return chip->base + gpio;
	}

	return -ENODEV;
}

#ifdef CONFIG_CMD_GPIO
static int do_gpiolib(int argc, char *argv[])
{
	int i;

	printf("gpiolib: gpio lists\n");
	printf("%*crequested  label\n", 11, ' ');

	for (i = 0; i < ARCH_NR_GPIOS; i++) {
		struct gpio_info *gi = &gpio_desc[i];

		if (!gi->chip)
			continue;

		printf("gpio %*d: %*s  %s\n", 4,
			i, 9, gi->requested ? "true" : "false",
			gi->label ? gi->label : "");
	}

	return 0;
}

BAREBOX_CMD_HELP_START(gpiolib)
BAREBOX_CMD_HELP_USAGE("gpiolib\n")
BAREBOX_CMD_HELP_SHORT("dump current registered gpio\n");
BAREBOX_CMD_HELP_END

BAREBOX_CMD_START(gpiolib)
	.cmd		= do_gpiolib,
	.usage		= "dump current registered gpio",
	BAREBOX_CMD_HELP(cmd_gpiolib_help)
	BAREBOX_CMD_COMPLETE(empty_complete)
BAREBOX_CMD_END
#endif