path: root/drivers/gpio/gpiolib-of.c

// SPDX-License-Identifier: GPL-2.0+
/*
 * OF helpers for the GPIO API
 *
 * Copyright (c) 2007-2008  MontaVista Software, Inc.
 *
 * Author: Anton Vorontsov <avorontsov@ru.mvista.com>
 */

#include <linux/device.h>
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/io.h>
#include <linux/module.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/of_gpio.h>
#include <linux/pinctrl/pinctrl.h>
#include <linux/slab.h>
#include <linux/string.h>

#include <linux/gpio/consumer.h>
#include <linux/gpio/machine.h>

#include "gpiolib.h"
#include "gpiolib-of.h"

/*
 * This is Linux-specific flags. By default controllers' and Linux' mapping
 * match, but GPIO controllers are free to translate their own flags to
 * Linux-specific in their .xlate callback. Though, 1:1 mapping is recommended.
 */
enum of_gpio_flags {
	OF_GPIO_ACTIVE_LOW = 0x1,
	OF_GPIO_SINGLE_ENDED = 0x2,
	OF_GPIO_OPEN_DRAIN = 0x4,
	OF_GPIO_TRANSITORY = 0x8,
	OF_GPIO_PULL_UP = 0x10,
	OF_GPIO_PULL_DOWN = 0x20,
	OF_GPIO_PULL_DISABLE = 0x40,
};

/**
 * of_gpio_named_count() - Count GPIOs for a device
 * @np:		device node to count GPIOs for
 * @propname:	property name containing gpio specifier(s)
 *
 * The function returns the count of GPIOs specified for a node.
 * Note that the empty GPIO specifiers count too. Returns either
 *   Number of gpios defined in property,
 *   -EINVAL for an incorrectly formed gpios property, or
 *   -ENOENT for a missing gpios property
 *
 * Example:
 * gpios = <0
 *          &gpio1 1 2
 *          0
 *          &gpio2 3 4>;
 *
 * The above example defines four GPIOs, two of which are not specified.
 * This function will return '4'
 */
static int of_gpio_named_count(const struct device_node *np,
			       const char *propname)
{
	return of_count_phandle_with_args(np, propname, "#gpio-cells");
}

/**
 * of_gpio_spi_cs_get_count() - special GPIO counting for SPI
 * @dev:    Consuming device
 * @con_id: Function within the GPIO consumer
 *
 * Some elder GPIO controllers need special quirks. Currently we handle
 * the Freescale and PPC GPIO controller with bindings that doesn't use the
 * established "cs-gpios" for chip selects but instead rely on
 * "gpios" for the chip select lines. If we detect this, we redirect
 * the counting of "cs-gpios" to count "gpios" transparent to the
 * driver.
 */
static int of_gpio_spi_cs_get_count(struct device *dev, const char *con_id)
{
	struct device_node *np = dev->of_node;

	if (!IS_ENABLED(CONFIG_SPI_MASTER))
		return 0;
	if (!con_id || strcmp(con_id, "cs"))
		return 0;
	if (!of_device_is_compatible(np, "fsl,spi") &&
	    !of_device_is_compatible(np, "aeroflexgaisler,spictrl") &&
	    !of_device_is_compatible(np, "ibm,ppc4xx-spi"))
		return 0;
	return of_gpio_named_count(np, "gpios");
}

int of_gpio_get_count(struct device *dev, const char *con_id)
{
	int ret;
	char propname[32];
	unsigned int i;

	ret = of_gpio_spi_cs_get_count(dev, con_id);
	if (ret > 0)
		return ret;

	for (i = 0; i < ARRAY_SIZE(gpio_suffixes); i++) {
		if (con_id)
			snprintf(propname, sizeof(propname), "%s-%s",
				 con_id, gpio_suffixes[i]);
		else
			snprintf(propname, sizeof(propname), "%s",
				 gpio_suffixes[i]);

		ret = of_gpio_named_count(dev->of_node, propname);
		if (ret > 0)
			break;
	}
	return ret ? ret : -ENOENT;
}

static int of_gpiochip_match_node_and_xlate(struct gpio_chip *chip, void *data)
{
	struct of_phandle_args *gpiospec = data;

	return device_match_of_node(&chip->gpiodev->dev, gpiospec->np) &&
				chip->of_xlate &&
				chip->of_xlate(chip, gpiospec, NULL) >= 0;
}

static struct gpio_device *
of_find_gpio_device_by_xlate(struct of_phandle_args *gpiospec)
{
	return gpio_device_find(gpiospec, of_gpiochip_match_node_and_xlate);
}

static struct gpio_desc *of_xlate_and_get_gpiod_flags(struct gpio_chip *chip,
					struct of_phandle_args *gpiospec,
					enum of_gpio_flags *flags)
{
	int ret;

	if (chip->of_gpio_n_cells != gpiospec->args_count)
		return ERR_PTR(-EINVAL);

	ret = chip->of_xlate(chip, gpiospec, flags);
	if (ret < 0)
		return ERR_PTR(ret);

	return gpiochip_get_desc(chip, ret);
}

/*
 * Overrides stated polarity of a gpio line and warns when there is a
 * discrepancy.
 */
static void of_gpio_quirk_polarity(const struct device_node *np,
				   bool active_high,
				   enum of_gpio_flags *flags)
{
	if (active_high) {
		if (*