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

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

/**
 * 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");
}

/*
 * This is used by external users of of_gpio_count() from <linux/of_gpio.h>
 *
 * FIXME: get rid of those external users by converting them to GPIO
 * descriptors and let them all use gpiod_count()
 */
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 chip->gpiodev->dev.of_node == gpiospec->np &&
				chip->of_xlate &&
				chip->of_xlate(chip, gpiospec, NULL) >= 0;
}

static struct gpio_chip *of_find_gpiochip_by_xlate(
					struct of_phandle_args *gpiospec)
{
	return gpiochip_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);
}

/**
 * of_gpio_need_valid_mask() - figure out if the OF GPIO driver needs
 * to set the .valid_mask
 * @gc: the target gpio_chip
 *
 * Return: true if the valid mask needs to be set
 */
bool of_gpio_need_valid_mask(const struct gpio_chip *gc)
{
	int size;
	const struct device_node *np = gc->of_node;

	size = of_property_count_u32_elems(np,  "gpio-reserved-ranges");
	if (size > 0 && size % 2 == 0)
		return true;
	return false;
}

static void of_gpio_flags_quirks(const struct device_node *np,
				 const char *propname,
				 enum of_gpio_flags *flags,
				 int index)
{
	/*
	 * Some GPIO fixed regulator quirks.
	 * Note that active low is the default.
	 */
	if (IS_ENABLED(CONFIG_REGULATOR) &&
	    (of_device_is_compatible(np, "regulator-fixed") ||
	     of_device_is_compatible(np, "reg-fixed-voltage") ||
	     (!(strcmp(propname, "enable-gpio") &&
		strcmp(propname, "enable-gpios")) &&
	      of_device_is_compatible(np, "regulator-gpio")))) {
		bool active_low = !of_property_read_bool(np,
							 "enable-active-high");
		/*
		 * The regulator GPIO handles are specified such that the
		 * presence or absence of "enable-active-high" solely controls
		 * the polarity of the GPIO line. Any phandle flags must
		 * be actively ignored.
		 */
		if ((*flags & OF_GPIO_ACTIVE_LOW) && !active_low) {
			pr_warn("%s GPIO handle specifies active low - ignored\n",
				of_node_full_name(np));
			*flags &= ~OF_GPIO_ACTIVE_LOW;
		}
		if (active_low)
			*flags |= OF_GPIO_ACTIVE_LOW;
	}
	/*
	 * Legacy open drain handling for fixed voltage regulators.
	 */
	if (IS_ENABLED(CONFIG_REGULATOR) &&
	    of_device_is_compatible(np, "reg-fixed-voltage") &&
	    of_property_read_bool(np, "gpio-open-drain")) {
		*flags |= (OF_GPIO_SINGLE_ENDED | OF_GPIO_OPEN_DRAIN);
		pr_info("%s uses legacy open drain flag - update the DTS if you can\n",
			of_node_full_name(np));
	}