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// SPDX-License-Identifier: GPL-2.0+
/*
* Software Node helpers for the GPIO API
*
* Copyright 2022 Google LLC
*/
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/printk.h>
#include <linux/property.h>
#include <linux/string.h>
#include <linux/gpio/consumer.h>
#include <linux/gpio/driver.h>
#include "gpiolib.h"
#include "gpiolib-swnode.h"
static void swnode_format_propname(const char *con_id, char *propname,
size_t max_size)
{
/*
* Note we do not need to try both -gpios and -gpio suffixes,
* as, unlike OF and ACPI, we can fix software nodes to conform
* to the proper binding.
*/
if (con_id)
snprintf(propname, max_size, "%s-gpios", con_id);
else
strscpy(propname, "gpios", max_size);
}
static int swnode_gpiochip_match_name(struct gpio_chip *chip, void *data)
{
return !strcmp(chip->label, data);
}
static struct gpio_chip *swnode_get_chip(struct fwnode_handle *fwnode)
{
const struct software_node *chip_node;
struct gpio_chip *chip;
chip_node = to_software_node(fwnode);
if (!chip_node || !chip_node->name)
return ERR_PTR(-EINVAL);
chip = gpiochip_find((void *)chip_node->name, swnode_gpiochip_match_name);
return chip ?: ERR_PTR(-EPROBE_DEFER);
}
struct gpio_desc *swnode_find_gpio(struct fwnode_handle *fwnode,
const char *con_id, unsigned int idx,
unsigned long *flags)
{
const struct software_node *swnode;
struct fwnode_reference_args args;
struct gpio_chip *chip;
struct gpio_desc *desc;
char propname[32]; /* 32 is max size of property name */
int error;
swnode = to_software_node(fwnode);
if (!swnode)
return ERR_PTR(-EINVAL);
swnode_format_propname(con_id, propname, sizeof(propname));
/*
* We expect all swnode-described GPIOs have GPIO number and
* polarity arguments, hence nargs is set to 2.
*/
error = fwnode_property_get_reference_args(fwnode, propname, NULL, 2, idx, &args);
if (error) {
pr_debug("%s: can't parse '%s' property of node '%pfwP[%d]'\n",
__func__, propname, fwnode, idx);
return ERR_PTR(error);
}
chip = swnode_get_chip(args.fwnode);
fwnode_handle_put(args.fwnode);
if (IS_ERR(chip))
return ERR_CAST(chip);
desc = gpiochip_get_desc(chip, args.args[0]);
*flags = args.args[1]; /* We expect native GPIO flags */
pr_debug("%s: parsed '%s' property of node '%pfwP[%d]' - status (%d)\n",
__func__, propname, fwnode, idx, PTR_ERR_OR_ZERO(desc));
return desc;
}
/**
* swnode_gpio_count - count the GPIOs associated with a device / function
* @fwnode: firmware node of the GPIO consumer, can be %NULL for
* system-global GPIOs
* @con_id: function within the GPIO consumer
*
* Return:
* The number of GPIOs associated with a device / function or %-ENOENT,
* if no GPIO has been assigned to the requested function.
*/
int swnode_gpio_count(const struct fwnode_handle *fwnode, const char *con_id)
{
struct fwnode_reference_args args;
char propname[32];
int count;
swnode_format_propname(con_id, propname, sizeof(propname));
/*
* This is not very efficient, but GPIO lists usually have only
* 1 or 2 entries.
*/
count = 0;
while (fwnode_property_get_reference_args(fwnode, propname, NULL, 0,
count, &args) == 0) {
fwnode_handle_put(args.fwnode);
count++;
}
return count ?: -ENOENT;
}
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