1 // SPDX-License-Identifier: GPL-2.0+
3 * Software Node helpers for the GPIO API
5 * Copyright 2022 Google LLC
8 #include <linux/errno.h>
9 #include <linux/kernel.h>
10 #include <linux/printk.h>
11 #include <linux/property.h>
12 #include <linux/string.h>
14 #include <linux/gpio/consumer.h>
15 #include <linux/gpio/driver.h>
18 #include "gpiolib-swnode.h"
20 static void swnode_format_propname(const char *con_id, char *propname,
24 * Note we do not need to try both -gpios and -gpio suffixes,
25 * as, unlike OF and ACPI, we can fix software nodes to conform
26 * to the proper binding.
29 snprintf(propname, max_size, "%s-gpios", con_id);
31 strscpy(propname, "gpios", max_size);
34 static struct gpio_device *swnode_get_gpio_device(struct fwnode_handle *fwnode)
36 const struct software_node *gdev_node;
37 struct gpio_device *gdev;
39 gdev_node = to_software_node(fwnode);
40 if (!gdev_node || !gdev_node->name)
41 return ERR_PTR(-EINVAL);
43 gdev = gpio_device_find_by_label(gdev_node->name);
44 return gdev ?: ERR_PTR(-EPROBE_DEFER);
47 struct gpio_desc *swnode_find_gpio(struct fwnode_handle *fwnode,
48 const char *con_id, unsigned int idx,
51 const struct software_node *swnode;
52 struct fwnode_reference_args args;
53 struct gpio_desc *desc;
54 char propname[32]; /* 32 is max size of property name */
57 swnode = to_software_node(fwnode);
59 return ERR_PTR(-EINVAL);
61 swnode_format_propname(con_id, propname, sizeof(propname));
64 * We expect all swnode-described GPIOs have GPIO number and
65 * polarity arguments, hence nargs is set to 2.
67 error = fwnode_property_get_reference_args(fwnode, propname, NULL, 2, idx, &args);
69 pr_debug("%s: can't parse '%s' property of node '%pfwP[%d]'\n",
70 __func__, propname, fwnode, idx);
71 return ERR_PTR(error);
74 struct gpio_device *gdev __free(gpio_device_put) =
75 swnode_get_gpio_device(args.fwnode);
76 fwnode_handle_put(args.fwnode);
78 return ERR_CAST(gdev);
81 * FIXME: The GPIO device reference is put at return but the descriptor
82 * is passed on. Find a proper solution.
84 desc = gpio_device_get_desc(gdev, args.args[0]);
85 *flags = args.args[1]; /* We expect native GPIO flags */
87 pr_debug("%s: parsed '%s' property of node '%pfwP[%d]' - status (%d)\n",
88 __func__, propname, fwnode, idx, PTR_ERR_OR_ZERO(desc));
94 * swnode_gpio_count - count the GPIOs associated with a device / function
95 * @fwnode: firmware node of the GPIO consumer, can be %NULL for
97 * @con_id: function within the GPIO consumer
100 * The number of GPIOs associated with a device / function or %-ENOENT,
101 * if no GPIO has been assigned to the requested function.
103 int swnode_gpio_count(const struct fwnode_handle *fwnode, const char *con_id)
105 struct fwnode_reference_args args;
109 swnode_format_propname(con_id, propname, sizeof(propname));
112 * This is not very efficient, but GPIO lists usually have only
116 while (fwnode_property_get_reference_args(fwnode, propname, NULL, 0,
117 count, &args) == 0) {
118 fwnode_handle_put(args.fwnode);
122 return count ?: -ENOENT;