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e7f9ff5d DT |
1 | // SPDX-License-Identifier: GPL-2.0+ |
2 | /* | |
3 | * Software Node helpers for the GPIO API | |
4 | * | |
5 | * Copyright 2022 Google LLC | |
6 | */ | |
7 | #include <linux/err.h> | |
8 | #include <linux/errno.h> | |
e7f9ff5d DT |
9 | #include <linux/kernel.h> |
10 | #include <linux/printk.h> | |
11 | #include <linux/property.h> | |
12 | #include <linux/string.h> | |
13 | ||
380c7ba3 AS |
14 | #include <linux/gpio/consumer.h> |
15 | #include <linux/gpio/driver.h> | |
16 | ||
e7f9ff5d DT |
17 | #include "gpiolib.h" |
18 | #include "gpiolib-swnode.h" | |
19 | ||
20 | static void swnode_format_propname(const char *con_id, char *propname, | |
21 | size_t max_size) | |
22 | { | |
23 | /* | |
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. | |
27 | */ | |
28 | if (con_id) | |
29 | snprintf(propname, max_size, "%s-gpios", con_id); | |
30 | else | |
31 | strscpy(propname, "gpios", max_size); | |
32 | } | |
33 | ||
b7b56e64 | 34 | static struct gpio_device *swnode_get_gpio_device(struct fwnode_handle *fwnode) |
e7f9ff5d | 35 | { |
b7b56e64 BG |
36 | const struct software_node *gdev_node; |
37 | struct gpio_device *gdev; | |
e7f9ff5d | 38 | |
b7b56e64 BG |
39 | gdev_node = to_software_node(fwnode); |
40 | if (!gdev_node || !gdev_node->name) | |
e7f9ff5d DT |
41 | return ERR_PTR(-EINVAL); |
42 | ||
b7b56e64 BG |
43 | gdev = gpio_device_find_by_label(gdev_node->name); |
44 | return gdev ?: ERR_PTR(-EPROBE_DEFER); | |
e7f9ff5d DT |
45 | } |
46 | ||
47 | struct gpio_desc *swnode_find_gpio(struct fwnode_handle *fwnode, | |
48 | const char *con_id, unsigned int idx, | |
49 | unsigned long *flags) | |
50 | { | |
51 | const struct software_node *swnode; | |
52 | struct fwnode_reference_args args; | |
e7f9ff5d DT |
53 | struct gpio_desc *desc; |
54 | char propname[32]; /* 32 is max size of property name */ | |
55 | int error; | |
56 | ||
57 | swnode = to_software_node(fwnode); | |
58 | if (!swnode) | |
59 | return ERR_PTR(-EINVAL); | |
60 | ||
61 | swnode_format_propname(con_id, propname, sizeof(propname)); | |
62 | ||
63 | /* | |
64 | * We expect all swnode-described GPIOs have GPIO number and | |
65 | * polarity arguments, hence nargs is set to 2. | |
66 | */ | |
67 | error = fwnode_property_get_reference_args(fwnode, propname, NULL, 2, idx, &args); | |
68 | if (error) { | |
69 | pr_debug("%s: can't parse '%s' property of node '%pfwP[%d]'\n", | |
70 | __func__, propname, fwnode, idx); | |
71 | return ERR_PTR(error); | |
72 | } | |
73 | ||
b7b56e64 BG |
74 | struct gpio_device *gdev __free(gpio_device_put) = |
75 | swnode_get_gpio_device(args.fwnode); | |
e7f9ff5d | 76 | fwnode_handle_put(args.fwnode); |
b7b56e64 BG |
77 | if (IS_ERR(gdev)) |
78 | return ERR_CAST(gdev); | |
e7f9ff5d | 79 | |
b7b56e64 BG |
80 | /* |
81 | * FIXME: The GPIO device reference is put at return but the descriptor | |
82 | * is passed on. Find a proper solution. | |
83 | */ | |
84 | desc = gpio_device_get_desc(gdev, args.args[0]); | |
e7f9ff5d DT |
85 | *flags = args.args[1]; /* We expect native GPIO flags */ |
86 | ||
87 | pr_debug("%s: parsed '%s' property of node '%pfwP[%d]' - status (%d)\n", | |
88 | __func__, propname, fwnode, idx, PTR_ERR_OR_ZERO(desc)); | |
89 | ||
90 | return desc; | |
91 | } | |
92 | ||
93 | /** | |
94 | * swnode_gpio_count - count the GPIOs associated with a device / function | |
95 | * @fwnode: firmware node of the GPIO consumer, can be %NULL for | |
96 | * system-global GPIOs | |
97 | * @con_id: function within the GPIO consumer | |
98 | * | |
99 | * Return: | |
100 | * The number of GPIOs associated with a device / function or %-ENOENT, | |
101 | * if no GPIO has been assigned to the requested function. | |
102 | */ | |
103 | int swnode_gpio_count(const struct fwnode_handle *fwnode, const char *con_id) | |
104 | { | |
105 | struct fwnode_reference_args args; | |
106 | char propname[32]; | |
107 | int count; | |
108 | ||
109 | swnode_format_propname(con_id, propname, sizeof(propname)); | |
110 | ||
111 | /* | |
112 | * This is not very efficient, but GPIO lists usually have only | |
113 | * 1 or 2 entries. | |
114 | */ | |
115 | count = 0; | |
116 | while (fwnode_property_get_reference_args(fwnode, propname, NULL, 0, | |
117 | count, &args) == 0) { | |
118 | fwnode_handle_put(args.fwnode); | |
119 | count++; | |
120 | } | |
121 | ||
122 | return count ?: -ENOENT; | |
123 | } |