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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 | */ | |
9d50f95b CK |
7 | |
8 | #define pr_fmt(fmt) "gpiolib: swnode: " fmt | |
9 | ||
e7f9ff5d DT |
10 | #include <linux/err.h> |
11 | #include <linux/errno.h> | |
9d50f95b CK |
12 | #include <linux/export.h> |
13 | #include <linux/init.h> | |
e7f9ff5d DT |
14 | #include <linux/kernel.h> |
15 | #include <linux/printk.h> | |
16 | #include <linux/property.h> | |
17 | #include <linux/string.h> | |
18 | ||
380c7ba3 AS |
19 | #include <linux/gpio/consumer.h> |
20 | #include <linux/gpio/driver.h> | |
21 | ||
e7f9ff5d DT |
22 | #include "gpiolib.h" |
23 | #include "gpiolib-swnode.h" | |
24 | ||
9d50f95b CK |
25 | #define GPIOLIB_SWNODE_UNDEFINED_NAME "swnode-gpio-undefined" |
26 | ||
b7b56e64 | 27 | static struct gpio_device *swnode_get_gpio_device(struct fwnode_handle *fwnode) |
e7f9ff5d | 28 | { |
b7b56e64 BG |
29 | const struct software_node *gdev_node; |
30 | struct gpio_device *gdev; | |
e7f9ff5d | 31 | |
b7b56e64 BG |
32 | gdev_node = to_software_node(fwnode); |
33 | if (!gdev_node || !gdev_node->name) | |
e7f9ff5d DT |
34 | return ERR_PTR(-EINVAL); |
35 | ||
9d50f95b CK |
36 | /* |
37 | * Check for a special node that identifies undefined GPIOs, this is | |
38 | * primarily used as a key for internal chip selects in SPI bindings. | |
39 | */ | |
40 | if (IS_ENABLED(CONFIG_GPIO_SWNODE_UNDEFINED) && | |
41 | !strcmp(gdev_node->name, GPIOLIB_SWNODE_UNDEFINED_NAME)) | |
42 | return ERR_PTR(-ENOENT); | |
43 | ||
b7b56e64 BG |
44 | gdev = gpio_device_find_by_label(gdev_node->name); |
45 | return gdev ?: ERR_PTR(-EPROBE_DEFER); | |
e7f9ff5d DT |
46 | } |
47 | ||
7fd68098 AS |
48 | static int swnode_gpio_get_reference(const struct fwnode_handle *fwnode, |
49 | const char *propname, unsigned int idx, | |
50 | struct fwnode_reference_args *args) | |
51 | { | |
52 | /* | |
53 | * We expect all swnode-described GPIOs have GPIO number and | |
54 | * polarity arguments, hence nargs is set to 2. | |
55 | */ | |
56 | return fwnode_property_get_reference_args(fwnode, propname, NULL, 2, idx, args); | |
57 | } | |
58 | ||
e7f9ff5d DT |
59 | struct gpio_desc *swnode_find_gpio(struct fwnode_handle *fwnode, |
60 | const char *con_id, unsigned int idx, | |
61 | unsigned long *flags) | |
62 | { | |
63 | const struct software_node *swnode; | |
64 | struct fwnode_reference_args args; | |
e7f9ff5d DT |
65 | struct gpio_desc *desc; |
66 | char propname[32]; /* 32 is max size of property name */ | |
a14968ae | 67 | int ret = 0; |
e7f9ff5d DT |
68 | |
69 | swnode = to_software_node(fwnode); | |
70 | if (!swnode) | |
71 | return ERR_PTR(-EINVAL); | |
72 | ||
a975a646 AS |
73 | for_each_gpio_property_name(propname, con_id) { |
74 | ret = swnode_gpio_get_reference(fwnode, propname, idx, &args); | |
75 | if (ret == 0) | |
76 | break; | |
77 | } | |
e42fce0f | 78 | if (ret) { |
e7f9ff5d DT |
79 | pr_debug("%s: can't parse '%s' property of node '%pfwP[%d]'\n", |
80 | __func__, propname, fwnode, idx); | |
e42fce0f | 81 | return ERR_PTR(ret); |
e7f9ff5d DT |
82 | } |
83 | ||
b7b56e64 BG |
84 | struct gpio_device *gdev __free(gpio_device_put) = |
85 | swnode_get_gpio_device(args.fwnode); | |
e7f9ff5d | 86 | fwnode_handle_put(args.fwnode); |
b7b56e64 BG |
87 | if (IS_ERR(gdev)) |
88 | return ERR_CAST(gdev); | |
e7f9ff5d | 89 | |
b7b56e64 BG |
90 | /* |
91 | * FIXME: The GPIO device reference is put at return but the descriptor | |
92 | * is passed on. Find a proper solution. | |
93 | */ | |
94 | desc = gpio_device_get_desc(gdev, args.args[0]); | |
e7f9ff5d DT |
95 | *flags = args.args[1]; /* We expect native GPIO flags */ |
96 | ||
97 | pr_debug("%s: parsed '%s' property of node '%pfwP[%d]' - status (%d)\n", | |
98 | __func__, propname, fwnode, idx, PTR_ERR_OR_ZERO(desc)); | |
99 | ||
100 | return desc; | |
101 | } | |
102 | ||
103 | /** | |
104 | * swnode_gpio_count - count the GPIOs associated with a device / function | |
105 | * @fwnode: firmware node of the GPIO consumer, can be %NULL for | |
106 | * system-global GPIOs | |
107 | * @con_id: function within the GPIO consumer | |
108 | * | |
94bd9ce1 | 109 | * Returns: |
e7f9ff5d DT |
110 | * The number of GPIOs associated with a device / function or %-ENOENT, |
111 | * if no GPIO has been assigned to the requested function. | |
112 | */ | |
113 | int swnode_gpio_count(const struct fwnode_handle *fwnode, const char *con_id) | |
114 | { | |
115 | struct fwnode_reference_args args; | |
116 | char propname[32]; | |
117 | int count; | |
118 | ||
e7f9ff5d DT |
119 | /* |
120 | * This is not very efficient, but GPIO lists usually have only | |
121 | * 1 or 2 entries. | |
122 | */ | |
a975a646 AS |
123 | for_each_gpio_property_name(propname, con_id) { |
124 | count = 0; | |
125 | while (swnode_gpio_get_reference(fwnode, propname, count, &args) == 0) { | |
126 | fwnode_handle_put(args.fwnode); | |
127 | count++; | |
128 | } | |
129 | if (count) | |
130 | return count; | |
e7f9ff5d DT |
131 | } |
132 | ||
a975a646 | 133 | return -ENOENT; |
e7f9ff5d | 134 | } |
9d50f95b CK |
135 | |
136 | #if IS_ENABLED(CONFIG_GPIO_SWNODE_UNDEFINED) | |
137 | /* | |
138 | * A special node that identifies undefined GPIOs, this is primarily used as | |
139 | * a key for internal chip selects in SPI bindings. | |
140 | */ | |
141 | const struct software_node swnode_gpio_undefined = { | |
142 | .name = GPIOLIB_SWNODE_UNDEFINED_NAME, | |
143 | }; | |
cdd30ebb | 144 | EXPORT_SYMBOL_NS_GPL(swnode_gpio_undefined, "GPIO_SWNODE"); |
9d50f95b CK |
145 | |
146 | static int __init swnode_gpio_init(void) | |
147 | { | |
148 | int ret; | |
149 | ||
150 | ret = software_node_register(&swnode_gpio_undefined); | |
151 | if (ret < 0) | |
152 | pr_err("failed to register swnode: %d\n", ret); | |
153 | ||
154 | return ret; | |
155 | } | |
156 | subsys_initcall(swnode_gpio_init); | |
157 | ||
158 | static void __exit swnode_gpio_cleanup(void) | |
159 | { | |
160 | software_node_unregister(&swnode_gpio_undefined); | |
161 | } | |
162 | __exitcall(swnode_gpio_cleanup); | |
163 | #endif |