1// SPDX-License-Identifier: GPL-2.0
2
3#include <linux/auxiliary_bus.h>
4#include <linux/gpio/consumer.h>
5#include <linux/mod_devicetable.h>
6#include <linux/module.h>
7#include <linux/of.h>
8#include <linux/reset-controller.h>
9
10struct reset_gpio_priv {
11 struct reset_controller_dev rc;
12 struct gpio_desc *reset;
13};
14
15static inline struct reset_gpio_priv
16*rc_to_reset_gpio(struct reset_controller_dev *rc)
17{
18 return container_of(rc, struct reset_gpio_priv, rc);
19}
20
21static int reset_gpio_assert(struct reset_controller_dev *rc, unsigned long id)
22{
23 struct reset_gpio_priv *priv = rc_to_reset_gpio(rc);
24
25 gpiod_set_value_cansleep(desc: priv->reset, value: 1);
26
27 return 0;
28}
29
30static int reset_gpio_deassert(struct reset_controller_dev *rc,
31 unsigned long id)
32{
33 struct reset_gpio_priv *priv = rc_to_reset_gpio(rc);
34
35 gpiod_set_value_cansleep(desc: priv->reset, value: 0);
36
37 return 0;
38}
39
40static int reset_gpio_status(struct reset_controller_dev *rc, unsigned long id)
41{
42 struct reset_gpio_priv *priv = rc_to_reset_gpio(rc);
43
44 return gpiod_get_value_cansleep(desc: priv->reset);
45}
46
47static const struct reset_control_ops reset_gpio_ops = {
48 .assert = reset_gpio_assert,
49 .deassert = reset_gpio_deassert,
50 .status = reset_gpio_status,
51};
52
53static int reset_gpio_of_xlate(struct reset_controller_dev *rcdev,
54 const struct of_phandle_args *reset_spec)
55{
56 return reset_spec->args[0];
57}
58
59static void reset_gpio_of_node_put(void *data)
60{
61 of_node_put(node: data);
62}
63
64static int reset_gpio_probe(struct auxiliary_device *adev,
65 const struct auxiliary_device_id *id)
66{
67 struct device *dev = &adev->dev;
68 struct of_phandle_args *platdata = dev_get_platdata(dev);
69 struct reset_gpio_priv *priv;
70 int ret;
71
72 if (!platdata)
73 return -EINVAL;
74
75 priv = devm_kzalloc(dev, size: sizeof(*priv), GFP_KERNEL);
76 if (!priv)
77 return -ENOMEM;
78
79 auxiliary_set_drvdata(auxdev: adev, data: &priv->rc);
80
81 priv->reset = devm_gpiod_get(dev, con_id: "reset", flags: GPIOD_OUT_HIGH);
82 if (IS_ERR(ptr: priv->reset))
83 return dev_err_probe(dev, err: PTR_ERR(ptr: priv->reset),
84 fmt: "Could not get reset gpios\n");
85
86 priv->rc.ops = &reset_gpio_ops;
87 priv->rc.owner = THIS_MODULE;
88 priv->rc.dev = dev;
89 priv->rc.of_args = platdata;
90 ret = devm_add_action_or_reset(dev, reset_gpio_of_node_put,
91 priv->rc.of_node);
92 if (ret)
93 return ret;
94
95 /* Cells to match GPIO specifier, but it's not really used */
96 priv->rc.of_reset_n_cells = 2;
97 priv->rc.of_xlate = reset_gpio_of_xlate;
98 priv->rc.nr_resets = 1;
99
100 return devm_reset_controller_register(dev, rcdev: &priv->rc);
101}
102
103static const struct auxiliary_device_id reset_gpio_ids[] = {
104 { .name = "reset.gpio" },
105 {}
106};
107MODULE_DEVICE_TABLE(auxiliary, reset_gpio_ids);
108
109static struct auxiliary_driver reset_gpio_driver = {
110 .probe = reset_gpio_probe,
111 .id_table = reset_gpio_ids,
112 .driver = {
113 .name = "reset-gpio",
114 },
115};
116module_auxiliary_driver(reset_gpio_driver);
117
118MODULE_AUTHOR("Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>");
119MODULE_DESCRIPTION("Generic GPIO reset driver");
120MODULE_LICENSE("GPL");
121

source code of linux/drivers/reset/reset-gpio.c