1 | // SPDX-License-Identifier: GPL-2.0 |
2 | |
3 | #include <linux/gpio/consumer.h> |
4 | #include <linux/mod_devicetable.h> |
5 | #include <linux/module.h> |
6 | #include <linux/of.h> |
7 | #include <linux/platform_device.h> |
8 | #include <linux/reset-controller.h> |
9 | |
10 | struct reset_gpio_priv { |
11 | struct reset_controller_dev rc; |
12 | struct gpio_desc *reset; |
13 | }; |
14 | |
15 | static 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 | |
21 | static 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 | |
30 | static 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 | |
40 | static 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 | |
47 | static 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 | |
53 | static 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 | |
59 | static void reset_gpio_of_node_put(void *data) |
60 | { |
61 | of_node_put(node: data); |
62 | } |
63 | |
64 | static int reset_gpio_probe(struct platform_device *pdev) |
65 | { |
66 | struct device *dev = &pdev->dev; |
67 | struct of_phandle_args *platdata = dev_get_platdata(dev); |
68 | struct reset_gpio_priv *priv; |
69 | int ret; |
70 | |
71 | if (!platdata) |
72 | return -EINVAL; |
73 | |
74 | priv = devm_kzalloc(dev, size: sizeof(*priv), GFP_KERNEL); |
75 | if (!priv) |
76 | return -ENOMEM; |
77 | |
78 | platform_set_drvdata(pdev, data: &priv->rc); |
79 | |
80 | priv->reset = devm_gpiod_get(dev, con_id: "reset" , flags: GPIOD_OUT_HIGH); |
81 | if (IS_ERR(ptr: priv->reset)) |
82 | return dev_err_probe(dev, err: PTR_ERR(ptr: priv->reset), |
83 | fmt: "Could not get reset gpios\n" ); |
84 | |
85 | priv->rc.ops = &reset_gpio_ops; |
86 | priv->rc.owner = THIS_MODULE; |
87 | priv->rc.dev = dev; |
88 | priv->rc.of_args = platdata; |
89 | ret = devm_add_action_or_reset(dev, reset_gpio_of_node_put, |
90 | priv->rc.of_node); |
91 | if (ret) |
92 | return ret; |
93 | |
94 | /* Cells to match GPIO specifier, but it's not really used */ |
95 | priv->rc.of_reset_n_cells = 2; |
96 | priv->rc.of_xlate = reset_gpio_of_xlate; |
97 | priv->rc.nr_resets = 1; |
98 | |
99 | return devm_reset_controller_register(dev, rcdev: &priv->rc); |
100 | } |
101 | |
102 | static const struct platform_device_id reset_gpio_ids[] = { |
103 | { .name = "reset-gpio" , }, |
104 | {} |
105 | }; |
106 | MODULE_DEVICE_TABLE(platform, reset_gpio_ids); |
107 | |
108 | static struct platform_driver reset_gpio_driver = { |
109 | .probe = reset_gpio_probe, |
110 | .id_table = reset_gpio_ids, |
111 | .driver = { |
112 | .name = "reset-gpio" , |
113 | }, |
114 | }; |
115 | module_platform_driver(reset_gpio_driver); |
116 | |
117 | MODULE_AUTHOR("Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>" ); |
118 | MODULE_DESCRIPTION("Generic GPIO reset driver" ); |
119 | MODULE_LICENSE("GPL" ); |
120 | |