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
rc_to_reset_gpio(struct reset_controller_dev * rc)16 *rc_to_reset_gpio(struct reset_controller_dev *rc)
17 {
18 return container_of(rc, struct reset_gpio_priv, rc);
19 }
20
reset_gpio_assert(struct reset_controller_dev * rc,unsigned long id)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(priv->reset, 1);
26
27 return 0;
28 }
29
reset_gpio_deassert(struct reset_controller_dev * rc,unsigned long id)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(priv->reset, 0);
36
37 return 0;
38 }
39
reset_gpio_status(struct reset_controller_dev * rc,unsigned long id)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(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
reset_gpio_of_xlate(struct reset_controller_dev * rcdev,const struct of_phandle_args * reset_spec)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
reset_gpio_of_node_put(void * data)59 static void reset_gpio_of_node_put(void *data)
60 {
61 of_node_put(data);
62 }
63
reset_gpio_probe(struct platform_device * pdev)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, sizeof(*priv), GFP_KERNEL);
75 if (!priv)
76 return -ENOMEM;
77
78 platform_set_drvdata(pdev, &priv->rc);
79
80 priv->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
81 if (IS_ERR(priv->reset))
82 return dev_err_probe(dev, PTR_ERR(priv->reset),
83 "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, &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