1 // SPDX-License-Identifier: GPL-2.0
2
3 #include <linux/auxiliary_bus.h>
4 #include <linux/gpio/consumer.h>
5 #include <linux/module.h>
6 #include <linux/property.h>
7 #include <linux/reset-controller.h>
8
9 struct reset_gpio_priv {
10 struct reset_controller_dev rc;
11 struct gpio_desc *reset;
12 };
13
14 static inline struct reset_gpio_priv
rc_to_reset_gpio(struct reset_controller_dev * rc)15 *rc_to_reset_gpio(struct reset_controller_dev *rc)
16 {
17 return container_of(rc, struct reset_gpio_priv, rc);
18 }
19
reset_gpio_assert(struct reset_controller_dev * rc,unsigned long id)20 static int reset_gpio_assert(struct reset_controller_dev *rc, unsigned long id)
21 {
22 struct reset_gpio_priv *priv = rc_to_reset_gpio(rc);
23
24 return gpiod_set_value_cansleep(priv->reset, 1);
25 }
26
reset_gpio_deassert(struct reset_controller_dev * rc,unsigned long id)27 static int reset_gpio_deassert(struct reset_controller_dev *rc,
28 unsigned long id)
29 {
30 struct reset_gpio_priv *priv = rc_to_reset_gpio(rc);
31
32 return gpiod_set_value_cansleep(priv->reset, 0);
33 }
34
reset_gpio_status(struct reset_controller_dev * rc,unsigned long id)35 static int reset_gpio_status(struct reset_controller_dev *rc, unsigned long id)
36 {
37 struct reset_gpio_priv *priv = rc_to_reset_gpio(rc);
38
39 return gpiod_get_value_cansleep(priv->reset);
40 }
41
42 static const struct reset_control_ops reset_gpio_ops = {
43 .assert = reset_gpio_assert,
44 .deassert = reset_gpio_deassert,
45 .status = reset_gpio_status,
46 };
47
reset_gpio_fwnode_xlate(struct reset_controller_dev * rcdev,const struct fwnode_reference_args * reset_spec)48 static int reset_gpio_fwnode_xlate(struct reset_controller_dev *rcdev,
49 const struct fwnode_reference_args *reset_spec)
50 {
51 return reset_spec->args[0];
52 }
53
reset_gpio_probe(struct auxiliary_device * adev,const struct auxiliary_device_id * id)54 static int reset_gpio_probe(struct auxiliary_device *adev,
55 const struct auxiliary_device_id *id)
56 {
57 struct device *dev = &adev->dev;
58 struct reset_gpio_priv *priv;
59
60 priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
61 if (!priv)
62 return -ENOMEM;
63
64 priv->reset = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
65 if (IS_ERR(priv->reset))
66 return dev_err_probe(dev, PTR_ERR(priv->reset),
67 "Could not get reset gpios\n");
68
69 priv->rc.ops = &reset_gpio_ops;
70 priv->rc.owner = THIS_MODULE;
71 priv->rc.dev = dev;
72
73 /* Cells to match GPIO specifier, but it's not really used */
74 priv->rc.fwnode_reset_n_cells = 2;
75 priv->rc.fwnode_xlate = reset_gpio_fwnode_xlate;
76 priv->rc.nr_resets = 1;
77
78 return devm_reset_controller_register(dev, &priv->rc);
79 }
80
81 static const struct auxiliary_device_id reset_gpio_ids[] = {
82 { .name = "reset.gpio" },
83 {}
84 };
85 MODULE_DEVICE_TABLE(auxiliary, reset_gpio_ids);
86
87 static struct auxiliary_driver reset_gpio_driver = {
88 .probe = reset_gpio_probe,
89 .id_table = reset_gpio_ids,
90 .driver = {
91 .name = "reset-gpio",
92 .suppress_bind_attrs = true,
93 },
94 };
95 module_auxiliary_driver(reset_gpio_driver);
96
97 MODULE_AUTHOR("Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>");
98 MODULE_DESCRIPTION("Generic GPIO reset driver");
99 MODULE_LICENSE("GPL");
100