1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * TI TPS380x Supply Voltage Supervisor and Reset Controller Driver
4 *
5 * Copyright (C) 2022 Pengutronix, Marco Felsch <kernel@pengutronix.de>
6 *
7 * Based on Simple Reset Controller Driver
8 *
9 * Copyright (C) 2017 Pengutronix, Philipp Zabel <kernel@pengutronix.de>
10 */
11
12 #include <linux/delay.h>
13 #include <linux/gpio/consumer.h>
14 #include <linux/module.h>
15 #include <linux/of.h>
16 #include <linux/platform_device.h>
17 #include <linux/property.h>
18 #include <linux/reset-controller.h>
19
20 struct tps380x_reset {
21 struct reset_controller_dev rcdev;
22 struct gpio_desc *reset_gpio;
23 unsigned int reset_ms;
24 };
25
26 struct tps380x_reset_devdata {
27 unsigned int min_reset_ms;
28 unsigned int typ_reset_ms;
29 unsigned int max_reset_ms;
30 };
31
32 static inline
to_tps380x_reset(struct reset_controller_dev * rcdev)33 struct tps380x_reset *to_tps380x_reset(struct reset_controller_dev *rcdev)
34 {
35 return container_of(rcdev, struct tps380x_reset, rcdev);
36 }
37
38 static int
tps380x_reset_assert(struct reset_controller_dev * rcdev,unsigned long id)39 tps380x_reset_assert(struct reset_controller_dev *rcdev, unsigned long id)
40 {
41 struct tps380x_reset *tps380x = to_tps380x_reset(rcdev);
42
43 gpiod_set_value_cansleep(tps380x->reset_gpio, 1);
44
45 return 0;
46 }
47
48 static int
tps380x_reset_deassert(struct reset_controller_dev * rcdev,unsigned long id)49 tps380x_reset_deassert(struct reset_controller_dev *rcdev, unsigned long id)
50 {
51 struct tps380x_reset *tps380x = to_tps380x_reset(rcdev);
52
53 gpiod_set_value_cansleep(tps380x->reset_gpio, 0);
54 msleep(tps380x->reset_ms);
55
56 return 0;
57 }
58
59 static const struct reset_control_ops reset_tps380x_ops = {
60 .assert = tps380x_reset_assert,
61 .deassert = tps380x_reset_deassert,
62 };
63
tps380x_reset_of_xlate(struct reset_controller_dev * rcdev,const struct of_phandle_args * reset_spec)64 static int tps380x_reset_of_xlate(struct reset_controller_dev *rcdev,
65 const struct of_phandle_args *reset_spec)
66 {
67 /* No special handling needed, we have only one reset line per device */
68 return 0;
69 }
70
tps380x_reset_probe(struct platform_device * pdev)71 static int tps380x_reset_probe(struct platform_device *pdev)
72 {
73 struct device *dev = &pdev->dev;
74 const struct tps380x_reset_devdata *devdata;
75 struct tps380x_reset *tps380x;
76
77 devdata = device_get_match_data(dev);
78 if (!devdata)
79 return -EINVAL;
80
81 tps380x = devm_kzalloc(dev, sizeof(*tps380x), GFP_KERNEL);
82 if (!tps380x)
83 return -ENOMEM;
84
85 tps380x->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_HIGH);
86 if (IS_ERR(tps380x->reset_gpio))
87 return dev_err_probe(dev, PTR_ERR(tps380x->reset_gpio),
88 "Failed to get GPIO\n");
89
90 tps380x->reset_ms = devdata->max_reset_ms;
91
92 tps380x->rcdev.ops = &reset_tps380x_ops;
93 tps380x->rcdev.owner = THIS_MODULE;
94 tps380x->rcdev.dev = dev;
95 tps380x->rcdev.of_node = dev->of_node;
96 tps380x->rcdev.of_reset_n_cells = 0;
97 tps380x->rcdev.of_xlate = tps380x_reset_of_xlate;
98 tps380x->rcdev.nr_resets = 1;
99
100 return devm_reset_controller_register(dev, &tps380x->rcdev);
101 }
102
103 static const struct tps380x_reset_devdata tps3801_reset_data = {
104 .min_reset_ms = 120,
105 .typ_reset_ms = 200,
106 .max_reset_ms = 280,
107 };
108
109 static const struct of_device_id tps380x_reset_dt_ids[] = {
110 { .compatible = "ti,tps3801", .data = &tps3801_reset_data },
111 { /* sentinel */ },
112 };
113 MODULE_DEVICE_TABLE(of, tps380x_reset_dt_ids);
114
115 static struct platform_driver tps380x_reset_driver = {
116 .probe = tps380x_reset_probe,
117 .driver = {
118 .name = "tps380x-reset",
119 .of_match_table = tps380x_reset_dt_ids,
120 },
121 };
122 module_platform_driver(tps380x_reset_driver);
123
124 MODULE_AUTHOR("Marco Felsch <kernel@pengutronix.de>");
125 MODULE_DESCRIPTION("TI TPS380x Supply Voltage Supervisor and Reset Driver");
126 MODULE_LICENSE("GPL v2");
127