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
20struct tps380x_reset {
21 struct reset_controller_dev rcdev;
22 struct gpio_desc *reset_gpio;
23 unsigned int reset_ms;
24};
25
26struct tps380x_reset_devdata {
27 unsigned int min_reset_ms;
28 unsigned int typ_reset_ms;
29 unsigned int max_reset_ms;
30};
31
32static inline
33struct tps380x_reset *to_tps380x_reset(struct reset_controller_dev *rcdev)
34{
35 return container_of(rcdev, struct tps380x_reset, rcdev);
36}
37
38static int
39tps380x_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(desc: tps380x->reset_gpio, value: 1);
44
45 return 0;
46}
47
48static int
49tps380x_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(desc: tps380x->reset_gpio, value: 0);
54 msleep(msecs: tps380x->reset_ms);
55
56 return 0;
57}
58
59static const struct reset_control_ops reset_tps380x_ops = {
60 .assert = tps380x_reset_assert,
61 .deassert = tps380x_reset_deassert,
62};
63
64static 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
71static 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, size: sizeof(*tps380x), GFP_KERNEL);
82 if (!tps380x)
83 return -ENOMEM;
84
85 tps380x->reset_gpio = devm_gpiod_get(dev, con_id: "reset", flags: GPIOD_OUT_HIGH);
86 if (IS_ERR(ptr: tps380x->reset_gpio))
87 return dev_err_probe(dev, err: PTR_ERR(ptr: tps380x->reset_gpio),
88 fmt: "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, rcdev: &tps380x->rcdev);
101}
102
103static 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
109static const struct of_device_id tps380x_reset_dt_ids[] = {
110 { .compatible = "ti,tps3801", .data = &tps3801_reset_data },
111 { /* sentinel */ },
112};
113MODULE_DEVICE_TABLE(of, tps380x_reset_dt_ids);
114
115static 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};
122module_platform_driver(tps380x_reset_driver);
123
124MODULE_AUTHOR("Marco Felsch <kernel@pengutronix.de>");
125MODULE_DESCRIPTION("TI TPS380x Supply Voltage Supervisor and Reset Driver");
126MODULE_LICENSE("GPL v2");
127

source code of linux/drivers/reset/reset-tps380x.c