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(tps380x->reset_gpio, 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(tps380x->reset_gpio, 0);
 54	msleep(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, 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
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");