1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 * Oxford Semiconductor Reset Controller driver
  4 *
  5 * Copyright (C) 2016 Neil Armstrong <narmstrong@baylibre.com>
  6 * Copyright (C) 2014 Ma Haijun <mahaijuns@gmail.com>
  7 * Copyright (C) 2009 Oxford Semiconductor Ltd
  8 */
  9#include <linux/err.h>
 10#include <linux/init.h>
 11#include <linux/of.h>
 12#include <linux/platform_device.h>
 13#include <linux/reset-controller.h>
 14#include <linux/slab.h>
 15#include <linux/delay.h>
 16#include <linux/types.h>
 17#include <linux/regmap.h>
 18#include <linux/mfd/syscon.h>
 19
 20/* Regmap offsets */
 21#define RST_SET_REGOFFSET	0x34
 22#define RST_CLR_REGOFFSET	0x38
 23
 24struct oxnas_reset {
 25	struct regmap *regmap;
 26	struct reset_controller_dev rcdev;
 27};
 28
 29static int oxnas_reset_reset(struct reset_controller_dev *rcdev,
 30			      unsigned long id)
 31{
 32	struct oxnas_reset *data =
 33		container_of(rcdev, struct oxnas_reset, rcdev);
 34
 35	regmap_write(data->regmap, RST_SET_REGOFFSET, BIT(id));
 36	msleep(50);
 37	regmap_write(data->regmap, RST_CLR_REGOFFSET, BIT(id));
 38
 39	return 0;
 40}
 41
 42static int oxnas_reset_assert(struct reset_controller_dev *rcdev,
 43			      unsigned long id)
 44{
 45	struct oxnas_reset *data =
 46		container_of(rcdev, struct oxnas_reset, rcdev);
 47
 48	regmap_write(data->regmap, RST_SET_REGOFFSET, BIT(id));
 49
 50	return 0;
 51}
 52
 53static int oxnas_reset_deassert(struct reset_controller_dev *rcdev,
 54				unsigned long id)
 55{
 56	struct oxnas_reset *data =
 57		container_of(rcdev, struct oxnas_reset, rcdev);
 58
 59	regmap_write(data->regmap, RST_CLR_REGOFFSET, BIT(id));
 60
 61	return 0;
 62}
 63
 64static const struct reset_control_ops oxnas_reset_ops = {
 65	.reset		= oxnas_reset_reset,
 66	.assert		= oxnas_reset_assert,
 67	.deassert	= oxnas_reset_deassert,
 68};
 69
 70static const struct of_device_id oxnas_reset_dt_ids[] = {
 71	 { .compatible = "oxsemi,ox810se-reset", },
 72	 { .compatible = "oxsemi,ox820-reset", },
 73	 { /* sentinel */ },
 74};
 75
 76static int oxnas_reset_probe(struct platform_device *pdev)
 77{
 78	struct oxnas_reset *data;
 79	struct device *parent;
 80
 81	parent = pdev->dev.parent;
 82	if (!parent) {
 83		dev_err(&pdev->dev, "no parent\n");
 84		return -ENODEV;
 85	}
 86
 87	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 88	if (!data)
 89		return -ENOMEM;
 90
 91	data->regmap = syscon_node_to_regmap(parent->of_node);
 92	if (IS_ERR(data->regmap)) {
 93		dev_err(&pdev->dev, "failed to get parent regmap\n");
 94		return PTR_ERR(data->regmap);
 95	}
 96
 97	platform_set_drvdata(pdev, data);
 98
 99	data->rcdev.owner = THIS_MODULE;
100	data->rcdev.nr_resets = 32;
101	data->rcdev.ops = &oxnas_reset_ops;
102	data->rcdev.of_node = pdev->dev.of_node;
103
104	return devm_reset_controller_register(&pdev->dev, &data->rcdev);
105}
106
107static struct platform_driver oxnas_reset_driver = {
108	.probe	= oxnas_reset_probe,
109	.driver = {
110		.name		= "oxnas-reset",
111		.of_match_table	= oxnas_reset_dt_ids,
112	},
113};
114builtin_platform_driver(oxnas_reset_driver);