1/*
  2 * drivers/reset/reset-oxnas.c
  3 *
  4 * Copyright (C) 2016 Neil Armstrong <narmstrong@baylibre.com>
  5 * Copyright (C) 2014 Ma Haijun <mahaijuns@gmail.com>
  6 * Copyright (C) 2009 Oxford Semiconductor Ltd
  7 *
  8 * This program is free software; you can redistribute it and/or modify it
  9 * under the terms and conditions of the GNU General Public License,
 10 * version 2, as published by the Free Software Foundation.
 11 *
 12 * This program is distributed in the hope it will be useful, but WITHOUT
 13 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 14 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 15 * more details.
 16 *
 17 * You should have received a copy of the GNU General Public License
 18 * along with this program.  If not, see <http://www.gnu.org/licenses/>.
 19 */
 20#include <linux/err.h>
 21#include <linux/module.h>
 22#include <linux/of.h>
 23#include <linux/platform_device.h>
 24#include <linux/reset-controller.h>
 25#include <linux/slab.h>
 26#include <linux/delay.h>
 27#include <linux/types.h>
 28#include <linux/regmap.h>
 29#include <linux/mfd/syscon.h>
 30
 31/* Regmap offsets */
 32#define RST_SET_REGOFFSET	0x34
 33#define RST_CLR_REGOFFSET	0x38
 34
 35struct oxnas_reset {
 36	struct regmap *regmap;
 37	struct reset_controller_dev rcdev;
 38};
 39
 40static int oxnas_reset_reset(struct reset_controller_dev *rcdev,
 41			      unsigned long id)
 42{
 43	struct oxnas_reset *data =
 44		container_of(rcdev, struct oxnas_reset, rcdev);
 45
 46	regmap_write(data->regmap, RST_SET_REGOFFSET, BIT(id));
 47	msleep(50);
 48	regmap_write(data->regmap, RST_CLR_REGOFFSET, BIT(id));
 49
 50	return 0;
 51}
 52
 53static int oxnas_reset_assert(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_SET_REGOFFSET, BIT(id));
 60
 61	return 0;
 62}
 63
 64static int oxnas_reset_deassert(struct reset_controller_dev *rcdev,
 65				unsigned long id)
 66{
 67	struct oxnas_reset *data =
 68		container_of(rcdev, struct oxnas_reset, rcdev);
 69
 70	regmap_write(data->regmap, RST_CLR_REGOFFSET, BIT(id));
 71
 72	return 0;
 73}
 74
 75static const struct reset_control_ops oxnas_reset_ops = {
 76	.reset		= oxnas_reset_reset,
 77	.assert		= oxnas_reset_assert,
 78	.deassert	= oxnas_reset_deassert,
 79};
 80
 81static const struct of_device_id oxnas_reset_dt_ids[] = {
 82	 { .compatible = "oxsemi,ox810se-reset", },
 83	 { .compatible = "oxsemi,ox820-reset", },
 84	 { /* sentinel */ },
 85};
 86MODULE_DEVICE_TABLE(of, oxnas_reset_dt_ids);
 87
 88static int oxnas_reset_probe(struct platform_device *pdev)
 89{
 90	struct oxnas_reset *data;
 91	struct device *parent;
 92
 93	parent = pdev->dev.parent;
 94	if (!parent) {
 95		dev_err(&pdev->dev, "no parent\n");
 96		return -ENODEV;
 97	}
 98
 99	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
100	if (!data)
101		return -ENOMEM;
102
103	data->regmap = syscon_node_to_regmap(parent->of_node);
104	if (IS_ERR(data->regmap)) {
105		dev_err(&pdev->dev, "failed to get parent regmap\n");
106		return PTR_ERR(data->regmap);
107	}
108
109	platform_set_drvdata(pdev, data);
110
111	data->rcdev.owner = THIS_MODULE;
112	data->rcdev.nr_resets = 32;
113	data->rcdev.ops = &oxnas_reset_ops;
114	data->rcdev.of_node = pdev->dev.of_node;
115
116	return devm_reset_controller_register(&pdev->dev, &data->rcdev);
117}
118
119static struct platform_driver oxnas_reset_driver = {
120	.probe	= oxnas_reset_probe,
121	.driver = {
122		.name		= "oxnas-reset",
123		.of_match_table	= oxnas_reset_dt_ids,
124	},
125};
126
127module_platform_driver(oxnas_reset_driver);