1/*
  2 * This file is provided under a dual BSD/GPLv2 license.  When using or
  3 * redistributing this file, you may do so under either license.
  4 *
  5 * GPL LICENSE SUMMARY
  6 *
  7 * Copyright (c) 2016 BayLibre, SAS.
  8 * Author: Neil Armstrong <narmstrong@baylibre.com>
  9 *
 10 * This program is free software; you can redistribute it and/or modify
 11 * it under the terms of version 2 of the GNU General Public License as
 12 * published by the Free Software Foundation.
 13 *
 14 * This program is distributed in the hope that it will be useful, but
 15 * WITHOUT ANY WARRANTY; without even the implied warranty of
 16 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 17 * General Public License for more details.
 18 *
 19 * You should have received a copy of the GNU General Public License
 20 * along with this program; if not, see <http://www.gnu.org/licenses/>.
 21 * The full GNU General Public License is included in this distribution
 22 * in the file called COPYING.
 23 *
 24 * BSD LICENSE
 25 *
 26 * Copyright (c) 2016 BayLibre, SAS.
 27 * Author: Neil Armstrong <narmstrong@baylibre.com>
 28 *
 29 * Redistribution and use in source and binary forms, with or without
 30 * modification, are permitted provided that the following conditions
 31 * are met:
 32 *
 33 *   * Redistributions of source code must retain the above copyright
 34 *     notice, this list of conditions and the following disclaimer.
 35 *   * Redistributions in binary form must reproduce the above copyright
 36 *     notice, this list of conditions and the following disclaimer in
 37 *     the documentation and/or other materials provided with the
 38 *     distribution.
 39 *   * Neither the name of Intel Corporation nor the names of its
 40 *     contributors may be used to endorse or promote products derived
 41 *     from this software without specific prior written permission.
 42 *
 43 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 44 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 45 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 46 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 47 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 48 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 49 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 50 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 51 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 52 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 53 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 54 */
 55#include <linux/err.h>
 56#include <linux/module.h>
 57#include <linux/io.h>
 58#include <linux/of.h>
 59#include <linux/platform_device.h>
 60#include <linux/reset-controller.h>
 61#include <linux/slab.h>
 62#include <linux/types.h>
 63
 64#define REG_COUNT	8
 65#define BITS_PER_REG	32
 66
 67struct meson_reset {
 68	void __iomem *reg_base;
 69	struct reset_controller_dev rcdev;
 70};
 71
 72static int meson_reset_reset(struct reset_controller_dev *rcdev,
 73			      unsigned long id)
 74{
 75	struct meson_reset *data =
 76		container_of(rcdev, struct meson_reset, rcdev);
 77	unsigned int bank = id / BITS_PER_REG;
 78	unsigned int offset = id % BITS_PER_REG;
 79	void __iomem *reg_addr = data->reg_base + (bank << 2);
 80
 81	if (bank >= REG_COUNT)
 82		return -EINVAL;
 83
 84	writel(BIT(offset), reg_addr);
 85
 86	return 0;
 87}
 88
 89static const struct reset_control_ops meson_reset_ops = {
 90	.reset		= meson_reset_reset,
 91};
 92
 93static const struct of_device_id meson_reset_dt_ids[] = {
 94	 { .compatible = "amlogic,meson8b-reset", },
 95	 { .compatible = "amlogic,meson-gxbb-reset", },
 96	 { /* sentinel */ },
 97};
 98MODULE_DEVICE_TABLE(of, meson_reset_dt_ids);
 99
100static int meson_reset_probe(struct platform_device *pdev)
101{
102	struct meson_reset *data;
103	struct resource *res;
104
105	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
106	if (!data)
107		return -ENOMEM;
108
109	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
110	data->reg_base = devm_ioremap_resource(&pdev->dev, res);
111	if (IS_ERR(data->reg_base))
112		return PTR_ERR(data->reg_base);
113
114	platform_set_drvdata(pdev, data);
115
116	data->rcdev.owner = THIS_MODULE;
117	data->rcdev.nr_resets = REG_COUNT * BITS_PER_REG;
118	data->rcdev.ops = &meson_reset_ops;
119	data->rcdev.of_node = pdev->dev.of_node;
120
121	return devm_reset_controller_register(&pdev->dev, &data->rcdev);
122}
123
124static struct platform_driver meson_reset_driver = {
125	.probe	= meson_reset_probe,
126	.driver = {
127		.name		= "meson_reset",
128		.of_match_table	= meson_reset_dt_ids,
129	},
130};
131
132module_platform_driver(meson_reset_driver);
133
134MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
135MODULE_DESCRIPTION("Amlogic Meson Reset Controller driver");
136MODULE_LICENSE("Dual BSD/GPL");