reset: Add support for the Amlogic Meson SoC Reset Controller

obj-$(CONFIG_ARCH_SOCFPGA) += reset-socfpga.o

obj-$(CONFIG_ARCH_BERLIN) += reset-berlin.o

obj-$(CONFIG_MACH_PISTACHIO) += reset-pistachio.o

obj-$(CONFIG_ARCH_MESON) += reset-meson.o

obj-$(CONFIG_ARCH_SUNXI) += reset-sunxi.o

obj-$(CONFIG_ARCH_STI) += sti/

obj-$(CONFIG_ARCH_HISI) += hisilicon/

/*

 * This file is provided under a dual BSD/GPLv2 license.  When using or

 * redistributing this file, you may do so under either license.

 *

 * GPL LICENSE SUMMARY

 *

 * Copyright (c) 2016 BayLibre, SAS.

 * Author: Neil Armstrong <narmstrong@baylibre.com>

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of version 2 of the GNU General Public License as

 * published by the Free Software Foundation.

 *

 * This program is distributed in the hope that it will be useful, but

 * WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU

 * General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License

 * along with this program; if not, see <http://www.gnu.org/licenses/>.

 * The full GNU General Public License is included in this distribution

 * in the file called COPYING.

 *

 * BSD LICENSE

 *

 * Copyright (c) 2016 BayLibre, SAS.

 * Author: Neil Armstrong <narmstrong@baylibre.com>

 *

 * Redistribution and use in source and binary forms, with or without

 * modification, are permitted provided that the following conditions

 * are met:

 *

 *   * Redistributions of source code must retain the above copyright

 *     notice, this list of conditions and the following disclaimer.

 *   * Redistributions in binary form must reproduce the above copyright

 *     notice, this list of conditions and the following disclaimer in

 *     the documentation and/or other materials provided with the

 *     distribution.

 *   * Neither the name of Intel Corporation nor the names of its

 *     contributors may be used to endorse or promote products derived

 *     from this software without specific prior written permission.

 *

 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS

 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT

 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR

 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT

 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,

 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT

 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,

 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY

 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT

 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE

 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.

 */

#include <linux/err.h>

#include <linux/module.h>

#include <linux/io.h>

#include <linux/of.h>

#include <linux/platform_device.h>

#include <linux/reset-controller.h>

#include <linux/slab.h>

#include <linux/types.h>

#define REG_COUNT	8

#define BITS_PER_REG	32

struct meson_reset {

	void __iomem *reg_base;

	struct reset_controller_dev rcdev;

};

static int meson_reset_reset(struct reset_controller_dev *rcdev,

			      unsigned long id)

{

	struct meson_reset *data =

		container_of(rcdev, struct meson_reset, rcdev);

	unsigned int bank = id / BITS_PER_REG;

	unsigned int offset = id % BITS_PER_REG;

	void __iomem *reg_addr = data->reg_base + (bank << 2);

	if (bank >= REG_COUNT)

		return -EINVAL;

	writel(BIT(offset), reg_addr);

	return 0;

}

static const struct reset_control_ops meson_reset_ops = {

	.reset		= meson_reset_reset,

};

static const struct of_device_id meson_reset_dt_ids[] = {

	 { .compatible = "amlogic,meson8b-reset", },

	 { .compatible = "amlogic,meson-gxbb-reset", },

	 { /* sentinel */ },

};

MODULE_DEVICE_TABLE(of, meson_reset_dt_ids);

static int meson_reset_probe(struct platform_device *pdev)

{

	struct meson_reset *data;

	struct resource *res;

	data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);

	if (!data)

		return -ENOMEM;

	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);

	data->reg_base = devm_ioremap_resource(&pdev->dev, res);

	if (IS_ERR(data->reg_base))

		return PTR_ERR(data->reg_base);

	platform_set_drvdata(pdev, data);

	data->rcdev.owner = THIS_MODULE;

	data->rcdev.nr_resets = REG_COUNT * BITS_PER_REG;

	data->rcdev.ops = &meson_reset_ops;

	data->rcdev.of_node = pdev->dev.of_node;

	return devm_reset_controller_register(&pdev->dev, &data->rcdev);

}

static struct platform_driver meson_reset_driver = {

	.probe	= meson_reset_probe,

	.driver = {

		.name		= "meson_reset",

		.of_match_table	= meson_reset_dt_ids,

	},

};

module_platform_driver(meson_reset_driver);

MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");

MODULE_DESCRIPTION("Amlogic Meson Reset Controller driver");

MODULE_LICENSE("Dual BSD/GPL");