LXR linux/drivers/reset/reset-meson.c

   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");
 137