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
  67 struct meson_reset {
  68         void __iomem *reg_base;
  69         struct reset_controller_dev rcdev;
  70 };
  71
  72 static 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
  89 static const struct reset_control_ops meson_reset_ops = {
  90         .reset          = meson_reset_reset,
  91 };
  92
  93 static const struct of_device_id meson_reset_dt_ids[] = {
  94          { .compatible = "amlogic,meson8b-reset", },
  95          { .compatible = "amlogic,meson-gxbb-reset", },
  96          { /* sentinel */ },
  97 };
  98 MODULE_DEVICE_TABLE(of, meson_reset_dt_ids);
  99
 100 static 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
 124 static 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
 132 module_platform_driver(meson_reset_driver);
 133
 134 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
 135 MODULE_DESCRIPTION("Amlogic Meson Reset Controller driver");
 136 MODULE_LICENSE("Dual BSD/GPL");