drivers/reset/reset-meson.c

   1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
   2 /*
   3  * Amlogic Meson Reset Controller driver
   4  *
   5  * Copyright (c) 2016 BayLibre, SAS.
   6  * Author: Neil Armstrong <narmstrong@baylibre.com>
   7  */
   8 #include <linux/err.h>
   9 #include <linux/init.h>
  10 #include <linux/io.h>
  11 #include <linux/of.h>
  12 #include <linux/module.h>
  13 #include <linux/platform_device.h>
  14 #include <linux/reset-controller.h>
  15 #include <linux/slab.h>
  16 #include <linux/types.h>
  17 #include <linux/of_device.h>
  18
  19 #define BITS_PER_REG    32
  20
  21 struct meson_reset_param {
  22         int reg_count;
  23         int level_offset;
  24 };
  25
  26 struct meson_reset {
  27         void __iomem *reg_base;
  28         const struct meson_reset_param *param;
  29         struct reset_controller_dev rcdev;
  30         spinlock_t lock;
  31 };
  32
  33 static int meson_reset_reset(struct reset_controller_dev *rcdev,
  34                               unsigned long id)
  35 {
  36         struct meson_reset *data =
  37                 container_of(rcdev, struct meson_reset, rcdev);
  38         unsigned int bank = id / BITS_PER_REG;
  39         unsigned int offset = id % BITS_PER_REG;
  40         void __iomem *reg_addr = data->reg_base + (bank << 2);
  41
  42         writel(BIT(offset), reg_addr);
  43
  44         return 0;
  45 }
  46
  47 static int meson_reset_level(struct reset_controller_dev *rcdev,
  48                             unsigned long id, bool assert)
  49 {
  50         struct meson_reset *data =
  51                 container_of(rcdev, struct meson_reset, rcdev);
  52         unsigned int bank = id / BITS_PER_REG;
  53         unsigned int offset = id % BITS_PER_REG;
  54         void __iomem *reg_addr;
  55         unsigned long flags;
  56         u32 reg;
  57
  58         reg_addr = data->reg_base + data->param->level_offset + (bank << 2);
  59
  60         spin_lock_irqsave(&data->lock, flags);
  61
  62         reg = readl(reg_addr);
  63         if (assert)
  64                 writel(reg & ~BIT(offset), reg_addr);
  65         else
  66                 writel(reg | BIT(offset), reg_addr);
  67
  68         spin_unlock_irqrestore(&data->lock, flags);
  69
  70         return 0;
  71 }
  72
  73 static int meson_reset_assert(struct reset_controller_dev *rcdev,
  74                               unsigned long id)
  75 {
  76         return meson_reset_level(rcdev, id, true);
  77 }
  78
  79 static int meson_reset_deassert(struct reset_controller_dev *rcdev,
  80                                 unsigned long id)
  81 {
  82         return meson_reset_level(rcdev, id, false);
  83 }
  84
  85 static const struct reset_control_ops meson_reset_ops = {
  86         .reset          = meson_reset_reset,
  87         .assert         = meson_reset_assert,
  88         .deassert       = meson_reset_deassert,
  89 };
  90
  91 static const struct meson_reset_param meson8b_param = {
  92         .reg_count      = 8,
  93         .level_offset   = 0x7c,
  94 };
  95
  96 static const struct meson_reset_param meson_a1_param = {
  97         .reg_count      = 3,
  98         .level_offset   = 0x40,
  99 };
 100
 101 static const struct of_device_id meson_reset_dt_ids[] = {
 102          { .compatible = "amlogic,meson8b-reset",    .data = &meson8b_param},
 103          { .compatible = "amlogic,meson-gxbb-reset", .data = &meson8b_param},
 104          { .compatible = "amlogic,meson-axg-reset",  .data = &meson8b_param},
 105          { .compatible = "amlogic,meson-a1-reset",   .data = &meson_a1_param},
 106          { /* sentinel */ },
 107 };
 108 MODULE_DEVICE_TABLE(of, meson_reset_dt_ids);
 109
 110 static int meson_reset_probe(struct platform_device *pdev)
 111 {
 112         struct meson_reset *data;
 113         struct resource *res;
 114
 115         data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
 116         if (!data)
 117                 return -ENOMEM;
 118
 119         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 120         data->reg_base = devm_ioremap_resource(&pdev->dev, res);
 121         if (IS_ERR(data->reg_base))
 122                 return PTR_ERR(data->reg_base);
 123
 124         data->param = of_device_get_match_data(&pdev->dev);
 125         if (!data->param)
 126                 return -ENODEV;
 127
 128         platform_set_drvdata(pdev, data);
 129
 130         spin_lock_init(&data->lock);
 131
 132         data->rcdev.owner = THIS_MODULE;
 133         data->rcdev.nr_resets = data->param->reg_count * BITS_PER_REG;
 134         data->rcdev.ops = &meson_reset_ops;
 135         data->rcdev.of_node = pdev->dev.of_node;
 136
 137         return devm_reset_controller_register(&pdev->dev, &data->rcdev);
 138 }
 139
 140 static struct platform_driver meson_reset_driver = {
 141         .probe  = meson_reset_probe,
 142         .driver = {
 143                 .name           = "meson_reset",
 144                 .of_match_table = meson_reset_dt_ids,
 145         },
 146 };
 147 module_platform_driver(meson_reset_driver);
 148
 149 MODULE_DESCRIPTION("Amlogic Meson Reset Controller driver");
 150 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
 151 MODULE_LICENSE("Dual BSD/GPL");