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