drivers/reset/reset-ath79.c

   1 /*
   2  * Copyright (C) 2015 Alban Bedel <albeu@free.fr>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  */
  14
  15 #include <linux/module.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/reset-controller.h>
  18
  19 struct ath79_reset {
  20         struct reset_controller_dev rcdev;
  21         void __iomem *base;
  22         spinlock_t lock;
  23 };
  24
  25 static int ath79_reset_update(struct reset_controller_dev *rcdev,
  26                         unsigned long id, bool assert)
  27 {
  28         struct ath79_reset *ath79_reset =
  29                 container_of(rcdev, struct ath79_reset, rcdev);
  30         unsigned long flags;
  31         u32 val;
  32
  33         spin_lock_irqsave(&ath79_reset->lock, flags);
  34         val = readl(ath79_reset->base);
  35         if (assert)
  36                 val |= BIT(id);
  37         else
  38                 val &= ~BIT(id);
  39         writel(val, ath79_reset->base);
  40         spin_unlock_irqrestore(&ath79_reset->lock, flags);
  41
  42         return 0;
  43 }
  44
  45 static int ath79_reset_assert(struct reset_controller_dev *rcdev,
  46                         unsigned long id)
  47 {
  48         return ath79_reset_update(rcdev, id, true);
  49 }
  50
  51 static int ath79_reset_deassert(struct reset_controller_dev *rcdev,
  52                                 unsigned long id)
  53 {
  54         return ath79_reset_update(rcdev, id, false);
  55 }
  56
  57 static int ath79_reset_status(struct reset_controller_dev *rcdev,
  58                         unsigned long id)
  59 {
  60         struct ath79_reset *ath79_reset =
  61                 container_of(rcdev, struct ath79_reset, rcdev);
  62         u32 val;
  63
  64         val = readl(ath79_reset->base);
  65
  66         return !!(val & BIT(id));
  67 }
  68
  69 static struct reset_control_ops ath79_reset_ops = {
  70         .assert = ath79_reset_assert,
  71         .deassert = ath79_reset_deassert,
  72         .status = ath79_reset_status,
  73 };
  74
  75 static int ath79_reset_probe(struct platform_device *pdev)
  76 {
  77         struct ath79_reset *ath79_reset;
  78         struct resource *res;
  79
  80         ath79_reset = devm_kzalloc(&pdev->dev,
  81                                 sizeof(*ath79_reset), GFP_KERNEL);
  82         if (!ath79_reset)
  83                 return -ENOMEM;
  84
  85         platform_set_drvdata(pdev, ath79_reset);
  86
  87         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  88         ath79_reset->base = devm_ioremap_resource(&pdev->dev, res);
  89         if (IS_ERR(ath79_reset->base))
  90                 return PTR_ERR(ath79_reset->base);
  91
  92         spin_lock_init(&ath79_reset->lock);
  93         ath79_reset->rcdev.ops = &ath79_reset_ops;
  94         ath79_reset->rcdev.owner = THIS_MODULE;
  95         ath79_reset->rcdev.of_node = pdev->dev.of_node;
  96         ath79_reset->rcdev.of_reset_n_cells = 1;
  97         ath79_reset->rcdev.nr_resets = 32;
  98
  99         return reset_controller_register(&ath79_reset->rcdev);
 100 }
 101
 102 static int ath79_reset_remove(struct platform_device *pdev)
 103 {
 104         struct ath79_reset *ath79_reset = platform_get_drvdata(pdev);
 105
 106         reset_controller_unregister(&ath79_reset->rcdev);
 107
 108         return 0;
 109 }
 110
 111 static const struct of_device_id ath79_reset_dt_ids[] = {
 112         { .compatible = "qca,ar7100-reset", },
 113         { },
 114 };
 115 MODULE_DEVICE_TABLE(of, ath79_reset_dt_ids);
 116
 117 static struct platform_driver ath79_reset_driver = {
 118         .probe  = ath79_reset_probe,
 119         .remove = ath79_reset_remove,
 120         .driver = {
 121                 .name           = "ath79-reset",
 122                 .of_match_table = ath79_reset_dt_ids,
 123         },
 124 };
 125 module_platform_driver(ath79_reset_driver);
 126
 127 MODULE_AUTHOR("Alban Bedel <albeu@free.fr>");
 128 MODULE_DESCRIPTION("AR71xx Reset Controller Driver");
 129 MODULE_LICENSE("GPL");