drivers/reset/reset-zx2967.c

   1 /*
   2  * ZTE's zx2967 family reset controller driver
   3  *
   4  * Copyright (C) 2017 ZTE Ltd.
   5  *
   6  * Author: Baoyou Xie <baoyou.xie@linaro.org>
   7  *
   8  * License terms: GNU General Public License (GPL) version 2
   9  */
  10
  11 #include <linux/of_address.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/reset-controller.h>
  14
  15 struct zx2967_reset {
  16         void __iomem                    *reg_base;
  17         spinlock_t                      lock;
  18         struct reset_controller_dev     rcdev;
  19 };
  20
  21 static int zx2967_reset_act(struct reset_controller_dev *rcdev,
  22                             unsigned long id, bool assert)
  23 {
  24         struct zx2967_reset *reset = NULL;
  25         int bank = id / 32;
  26         int offset = id % 32;
  27         u32 reg;
  28         unsigned long flags;
  29
  30         reset = container_of(rcdev, struct zx2967_reset, rcdev);
  31
  32         spin_lock_irqsave(&reset->lock, flags);
  33
  34         reg = readl_relaxed(reset->reg_base + (bank * 4));
  35         if (assert)
  36                 reg &= ~BIT(offset);
  37         else
  38                 reg |= BIT(offset);
  39         writel_relaxed(reg, reset->reg_base + (bank * 4));
  40
  41         spin_unlock_irqrestore(&reset->lock, flags);
  42
  43         return 0;
  44 }
  45
  46 static int zx2967_reset_assert(struct reset_controller_dev *rcdev,
  47                                unsigned long id)
  48 {
  49         return zx2967_reset_act(rcdev, id, true);
  50 }
  51
  52 static int zx2967_reset_deassert(struct reset_controller_dev *rcdev,
  53                                  unsigned long id)
  54 {
  55         return zx2967_reset_act(rcdev, id, false);
  56 }
  57
  58 static struct reset_control_ops zx2967_reset_ops = {
  59         .assert         = zx2967_reset_assert,
  60         .deassert       = zx2967_reset_deassert,
  61 };
  62
  63 static int zx2967_reset_probe(struct platform_device *pdev)
  64 {
  65         struct zx2967_reset *reset;
  66         struct resource *res;
  67
  68         reset = devm_kzalloc(&pdev->dev, sizeof(*reset), GFP_KERNEL);
  69         if (!reset)
  70                 return -ENOMEM;
  71
  72         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  73         reset->reg_base = devm_ioremap_resource(&pdev->dev, res);
  74         if (IS_ERR(reset->reg_base))
  75                 return PTR_ERR(reset->reg_base);
  76
  77         spin_lock_init(&reset->lock);
  78
  79         reset->rcdev.owner = THIS_MODULE;
  80         reset->rcdev.nr_resets = resource_size(res) * 8;
  81         reset->rcdev.ops = &zx2967_reset_ops;
  82         reset->rcdev.of_node = pdev->dev.of_node;
  83
  84         return devm_reset_controller_register(&pdev->dev, &reset->rcdev);
  85 }
  86
  87 static const struct of_device_id zx2967_reset_dt_ids[] = {
  88          { .compatible = "zte,zx296718-reset", },
  89          {},
  90 };
  91
  92 static struct platform_driver zx2967_reset_driver = {
  93         .probe  = zx2967_reset_probe,
  94         .driver = {
  95                 .name           = "zx2967-reset",
  96                 .of_match_table = zx2967_reset_dt_ids,
  97         },
  98 };
  99 builtin_platform_driver(zx2967_reset_driver);