drivers/clk/sunxi-ng/ccu_reset.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Copyright (C) 2016 Maxime Ripard
   4  * Maxime Ripard <maxime.ripard@free-electrons.com>
   5  */
   6
   7 #include <linux/delay.h>
   8 #include <linux/io.h>
   9 #include <linux/reset-controller.h>
  10
  11 #include "ccu_reset.h"
  12
  13 static int ccu_reset_assert(struct reset_controller_dev *rcdev,
  14                             unsigned long id)
  15 {
  16         struct ccu_reset *ccu = rcdev_to_ccu_reset(rcdev);
  17         const struct ccu_reset_map *map = &ccu->reset_map[id];
  18         unsigned long flags;
  19         u32 reg;
  20
  21         spin_lock_irqsave(ccu->lock, flags);
  22
  23         reg = readl(ccu->base + map->reg);
  24         writel(reg & ~map->bit, ccu->base + map->reg);
  25
  26         spin_unlock_irqrestore(ccu->lock, flags);
  27
  28         return 0;
  29 }
  30
  31 static int ccu_reset_deassert(struct reset_controller_dev *rcdev,
  32                               unsigned long id)
  33 {
  34         struct ccu_reset *ccu = rcdev_to_ccu_reset(rcdev);
  35         const struct ccu_reset_map *map = &ccu->reset_map[id];
  36         unsigned long flags;
  37         u32 reg;
  38
  39         spin_lock_irqsave(ccu->lock, flags);
  40
  41         reg = readl(ccu->base + map->reg);
  42         writel(reg | map->bit, ccu->base + map->reg);
  43
  44         spin_unlock_irqrestore(ccu->lock, flags);
  45
  46         return 0;
  47 }
  48
  49 static int ccu_reset_reset(struct reset_controller_dev *rcdev,
  50                            unsigned long id)
  51 {
  52         ccu_reset_assert(rcdev, id);
  53         udelay(10);
  54         ccu_reset_deassert(rcdev, id);
  55
  56         return 0;
  57 }
  58
  59 static int ccu_reset_status(struct reset_controller_dev *rcdev,
  60                             unsigned long id)
  61 {
  62         struct ccu_reset *ccu = rcdev_to_ccu_reset(rcdev);
  63         const struct ccu_reset_map *map = &ccu->reset_map[id];
  64
  65         /*
  66          * The reset control API expects 0 if reset is not asserted,
  67          * which is the opposite of what our hardware uses.
  68          */
  69         return !(map->bit & readl(ccu->base + map->reg));
  70 }
  71
  72 const struct reset_control_ops ccu_reset_ops = {
  73         .assert         = ccu_reset_assert,
  74         .deassert       = ccu_reset_deassert,
  75         .reset          = ccu_reset_reset,
  76         .status         = ccu_reset_status,
  77 };