drivers/clk/actions/owl-reset.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 //
   3 // Actions Semi Owl SoCs Reset Management Unit driver
   4 //
   5 // Copyright (c) 2018 Linaro Ltd.
   6 // Author: Manivannan Sadhasivam <manivannan.sadhasivam@linaro.org>
   7
   8 #include <linux/delay.h>
   9 #include <linux/regmap.h>
  10 #include <linux/reset-controller.h>
  11
  12 #include "owl-reset.h"
  13
  14 static int owl_reset_assert(struct reset_controller_dev *rcdev,
  15                             unsigned long id)
  16 {
  17         struct owl_reset *reset = to_owl_reset(rcdev);
  18         const struct owl_reset_map *map = &reset->reset_map[id];
  19
  20         return regmap_update_bits(reset->regmap, map->reg, map->bit, 0);
  21 }
  22
  23 static int owl_reset_deassert(struct reset_controller_dev *rcdev,
  24                               unsigned long id)
  25 {
  26         struct owl_reset *reset = to_owl_reset(rcdev);
  27         const struct owl_reset_map *map = &reset->reset_map[id];
  28
  29         return regmap_update_bits(reset->regmap, map->reg, map->bit, map->bit);
  30 }
  31
  32 static int owl_reset_reset(struct reset_controller_dev *rcdev,
  33                            unsigned long id)
  34 {
  35         owl_reset_assert(rcdev, id);
  36         udelay(1);
  37         owl_reset_deassert(rcdev, id);
  38
  39         return 0;
  40 }
  41
  42 static int owl_reset_status(struct reset_controller_dev *rcdev,
  43                             unsigned long id)
  44 {
  45         struct owl_reset *reset = to_owl_reset(rcdev);
  46         const struct owl_reset_map *map = &reset->reset_map[id];
  47         u32 reg;
  48         int ret;
  49
  50         ret = regmap_read(reset->regmap, map->reg, &reg);
  51         if (ret)
  52                 return ret;
  53
  54         /*
  55          * The reset control API expects 0 if reset is not asserted,
  56          * which is the opposite of what our hardware uses.
  57          */
  58         return !(map->bit & reg);
  59 }
  60
  61 const struct reset_control_ops owl_reset_ops = {
  62         .assert         = owl_reset_assert,
  63         .deassert       = owl_reset_deassert,
  64         .reset          = owl_reset_reset,
  65         .status         = owl_reset_status,
  66 };