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
14static 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(map: reset->regmap, reg: map->reg, mask: map->bit, val: 0);
21}
22
23static 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(map: reset->regmap, reg: map->reg, mask: map->bit, val: map->bit);
30}
31
32static 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
42static 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(map: reset->regmap, reg: map->reg, val: &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
61const 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};
67

source code of linux/drivers/clk/actions/owl-reset.c