tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1// SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
2/*
3 * Amlogic Meson Reset core functions
4 *
5 * Copyright (c) 2016-2024 BayLibre, SAS.
6 * Authors: Neil Armstrong <narmstrong@baylibre.com>
7 * Jerome Brunet <jbrunet@baylibre.com>
8 */
9
10#include <linux/device.h>
11#include <linux/module.h>
12#include <linux/regmap.h>
13#include <linux/reset-controller.h>
14
15#include "reset-meson.h"
16
17struct meson_reset {
18 const struct meson_reset_param *param;
19 struct reset_controller_dev rcdev;
20 struct regmap *map;
21};
22
23static void meson_reset_offset_and_bit(struct meson_reset *data,
24 unsigned long id,
25 unsigned int *offset,
26 unsigned int *bit)
27{
28 unsigned int stride = regmap_get_reg_stride(data->map);
29
30 *offset = (id / (stride * BITS_PER_BYTE)) * stride;
31 *bit = id % (stride * BITS_PER_BYTE);
32}
33
34static int meson_reset_reset(struct reset_controller_dev *rcdev,
35 unsigned long id)
36{
37 struct meson_reset *data =
38 container_of(rcdev, struct meson_reset, rcdev);
39 unsigned int offset, bit;
40
41 meson_reset_offset_and_bit(data, id, &offset, &bit);
42 offset += data->param->reset_offset;
43
44 return regmap_write(data->map, offset, BIT(bit));
45}
46
47static int meson_reset_level(struct reset_controller_dev *rcdev,
48 unsigned long id, bool assert)
49{
50 struct meson_reset *data =
51 container_of(rcdev, struct meson_reset, rcdev);
52 unsigned int offset, bit;
53
54 meson_reset_offset_and_bit(data, id, &offset, &bit);
55 offset += data->param->level_offset;
56 assert ^= data->param->level_low_reset;
57
58 return regmap_update_bits(data->map, offset,
59 BIT(bit), assert ? BIT(bit) : 0);
60}
61
62static int meson_reset_status(struct reset_controller_dev *rcdev,
63 unsigned long id)
64{
65 struct meson_reset *data =
66 container_of(rcdev, struct meson_reset, rcdev);
67 unsigned int val, offset, bit;
68
69 meson_reset_offset_and_bit(data, id, &offset, &bit);
70 offset += data->param->level_offset;
71
72 regmap_read(data->map, offset, &val);
73 val = !!(BIT(bit) & val);
74
75 return val ^ data->param->level_low_reset;
76}
77
78static int meson_reset_assert(struct reset_controller_dev *rcdev,
79 unsigned long id)
80{
81 return meson_reset_level(rcdev, id, true);
82}
83
84static int meson_reset_deassert(struct reset_controller_dev *rcdev,
85 unsigned long id)
86{
87 return meson_reset_level(rcdev, id, false);
88}
89
90static int meson_reset_level_toggle(struct reset_controller_dev *rcdev,
91 unsigned long id)
92{
93 int ret;
94
95 ret = meson_reset_assert(rcdev, id);
96 if (ret)
97 return ret;
98
99 return meson_reset_deassert(rcdev, id);
100}
101
102const struct reset_control_ops meson_reset_ops = {
103 .reset = meson_reset_reset,
104 .assert = meson_reset_assert,
105 .deassert = meson_reset_deassert,
106 .status = meson_reset_status,
107};
108EXPORT_SYMBOL_NS_GPL(meson_reset_ops, "MESON_RESET");
109
110const struct reset_control_ops meson_reset_toggle_ops = {
111 .reset = meson_reset_level_toggle,
112 .assert = meson_reset_assert,
113 .deassert = meson_reset_deassert,
114 .status = meson_reset_status,
115};
116EXPORT_SYMBOL_NS_GPL(meson_reset_toggle_ops, "MESON_RESET");
117
118int meson_reset_controller_register(struct device *dev, struct regmap *map,
119 const struct meson_reset_param *param)
120{
121 struct meson_reset *data;
122
123 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
124 if (!data)
125 return -ENOMEM;
126
127 data->param = param;
128 data->map = map;
129 data->rcdev.owner = dev->driver->owner;
130 data->rcdev.nr_resets = param->reset_num;
131 data->rcdev.ops = data->param->reset_ops;
132 data->rcdev.of_node = dev->of_node;
133
134 return devm_reset_controller_register(dev, &data->rcdev);
135}
136EXPORT_SYMBOL_NS_GPL(meson_reset_controller_register, "MESON_RESET");
137
138MODULE_DESCRIPTION("Amlogic Meson Reset Core function");
139MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
140MODULE_AUTHOR("Jerome Brunet <jbrunet@baylibre.com>");
141MODULE_LICENSE("Dual BSD/GPL");
142MODULE_IMPORT_NS("MESON_RESET");