reset-meson-common.c

  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");