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| 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 | + |
| 17 | +struct meson_reset { |
| 18 | + const struct meson_reset_param *param; |
| 19 | + struct reset_controller_dev rcdev; |
| 20 | + struct regmap *map; |
| 21 | +}; |
| 22 | + |
| 23 | +static 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 | + |
| 34 | +static 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 | + |
| 47 | +static 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 | + |
| 62 | +static 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 | + |
| 78 | +static int meson_reset_assert(struct reset_controller_dev *rcdev, |
| 79 | + unsigned long id) |
| 80 | +{ |
| 81 | + return meson_reset_level(rcdev, id, true); |
| 82 | +} |
| 83 | + |
| 84 | +static int meson_reset_deassert(struct reset_controller_dev *rcdev, |
| 85 | + unsigned long id) |
| 86 | +{ |
| 87 | + return meson_reset_level(rcdev, id, false); |
| 88 | +} |
| 89 | + |
| 90 | +static 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 | + |
| 102 | +const 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 | +}; |
| 108 | +EXPORT_SYMBOL_NS_GPL(meson_reset_ops, MESON_RESET); |
| 109 | + |
| 110 | +const 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 | +}; |
| 116 | +EXPORT_SYMBOL_NS_GPL(meson_reset_toggle_ops, MESON_RESET); |
| 117 | + |
| 118 | +int 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 | +} |
| 136 | +EXPORT_SYMBOL_NS_GPL(meson_reset_controller_register, MESON_RESET); |
| 137 | + |
| 138 | +MODULE_DESCRIPTION("Amlogic Meson Reset Core function"); |
| 139 | +MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>"); |
| 140 | +MODULE_AUTHOR("Jerome Brunet <jbrunet@baylibre.com>"); |
| 141 | +MODULE_LICENSE("Dual BSD/GPL"); |
| 142 | +MODULE_IMPORT_NS(MESON_RESET); |
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