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"); 143