1 // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause 2 /* 3 * Amlogic Meson Reset Controller driver 4 * 5 * Copyright (c) 2016 BayLibre, SAS. 6 * Author: Neil Armstrong <narmstrong@baylibre.com> 7 */ 8 #include <linux/err.h> 9 #include <linux/init.h> 10 #include <linux/io.h> 11 #include <linux/of.h> 12 #include <linux/module.h> 13 #include <linux/platform_device.h> 14 #include <linux/reset-controller.h> 15 #include <linux/slab.h> 16 #include <linux/types.h> 17 18 #define BITS_PER_REG 32 19 20 struct meson_reset_param { 21 int reg_count; 22 int level_offset; 23 }; 24 25 struct meson_reset { 26 void __iomem *reg_base; 27 const struct meson_reset_param *param; 28 struct reset_controller_dev rcdev; 29 spinlock_t lock; 30 }; 31 32 static int meson_reset_reset(struct reset_controller_dev *rcdev, 33 unsigned long id) 34 { 35 struct meson_reset *data = 36 container_of(rcdev, struct meson_reset, rcdev); 37 unsigned int bank = id / BITS_PER_REG; 38 unsigned int offset = id % BITS_PER_REG; 39 void __iomem *reg_addr = data->reg_base + (bank << 2); 40 41 writel(BIT(offset), reg_addr); 42 43 return 0; 44 } 45 46 static int meson_reset_level(struct reset_controller_dev *rcdev, 47 unsigned long id, bool assert) 48 { 49 struct meson_reset *data = 50 container_of(rcdev, struct meson_reset, rcdev); 51 unsigned int bank = id / BITS_PER_REG; 52 unsigned int offset = id % BITS_PER_REG; 53 void __iomem *reg_addr; 54 unsigned long flags; 55 u32 reg; 56 57 reg_addr = data->reg_base + data->param->level_offset + (bank << 2); 58 59 spin_lock_irqsave(&data->lock, flags); 60 61 reg = readl(reg_addr); 62 if (assert) 63 writel(reg & ~BIT(offset), reg_addr); 64 else 65 writel(reg | BIT(offset), reg_addr); 66 67 spin_unlock_irqrestore(&data->lock, flags); 68 69 return 0; 70 } 71 72 static int meson_reset_assert(struct reset_controller_dev *rcdev, 73 unsigned long id) 74 { 75 return meson_reset_level(rcdev, id, true); 76 } 77 78 static int meson_reset_deassert(struct reset_controller_dev *rcdev, 79 unsigned long id) 80 { 81 return meson_reset_level(rcdev, id, false); 82 } 83 84 static const struct reset_control_ops meson_reset_ops = { 85 .reset = meson_reset_reset, 86 .assert = meson_reset_assert, 87 .deassert = meson_reset_deassert, 88 }; 89 90 static const struct meson_reset_param meson8b_param = { 91 .reg_count = 8, 92 .level_offset = 0x7c, 93 }; 94 95 static const struct meson_reset_param meson_a1_param = { 96 .reg_count = 3, 97 .level_offset = 0x40, 98 }; 99 100 static const struct meson_reset_param meson_s4_param = { 101 .reg_count = 6, 102 .level_offset = 0x40, 103 }; 104 105 static const struct of_device_id meson_reset_dt_ids[] = { 106 { .compatible = "amlogic,meson8b-reset", .data = &meson8b_param}, 107 { .compatible = "amlogic,meson-gxbb-reset", .data = &meson8b_param}, 108 { .compatible = "amlogic,meson-axg-reset", .data = &meson8b_param}, 109 { .compatible = "amlogic,meson-a1-reset", .data = &meson_a1_param}, 110 { .compatible = "amlogic,meson-s4-reset", .data = &meson_s4_param}, 111 { /* sentinel */ }, 112 }; 113 MODULE_DEVICE_TABLE(of, meson_reset_dt_ids); 114 115 static int meson_reset_probe(struct platform_device *pdev) 116 { 117 struct meson_reset *data; 118 119 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL); 120 if (!data) 121 return -ENOMEM; 122 123 data->reg_base = devm_platform_ioremap_resource(pdev, 0); 124 if (IS_ERR(data->reg_base)) 125 return PTR_ERR(data->reg_base); 126 127 data->param = of_device_get_match_data(&pdev->dev); 128 if (!data->param) 129 return -ENODEV; 130 131 spin_lock_init(&data->lock); 132 133 data->rcdev.owner = THIS_MODULE; 134 data->rcdev.nr_resets = data->param->reg_count * BITS_PER_REG; 135 data->rcdev.ops = &meson_reset_ops; 136 data->rcdev.of_node = pdev->dev.of_node; 137 138 return devm_reset_controller_register(&pdev->dev, &data->rcdev); 139 } 140 141 static struct platform_driver meson_reset_driver = { 142 .probe = meson_reset_probe, 143 .driver = { 144 .name = "meson_reset", 145 .of_match_table = meson_reset_dt_ids, 146 }, 147 }; 148 module_platform_driver(meson_reset_driver); 149 150 MODULE_DESCRIPTION("Amlogic Meson Reset Controller driver"); 151 MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>"); 152 MODULE_LICENSE("Dual BSD/GPL"); 153