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