1 // SPDX-License-Identifier: GPL-2.0-or-later 2 /* 3 * Copyright (c) 2020 Western Digital Corporation or its affiliates. 4 */ 5 #include <linux/of.h> 6 #include <linux/of_device.h> 7 #include <linux/platform_device.h> 8 #include <linux/reset-controller.h> 9 #include <linux/delay.h> 10 #include <linux/mfd/syscon.h> 11 #include <linux/regmap.h> 12 #include <soc/canaan/k210-sysctl.h> 13 14 #include <dt-bindings/reset/k210-rst.h> 15 16 #define K210_RST_MASK 0x27FFFFFF 17 18 struct k210_rst { 19 struct regmap *map; 20 struct reset_controller_dev rcdev; 21 }; 22 23 static inline struct k210_rst * 24 to_k210_rst(struct reset_controller_dev *rcdev) 25 { 26 return container_of(rcdev, struct k210_rst, rcdev); 27 } 28 29 static inline int k210_rst_assert(struct reset_controller_dev *rcdev, 30 unsigned long id) 31 { 32 struct k210_rst *ksr = to_k210_rst(rcdev); 33 34 return regmap_update_bits(ksr->map, K210_SYSCTL_PERI_RESET, BIT(id), 1); 35 } 36 37 static inline int k210_rst_deassert(struct reset_controller_dev *rcdev, 38 unsigned long id) 39 { 40 struct k210_rst *ksr = to_k210_rst(rcdev); 41 42 return regmap_update_bits(ksr->map, K210_SYSCTL_PERI_RESET, BIT(id), 0); 43 } 44 45 static int k210_rst_reset(struct reset_controller_dev *rcdev, 46 unsigned long id) 47 { 48 int ret; 49 50 ret = k210_rst_assert(rcdev, id); 51 if (ret == 0) { 52 udelay(10); 53 ret = k210_rst_deassert(rcdev, id); 54 } 55 56 return ret; 57 } 58 59 static int k210_rst_status(struct reset_controller_dev *rcdev, 60 unsigned long id) 61 { 62 struct k210_rst *ksr = to_k210_rst(rcdev); 63 u32 reg, bit = BIT(id); 64 int ret; 65 66 ret = regmap_read(ksr->map, K210_SYSCTL_PERI_RESET, ®); 67 if (ret) 68 return ret; 69 70 return reg & bit; 71 } 72 73 static int k210_rst_xlate(struct reset_controller_dev *rcdev, 74 const struct of_phandle_args *reset_spec) 75 { 76 unsigned long id = reset_spec->args[0]; 77 78 if (!(BIT(id) & K210_RST_MASK)) 79 return -EINVAL; 80 81 return id; 82 } 83 84 static const struct reset_control_ops k210_rst_ops = { 85 .assert = k210_rst_assert, 86 .deassert = k210_rst_deassert, 87 .reset = k210_rst_reset, 88 .status = k210_rst_status, 89 }; 90 91 static int k210_rst_probe(struct platform_device *pdev) 92 { 93 struct device *dev = &pdev->dev; 94 struct device_node *parent_np = of_get_parent(dev->of_node); 95 struct k210_rst *ksr; 96 97 dev_info(dev, "K210 reset controller\n"); 98 99 ksr = devm_kzalloc(dev, sizeof(*ksr), GFP_KERNEL); 100 if (!ksr) 101 return -ENOMEM; 102 103 ksr->map = syscon_node_to_regmap(parent_np); 104 of_node_put(parent_np); 105 if (IS_ERR(ksr->map)) 106 return PTR_ERR(ksr->map); 107 108 ksr->rcdev.owner = THIS_MODULE; 109 ksr->rcdev.dev = dev; 110 ksr->rcdev.of_node = dev->of_node; 111 ksr->rcdev.ops = &k210_rst_ops; 112 ksr->rcdev.nr_resets = fls(K210_RST_MASK); 113 ksr->rcdev.of_reset_n_cells = 1; 114 ksr->rcdev.of_xlate = k210_rst_xlate; 115 116 return devm_reset_controller_register(dev, &ksr->rcdev); 117 } 118 119 static const struct of_device_id k210_rst_dt_ids[] = { 120 { .compatible = "canaan,k210-rst" }, 121 { /* sentinel */ }, 122 }; 123 124 static struct platform_driver k210_rst_driver = { 125 .probe = k210_rst_probe, 126 .driver = { 127 .name = "k210-rst", 128 .of_match_table = k210_rst_dt_ids, 129 }, 130 }; 131 builtin_platform_driver(k210_rst_driver); 132