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/platform_device.h> 7 #include <linux/reset-controller.h> 8 #include <linux/delay.h> 9 #include <linux/mfd/syscon.h> 10 #include <linux/regmap.h> 11 #include <soc/canaan/k210-sysctl.h> 12 13 #include <dt-bindings/reset/k210-rst.h> 14 15 #define K210_RST_MASK 0x27FFFFFF 16 17 struct k210_rst { 18 struct regmap *map; 19 struct reset_controller_dev rcdev; 20 }; 21 22 static inline struct k210_rst * 23 to_k210_rst(struct reset_controller_dev *rcdev) 24 { 25 return container_of(rcdev, struct k210_rst, rcdev); 26 } 27 28 static inline int k210_rst_assert(struct reset_controller_dev *rcdev, 29 unsigned long id) 30 { 31 struct k210_rst *ksr = to_k210_rst(rcdev); 32 33 return regmap_update_bits(ksr->map, K210_SYSCTL_PERI_RESET, BIT(id), 1); 34 } 35 36 static inline int k210_rst_deassert(struct reset_controller_dev *rcdev, 37 unsigned long id) 38 { 39 struct k210_rst *ksr = to_k210_rst(rcdev); 40 41 return regmap_update_bits(ksr->map, K210_SYSCTL_PERI_RESET, BIT(id), 0); 42 } 43 44 static int k210_rst_reset(struct reset_controller_dev *rcdev, 45 unsigned long id) 46 { 47 int ret; 48 49 ret = k210_rst_assert(rcdev, id); 50 if (ret == 0) { 51 udelay(10); 52 ret = k210_rst_deassert(rcdev, id); 53 } 54 55 return ret; 56 } 57 58 static int k210_rst_status(struct reset_controller_dev *rcdev, 59 unsigned long id) 60 { 61 struct k210_rst *ksr = to_k210_rst(rcdev); 62 u32 reg, bit = BIT(id); 63 int ret; 64 65 ret = regmap_read(ksr->map, K210_SYSCTL_PERI_RESET, ®); 66 if (ret) 67 return ret; 68 69 return reg & bit; 70 } 71 72 static int k210_rst_xlate(struct reset_controller_dev *rcdev, 73 const struct of_phandle_args *reset_spec) 74 { 75 unsigned long id = reset_spec->args[0]; 76 77 if (!(BIT(id) & K210_RST_MASK)) 78 return -EINVAL; 79 80 return id; 81 } 82 83 static const struct reset_control_ops k210_rst_ops = { 84 .assert = k210_rst_assert, 85 .deassert = k210_rst_deassert, 86 .reset = k210_rst_reset, 87 .status = k210_rst_status, 88 }; 89 90 static int k210_rst_probe(struct platform_device *pdev) 91 { 92 struct device *dev = &pdev->dev; 93 struct device_node *parent_np; 94 struct k210_rst *ksr; 95 96 dev_info(dev, "K210 reset controller\n"); 97 98 ksr = devm_kzalloc(dev, sizeof(*ksr), GFP_KERNEL); 99 if (!ksr) 100 return -ENOMEM; 101 102 parent_np = of_get_parent(dev->of_node); 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