drivers/reset/reset-k210.c

   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, &reg);
  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 = of_get_parent(dev->of_node);
  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         ksr->map = syscon_node_to_regmap(parent_np);
 103         of_node_put(parent_np);
 104         if (IS_ERR(ksr->map))
 105                 return PTR_ERR(ksr->map);
 106
 107         ksr->rcdev.owner = THIS_MODULE;
 108         ksr->rcdev.dev = dev;
 109         ksr->rcdev.of_node = dev->of_node;
 110         ksr->rcdev.ops = &k210_rst_ops;
 111         ksr->rcdev.nr_resets = fls(K210_RST_MASK);
 112         ksr->rcdev.of_reset_n_cells = 1;
 113         ksr->rcdev.of_xlate = k210_rst_xlate;
 114
 115         return devm_reset_controller_register(dev, &ksr->rcdev);
 116 }
 117
 118 static const struct of_device_id k210_rst_dt_ids[] = {
 119         { .compatible = "canaan,k210-rst" },
 120         { /* sentinel */ },
 121 };
 122
 123 static struct platform_driver k210_rst_driver = {
 124         .probe  = k210_rst_probe,
 125         .driver = {
 126                 .name           = "k210-rst",
 127                 .of_match_table = k210_rst_dt_ids,
 128         },
 129 };
 130 builtin_platform_driver(k210_rst_driver);