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/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, &reg);
  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);