drivers/reset/reset-tn48m.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Delta TN48M CPLD reset driver
   4  *
   5  * Copyright (C) 2021 Sartura Ltd.
   6  *
   7  * Author: Robert Marko <robert.marko@sartura.hr>
   8  */
   9
  10 #include <linux/device.h>
  11 #include <linux/kernel.h>
  12 #include <linux/mod_devicetable.h>
  13 #include <linux/module.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/regmap.h>
  16 #include <linux/reset-controller.h>
  17
  18 #include <dt-bindings/reset/delta,tn48m-reset.h>
  19
  20 #define TN48M_RESET_REG         0x10
  21
  22 #define TN48M_RESET_TIMEOUT_US  125000
  23 #define TN48M_RESET_SLEEP_US    10
  24
  25 struct tn48_reset_map {
  26         u8 bit;
  27 };
  28
  29 struct tn48_reset_data {
  30         struct reset_controller_dev rcdev;
  31         struct regmap *regmap;
  32 };
  33
  34 static const struct tn48_reset_map tn48m_resets[] = {
  35         [CPU_88F7040_RESET] = {0},
  36         [CPU_88F6820_RESET] = {1},
  37         [MAC_98DX3265_RESET] = {2},
  38         [PHY_88E1680_RESET] = {4},
  39         [PHY_88E1512_RESET] = {6},
  40         [POE_RESET] = {7},
  41 };
  42
  43 static inline struct tn48_reset_data *to_tn48_reset_data(
  44                         struct reset_controller_dev *rcdev)
  45 {
  46         return container_of(rcdev, struct tn48_reset_data, rcdev);
  47 }
  48
  49 static int tn48m_control_reset(struct reset_controller_dev *rcdev,
  50                                unsigned long id)
  51 {
  52         struct tn48_reset_data *data = to_tn48_reset_data(rcdev);
  53         unsigned int val;
  54
  55         regmap_update_bits(data->regmap, TN48M_RESET_REG,
  56                            BIT(tn48m_resets[id].bit), 0);
  57
  58         return regmap_read_poll_timeout(data->regmap,
  59                                         TN48M_RESET_REG,
  60                                         val,
  61                                         val & BIT(tn48m_resets[id].bit),
  62                                         TN48M_RESET_SLEEP_US,
  63                                         TN48M_RESET_TIMEOUT_US);
  64 }
  65
  66 static int tn48m_control_status(struct reset_controller_dev *rcdev,
  67                                 unsigned long id)
  68 {
  69         struct tn48_reset_data *data = to_tn48_reset_data(rcdev);
  70         unsigned int regval;
  71         int ret;
  72
  73         ret = regmap_read(data->regmap, TN48M_RESET_REG, &regval);
  74         if (ret < 0)
  75                 return ret;
  76
  77         if (BIT(tn48m_resets[id].bit) & regval)
  78                 return 0;
  79         else
  80                 return 1;
  81 }
  82
  83 static const struct reset_control_ops tn48_reset_ops = {
  84         .reset          = tn48m_control_reset,
  85         .status         = tn48m_control_status,
  86 };
  87
  88 static int tn48m_reset_probe(struct platform_device *pdev)
  89 {
  90         struct tn48_reset_data *data;
  91         struct regmap *regmap;
  92
  93         regmap = dev_get_regmap(pdev->dev.parent, NULL);
  94         if (!regmap)
  95                 return -ENODEV;
  96
  97         data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
  98         if (!data)
  99                 return -ENOMEM;
 100
 101         data->regmap = regmap;
 102
 103         data->rcdev.owner = THIS_MODULE;
 104         data->rcdev.ops = &tn48_reset_ops;
 105         data->rcdev.nr_resets = ARRAY_SIZE(tn48m_resets);
 106         data->rcdev.of_node = pdev->dev.of_node;
 107
 108         return devm_reset_controller_register(&pdev->dev, &data->rcdev);
 109 }
 110
 111 static const struct of_device_id tn48m_reset_of_match[] = {
 112         { .compatible = "delta,tn48m-reset" },
 113         { }
 114 };
 115 MODULE_DEVICE_TABLE(of, tn48m_reset_of_match);
 116
 117 static struct platform_driver tn48m_reset_driver = {
 118         .driver = {
 119                 .name = "delta-tn48m-reset",
 120                 .of_match_table = tn48m_reset_of_match,
 121         },
 122         .probe = tn48m_reset_probe,
 123 };
 124 module_platform_driver(tn48m_reset_driver);
 125
 126 MODULE_AUTHOR("Robert Marko <robert.marko@sartura.hr>");
 127 MODULE_DESCRIPTION("Delta TN48M CPLD reset driver");
 128 MODULE_LICENSE("GPL");