drivers/reset/reset-oxnas.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * drivers/reset/reset-oxnas.c
   4  *
   5  * Copyright (C) 2016 Neil Armstrong <narmstrong@baylibre.com>
   6  * Copyright (C) 2014 Ma Haijun <mahaijuns@gmail.com>
   7  * Copyright (C) 2009 Oxford Semiconductor Ltd
   8  */
   9 #include <linux/err.h>
  10 #include <linux/init.h>
  11 #include <linux/of.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/reset-controller.h>
  14 #include <linux/slab.h>
  15 #include <linux/delay.h>
  16 #include <linux/types.h>
  17 #include <linux/regmap.h>
  18 #include <linux/mfd/syscon.h>
  19
  20 /* Regmap offsets */
  21 #define RST_SET_REGOFFSET       0x34
  22 #define RST_CLR_REGOFFSET       0x38
  23
  24 struct oxnas_reset {
  25         struct regmap *regmap;
  26         struct reset_controller_dev rcdev;
  27 };
  28
  29 static int oxnas_reset_reset(struct reset_controller_dev *rcdev,
  30                               unsigned long id)
  31 {
  32         struct oxnas_reset *data =
  33                 container_of(rcdev, struct oxnas_reset, rcdev);
  34
  35         regmap_write(data->regmap, RST_SET_REGOFFSET, BIT(id));
  36         msleep(50);
  37         regmap_write(data->regmap, RST_CLR_REGOFFSET, BIT(id));
  38
  39         return 0;
  40 }
  41
  42 static int oxnas_reset_assert(struct reset_controller_dev *rcdev,
  43                               unsigned long id)
  44 {
  45         struct oxnas_reset *data =
  46                 container_of(rcdev, struct oxnas_reset, rcdev);
  47
  48         regmap_write(data->regmap, RST_SET_REGOFFSET, BIT(id));
  49
  50         return 0;
  51 }
  52
  53 static int oxnas_reset_deassert(struct reset_controller_dev *rcdev,
  54                                 unsigned long id)
  55 {
  56         struct oxnas_reset *data =
  57                 container_of(rcdev, struct oxnas_reset, rcdev);
  58
  59         regmap_write(data->regmap, RST_CLR_REGOFFSET, BIT(id));
  60
  61         return 0;
  62 }
  63
  64 static const struct reset_control_ops oxnas_reset_ops = {
  65         .reset          = oxnas_reset_reset,
  66         .assert         = oxnas_reset_assert,
  67         .deassert       = oxnas_reset_deassert,
  68 };
  69
  70 static const struct of_device_id oxnas_reset_dt_ids[] = {
  71          { .compatible = "oxsemi,ox810se-reset", },
  72          { .compatible = "oxsemi,ox820-reset", },
  73          { /* sentinel */ },
  74 };
  75
  76 static int oxnas_reset_probe(struct platform_device *pdev)
  77 {
  78         struct oxnas_reset *data;
  79         struct device *parent;
  80
  81         parent = pdev->dev.parent;
  82         if (!parent) {
  83                 dev_err(&pdev->dev, "no parent\n");
  84                 return -ENODEV;
  85         }
  86
  87         data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
  88         if (!data)
  89                 return -ENOMEM;
  90
  91         data->regmap = syscon_node_to_regmap(parent->of_node);
  92         if (IS_ERR(data->regmap)) {
  93                 dev_err(&pdev->dev, "failed to get parent regmap\n");
  94                 return PTR_ERR(data->regmap);
  95         }
  96
  97         platform_set_drvdata(pdev, data);
  98
  99         data->rcdev.owner = THIS_MODULE;
 100         data->rcdev.nr_resets = 32;
 101         data->rcdev.ops = &oxnas_reset_ops;
 102         data->rcdev.of_node = pdev->dev.of_node;
 103
 104         return devm_reset_controller_register(&pdev->dev, &data->rcdev);
 105 }
 106
 107 static struct platform_driver oxnas_reset_driver = {
 108         .probe  = oxnas_reset_probe,
 109         .driver = {
 110                 .name           = "oxnas-reset",
 111                 .of_match_table = oxnas_reset_dt_ids,
 112         },
 113 };
 114 builtin_platform_driver(oxnas_reset_driver);