LXR linux/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
  24struct oxnas_reset {
  25        struct regmap *regmap;
  26        struct reset_controller_dev rcdev;
  27};
  28
  29static 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
  42static 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
  53static 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
  64static 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
  70static const struct of_device_id oxnas_reset_dt_ids[] = {
  71         { .compatible = "oxsemi,ox810se-reset", },
  72         { .compatible = "oxsemi,ox820-reset", },
  73         { /* sentinel */ },
  74};
  75
  76static 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
 107static 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};
 114builtin_platform_driver(oxnas_reset_driver);
 115