linux/drivers/reset/hisilicon/reset-hi3660.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 * Copyright (c) 2016-2017 Linaro Ltd.
   4 * Copyright (c) 2016-2017 HiSilicon Technologies Co., Ltd.
   5 */
   6#include <linux/kernel.h>
   7#include <linux/mfd/syscon.h>
   8#include <linux/module.h>
   9#include <linux/of_device.h>
  10#include <linux/platform_device.h>
  11#include <linux/regmap.h>
  12#include <linux/reset-controller.h>
  13
  14struct hi3660_reset_controller {
  15        struct reset_controller_dev rst;
  16        struct regmap *map;
  17};
  18
  19#define to_hi3660_reset_controller(_rst) \
  20        container_of(_rst, struct hi3660_reset_controller, rst)
  21
  22static int hi3660_reset_program_hw(struct reset_controller_dev *rcdev,
  23                                   unsigned long idx, bool assert)
  24{
  25        struct hi3660_reset_controller *rc = to_hi3660_reset_controller(rcdev);
  26        unsigned int offset = idx >> 8;
  27        unsigned int mask = BIT(idx & 0x1f);
  28
  29        if (assert)
  30                return regmap_write(rc->map, offset, mask);
  31        else
  32                return regmap_write(rc->map, offset + 4, mask);
  33}
  34
  35static int hi3660_reset_assert(struct reset_controller_dev *rcdev,
  36                               unsigned long idx)
  37{
  38        return hi3660_reset_program_hw(rcdev, idx, true);
  39}
  40
  41static int hi3660_reset_deassert(struct reset_controller_dev *rcdev,
  42                                 unsigned long idx)
  43{
  44        return hi3660_reset_program_hw(rcdev, idx, false);
  45}
  46
  47static int hi3660_reset_dev(struct reset_controller_dev *rcdev,
  48                            unsigned long idx)
  49{
  50        int err;
  51
  52        err = hi3660_reset_assert(rcdev, idx);
  53        if (err)
  54                return err;
  55
  56        return hi3660_reset_deassert(rcdev, idx);
  57}
  58
  59static struct reset_control_ops hi3660_reset_ops = {
  60        .reset    = hi3660_reset_dev,
  61        .assert   = hi3660_reset_assert,
  62        .deassert = hi3660_reset_deassert,
  63};
  64
  65static int hi3660_reset_xlate(struct reset_controller_dev *rcdev,
  66                              const struct of_phandle_args *reset_spec)
  67{
  68        unsigned int offset, bit;
  69
  70        offset = reset_spec->args[0];
  71        bit = reset_spec->args[1];
  72
  73        return (offset << 8) | bit;
  74}
  75
  76static int hi3660_reset_probe(struct platform_device *pdev)
  77{
  78        struct hi3660_reset_controller *rc;
  79        struct device_node *np = pdev->dev.of_node;
  80        struct device *dev = &pdev->dev;
  81
  82        rc = devm_kzalloc(dev, sizeof(*rc), GFP_KERNEL);
  83        if (!rc)
  84                return -ENOMEM;
  85
  86        rc->map = syscon_regmap_lookup_by_phandle(np, "hisi,rst-syscon");
  87        if (IS_ERR(rc->map)) {
  88                dev_err(dev, "failed to get hi3660,rst-syscon\n");
  89                return PTR_ERR(rc->map);
  90        }
  91
  92        rc->rst.ops = &hi3660_reset_ops,
  93        rc->rst.of_node = np;
  94        rc->rst.of_reset_n_cells = 2;
  95        rc->rst.of_xlate = hi3660_reset_xlate;
  96
  97        return reset_controller_register(&rc->rst);
  98}
  99
 100static const struct of_device_id hi3660_reset_match[] = {
 101        { .compatible = "hisilicon,hi3660-reset", },
 102        {},
 103};
 104MODULE_DEVICE_TABLE(of, hi3660_reset_match);
 105
 106static struct platform_driver hi3660_reset_driver = {
 107        .probe = hi3660_reset_probe,
 108        .driver = {
 109                .name = "hi3660-reset",
 110                .of_match_table = hi3660_reset_match,
 111        },
 112};
 113
 114static int __init hi3660_reset_init(void)
 115{
 116        return platform_driver_register(&hi3660_reset_driver);
 117}
 118arch_initcall(hi3660_reset_init);
 119
 120MODULE_LICENSE("GPL");
 121MODULE_ALIAS("platform:hi3660-reset");
 122MODULE_DESCRIPTION("HiSilicon Hi3660 Reset Driver");
 123