drivers/reset/hisilicon/reset-hi3660.c

   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
  14 struct 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
  22 static 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
  35 static 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
  41 static 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
  47 static 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
  59 static const struct reset_control_ops hi3660_reset_ops = {
  60         .reset    = hi3660_reset_dev,
  61         .assert   = hi3660_reset_assert,
  62         .deassert = hi3660_reset_deassert,
  63 };
  64
  65 static 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
  76 static 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
 100 static const struct of_device_id hi3660_reset_match[] = {
 101         { .compatible = "hisilicon,hi3660-reset", },
 102         {},
 103 };
 104 MODULE_DEVICE_TABLE(of, hi3660_reset_match);
 105
 106 static 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
 114 static int __init hi3660_reset_init(void)
 115 {
 116         return platform_driver_register(&hi3660_reset_driver);
 117 }
 118 arch_initcall(hi3660_reset_init);
 119
 120 MODULE_LICENSE("GPL");
 121 MODULE_ALIAS("platform:hi3660-reset");
 122 MODULE_DESCRIPTION("HiSilicon Hi3660 Reset Driver");