drivers/reset/hisilicon/reset-hi3660.c

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