drivers/reset/reset-a10sr.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  Copyright Intel Corporation (C) 2017. All Rights Reserved
   4  *
   5  * Reset driver for Altera Arria10 MAX5 System Resource Chip
   6  *
   7  * Adapted from reset-socfpga.c
   8  */
   9
  10 #include <linux/err.h>
  11 #include <linux/mfd/altera-a10sr.h>
  12 #include <linux/module.h>
  13 #include <linux/of.h>
  14 #include <linux/platform_device.h>
  15 #include <linux/reset-controller.h>
  16
  17 #include <dt-bindings/reset/altr,rst-mgr-a10sr.h>
  18
  19 struct a10sr_reset {
  20         struct reset_controller_dev     rcdev;
  21         struct regmap *regmap;
  22 };
  23
  24 static inline struct a10sr_reset *to_a10sr_rst(struct reset_controller_dev *rc)
  25 {
  26         return container_of(rc, struct a10sr_reset, rcdev);
  27 }
  28
  29 static inline int a10sr_reset_shift(unsigned long id)
  30 {
  31         switch (id) {
  32         case A10SR_RESET_ENET_HPS:
  33                 return 1;
  34         case A10SR_RESET_PCIE:
  35         case A10SR_RESET_FILE:
  36         case A10SR_RESET_BQSPI:
  37         case A10SR_RESET_USB:
  38                 return id + 11;
  39         default:
  40                 return -EINVAL;
  41         }
  42 }
  43
  44 static int a10sr_reset_update(struct reset_controller_dev *rcdev,
  45                               unsigned long id, bool assert)
  46 {
  47         struct a10sr_reset *a10r = to_a10sr_rst(rcdev);
  48         int offset = a10sr_reset_shift(id);
  49         u8 mask = ALTR_A10SR_REG_BIT_MASK(offset);
  50         int index = ALTR_A10SR_HPS_RST_REG + ALTR_A10SR_REG_OFFSET(offset);
  51
  52         return regmap_update_bits(a10r->regmap, index, mask, assert ? 0 : mask);
  53 }
  54
  55 static int a10sr_reset_assert(struct reset_controller_dev *rcdev,
  56                               unsigned long id)
  57 {
  58         return a10sr_reset_update(rcdev, id, true);
  59 }
  60
  61 static int a10sr_reset_deassert(struct reset_controller_dev *rcdev,
  62                                 unsigned long id)
  63 {
  64         return a10sr_reset_update(rcdev, id, false);
  65 }
  66
  67 static int a10sr_reset_status(struct reset_controller_dev *rcdev,
  68                               unsigned long id)
  69 {
  70         int ret;
  71         struct a10sr_reset *a10r = to_a10sr_rst(rcdev);
  72         int offset = a10sr_reset_shift(id);
  73         u8 mask = ALTR_A10SR_REG_BIT_MASK(offset);
  74         int index = ALTR_A10SR_HPS_RST_REG + ALTR_A10SR_REG_OFFSET(offset);
  75         unsigned int value;
  76
  77         ret = regmap_read(a10r->regmap, index, &value);
  78         if (ret < 0)
  79                 return ret;
  80
  81         return !!(value & mask);
  82 }
  83
  84 static const struct reset_control_ops a10sr_reset_ops = {
  85         .assert         = a10sr_reset_assert,
  86         .deassert       = a10sr_reset_deassert,
  87         .status         = a10sr_reset_status,
  88 };
  89
  90 static int a10sr_reset_probe(struct platform_device *pdev)
  91 {
  92         struct altr_a10sr *a10sr = dev_get_drvdata(pdev->dev.parent);
  93         struct a10sr_reset *a10r;
  94
  95         a10r = devm_kzalloc(&pdev->dev, sizeof(struct a10sr_reset),
  96                             GFP_KERNEL);
  97         if (!a10r)
  98                 return -ENOMEM;
  99
 100         a10r->rcdev.owner = THIS_MODULE;
 101         a10r->rcdev.nr_resets = A10SR_RESET_NUM;
 102         a10r->rcdev.ops = &a10sr_reset_ops;
 103         a10r->rcdev.of_node = pdev->dev.of_node;
 104         a10r->regmap = a10sr->regmap;
 105
 106         platform_set_drvdata(pdev, a10r);
 107
 108         return devm_reset_controller_register(&pdev->dev, &a10r->rcdev);
 109 }
 110
 111 static const struct of_device_id a10sr_reset_of_match[] = {
 112         { .compatible = "altr,a10sr-reset" },
 113         { },
 114 };
 115 MODULE_DEVICE_TABLE(of, a10sr_reset_of_match);
 116
 117 static struct platform_driver a10sr_reset_driver = {
 118         .probe  = a10sr_reset_probe,
 119         .driver = {
 120                 .name           = "altr_a10sr_reset",
 121         },
 122 };
 123 module_platform_driver(a10sr_reset_driver);
 124
 125 MODULE_AUTHOR("Thor Thayer <thor.thayer@linux.intel.com>");
 126 MODULE_DESCRIPTION("Altera Arria10 System Resource Reset Controller Driver");
 127 MODULE_LICENSE("GPL v2");