LXR linux/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
  19struct a10sr_reset {
  20        struct reset_controller_dev     rcdev;
  21        struct regmap *regmap;
  22};
  23
  24static inline struct a10sr_reset *to_a10sr_rst(struct reset_controller_dev *rc)
  25{
  26        return container_of(rc, struct a10sr_reset, rcdev);
  27}
  28
  29static 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
  44static 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
  55static int a10sr_reset_assert(struct reset_controller_dev *rcdev,
  56                              unsigned long id)
  57{
  58        return a10sr_reset_update(rcdev, id, true);
  59}
  60
  61static int a10sr_reset_deassert(struct reset_controller_dev *rcdev,
  62                                unsigned long id)
  63{
  64        return a10sr_reset_update(rcdev, id, false);
  65}
  66
  67static 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
  84static 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
  90static 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
 111static const struct of_device_id a10sr_reset_of_match[] = {
 112        { .compatible = "altr,a10sr-reset" },
 113        { },
 114};
 115MODULE_DEVICE_TABLE(of, a10sr_reset_of_match);
 116
 117static struct platform_driver a10sr_reset_driver = {
 118        .probe  = a10sr_reset_probe,
 119        .driver = {
 120                .name           = "altr_a10sr_reset",
 121        },
 122};
 123module_platform_driver(a10sr_reset_driver);
 124
 125MODULE_AUTHOR("Thor Thayer <thor.thayer@linux.intel.com>");
 126MODULE_DESCRIPTION("Altera Arria10 System Resource Reset Controller Driver");
 127MODULE_LICENSE("GPL v2");
 128