linux/drivers/reset/reset-brcmstb-rescal.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/* Copyright (C) 2018-2020 Broadcom */
   3
   4#include <linux/device.h>
   5#include <linux/iopoll.h>
   6#include <linux/module.h>
   7#include <linux/of.h>
   8#include <linux/platform_device.h>
   9#include <linux/reset-controller.h>
  10
  11#define BRCM_RESCAL_START       0x0
  12#define  BRCM_RESCAL_START_BIT  BIT(0)
  13#define BRCM_RESCAL_CTRL        0x4
  14#define BRCM_RESCAL_STATUS      0x8
  15#define  BRCM_RESCAL_STATUS_BIT BIT(0)
  16
  17struct brcm_rescal_reset {
  18        void __iomem *base;
  19        struct device *dev;
  20        struct reset_controller_dev rcdev;
  21};
  22
  23static int brcm_rescal_reset_set(struct reset_controller_dev *rcdev,
  24                                 unsigned long id)
  25{
  26        struct brcm_rescal_reset *data =
  27                container_of(rcdev, struct brcm_rescal_reset, rcdev);
  28        void __iomem *base = data->base;
  29        u32 reg;
  30        int ret;
  31
  32        reg = readl(base + BRCM_RESCAL_START);
  33        writel(reg | BRCM_RESCAL_START_BIT, base + BRCM_RESCAL_START);
  34        reg = readl(base + BRCM_RESCAL_START);
  35        if (!(reg & BRCM_RESCAL_START_BIT)) {
  36                dev_err(data->dev, "failed to start SATA/PCIe rescal\n");
  37                return -EIO;
  38        }
  39
  40        ret = readl_poll_timeout(base + BRCM_RESCAL_STATUS, reg,
  41                                 !(reg & BRCM_RESCAL_STATUS_BIT), 100, 1000);
  42        if (ret) {
  43                dev_err(data->dev, "time out on SATA/PCIe rescal\n");
  44                return ret;
  45        }
  46
  47        reg = readl(base + BRCM_RESCAL_START);
  48        writel(reg & ~BRCM_RESCAL_START_BIT, base + BRCM_RESCAL_START);
  49
  50        dev_dbg(data->dev, "SATA/PCIe rescal success\n");
  51
  52        return 0;
  53}
  54
  55static int brcm_rescal_reset_xlate(struct reset_controller_dev *rcdev,
  56                                   const struct of_phandle_args *reset_spec)
  57{
  58        /* This is needed if #reset-cells == 0. */
  59        return 0;
  60}
  61
  62static const struct reset_control_ops brcm_rescal_reset_ops = {
  63        .reset = brcm_rescal_reset_set,
  64};
  65
  66static int brcm_rescal_reset_probe(struct platform_device *pdev)
  67{
  68        struct brcm_rescal_reset *data;
  69        struct resource *res;
  70
  71        data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
  72        if (!data)
  73                return -ENOMEM;
  74
  75        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  76        data->base = devm_ioremap_resource(&pdev->dev, res);
  77        if (IS_ERR(data->base))
  78                return PTR_ERR(data->base);
  79
  80        data->rcdev.owner = THIS_MODULE;
  81        data->rcdev.nr_resets = 1;
  82        data->rcdev.ops = &brcm_rescal_reset_ops;
  83        data->rcdev.of_node = pdev->dev.of_node;
  84        data->rcdev.of_xlate = brcm_rescal_reset_xlate;
  85        data->dev = &pdev->dev;
  86
  87        return devm_reset_controller_register(&pdev->dev, &data->rcdev);
  88}
  89
  90static const struct of_device_id brcm_rescal_reset_of_match[] = {
  91        { .compatible = "brcm,bcm7216-pcie-sata-rescal" },
  92        { },
  93};
  94MODULE_DEVICE_TABLE(of, brcm_rescal_reset_of_match);
  95
  96static struct platform_driver brcm_rescal_reset_driver = {
  97        .probe = brcm_rescal_reset_probe,
  98        .driver = {
  99                .name   = "brcm-rescal-reset",
 100                .of_match_table = brcm_rescal_reset_of_match,
 101        }
 102};
 103module_platform_driver(brcm_rescal_reset_driver);
 104
 105MODULE_AUTHOR("Broadcom");
 106MODULE_DESCRIPTION("Broadcom SATA/PCIe rescal reset controller");
 107MODULE_LICENSE("GPL v2");
 108