drivers/reset/reset-brcmstb-rescal.c

   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
  17 struct brcm_rescal_reset {
  18         void __iomem *base;
  19         struct device *dev;
  20         struct reset_controller_dev rcdev;
  21 };
  22
  23 static 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
  55 static 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
  62 static const struct reset_control_ops brcm_rescal_reset_ops = {
  63         .reset = brcm_rescal_reset_set,
  64 };
  65
  66 static int brcm_rescal_reset_probe(struct platform_device *pdev)
  67 {
  68         struct brcm_rescal_reset *data;
  69
  70         data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
  71         if (!data)
  72                 return -ENOMEM;
  73
  74         data->base = devm_platform_ioremap_resource(pdev, 0);
  75         if (IS_ERR(data->base))
  76                 return PTR_ERR(data->base);
  77
  78         data->rcdev.owner = THIS_MODULE;
  79         data->rcdev.nr_resets = 1;
  80         data->rcdev.ops = &brcm_rescal_reset_ops;
  81         data->rcdev.of_node = pdev->dev.of_node;
  82         data->rcdev.of_xlate = brcm_rescal_reset_xlate;
  83         data->dev = &pdev->dev;
  84
  85         return devm_reset_controller_register(&pdev->dev, &data->rcdev);
  86 }
  87
  88 static const struct of_device_id brcm_rescal_reset_of_match[] = {
  89         { .compatible = "brcm,bcm7216-pcie-sata-rescal" },
  90         { },
  91 };
  92 MODULE_DEVICE_TABLE(of, brcm_rescal_reset_of_match);
  93
  94 static struct platform_driver brcm_rescal_reset_driver = {
  95         .probe = brcm_rescal_reset_probe,
  96         .driver = {
  97                 .name   = "brcm-rescal-reset",
  98                 .of_match_table = brcm_rescal_reset_of_match,
  99         }
 100 };
 101 module_platform_driver(brcm_rescal_reset_driver);
 102
 103 MODULE_AUTHOR("Broadcom");
 104 MODULE_DESCRIPTION("Broadcom SATA/PCIe rescal reset controller");
 105 MODULE_LICENSE("GPL v2");