1 // SPDX-License-Identifier: GPL-2.0
2 /* Copyright (C) 2018-2020 Broadcom */
4 #include <linux/device.h>
5 #include <linux/iopoll.h>
6 #include <linux/module.h>
8 #include <linux/platform_device.h>
9 #include <linux/reset-controller.h>
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)
17 struct brcm_rescal_reset {
20 struct reset_controller_dev rcdev;
23 /* Also doubles a deassert */
24 static int brcm_rescal_reset_set(struct reset_controller_dev *rcdev,
27 struct brcm_rescal_reset *data =
28 container_of(rcdev, struct brcm_rescal_reset, rcdev);
29 void __iomem *base = data->base;
33 reg = readl(base + BRCM_RESCAL_START);
34 writel(reg | BRCM_RESCAL_START_BIT, base + BRCM_RESCAL_START);
35 reg = readl(base + BRCM_RESCAL_START);
36 if (!(reg & BRCM_RESCAL_START_BIT)) {
37 dev_err(data->dev, "failed to start SATA/PCIe rescal\n");
41 ret = readl_poll_timeout(base + BRCM_RESCAL_STATUS, reg,
42 (reg & BRCM_RESCAL_STATUS_BIT), 100, 1000);
44 dev_err(data->dev, "time out on SATA/PCIe rescal\n");
48 reg = readl(base + BRCM_RESCAL_START);
49 writel(reg & ~BRCM_RESCAL_START_BIT, base + BRCM_RESCAL_START);
51 dev_dbg(data->dev, "SATA/PCIe rescal success\n");
56 /* A dummy function - deassert/reset does all the work */
57 static int brcm_rescal_reset_assert(struct reset_controller_dev *rcdev,
63 static int brcm_rescal_reset_xlate(struct reset_controller_dev *rcdev,
64 const struct of_phandle_args *reset_spec)
66 /* This is needed if #reset-cells == 0. */
70 static const struct reset_control_ops brcm_rescal_reset_ops = {
71 .reset = brcm_rescal_reset_set,
72 .deassert = brcm_rescal_reset_set,
73 .assert = brcm_rescal_reset_assert,
76 static int brcm_rescal_reset_probe(struct platform_device *pdev)
78 struct brcm_rescal_reset *data;
80 data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
84 data->base = devm_platform_ioremap_resource(pdev, 0);
85 if (IS_ERR(data->base))
86 return PTR_ERR(data->base);
88 data->rcdev.owner = THIS_MODULE;
89 data->rcdev.nr_resets = 1;
90 data->rcdev.ops = &brcm_rescal_reset_ops;
91 data->rcdev.of_node = pdev->dev.of_node;
92 data->rcdev.of_xlate = brcm_rescal_reset_xlate;
93 data->dev = &pdev->dev;
95 return devm_reset_controller_register(&pdev->dev, &data->rcdev);
98 static const struct of_device_id brcm_rescal_reset_of_match[] = {
99 { .compatible = "brcm,bcm7216-pcie-sata-rescal" },
102 MODULE_DEVICE_TABLE(of, brcm_rescal_reset_of_match);
104 static struct platform_driver brcm_rescal_reset_driver = {
105 .probe = brcm_rescal_reset_probe,
107 .name = "brcm-rescal-reset",
108 .of_match_table = brcm_rescal_reset_of_match,
111 module_platform_driver(brcm_rescal_reset_driver);
113 MODULE_AUTHOR("Broadcom");
114 MODULE_DESCRIPTION("Broadcom SATA/PCIe rescal reset controller");
115 MODULE_LICENSE("GPL v2");