GNU Linux-libre 5.19-rc6-gnu
[releases.git] / 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         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
90 static const struct of_device_id brcm_rescal_reset_of_match[] = {
91         { .compatible = "brcm,bcm7216-pcie-sata-rescal" },
92         { },
93 };
94 MODULE_DEVICE_TABLE(of, brcm_rescal_reset_of_match);
95
96 static 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 };
103 module_platform_driver(brcm_rescal_reset_driver);
104
105 MODULE_AUTHOR("Broadcom");
106 MODULE_DESCRIPTION("Broadcom SATA/PCIe rescal reset controller");
107 MODULE_LICENSE("GPL v2");