GNU Linux-libre 5.19-rc6-gnu
[releases.git] / drivers / reset / reset-brcmstb.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Broadcom STB generic reset controller for SW_INIT style reset controller
4  *
5  * Author: Florian Fainelli <f.fainelli@gmail.com>
6  * Copyright (C) 2018 Broadcom
7  */
8 #include <linux/delay.h>
9 #include <linux/device.h>
10 #include <linux/io.h>
11 #include <linux/module.h>
12 #include <linux/of.h>
13 #include <linux/platform_device.h>
14 #include <linux/reset-controller.h>
15 #include <linux/types.h>
16
17 struct brcmstb_reset {
18         void __iomem *base;
19         struct reset_controller_dev rcdev;
20 };
21
22 #define SW_INIT_SET             0x00
23 #define SW_INIT_CLEAR           0x04
24 #define SW_INIT_STATUS          0x08
25
26 #define SW_INIT_BIT(id)         BIT((id) & 0x1f)
27 #define SW_INIT_BANK(id)        ((id) >> 5)
28
29 /* A full bank contains extra registers that we are not utilizing but still
30  * qualify as a single bank.
31  */
32 #define SW_INIT_BANK_SIZE       0x18
33
34 static inline
35 struct brcmstb_reset *to_brcmstb(struct reset_controller_dev *rcdev)
36 {
37         return container_of(rcdev, struct brcmstb_reset, rcdev);
38 }
39
40 static int brcmstb_reset_assert(struct reset_controller_dev *rcdev,
41                                 unsigned long id)
42 {
43         unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE;
44         struct brcmstb_reset *priv = to_brcmstb(rcdev);
45
46         writel_relaxed(SW_INIT_BIT(id), priv->base + off + SW_INIT_SET);
47
48         return 0;
49 }
50
51 static int brcmstb_reset_deassert(struct reset_controller_dev *rcdev,
52                                   unsigned long id)
53 {
54         unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE;
55         struct brcmstb_reset *priv = to_brcmstb(rcdev);
56
57         writel_relaxed(SW_INIT_BIT(id), priv->base + off + SW_INIT_CLEAR);
58         /* Maximum reset delay after de-asserting a line and seeing block
59          * operation is typically 14us for the worst case, build some slack
60          * here.
61          */
62         usleep_range(100, 200);
63
64         return 0;
65 }
66
67 static int brcmstb_reset_status(struct reset_controller_dev *rcdev,
68                                 unsigned long id)
69 {
70         unsigned int off = SW_INIT_BANK(id) * SW_INIT_BANK_SIZE;
71         struct brcmstb_reset *priv = to_brcmstb(rcdev);
72
73         return readl_relaxed(priv->base + off + SW_INIT_STATUS) &
74                              SW_INIT_BIT(id);
75 }
76
77 static const struct reset_control_ops brcmstb_reset_ops = {
78         .assert = brcmstb_reset_assert,
79         .deassert = brcmstb_reset_deassert,
80         .status = brcmstb_reset_status,
81 };
82
83 static int brcmstb_reset_probe(struct platform_device *pdev)
84 {
85         struct device *kdev = &pdev->dev;
86         struct brcmstb_reset *priv;
87         struct resource *res;
88
89         priv = devm_kzalloc(kdev, sizeof(*priv), GFP_KERNEL);
90         if (!priv)
91                 return -ENOMEM;
92
93         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
94         priv->base = devm_ioremap_resource(kdev, res);
95         if (IS_ERR(priv->base))
96                 return PTR_ERR(priv->base);
97
98         dev_set_drvdata(kdev, priv);
99
100         priv->rcdev.owner = THIS_MODULE;
101         priv->rcdev.nr_resets = DIV_ROUND_DOWN_ULL(resource_size(res),
102                                                    SW_INIT_BANK_SIZE) * 32;
103         priv->rcdev.ops = &brcmstb_reset_ops;
104         priv->rcdev.of_node = kdev->of_node;
105         /* Use defaults: 1 cell and simple xlate function */
106
107         return devm_reset_controller_register(kdev, &priv->rcdev);
108 }
109
110 static const struct of_device_id brcmstb_reset_of_match[] = {
111         { .compatible = "brcm,brcmstb-reset" },
112         { /* sentinel */ }
113 };
114 MODULE_DEVICE_TABLE(of, brcmstb_reset_of_match);
115
116 static struct platform_driver brcmstb_reset_driver = {
117         .probe  = brcmstb_reset_probe,
118         .driver = {
119                 .name = "brcmstb-reset",
120                 .of_match_table = brcmstb_reset_of_match,
121         },
122 };
123 module_platform_driver(brcmstb_reset_driver);
124
125 MODULE_AUTHOR("Broadcom");
126 MODULE_DESCRIPTION("Broadcom STB reset controller");
127 MODULE_LICENSE("GPL");