treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 157
[sfrench/cifs-2.6.git] / drivers / reset / reset-ath79.c
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * AR71xx Reset Controller Driver
4  * Author: Alban Bedel
5  *
6  * Copyright (C) 2015 Alban Bedel <albeu@free.fr>
7  */
8
9 #include <linux/io.h>
10 #include <linux/init.h>
11 #include <linux/mod_devicetable.h>
12 #include <linux/platform_device.h>
13 #include <linux/reset-controller.h>
14 #include <linux/reboot.h>
15
16 struct ath79_reset {
17         struct reset_controller_dev rcdev;
18         struct notifier_block restart_nb;
19         void __iomem *base;
20         spinlock_t lock;
21 };
22
23 #define FULL_CHIP_RESET 24
24
25 static int ath79_reset_update(struct reset_controller_dev *rcdev,
26                         unsigned long id, bool assert)
27 {
28         struct ath79_reset *ath79_reset =
29                 container_of(rcdev, struct ath79_reset, rcdev);
30         unsigned long flags;
31         u32 val;
32
33         spin_lock_irqsave(&ath79_reset->lock, flags);
34         val = readl(ath79_reset->base);
35         if (assert)
36                 val |= BIT(id);
37         else
38                 val &= ~BIT(id);
39         writel(val, ath79_reset->base);
40         spin_unlock_irqrestore(&ath79_reset->lock, flags);
41
42         return 0;
43 }
44
45 static int ath79_reset_assert(struct reset_controller_dev *rcdev,
46                         unsigned long id)
47 {
48         return ath79_reset_update(rcdev, id, true);
49 }
50
51 static int ath79_reset_deassert(struct reset_controller_dev *rcdev,
52                                 unsigned long id)
53 {
54         return ath79_reset_update(rcdev, id, false);
55 }
56
57 static int ath79_reset_status(struct reset_controller_dev *rcdev,
58                         unsigned long id)
59 {
60         struct ath79_reset *ath79_reset =
61                 container_of(rcdev, struct ath79_reset, rcdev);
62         u32 val;
63
64         val = readl(ath79_reset->base);
65
66         return !!(val & BIT(id));
67 }
68
69 static const struct reset_control_ops ath79_reset_ops = {
70         .assert = ath79_reset_assert,
71         .deassert = ath79_reset_deassert,
72         .status = ath79_reset_status,
73 };
74
75 static int ath79_reset_restart_handler(struct notifier_block *nb,
76                                 unsigned long action, void *data)
77 {
78         struct ath79_reset *ath79_reset =
79                 container_of(nb, struct ath79_reset, restart_nb);
80
81         ath79_reset_assert(&ath79_reset->rcdev, FULL_CHIP_RESET);
82
83         return NOTIFY_DONE;
84 }
85
86 static int ath79_reset_probe(struct platform_device *pdev)
87 {
88         struct ath79_reset *ath79_reset;
89         struct resource *res;
90         int err;
91
92         ath79_reset = devm_kzalloc(&pdev->dev,
93                                 sizeof(*ath79_reset), GFP_KERNEL);
94         if (!ath79_reset)
95                 return -ENOMEM;
96
97         platform_set_drvdata(pdev, ath79_reset);
98
99         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
100         ath79_reset->base = devm_ioremap_resource(&pdev->dev, res);
101         if (IS_ERR(ath79_reset->base))
102                 return PTR_ERR(ath79_reset->base);
103
104         spin_lock_init(&ath79_reset->lock);
105         ath79_reset->rcdev.ops = &ath79_reset_ops;
106         ath79_reset->rcdev.owner = THIS_MODULE;
107         ath79_reset->rcdev.of_node = pdev->dev.of_node;
108         ath79_reset->rcdev.of_reset_n_cells = 1;
109         ath79_reset->rcdev.nr_resets = 32;
110
111         err = devm_reset_controller_register(&pdev->dev, &ath79_reset->rcdev);
112         if (err)
113                 return err;
114
115         ath79_reset->restart_nb.notifier_call = ath79_reset_restart_handler;
116         ath79_reset->restart_nb.priority = 128;
117
118         err = register_restart_handler(&ath79_reset->restart_nb);
119         if (err)
120                 dev_warn(&pdev->dev, "Failed to register restart handler\n");
121
122         return 0;
123 }
124
125 static const struct of_device_id ath79_reset_dt_ids[] = {
126         { .compatible = "qca,ar7100-reset", },
127         { },
128 };
129
130 static struct platform_driver ath79_reset_driver = {
131         .probe  = ath79_reset_probe,
132         .driver = {
133                 .name                   = "ath79-reset",
134                 .of_match_table         = ath79_reset_dt_ids,
135                 .suppress_bind_attrs    = true,
136         },
137 };
138 builtin_platform_driver(ath79_reset_driver);