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[linux-2.6-microblaze.git] / drivers / reset / reset-ath79.c
1 /*
2  * AR71xx Reset Controller Driver
3  * Author: Alban Bedel
4  *
5  * Copyright (C) 2015 Alban Bedel <albeu@free.fr>
6  *
7  * This program is free software; you can redistribute it and/or modify
8  * it under the terms of the GNU General Public License as published by
9  * the Free Software Foundation; either version 2 of the License, or
10  * (at your option) any later version.
11  *
12  * This program is distributed in the hope that it will be useful,
13  * but WITHOUT ANY WARRANTY; without even the implied warranty of
14  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
15  * GNU General Public License for more details.
16  */
17
18 #include <linux/io.h>
19 #include <linux/init.h>
20 #include <linux/platform_device.h>
21 #include <linux/reset-controller.h>
22 #include <linux/reboot.h>
23
24 struct ath79_reset {
25         struct reset_controller_dev rcdev;
26         struct notifier_block restart_nb;
27         void __iomem *base;
28         spinlock_t lock;
29 };
30
31 #define FULL_CHIP_RESET 24
32
33 static int ath79_reset_update(struct reset_controller_dev *rcdev,
34                         unsigned long id, bool assert)
35 {
36         struct ath79_reset *ath79_reset =
37                 container_of(rcdev, struct ath79_reset, rcdev);
38         unsigned long flags;
39         u32 val;
40
41         spin_lock_irqsave(&ath79_reset->lock, flags);
42         val = readl(ath79_reset->base);
43         if (assert)
44                 val |= BIT(id);
45         else
46                 val &= ~BIT(id);
47         writel(val, ath79_reset->base);
48         spin_unlock_irqrestore(&ath79_reset->lock, flags);
49
50         return 0;
51 }
52
53 static int ath79_reset_assert(struct reset_controller_dev *rcdev,
54                         unsigned long id)
55 {
56         return ath79_reset_update(rcdev, id, true);
57 }
58
59 static int ath79_reset_deassert(struct reset_controller_dev *rcdev,
60                                 unsigned long id)
61 {
62         return ath79_reset_update(rcdev, id, false);
63 }
64
65 static int ath79_reset_status(struct reset_controller_dev *rcdev,
66                         unsigned long id)
67 {
68         struct ath79_reset *ath79_reset =
69                 container_of(rcdev, struct ath79_reset, rcdev);
70         u32 val;
71
72         val = readl(ath79_reset->base);
73
74         return !!(val & BIT(id));
75 }
76
77 static const struct reset_control_ops ath79_reset_ops = {
78         .assert = ath79_reset_assert,
79         .deassert = ath79_reset_deassert,
80         .status = ath79_reset_status,
81 };
82
83 static int ath79_reset_restart_handler(struct notifier_block *nb,
84                                 unsigned long action, void *data)
85 {
86         struct ath79_reset *ath79_reset =
87                 container_of(nb, struct ath79_reset, restart_nb);
88
89         ath79_reset_assert(&ath79_reset->rcdev, FULL_CHIP_RESET);
90
91         return NOTIFY_DONE;
92 }
93
94 static int ath79_reset_probe(struct platform_device *pdev)
95 {
96         struct ath79_reset *ath79_reset;
97         struct resource *res;
98         int err;
99
100         ath79_reset = devm_kzalloc(&pdev->dev,
101                                 sizeof(*ath79_reset), GFP_KERNEL);
102         if (!ath79_reset)
103                 return -ENOMEM;
104
105         platform_set_drvdata(pdev, ath79_reset);
106
107         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
108         ath79_reset->base = devm_ioremap_resource(&pdev->dev, res);
109         if (IS_ERR(ath79_reset->base))
110                 return PTR_ERR(ath79_reset->base);
111
112         spin_lock_init(&ath79_reset->lock);
113         ath79_reset->rcdev.ops = &ath79_reset_ops;
114         ath79_reset->rcdev.owner = THIS_MODULE;
115         ath79_reset->rcdev.of_node = pdev->dev.of_node;
116         ath79_reset->rcdev.of_reset_n_cells = 1;
117         ath79_reset->rcdev.nr_resets = 32;
118
119         err = devm_reset_controller_register(&pdev->dev, &ath79_reset->rcdev);
120         if (err)
121                 return err;
122
123         ath79_reset->restart_nb.notifier_call = ath79_reset_restart_handler;
124         ath79_reset->restart_nb.priority = 128;
125
126         err = register_restart_handler(&ath79_reset->restart_nb);
127         if (err)
128                 dev_warn(&pdev->dev, "Failed to register restart handler\n");
129
130         return 0;
131 }
132
133 static const struct of_device_id ath79_reset_dt_ids[] = {
134         { .compatible = "qca,ar7100-reset", },
135         { },
136 };
137
138 static struct platform_driver ath79_reset_driver = {
139         .probe  = ath79_reset_probe,
140         .driver = {
141                 .name                   = "ath79-reset",
142                 .of_match_table         = ath79_reset_dt_ids,
143                 .suppress_bind_attrs    = true,
144         },
145 };
146 builtin_platform_driver(ath79_reset_driver);