tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Copyright (C) 2015 Alban Bedel <albeu@free.fr>
3 *
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 */
14
15#include <linux/io.h>
16#include <linux/module.h>
17#include <linux/platform_device.h>
18#include <linux/reset-controller.h>
19#include <linux/reboot.h>
20
21struct ath79_reset {
22 struct reset_controller_dev rcdev;
23 struct notifier_block restart_nb;
24 void __iomem *base;
25 spinlock_t lock;
26};
27
28#define FULL_CHIP_RESET 24
29
30static int ath79_reset_update(struct reset_controller_dev *rcdev,
31 unsigned long id, bool assert)
32{
33 struct ath79_reset *ath79_reset =
34 container_of(rcdev, struct ath79_reset, rcdev);
35 unsigned long flags;
36 u32 val;
37
38 spin_lock_irqsave(&ath79_reset->lock, flags);
39 val = readl(ath79_reset->base);
40 if (assert)
41 val |= BIT(id);
42 else
43 val &= ~BIT(id);
44 writel(val, ath79_reset->base);
45 spin_unlock_irqrestore(&ath79_reset->lock, flags);
46
47 return 0;
48}
49
50static int ath79_reset_assert(struct reset_controller_dev *rcdev,
51 unsigned long id)
52{
53 return ath79_reset_update(rcdev, id, true);
54}
55
56static int ath79_reset_deassert(struct reset_controller_dev *rcdev,
57 unsigned long id)
58{
59 return ath79_reset_update(rcdev, id, false);
60}
61
62static int ath79_reset_status(struct reset_controller_dev *rcdev,
63 unsigned long id)
64{
65 struct ath79_reset *ath79_reset =
66 container_of(rcdev, struct ath79_reset, rcdev);
67 u32 val;
68
69 val = readl(ath79_reset->base);
70
71 return !!(val & BIT(id));
72}
73
74static const struct reset_control_ops ath79_reset_ops = {
75 .assert = ath79_reset_assert,
76 .deassert = ath79_reset_deassert,
77 .status = ath79_reset_status,
78};
79
80static int ath79_reset_restart_handler(struct notifier_block *nb,
81 unsigned long action, void *data)
82{
83 struct ath79_reset *ath79_reset =
84 container_of(nb, struct ath79_reset, restart_nb);
85
86 ath79_reset_assert(&ath79_reset->rcdev, FULL_CHIP_RESET);
87
88 return NOTIFY_DONE;
89}
90
91static int ath79_reset_probe(struct platform_device *pdev)
92{
93 struct ath79_reset *ath79_reset;
94 struct resource *res;
95 int err;
96
97 ath79_reset = devm_kzalloc(&pdev->dev,
98 sizeof(*ath79_reset), GFP_KERNEL);
99 if (!ath79_reset)
100 return -ENOMEM;
101
102 platform_set_drvdata(pdev, ath79_reset);
103
104 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
105 ath79_reset->base = devm_ioremap_resource(&pdev->dev, res);
106 if (IS_ERR(ath79_reset->base))
107 return PTR_ERR(ath79_reset->base);
108
109 spin_lock_init(&ath79_reset->lock);
110 ath79_reset->rcdev.ops = &ath79_reset_ops;
111 ath79_reset->rcdev.owner = THIS_MODULE;
112 ath79_reset->rcdev.of_node = pdev->dev.of_node;
113 ath79_reset->rcdev.of_reset_n_cells = 1;
114 ath79_reset->rcdev.nr_resets = 32;
115
116 err = devm_reset_controller_register(&pdev->dev, &ath79_reset->rcdev);
117 if (err)
118 return err;
119
120 ath79_reset->restart_nb.notifier_call = ath79_reset_restart_handler;
121 ath79_reset->restart_nb.priority = 128;
122
123 err = register_restart_handler(&ath79_reset->restart_nb);
124 if (err)
125 dev_warn(&pdev->dev, "Failed to register restart handler\n");
126
127 return 0;
128}
129
130static int ath79_reset_remove(struct platform_device *pdev)
131{
132 struct ath79_reset *ath79_reset = platform_get_drvdata(pdev);
133
134 unregister_restart_handler(&ath79_reset->restart_nb);
135
136 return 0;
137}
138
139static const struct of_device_id ath79_reset_dt_ids[] = {
140 { .compatible = "qca,ar7100-reset", },
141 { },
142};
143MODULE_DEVICE_TABLE(of, ath79_reset_dt_ids);
144
145static struct platform_driver ath79_reset_driver = {
146 .probe = ath79_reset_probe,
147 .remove = ath79_reset_remove,
148 .driver = {
149 .name = "ath79-reset",
150 .of_match_table = ath79_reset_dt_ids,
151 },
152};
153module_platform_driver(ath79_reset_driver);
154
155MODULE_AUTHOR("Alban Bedel <albeu@free.fr>");
156MODULE_DESCRIPTION("AR71xx Reset Controller Driver");
157MODULE_LICENSE("GPL");