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1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * BCM6345 Reset Controller Driver
4 *
5 * Copyright (C) 2020 Álvaro Fernández Rojas <[email protected]>
6 */
7
8#include <linux/delay.h>
9#include <linux/init.h>
10#include <linux/io.h>
11#include <linux/platform_device.h>
12#include <linux/reset-controller.h>
13
14#define BCM6345_RESET_NUM 32
15#define BCM6345_RESET_SLEEP_MIN_US 10000
16#define BCM6345_RESET_SLEEP_MAX_US 20000
17
18struct bcm6345_reset {
19 struct reset_controller_dev rcdev;
20 void __iomem *base;
21 spinlock_t lock;
22};
23
24static inline struct bcm6345_reset *
25to_bcm6345_reset(struct reset_controller_dev *rcdev)
26{
27 return container_of(rcdev, struct bcm6345_reset, rcdev);
28}
29
30static int bcm6345_reset_update(struct reset_controller_dev *rcdev,
31 unsigned long id, bool assert)
32{
33 struct bcm6345_reset *bcm6345_reset = to_bcm6345_reset(rcdev);
34 unsigned long flags;
35 uint32_t val;
36
37 spin_lock_irqsave(&bcm6345_reset->lock, flags);
38 val = __raw_readl(bcm6345_reset->base);
39 if (assert)
40 val &= ~BIT(id);
41 else
42 val |= BIT(id);
43 __raw_writel(val, bcm6345_reset->base);
44 spin_unlock_irqrestore(&bcm6345_reset->lock, flags);
45
46 return 0;
47}
48
49static int bcm6345_reset_assert(struct reset_controller_dev *rcdev,
50 unsigned long id)
51{
52 return bcm6345_reset_update(rcdev, id, true);
53}
54
55static int bcm6345_reset_deassert(struct reset_controller_dev *rcdev,
56 unsigned long id)
57{
58 return bcm6345_reset_update(rcdev, id, false);
59}
60
61static int bcm6345_reset_reset(struct reset_controller_dev *rcdev,
62 unsigned long id)
63{
64 bcm6345_reset_update(rcdev, id, true);
65 usleep_range(BCM6345_RESET_SLEEP_MIN_US,
66 BCM6345_RESET_SLEEP_MAX_US);
67
68 bcm6345_reset_update(rcdev, id, false);
69 /*
70 * Ensure component is taken out reset state by sleeping also after
71 * deasserting the reset. Otherwise, the component may not be ready
72 * for operation.
73 */
74 usleep_range(BCM6345_RESET_SLEEP_MIN_US,
75 BCM6345_RESET_SLEEP_MAX_US);
76
77 return 0;
78}
79
80static int bcm6345_reset_status(struct reset_controller_dev *rcdev,
81 unsigned long id)
82{
83 struct bcm6345_reset *bcm6345_reset = to_bcm6345_reset(rcdev);
84
85 return !(__raw_readl(bcm6345_reset->base) & BIT(id));
86}
87
88static const struct reset_control_ops bcm6345_reset_ops = {
89 .assert = bcm6345_reset_assert,
90 .deassert = bcm6345_reset_deassert,
91 .reset = bcm6345_reset_reset,
92 .status = bcm6345_reset_status,
93};
94
95static int bcm6345_reset_probe(struct platform_device *pdev)
96{
97 struct bcm6345_reset *bcm6345_reset;
98
99 bcm6345_reset = devm_kzalloc(&pdev->dev,
100 sizeof(*bcm6345_reset), GFP_KERNEL);
101 if (!bcm6345_reset)
102 return -ENOMEM;
103
104 bcm6345_reset->base = devm_platform_ioremap_resource(pdev, 0);
105 if (IS_ERR(bcm6345_reset->base))
106 return PTR_ERR(bcm6345_reset->base);
107
108 spin_lock_init(&bcm6345_reset->lock);
109 bcm6345_reset->rcdev.ops = &bcm6345_reset_ops;
110 bcm6345_reset->rcdev.owner = THIS_MODULE;
111 bcm6345_reset->rcdev.of_node = pdev->dev.of_node;
112 bcm6345_reset->rcdev.of_reset_n_cells = 1;
113 bcm6345_reset->rcdev.nr_resets = BCM6345_RESET_NUM;
114
115 return devm_reset_controller_register(&pdev->dev,
116 &bcm6345_reset->rcdev);
117}
118
119static const struct of_device_id bcm6345_reset_of_match[] = {
120 { .compatible = "brcm,bcm6345-reset" },
121 { .compatible = "brcm,bcm63xx-ephy-ctrl" },
122 { /* sentinel */ },
123};
124
125static struct platform_driver bcm6345_reset_driver = {
126 .probe = bcm6345_reset_probe,
127 .driver = {
128 .name = "bcm6345-reset",
129 .of_match_table = bcm6345_reset_of_match,
130 .suppress_bind_attrs = true,
131 },
132};
133builtin_platform_driver(bcm6345_reset_driver);