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aac02543 ÁFR |
1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* | |
3 | * BCM6345 Reset Controller Driver | |
4 | * | |
5 | * Copyright (C) 2020 Álvaro Fernández Rojas <noltari@gmail.com> | |
6 | */ | |
7 | ||
8 | #include <linux/delay.h> | |
9 | #include <linux/init.h> | |
10 | #include <linux/io.h> | |
11 | #include <linux/mod_devicetable.h> | |
12 | #include <linux/platform_device.h> | |
13 | #include <linux/reset-controller.h> | |
14 | ||
15 | #define BCM6345_RESET_NUM 32 | |
16 | #define BCM6345_RESET_SLEEP_MIN_US 10000 | |
17 | #define BCM6345_RESET_SLEEP_MAX_US 20000 | |
18 | ||
19 | struct bcm6345_reset { | |
20 | struct reset_controller_dev rcdev; | |
21 | void __iomem *base; | |
22 | spinlock_t lock; | |
23 | }; | |
24 | ||
25 | static inline struct bcm6345_reset * | |
26 | to_bcm6345_reset(struct reset_controller_dev *rcdev) | |
27 | { | |
28 | return container_of(rcdev, struct bcm6345_reset, rcdev); | |
29 | } | |
30 | ||
31 | static int bcm6345_reset_update(struct reset_controller_dev *rcdev, | |
32 | unsigned long id, bool assert) | |
33 | { | |
34 | struct bcm6345_reset *bcm6345_reset = to_bcm6345_reset(rcdev); | |
35 | unsigned long flags; | |
36 | uint32_t val; | |
37 | ||
38 | spin_lock_irqsave(&bcm6345_reset->lock, flags); | |
39 | val = __raw_readl(bcm6345_reset->base); | |
40 | if (assert) | |
41 | val &= ~BIT(id); | |
42 | else | |
43 | val |= BIT(id); | |
44 | __raw_writel(val, bcm6345_reset->base); | |
45 | spin_unlock_irqrestore(&bcm6345_reset->lock, flags); | |
46 | ||
47 | return 0; | |
48 | } | |
49 | ||
50 | static int bcm6345_reset_assert(struct reset_controller_dev *rcdev, | |
51 | unsigned long id) | |
52 | { | |
53 | return bcm6345_reset_update(rcdev, id, true); | |
54 | } | |
55 | ||
56 | static int bcm6345_reset_deassert(struct reset_controller_dev *rcdev, | |
57 | unsigned long id) | |
58 | { | |
59 | return bcm6345_reset_update(rcdev, id, false); | |
60 | } | |
61 | ||
62 | static int bcm6345_reset_reset(struct reset_controller_dev *rcdev, | |
63 | unsigned long id) | |
64 | { | |
65 | bcm6345_reset_update(rcdev, id, true); | |
66 | usleep_range(BCM6345_RESET_SLEEP_MIN_US, | |
67 | BCM6345_RESET_SLEEP_MAX_US); | |
68 | ||
69 | bcm6345_reset_update(rcdev, id, false); | |
70 | /* | |
71 | * Ensure component is taken out reset state by sleeping also after | |
72 | * deasserting the reset. Otherwise, the component may not be ready | |
73 | * for operation. | |
74 | */ | |
75 | usleep_range(BCM6345_RESET_SLEEP_MIN_US, | |
76 | BCM6345_RESET_SLEEP_MAX_US); | |
77 | ||
78 | return 0; | |
79 | } | |
80 | ||
81 | static int bcm6345_reset_status(struct reset_controller_dev *rcdev, | |
82 | unsigned long id) | |
83 | { | |
84 | struct bcm6345_reset *bcm6345_reset = to_bcm6345_reset(rcdev); | |
85 | ||
86 | return !(__raw_readl(bcm6345_reset->base) & BIT(id)); | |
87 | } | |
88 | ||
89 | static struct reset_control_ops bcm6345_reset_ops = { | |
90 | .assert = bcm6345_reset_assert, | |
91 | .deassert = bcm6345_reset_deassert, | |
92 | .reset = bcm6345_reset_reset, | |
93 | .status = bcm6345_reset_status, | |
94 | }; | |
95 | ||
96 | static int bcm6345_reset_probe(struct platform_device *pdev) | |
97 | { | |
98 | struct bcm6345_reset *bcm6345_reset; | |
99 | ||
100 | bcm6345_reset = devm_kzalloc(&pdev->dev, | |
101 | sizeof(*bcm6345_reset), GFP_KERNEL); | |
102 | if (!bcm6345_reset) | |
103 | return -ENOMEM; | |
104 | ||
105 | platform_set_drvdata(pdev, bcm6345_reset); | |
106 | ||
107 | bcm6345_reset->base = devm_platform_ioremap_resource(pdev, 0); | |
108 | if (IS_ERR(bcm6345_reset->base)) | |
109 | return PTR_ERR(bcm6345_reset->base); | |
110 | ||
111 | spin_lock_init(&bcm6345_reset->lock); | |
112 | bcm6345_reset->rcdev.ops = &bcm6345_reset_ops; | |
113 | bcm6345_reset->rcdev.owner = THIS_MODULE; | |
114 | bcm6345_reset->rcdev.of_node = pdev->dev.of_node; | |
115 | bcm6345_reset->rcdev.of_reset_n_cells = 1; | |
116 | bcm6345_reset->rcdev.nr_resets = BCM6345_RESET_NUM; | |
117 | ||
118 | return devm_reset_controller_register(&pdev->dev, | |
119 | &bcm6345_reset->rcdev); | |
120 | } | |
121 | ||
122 | static const struct of_device_id bcm6345_reset_of_match[] = { | |
123 | { .compatible = "brcm,bcm6345-reset" }, | |
124 | { /* sentinel */ }, | |
125 | }; | |
126 | ||
127 | static struct platform_driver bcm6345_reset_driver = { | |
128 | .probe = bcm6345_reset_probe, | |
129 | .driver = { | |
130 | .name = "bcm6345-reset", | |
131 | .of_match_table = bcm6345_reset_of_match, | |
132 | .suppress_bind_attrs = true, | |
133 | }, | |
134 | }; | |
135 | builtin_platform_driver(bcm6345_reset_driver); |