1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
|
/*
* Copyright (C) Maxime Coquelin 2015
* Author: Maxime Coquelin <mcoquelin.stm32@gmail.com>
* License terms: GNU General Public License (GPL), version 2
*
* Heavily based on sunxi driver from Maxime Ripard.
*/
#include <linux/err.h>
#include <linux/io.h>
#include <linux/of.h>
#include <linux/of_address.h>
#include <linux/platform_device.h>
#include <linux/reset-controller.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/types.h>
struct stm32_reset_data {
spinlock_t lock;
void __iomem *membase;
struct reset_controller_dev rcdev;
};
static int stm32_reset_assert(struct reset_controller_dev *rcdev,
unsigned long id)
{
struct stm32_reset_data *data = container_of(rcdev,
struct stm32_reset_data,
rcdev);
int bank = id / BITS_PER_LONG;
int offset = id % BITS_PER_LONG;
unsigned long flags;
u32 reg;
spin_lock_irqsave(&data->lock, flags);
reg = readl(data->membase + (bank * 4));
writel(reg | BIT(offset), data->membase + (bank * 4));
spin_unlock_irqrestore(&data->lock, flags);
return 0;
}
static int stm32_reset_deassert(struct reset_controller_dev *rcdev,
unsigned long id)
{
struct stm32_reset_data *data = container_of(rcdev,
struct stm32_reset_data,
rcdev);
int bank = id / BITS_PER_LONG;
int offset = id % BITS_PER_LONG;
unsigned long flags;
u32 reg;
spin_lock_irqsave(&data->lock, flags);
reg = readl(data->membase + (bank * 4));
writel(reg & ~BIT(offset), data->membase + (bank * 4));
spin_unlock_irqrestore(&data->lock, flags);
return 0;
}
static const struct reset_control_ops stm32_reset_ops = {
.assert = stm32_reset_assert,
.deassert = stm32_reset_deassert,
};
static const struct of_device_id stm32_reset_dt_ids[] = {
{ .compatible = "st,stm32-rcc", },
{ /* sentinel */ },
};
static int stm32_reset_probe(struct platform_device *pdev)
{
struct stm32_reset_data *data;
struct resource *res;
data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
if (!data)
return -ENOMEM;
res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
data->membase = devm_ioremap_resource(&pdev->dev, res);
if (IS_ERR(data->membase))
return PTR_ERR(data->membase);
spin_lock_init(&data->lock);
data->rcdev.owner = THIS_MODULE;
data->rcdev.nr_resets = resource_size(res) * 8;
data->rcdev.ops = &stm32_reset_ops;
data->rcdev.of_node = pdev->dev.of_node;
return devm_reset_controller_register(&pdev->dev, &data->rcdev);
}
static struct platform_driver stm32_reset_driver = {
.probe = stm32_reset_probe,
.driver = {
.name = "stm32-rcc-reset",
.of_match_table = stm32_reset_dt_ids,
},
};
builtin_platform_driver(stm32_reset_driver);
|
