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
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
|
/*
* Atmel SSC driver
*
* Copyright (C) 2007 Atmel Corporation
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/platform_device.h>
#include <linux/list.h>
#include <linux/clk.h>
#include <linux/err.h>
#include <linux/io.h>
#include <linux/spinlock.h>
#include <linux/atmel-ssc.h>
#include <linux/slab.h>
#include <linux/module.h>
/* Serialize access to ssc_list and user count */
static DEFINE_SPINLOCK(user_lock);
static LIST_HEAD(ssc_list);
struct ssc_device *ssc_request(unsigned int ssc_num)
{
int ssc_valid = 0;
struct ssc_device *ssc;
spin_lock(&user_lock);
list_for_each_entry(ssc, &ssc_list, list) {
if (ssc->pdev->id == ssc_num) {
ssc_valid = 1;
break;
}
}
if (!ssc_valid) {
spin_unlock(&user_lock);
pr_err("ssc: ssc%d platform device is missing\n", ssc_num);
return ERR_PTR(-ENODEV);
}
if (ssc->user) {
spin_unlock(&user_lock);
dev_dbg(&ssc->pdev->dev, "module busy\n");
return ERR_PTR(-EBUSY);
}
ssc->user++;
spin_unlock(&user_lock);
clk_enable(ssc->clk);
return ssc;
}
EXPORT_SYMBOL(ssc_request);
void ssc_free(struct ssc_device *ssc)
{
spin_lock(&user_lock);
if (ssc->user) {
ssc->user--;
clk_disable(ssc->clk);
} else {
dev_dbg(&ssc->pdev->dev, "device already free\n");
}
spin_unlock(&user_lock);
}
EXPORT_SYMBOL(ssc_free);
static int __init ssc_probe(struct platform_device *pdev)
{
struct resource *regs;
struct ssc_device *ssc;
ssc = devm_kzalloc(&pdev->dev, sizeof(struct ssc_device), GFP_KERNEL);
if (!ssc) {
dev_dbg(&pdev->dev, "out of memory\n");
return -ENOMEM;
}
ssc->pdev = pdev;
regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
if (!regs) {
dev_dbg(&pdev->dev, "no mmio resource defined\n");
return -ENXIO;
}
ssc->regs = devm_request_and_ioremap(&pdev->dev, regs);
if (!ssc->regs) {
dev_dbg(&pdev->dev, "ioremap failed\n");
return -EINVAL;
}
ssc->clk = devm_clk_get(&pdev->dev, "pclk");
if (IS_ERR(ssc->clk)) {
dev_dbg(&pdev->dev, "no pclk clock defined\n");
return -ENXIO;
}
/* disable all interrupts */
clk_enable(ssc->clk);
ssc_writel(ssc->regs, IDR, ~0UL);
ssc_readl(ssc->regs, SR);
clk_disable(ssc->clk);
ssc->irq = platform_get_irq(pdev, 0);
if (!ssc->irq) {
dev_dbg(&pdev->dev, "could not get irq\n");
return -ENXIO;
}
spin_lock(&user_lock);
list_add_tail(&ssc->list, &ssc_list);
spin_unlock(&user_lock);
platform_set_drvdata(pdev, ssc);
dev_info(&pdev->dev, "Atmel SSC device at 0x%p (irq %d)\n",
ssc->regs, ssc->irq);
return 0;
}
static int __devexit ssc_remove(struct platform_device *pdev)
{
struct ssc_device *ssc = platform_get_drvdata(pdev);
spin_lock(&user_lock);
list_del(&ssc->list);
spin_unlock(&user_lock);
return 0;
}
static struct platform_driver ssc_driver = {
.remove = __devexit_p(ssc_remove),
.driver = {
.name = "ssc",
.owner = THIS_MODULE,
},
};
static int __init ssc_init(void)
{
return platform_driver_probe(&ssc_driver, ssc_probe);
}
module_init(ssc_init);
static void __exit ssc_exit(void)
{
platform_driver_unregister(&ssc_driver);
}
module_exit(ssc_exit);
MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
MODULE_DESCRIPTION("SSC driver for Atmel AVR32 and AT91");
MODULE_LICENSE("GPL");
MODULE_ALIAS("platform:ssc");
|
