tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
1/*
2 * Atmel SSC driver
3 *
4 * Copyright (C) 2007 Atmel Corporation
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 */
10
11#include <linux/platform_device.h>
12#include <linux/list.h>
13#include <linux/clk.h>
14#include <linux/err.h>
15#include <linux/io.h>
16#include <linux/list.h>
17#include <linux/spinlock.h>
18#include <linux/atmel-ssc.h>
19
20/* Serialize access to ssc_list and user count */
21static DEFINE_SPINLOCK(user_lock);
22static LIST_HEAD(ssc_list);
23
24struct ssc_device *ssc_request(unsigned int ssc_num)
25{
26 int ssc_valid = 0;
27 struct ssc_device *ssc;
28
29 spin_lock(&user_lock);
30 list_for_each_entry(ssc, &ssc_list, list) {
31 if (ssc->pdev->id == ssc_num) {
32 ssc_valid = 1;
33 break;
34 }
35 }
36
37 if (!ssc_valid) {
38 spin_unlock(&user_lock);
39 dev_dbg(&ssc->pdev->dev, "could not find requested device\n");
40 return ERR_PTR(-ENODEV);
41 }
42
43 if (ssc->user) {
44 spin_unlock(&user_lock);
45 dev_dbg(&ssc->pdev->dev, "module busy\n");
46 return ERR_PTR(-EBUSY);
47 }
48 ssc->user++;
49 spin_unlock(&user_lock);
50
51 clk_enable(ssc->clk);
52
53 return ssc;
54}
55EXPORT_SYMBOL(ssc_request);
56
57void ssc_free(struct ssc_device *ssc)
58{
59 spin_lock(&user_lock);
60 if (ssc->user) {
61 ssc->user--;
62 clk_disable(ssc->clk);
63 } else {
64 dev_dbg(&ssc->pdev->dev, "device already free\n");
65 }
66 spin_unlock(&user_lock);
67}
68EXPORT_SYMBOL(ssc_free);
69
70static int __init ssc_probe(struct platform_device *pdev)
71{
72 int retval = 0;
73 struct resource *regs;
74 struct ssc_device *ssc;
75
76 ssc = kzalloc(sizeof(struct ssc_device), GFP_KERNEL);
77 if (!ssc) {
78 dev_dbg(&pdev->dev, "out of memory\n");
79 retval = -ENOMEM;
80 goto out;
81 }
82
83 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
84 if (!regs) {
85 dev_dbg(&pdev->dev, "no mmio resource defined\n");
86 retval = -ENXIO;
87 goto out_free;
88 }
89
90 ssc->clk = clk_get(&pdev->dev, "pclk");
91 if (IS_ERR(ssc->clk)) {
92 dev_dbg(&pdev->dev, "no pclk clock defined\n");
93 retval = -ENXIO;
94 goto out_free;
95 }
96
97 ssc->pdev = pdev;
98 ssc->regs = ioremap(regs->start, regs->end - regs->start + 1);
99 if (!ssc->regs) {
100 dev_dbg(&pdev->dev, "ioremap failed\n");
101 retval = -EINVAL;
102 goto out_clk;
103 }
104
105 /* disable all interrupts */
106 clk_enable(ssc->clk);
107 ssc_writel(ssc->regs, IDR, ~0UL);
108 ssc_readl(ssc->regs, SR);
109 clk_disable(ssc->clk);
110
111 ssc->irq = platform_get_irq(pdev, 0);
112 if (!ssc->irq) {
113 dev_dbg(&pdev->dev, "could not get irq\n");
114 retval = -ENXIO;
115 goto out_unmap;
116 }
117
118 spin_lock(&user_lock);
119 list_add_tail(&ssc->list, &ssc_list);
120 spin_unlock(&user_lock);
121
122 platform_set_drvdata(pdev, ssc);
123
124 dev_info(&pdev->dev, "Atmel SSC device at 0x%p (irq %d)\n",
125 ssc->regs, ssc->irq);
126
127 goto out;
128
129out_unmap:
130 iounmap(ssc->regs);
131out_clk:
132 clk_put(ssc->clk);
133out_free:
134 kfree(ssc);
135out:
136 return retval;
137}
138
139static int __devexit ssc_remove(struct platform_device *pdev)
140{
141 struct ssc_device *ssc = platform_get_drvdata(pdev);
142
143 spin_lock(&user_lock);
144 iounmap(ssc->regs);
145 clk_put(ssc->clk);
146 list_del(&ssc->list);
147 kfree(ssc);
148 spin_unlock(&user_lock);
149
150 return 0;
151}
152
153static struct platform_driver ssc_driver = {
154 .remove = __devexit_p(ssc_remove),
155 .driver = {
156 .name = "ssc",
157 .owner = THIS_MODULE,
158 },
159};
160
161static int __init ssc_init(void)
162{
163 return platform_driver_probe(&ssc_driver, ssc_probe);
164}
165module_init(ssc_init);
166
167static void __exit ssc_exit(void)
168{
169 platform_driver_unregister(&ssc_driver);
170}
171module_exit(ssc_exit);
172
173MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>");
174MODULE_DESCRIPTION("SSC driver for Atmel AVR32 and AT91");
175MODULE_LICENSE("GPL");
176MODULE_ALIAS("platform:ssc");