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eb1f2930 HCE |
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> | |
eb1f2930 HCE |
16 | #include <linux/spinlock.h> |
17 | #include <linux/atmel-ssc.h> | |
5a0e3ad6 | 18 | #include <linux/slab.h> |
eb1f2930 HCE |
19 | |
20 | /* Serialize access to ssc_list and user count */ | |
21 | static DEFINE_SPINLOCK(user_lock); | |
22 | static LIST_HEAD(ssc_list); | |
23 | ||
24 | struct 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); | |
dfecb716 | 39 | pr_err("ssc: ssc%d platform device is missing\n", ssc_num); |
eb1f2930 HCE |
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 | } | |
55 | EXPORT_SYMBOL(ssc_request); | |
56 | ||
57 | void 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 | } | |
68 | EXPORT_SYMBOL(ssc_free); | |
69 | ||
70 | static 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 | ||
129 | out_unmap: | |
130 | iounmap(ssc->regs); | |
131 | out_clk: | |
132 | clk_put(ssc->clk); | |
133 | out_free: | |
134 | kfree(ssc); | |
135 | out: | |
136 | return retval; | |
137 | } | |
138 | ||
139 | static 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 | ||
153 | static struct platform_driver ssc_driver = { | |
154 | .remove = __devexit_p(ssc_remove), | |
155 | .driver = { | |
156 | .name = "ssc", | |
d6c23850 | 157 | .owner = THIS_MODULE, |
eb1f2930 HCE |
158 | }, |
159 | }; | |
160 | ||
161 | static int __init ssc_init(void) | |
162 | { | |
163 | return platform_driver_probe(&ssc_driver, ssc_probe); | |
164 | } | |
165 | module_init(ssc_init); | |
166 | ||
167 | static void __exit ssc_exit(void) | |
168 | { | |
169 | platform_driver_unregister(&ssc_driver); | |
170 | } | |
171 | module_exit(ssc_exit); | |
172 | ||
173 | MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>"); | |
174 | MODULE_DESCRIPTION("SSC driver for Atmel AVR32 and AT91"); | |
175 | MODULE_LICENSE("GPL"); | |
d6c23850 | 176 | MODULE_ALIAS("platform:ssc"); |