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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> |
eb12a679 | 19 | #include <linux/module.h> |
eb1f2930 HCE |
20 | |
21 | /* Serialize access to ssc_list and user count */ | |
22 | static DEFINE_SPINLOCK(user_lock); | |
23 | static LIST_HEAD(ssc_list); | |
24 | ||
25 | struct ssc_device *ssc_request(unsigned int ssc_num) | |
26 | { | |
27 | int ssc_valid = 0; | |
28 | struct ssc_device *ssc; | |
29 | ||
30 | spin_lock(&user_lock); | |
31 | list_for_each_entry(ssc, &ssc_list, list) { | |
32 | if (ssc->pdev->id == ssc_num) { | |
33 | ssc_valid = 1; | |
34 | break; | |
35 | } | |
36 | } | |
37 | ||
38 | if (!ssc_valid) { | |
39 | spin_unlock(&user_lock); | |
dfecb716 | 40 | pr_err("ssc: ssc%d platform device is missing\n", ssc_num); |
eb1f2930 HCE |
41 | return ERR_PTR(-ENODEV); |
42 | } | |
43 | ||
44 | if (ssc->user) { | |
45 | spin_unlock(&user_lock); | |
46 | dev_dbg(&ssc->pdev->dev, "module busy\n"); | |
47 | return ERR_PTR(-EBUSY); | |
48 | } | |
49 | ssc->user++; | |
50 | spin_unlock(&user_lock); | |
51 | ||
52 | clk_enable(ssc->clk); | |
53 | ||
54 | return ssc; | |
55 | } | |
56 | EXPORT_SYMBOL(ssc_request); | |
57 | ||
58 | void ssc_free(struct ssc_device *ssc) | |
59 | { | |
60 | spin_lock(&user_lock); | |
61 | if (ssc->user) { | |
62 | ssc->user--; | |
63 | clk_disable(ssc->clk); | |
64 | } else { | |
65 | dev_dbg(&ssc->pdev->dev, "device already free\n"); | |
66 | } | |
67 | spin_unlock(&user_lock); | |
68 | } | |
69 | EXPORT_SYMBOL(ssc_free); | |
70 | ||
71 | static int __init ssc_probe(struct platform_device *pdev) | |
72 | { | |
73 | int retval = 0; | |
74 | struct resource *regs; | |
75 | struct ssc_device *ssc; | |
76 | ||
77 | ssc = kzalloc(sizeof(struct ssc_device), GFP_KERNEL); | |
78 | if (!ssc) { | |
79 | dev_dbg(&pdev->dev, "out of memory\n"); | |
80 | retval = -ENOMEM; | |
81 | goto out; | |
82 | } | |
83 | ||
84 | regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
85 | if (!regs) { | |
86 | dev_dbg(&pdev->dev, "no mmio resource defined\n"); | |
87 | retval = -ENXIO; | |
88 | goto out_free; | |
89 | } | |
90 | ||
91 | ssc->clk = clk_get(&pdev->dev, "pclk"); | |
92 | if (IS_ERR(ssc->clk)) { | |
93 | dev_dbg(&pdev->dev, "no pclk clock defined\n"); | |
94 | retval = -ENXIO; | |
95 | goto out_free; | |
96 | } | |
97 | ||
98 | ssc->pdev = pdev; | |
28f65c11 | 99 | ssc->regs = ioremap(regs->start, resource_size(regs)); |
eb1f2930 HCE |
100 | if (!ssc->regs) { |
101 | dev_dbg(&pdev->dev, "ioremap failed\n"); | |
102 | retval = -EINVAL; | |
103 | goto out_clk; | |
104 | } | |
105 | ||
106 | /* disable all interrupts */ | |
107 | clk_enable(ssc->clk); | |
108 | ssc_writel(ssc->regs, IDR, ~0UL); | |
109 | ssc_readl(ssc->regs, SR); | |
110 | clk_disable(ssc->clk); | |
111 | ||
112 | ssc->irq = platform_get_irq(pdev, 0); | |
113 | if (!ssc->irq) { | |
114 | dev_dbg(&pdev->dev, "could not get irq\n"); | |
115 | retval = -ENXIO; | |
116 | goto out_unmap; | |
117 | } | |
118 | ||
119 | spin_lock(&user_lock); | |
120 | list_add_tail(&ssc->list, &ssc_list); | |
121 | spin_unlock(&user_lock); | |
122 | ||
123 | platform_set_drvdata(pdev, ssc); | |
124 | ||
125 | dev_info(&pdev->dev, "Atmel SSC device at 0x%p (irq %d)\n", | |
126 | ssc->regs, ssc->irq); | |
127 | ||
128 | goto out; | |
129 | ||
130 | out_unmap: | |
131 | iounmap(ssc->regs); | |
132 | out_clk: | |
133 | clk_put(ssc->clk); | |
134 | out_free: | |
135 | kfree(ssc); | |
136 | out: | |
137 | return retval; | |
138 | } | |
139 | ||
140 | static int __devexit ssc_remove(struct platform_device *pdev) | |
141 | { | |
142 | struct ssc_device *ssc = platform_get_drvdata(pdev); | |
143 | ||
144 | spin_lock(&user_lock); | |
145 | iounmap(ssc->regs); | |
146 | clk_put(ssc->clk); | |
147 | list_del(&ssc->list); | |
148 | kfree(ssc); | |
149 | spin_unlock(&user_lock); | |
150 | ||
151 | return 0; | |
152 | } | |
153 | ||
154 | static struct platform_driver ssc_driver = { | |
155 | .remove = __devexit_p(ssc_remove), | |
156 | .driver = { | |
157 | .name = "ssc", | |
d6c23850 | 158 | .owner = THIS_MODULE, |
eb1f2930 HCE |
159 | }, |
160 | }; | |
161 | ||
162 | static int __init ssc_init(void) | |
163 | { | |
164 | return platform_driver_probe(&ssc_driver, ssc_probe); | |
165 | } | |
166 | module_init(ssc_init); | |
167 | ||
168 | static void __exit ssc_exit(void) | |
169 | { | |
170 | platform_driver_unregister(&ssc_driver); | |
171 | } | |
172 | module_exit(ssc_exit); | |
173 | ||
174 | MODULE_AUTHOR("Hans-Christian Egtvedt <hcegtvedt@atmel.com>"); | |
175 | MODULE_DESCRIPTION("SSC driver for Atmel AVR32 and AT91"); | |
176 | MODULE_LICENSE("GPL"); | |
d6c23850 | 177 | MODULE_ALIAS("platform:ssc"); |