mfd: Correct WM8350 I2C return code usage
[linux-2.6.git] / drivers / rtc / rtc-sun4v.c
1 /* rtc-sun4c.c: Hypervisor based RTC for SUN4V systems.
2  *
3  * Copyright (C) 2008 David S. Miller <davem@davemloft.net>
4  */
5
6 #include <linux/kernel.h>
7 #include <linux/module.h>
8 #include <linux/delay.h>
9 #include <linux/init.h>
10 #include <linux/time.h>
11 #include <linux/rtc.h>
12 #include <linux/platform_device.h>
13
14 #include <asm/hypervisor.h>
15
16 MODULE_AUTHOR("David S. Miller <davem@davemloft.net>");
17 MODULE_DESCRIPTION("SUN4V RTC driver");
18 MODULE_LICENSE("GPL");
19
20 struct sun4v_rtc {
21         struct rtc_device       *rtc;
22         spinlock_t              lock;
23 };
24
25 static unsigned long hypervisor_get_time(void)
26 {
27         unsigned long ret, time;
28         int retries = 10000;
29
30 retry:
31         ret = sun4v_tod_get(&time);
32         if (ret == HV_EOK)
33                 return time;
34         if (ret == HV_EWOULDBLOCK) {
35                 if (--retries > 0) {
36                         udelay(100);
37                         goto retry;
38                 }
39                 printk(KERN_WARNING "SUN4V: tod_get() timed out.\n");
40                 return 0;
41         }
42         printk(KERN_WARNING "SUN4V: tod_get() not supported.\n");
43         return 0;
44 }
45
46 static int sun4v_read_time(struct device *dev, struct rtc_time *tm)
47 {
48         struct sun4v_rtc *p = dev_get_drvdata(dev);
49         unsigned long flags, secs;
50
51         spin_lock_irqsave(&p->lock, flags);
52         secs = hypervisor_get_time();
53         spin_unlock_irqrestore(&p->lock, flags);
54
55         rtc_time_to_tm(secs, tm);
56
57         return 0;
58 }
59
60 static int hypervisor_set_time(unsigned long secs)
61 {
62         unsigned long ret;
63         int retries = 10000;
64
65 retry:
66         ret = sun4v_tod_set(secs);
67         if (ret == HV_EOK)
68                 return 0;
69         if (ret == HV_EWOULDBLOCK) {
70                 if (--retries > 0) {
71                         udelay(100);
72                         goto retry;
73                 }
74                 printk(KERN_WARNING "SUN4V: tod_set() timed out.\n");
75                 return -EAGAIN;
76         }
77         printk(KERN_WARNING "SUN4V: tod_set() not supported.\n");
78         return -EOPNOTSUPP;
79 }
80
81 static int sun4v_set_time(struct device *dev, struct rtc_time *tm)
82 {
83         struct sun4v_rtc *p = dev_get_drvdata(dev);
84         unsigned long flags, secs;
85         int err;
86
87         err = rtc_tm_to_time(tm, &secs);
88         if (err)
89                 return err;
90
91         spin_lock_irqsave(&p->lock, flags);
92         err = hypervisor_set_time(secs);
93         spin_unlock_irqrestore(&p->lock, flags);
94
95         return err;
96 }
97
98 static const struct rtc_class_ops sun4v_rtc_ops = {
99         .read_time      = sun4v_read_time,
100         .set_time       = sun4v_set_time,
101 };
102
103 static int __devinit sun4v_rtc_probe(struct platform_device *pdev)
104 {
105         struct sun4v_rtc *p = kzalloc(sizeof(*p), GFP_KERNEL);
106
107         if (!p)
108                 return -ENOMEM;
109
110         spin_lock_init(&p->lock);
111
112         p->rtc = rtc_device_register("sun4v", &pdev->dev,
113                                      &sun4v_rtc_ops, THIS_MODULE);
114         if (IS_ERR(p->rtc)) {
115                 int err = PTR_ERR(p->rtc);
116                 kfree(p);
117                 return err;
118         }
119         platform_set_drvdata(pdev, p);
120         return 0;
121 }
122
123 static int __devexit sun4v_rtc_remove(struct platform_device *pdev)
124 {
125         struct sun4v_rtc *p = platform_get_drvdata(pdev);
126
127         rtc_device_unregister(p->rtc);
128         kfree(p);
129
130         return 0;
131 }
132
133 static struct platform_driver sun4v_rtc_driver = {
134         .driver         = {
135                 .name   = "rtc-sun4v",
136                 .owner  = THIS_MODULE,
137         },
138         .probe          = sun4v_rtc_probe,
139         .remove         = __devexit_p(sun4v_rtc_remove),
140 };
141
142 static int __init sun4v_rtc_init(void)
143 {
144         return platform_driver_register(&sun4v_rtc_driver);
145 }
146
147 static void __exit sun4v_rtc_exit(void)
148 {
149         platform_driver_unregister(&sun4v_rtc_driver);
150 }
151
152 module_init(sun4v_rtc_init);
153 module_exit(sun4v_rtc_exit);