1 /*
2  * MPIC timer wakeup driver
3  *
4  * Copyright 2013 Freescale Semiconductor, Inc.
5  *
6  * This program is free software; you can redistribute it and/or modify it
7  * under the terms of the GNU General Public License as published by the
8  * Free Software Foundation; either version 2 of the License, or (at your
9  * option) any later version.
10  */
11 
12 #include <linux/kernel.h>
13 #include <linux/slab.h>
14 #include <linux/errno.h>
15 #include <linux/module.h>
16 #include <linux/interrupt.h>
17 #include <linux/device.h>
18 
19 #include <asm/mpic_timer.h>
20 #include <asm/mpic.h>
21 
22 struct fsl_mpic_timer_wakeup {
23 	struct mpic_timer *timer;
24 	struct work_struct free_work;
25 };
26 
27 static struct fsl_mpic_timer_wakeup *fsl_wakeup;
28 static DEFINE_MUTEX(sysfs_lock);
29 
30 static void fsl_free_resource(struct work_struct *ws)
31 {
32 	struct fsl_mpic_timer_wakeup *wakeup =
33 		container_of(ws, struct fsl_mpic_timer_wakeup, free_work);
34 
35 	mutex_lock(&sysfs_lock);
36 
37 	if (wakeup->timer) {
38 		disable_irq_wake(wakeup->timer->irq);
39 		mpic_free_timer(wakeup->timer);
40 	}
41 
42 	wakeup->timer = NULL;
43 	mutex_unlock(&sysfs_lock);
44 }
45 
46 static irqreturn_t fsl_mpic_timer_irq(int irq, void *dev_id)
47 {
48 	struct fsl_mpic_timer_wakeup *wakeup = dev_id;
49 
50 	schedule_work(&wakeup->free_work);
51 
52 	return wakeup->timer ? IRQ_HANDLED : IRQ_NONE;
53 }
54 
55 static ssize_t fsl_timer_wakeup_show(struct device *dev,
56 				struct device_attribute *attr,
57 				char *buf)
58 {
59 	struct timeval interval;
60 	int val = 0;
61 
62 	mutex_lock(&sysfs_lock);
63 	if (fsl_wakeup->timer) {
64 		mpic_get_remain_time(fsl_wakeup->timer, &interval);
65 		val = interval.tv_sec + 1;
66 	}
67 	mutex_unlock(&sysfs_lock);
68 
69 	return sprintf(buf, "%d\n", val);
70 }
71 
72 static ssize_t fsl_timer_wakeup_store(struct device *dev,
73 				struct device_attribute *attr,
74 				const char *buf,
75 				size_t count)
76 {
77 	struct timeval interval;
78 	int ret;
79 
80 	interval.tv_usec = 0;
81 	if (kstrtol(buf, 0, &interval.tv_sec))
82 		return -EINVAL;
83 
84 	mutex_lock(&sysfs_lock);
85 
86 	if (fsl_wakeup->timer) {
87 		disable_irq_wake(fsl_wakeup->timer->irq);
88 		mpic_free_timer(fsl_wakeup->timer);
89 		fsl_wakeup->timer = NULL;
90 	}
91 
92 	if (!interval.tv_sec) {
93 		mutex_unlock(&sysfs_lock);
94 		return count;
95 	}
96 
97 	fsl_wakeup->timer = mpic_request_timer(fsl_mpic_timer_irq,
98 						fsl_wakeup, &interval);
99 	if (!fsl_wakeup->timer) {
100 		mutex_unlock(&sysfs_lock);
101 		return -EINVAL;
102 	}
103 
104 	ret = enable_irq_wake(fsl_wakeup->timer->irq);
105 	if (ret) {
106 		mpic_free_timer(fsl_wakeup->timer);
107 		fsl_wakeup->timer = NULL;
108 		mutex_unlock(&sysfs_lock);
109 
110 		return ret;
111 	}
112 
113 	mpic_start_timer(fsl_wakeup->timer);
114 
115 	mutex_unlock(&sysfs_lock);
116 
117 	return count;
118 }
119 
120 static struct device_attribute mpic_attributes = __ATTR(timer_wakeup, 0644,
121 			fsl_timer_wakeup_show, fsl_timer_wakeup_store);
122 
123 static int __init fsl_wakeup_sys_init(void)
124 {
125 	int ret;
126 
127 	fsl_wakeup = kzalloc(sizeof(struct fsl_mpic_timer_wakeup), GFP_KERNEL);
128 	if (!fsl_wakeup)
129 		return -ENOMEM;
130 
131 	INIT_WORK(&fsl_wakeup->free_work, fsl_free_resource);
132 
133 	ret = device_create_file(mpic_subsys.dev_root, &mpic_attributes);
134 	if (ret)
135 		kfree(fsl_wakeup);
136 
137 	return ret;
138 }
139 
140 static void __exit fsl_wakeup_sys_exit(void)
141 {
142 	device_remove_file(mpic_subsys.dev_root, &mpic_attributes);
143 
144 	mutex_lock(&sysfs_lock);
145 
146 	if (fsl_wakeup->timer) {
147 		disable_irq_wake(fsl_wakeup->timer->irq);
148 		mpic_free_timer(fsl_wakeup->timer);
149 	}
150 
151 	kfree(fsl_wakeup);
152 
153 	mutex_unlock(&sysfs_lock);
154 }
155 
156 module_init(fsl_wakeup_sys_init);
157 module_exit(fsl_wakeup_sys_exit);
158 
159 MODULE_DESCRIPTION("Freescale MPIC global timer wakeup driver");
160 MODULE_LICENSE("GPL v2");
161 MODULE_AUTHOR("Wang Dongsheng <dongsheng.wang@freescale.com>");
162