1 /*
2 * Generic heartbeat driver for regular LED banks
3 *
4 * Copyright (C) 2007 Paul Mundt
5 *
6 * Most SH reference boards include a number of individual LEDs that can
7 * be independently controlled (either via a pre-defined hardware
8 * function or via the LED class, if desired -- the hardware tends to
9 * encapsulate some of the same "triggers" that the LED class supports,
10 * so there's not too much value in it).
11 *
12 * Additionally, most of these boards also have a LED bank that we've
13 * traditionally used for strobing the load average. This use case is
14 * handled by this driver, rather than giving each LED bit position its
15 * own struct device.
16 *
17 * This file is subject to the terms and conditions of the GNU General Public
18 * License. See the file "COPYING" in the main directory of this archive
19 * for more details.
20 */
21 #include <linux/init.h>
22 #include <linux/module.h>
23 #include <linux/platform_device.h>
24 #include <linux/sched.h>
25 #include <linux/timer.h>
26 #include <linux/io.h>
27 #include <asm/heartbeat.h>
28
29 #define DRV_NAME "heartbeat"
30 #define DRV_VERSION "0.1.1"
31
32 static unsigned char default_bit_pos[] = { 0, 1, 2, 3, 4, 5, 6, 7 };
33
heartbeat_toggle_bit(struct heartbeat_data * hd,unsigned bit,unsigned int inverted)34 static inline void heartbeat_toggle_bit(struct heartbeat_data *hd,
35 unsigned bit, unsigned int inverted)
36 {
37 unsigned int new;
38
39 new = (1 << hd->bit_pos[bit]);
40 if (inverted)
41 new = ~new;
42
43 switch (hd->regsize) {
44 case 32:
45 iowrite32(new, hd->base);
46 break;
47 case 16:
48 iowrite16(new, hd->base);
49 break;
50 default:
51 iowrite8(new, hd->base);
52 break;
53 }
54 }
55
heartbeat_timer(unsigned long data)56 static void heartbeat_timer(unsigned long data)
57 {
58 struct heartbeat_data *hd = (struct heartbeat_data *)data;
59 static unsigned bit = 0, up = 1;
60
61 heartbeat_toggle_bit(hd, bit, hd->flags & HEARTBEAT_INVERTED);
62
63 bit += up;
64 if ((bit == 0) || (bit == (hd->nr_bits)-1))
65 up = -up;
66
67 mod_timer(&hd->timer, jiffies + (110 - ((300 << FSHIFT) /
68 ((avenrun[0] / 5) + (3 << FSHIFT)))));
69 }
70
heartbeat_drv_probe(struct platform_device * pdev)71 static int heartbeat_drv_probe(struct platform_device *pdev)
72 {
73 struct resource *res;
74 struct heartbeat_data *hd;
75
76 if (unlikely(pdev->num_resources != 1)) {
77 dev_err(&pdev->dev, "invalid number of resources\n");
78 return -EINVAL;
79 }
80
81 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
82 if (unlikely(res == NULL)) {
83 dev_err(&pdev->dev, "invalid resource\n");
84 return -EINVAL;
85 }
86
87 if (pdev->dev.platform_data) {
88 hd = pdev->dev.platform_data;
89 } else {
90 hd = kzalloc(sizeof(struct heartbeat_data), GFP_KERNEL);
91 if (unlikely(!hd))
92 return -ENOMEM;
93 }
94
95 hd->base = ioremap_nocache(res->start, res->end - res->start + 1);
96 if (unlikely(!hd->base)) {
97 dev_err(&pdev->dev, "ioremap failed\n");
98
99 if (!pdev->dev.platform_data)
100 kfree(hd);
101
102 return -ENXIO;
103 }
104
105 if (!hd->nr_bits) {
106 hd->bit_pos = default_bit_pos;
107 hd->nr_bits = ARRAY_SIZE(default_bit_pos);
108 }
109
110 if (!hd->regsize)
111 hd->regsize = 8; /* default access size */
112
113 setup_timer(&hd->timer, heartbeat_timer, (unsigned long)hd);
114 platform_set_drvdata(pdev, hd);
115
116 return mod_timer(&hd->timer, jiffies + 1);
117 }
118
heartbeat_drv_remove(struct platform_device * pdev)119 static int heartbeat_drv_remove(struct platform_device *pdev)
120 {
121 struct heartbeat_data *hd = platform_get_drvdata(pdev);
122
123 del_timer_sync(&hd->timer);
124 iounmap(hd->base);
125
126 platform_set_drvdata(pdev, NULL);
127
128 if (!pdev->dev.platform_data)
129 kfree(hd);
130
131 return 0;
132 }
133
134 static struct platform_driver heartbeat_driver = {
135 .probe = heartbeat_drv_probe,
136 .remove = heartbeat_drv_remove,
137 .driver = {
138 .name = DRV_NAME,
139 },
140 };
141
heartbeat_init(void)142 static int __init heartbeat_init(void)
143 {
144 printk(KERN_NOTICE DRV_NAME ": version %s loaded\n", DRV_VERSION);
145 return platform_driver_register(&heartbeat_driver);
146 }
147
heartbeat_exit(void)148 static void __exit heartbeat_exit(void)
149 {
150 platform_driver_unregister(&heartbeat_driver);
151 }
152 module_init(heartbeat_init);
153 module_exit(heartbeat_exit);
154
155 MODULE_VERSION(DRV_VERSION);
156 MODULE_AUTHOR("Paul Mundt");
157 MODULE_LICENSE("GPL v2");
158