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401e9093 PM |
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 | ||
28 | #define DRV_NAME "heartbeat" | |
29 | #define DRV_VERSION "0.1.0" | |
30 | ||
31 | struct heartbeat_data { | |
32 | void __iomem *base; | |
33 | unsigned char bit_pos[8]; | |
34 | struct timer_list timer; | |
35 | }; | |
36 | ||
37 | static void heartbeat_timer(unsigned long data) | |
38 | { | |
39 | struct heartbeat_data *hd = (struct heartbeat_data *)data; | |
40 | static unsigned bit = 0, up = 1; | |
41 | ||
42 | ctrl_outw(1 << hd->bit_pos[bit], (unsigned long)hd->base); | |
43 | if (up) | |
44 | if (bit == (ARRAY_SIZE(hd->bit_pos) - 1)) { | |
45 | bit--; | |
46 | up = 0; | |
47 | } else | |
48 | bit++; | |
49 | else if (bit == 0) | |
50 | up = 1; | |
51 | else | |
52 | bit--; | |
53 | ||
54 | mod_timer(&hd->timer, jiffies + (110 - ((300 << FSHIFT) / | |
55 | ((avenrun[0] / 5) + (3 << FSHIFT))))); | |
56 | } | |
57 | ||
58 | static int heartbeat_drv_probe(struct platform_device *pdev) | |
59 | { | |
60 | struct resource *res; | |
61 | struct heartbeat_data *hd; | |
62 | ||
63 | if (unlikely(pdev->num_resources != 1)) { | |
64 | dev_err(&pdev->dev, "invalid number of resources\n"); | |
65 | return -EINVAL; | |
66 | } | |
67 | ||
68 | res = platform_get_resource(pdev, IORESOURCE_MEM, 0); | |
69 | if (unlikely(res == NULL)) { | |
70 | dev_err(&pdev->dev, "invalid resource\n"); | |
71 | return -EINVAL; | |
72 | } | |
73 | ||
74 | hd = kmalloc(sizeof(struct heartbeat_data), GFP_KERNEL); | |
75 | if (unlikely(!hd)) | |
76 | return -ENOMEM; | |
77 | ||
78 | if (pdev->dev.platform_data) { | |
79 | memcpy(hd->bit_pos, pdev->dev.platform_data, | |
80 | ARRAY_SIZE(hd->bit_pos)); | |
81 | } else { | |
82 | int i; | |
83 | ||
84 | for (i = 0; i < ARRAY_SIZE(hd->bit_pos); i++) | |
85 | hd->bit_pos[i] = i; | |
86 | } | |
87 | ||
88 | hd->base = (void __iomem *)res->start; | |
89 | ||
90 | setup_timer(&hd->timer, heartbeat_timer, (unsigned long)hd); | |
91 | platform_set_drvdata(pdev, hd); | |
92 | ||
93 | return mod_timer(&hd->timer, jiffies + 1); | |
94 | } | |
95 | ||
96 | static int heartbeat_drv_remove(struct platform_device *pdev) | |
97 | { | |
98 | struct heartbeat_data *hd = platform_get_drvdata(pdev); | |
99 | ||
100 | del_timer_sync(&hd->timer); | |
101 | ||
102 | platform_set_drvdata(pdev, NULL); | |
103 | ||
104 | kfree(hd); | |
105 | ||
106 | return 0; | |
107 | } | |
108 | ||
109 | static struct platform_driver heartbeat_driver = { | |
110 | .probe = heartbeat_drv_probe, | |
111 | .remove = heartbeat_drv_remove, | |
112 | .driver = { | |
113 | .name = DRV_NAME, | |
114 | }, | |
115 | }; | |
116 | ||
117 | static int __init heartbeat_init(void) | |
118 | { | |
119 | printk(KERN_NOTICE DRV_NAME ": version %s loaded\n", DRV_VERSION); | |
120 | return platform_driver_register(&heartbeat_driver); | |
121 | } | |
122 | ||
123 | static void __exit heartbeat_exit(void) | |
124 | { | |
125 | platform_driver_unregister(&heartbeat_driver); | |
126 | } | |
127 | module_init(heartbeat_init); | |
128 | module_exit(heartbeat_exit); | |
129 | ||
130 | MODULE_VERSION(DRV_VERSION); | |
131 | MODULE_AUTHOR("Paul Mundt"); | |
132 | MODULE_LICENSE("GPLv2"); |