release/src-rt-6.x/linux/linux-2.6/arch/sh/drivers/heartbeat.c

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