LXR linux/arch/sh/drivers/heartbeat.c

   1/*
   2 * Generic heartbeat driver for regular LED banks
   3 *
   4 * Copyright (C) 2007 - 2010  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 <linux/slab.h>
  28#include <asm/heartbeat.h>
  29
  30#define DRV_NAME "heartbeat"
  31#define DRV_VERSION "0.1.2"
  32
  33static unsigned char default_bit_pos[] = { 0, 1, 2, 3, 4, 5, 6, 7 };
  34
  35static inline void heartbeat_toggle_bit(struct heartbeat_data *hd,
  36                                        unsigned bit, unsigned int inverted)
  37{
  38        unsigned int new;
  39
  40        new = (1 << hd->bit_pos[bit]);
  41        if (inverted)
  42                new = ~new;
  43
  44        new &= hd->mask;
  45
  46        switch (hd->regsize) {
  47        case 32:
  48                new |= ioread32(hd->base) & ~hd->mask;
  49                iowrite32(new, hd->base);
  50                break;
  51        case 16:
  52                new |= ioread16(hd->base) & ~hd->mask;
  53                iowrite16(new, hd->base);
  54                break;
  55        default:
  56                new |= ioread8(hd->base) & ~hd->mask;
  57                iowrite8(new, hd->base);
  58                break;
  59        }
  60}
  61
  62static void heartbeat_timer(unsigned long data)
  63{
  64        struct heartbeat_data *hd = (struct heartbeat_data *)data;
  65        static unsigned bit = 0, up = 1;
  66
  67        heartbeat_toggle_bit(hd, bit, hd->flags & HEARTBEAT_INVERTED);
  68
  69        bit += up;
  70        if ((bit == 0) || (bit == (hd->nr_bits)-1))
  71                up = -up;
  72
  73        mod_timer(&hd->timer, jiffies + (110 - ((300 << FSHIFT) /
  74                        ((avenrun[0] / 5) + (3 << FSHIFT)))));
  75}
  76
  77static int heartbeat_drv_probe(struct platform_device *pdev)
  78{
  79        struct resource *res;
  80        struct heartbeat_data *hd;
  81        int i;
  82
  83        if (unlikely(pdev->num_resources != 1)) {
  84                dev_err(&pdev->dev, "invalid number of resources\n");
  85                return -EINVAL;
  86        }
  87
  88        res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  89        if (unlikely(res == NULL)) {
  90                dev_err(&pdev->dev, "invalid resource\n");
  91                return -EINVAL;
  92        }
  93
  94        if (pdev->dev.platform_data) {
  95                hd = pdev->dev.platform_data;
  96        } else {
  97                hd = kzalloc(sizeof(struct heartbeat_data), GFP_KERNEL);
  98                if (unlikely(!hd))
  99                        return -ENOMEM;
 100        }
 101
 102        hd->base = ioremap_nocache(res->start, resource_size(res));
 103        if (unlikely(!hd->base)) {
 104                dev_err(&pdev->dev, "ioremap failed\n");
 105
 106                if (!pdev->dev.platform_data)
 107                        kfree(hd);
 108
 109                return -ENXIO;
 110        }
 111
 112        if (!hd->nr_bits) {
 113                hd->bit_pos = default_bit_pos;
 114                hd->nr_bits = ARRAY_SIZE(default_bit_pos);
 115        }
 116
 117        hd->mask = 0;
 118        for (i = 0; i < hd->nr_bits; i++)
 119                hd->mask |= (1 << hd->bit_pos[i]);
 120
 121        if (!hd->regsize) {
 122                switch (res->flags & IORESOURCE_MEM_TYPE_MASK) {
 123                case IORESOURCE_MEM_32BIT:
 124                        hd->regsize = 32;
 125                        break;
 126                case IORESOURCE_MEM_16BIT:
 127                        hd->regsize = 16;
 128                        break;
 129                case IORESOURCE_MEM_8BIT:
 130                default:
 131                        hd->regsize = 8;
 132                        break;
 133                }
 134        }
 135
 136        setup_timer(&hd->timer, heartbeat_timer, (unsigned long)hd);
 137        platform_set_drvdata(pdev, hd);
 138
 139        return mod_timer(&hd->timer, jiffies + 1);
 140}
 141
 142static int heartbeat_drv_remove(struct platform_device *pdev)
 143{
 144        struct heartbeat_data *hd = platform_get_drvdata(pdev);
 145
 146        del_timer_sync(&hd->timer);
 147        iounmap(hd->base);
 148
 149        platform_set_drvdata(pdev, NULL);
 150
 151        if (!pdev->dev.platform_data)
 152                kfree(hd);
 153
 154        return 0;
 155}
 156
 157static struct platform_driver heartbeat_driver = {
 158        .probe          = heartbeat_drv_probe,
 159        .remove         = heartbeat_drv_remove,
 160        .driver         = {
 161                .name   = DRV_NAME,
 162        },
 163};
 164
 165static int __init heartbeat_init(void)
 166{
 167        printk(KERN_NOTICE DRV_NAME ": version %s loaded\n", DRV_VERSION);
 168        return platform_driver_register(&heartbeat_driver);
 169}
 170
 171static void __exit heartbeat_exit(void)
 172{
 173        platform_driver_unregister(&heartbeat_driver);
 174}
 175module_init(heartbeat_init);
 176module_exit(heartbeat_exit);
 177
 178MODULE_VERSION(DRV_VERSION);
 179MODULE_AUTHOR("Paul Mundt");
 180MODULE_LICENSE("GPL v2");
 181