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/platform_device.h>
  23 #include <linux/sched.h>
  24 #include <linux/sched/loadavg.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
  33 static unsigned char default_bit_pos[] = { 0, 1, 2, 3, 4, 5, 6, 7 };
  34
  35 static 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
  62 static void heartbeat_timer(struct timer_list *t)
  63 {
  64         struct heartbeat_data *hd = from_timer(hd, t, timer);
  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
  77 static 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         timer_setup(&hd->timer, heartbeat_timer, 0);
 137         platform_set_drvdata(pdev, hd);
 138
 139         return mod_timer(&hd->timer, jiffies + 1);
 140 }
 141
 142 static struct platform_driver heartbeat_driver = {
 143         .probe          = heartbeat_drv_probe,
 144         .driver         = {
 145                 .name                   = DRV_NAME,
 146                 .suppress_bind_attrs    = true,
 147         },
 148 };
 149
 150 static int __init heartbeat_init(void)
 151 {
 152         printk(KERN_NOTICE DRV_NAME ": version %s loaded\n", DRV_VERSION);
 153         return platform_driver_register(&heartbeat_driver);
 154 }
 155 device_initcall(heartbeat_init);