text: /*
   * Generic heartbeat driver for regular LED banks
   *
   * Copyright (C) 2007  Paul Mundt
   *
   * Most SH reference boards include a number of individual LEDs that can
   * be independently controlled (either via a pre-defined hardware
   * function or via the LED class, if desired -- the hardware tends to
   * encapsulate some of the same "triggers" that the LED class supports,
   * so there's not too much value in it).
   *
   * Additionally, most of these boards also have a LED bank that we've
   * traditionally used for strobing the load average. This use case is
   * handled by this driver, rather than giving each LED bit position its
   * own struct device.
   *
   * This file is subject to the terms and conditions of the GNU General Public
   * License.  See the file "COPYING" in the main directory of this archive
   * for more details.
   */
  #include <linux/init.h>
  #include <linux/module.h>
  #include <linux/platform_device.h>
  #include <linux/sched.h>
  #include <linux/timer.h>
  #include <linux/io.h>
  #include <asm/heartbeat.h>
  
  #define DRV_NAME "heartbeat"
  #define DRV_VERSION "0.1.1"
  
  static unsigned char default_bit_pos[] = { 0, 1, 2, 3, 4, 5, 6, 7 };
  
  static inline void heartbeat_toggle_bit(struct heartbeat_data *hd,
  					unsigned bit, unsigned int inverted)
  {
  	unsigned int new;
  
  	new = (1 << hd->bit_pos[bit]);
  	if (inverted)
  		new = ~new;
  
  	switch (hd->regsize) {
  	case 32:
  		iowrite32(new, hd->base);
  		break;
  	case 16:
  		iowrite16(new, hd->base);
  		break;
  	default:
  		iowrite8(new, hd->base);
  		break;
  	}
  }
  
  static void heartbeat_timer(unsigned long data)
  {
  	struct heartbeat_data *hd = (struct heartbeat_data *)data;
  	static unsigned bit = 0, up = 1;
  
  	heartbeat_toggle_bit(hd, bit, hd->flags & HEARTBEAT_INVERTED);
  
  	bit += up;
  	if ((bit == 0) || (bit == (hd->nr_bits)-1))
  		up = -up;
  
  	mod_timer(&hd->timer, jiffies + (110 - ((300 << FSHIFT) /
  			((avenrun[0] / 5) + (3 << FSHIFT)))));
  }
  
  static int heartbeat_drv_probe(struct platform_device *pdev)
  {
  	struct resource *res;
  	struct heartbeat_data *hd;
  
  	if (unlikely(pdev->num_resources != 1)) {
  		dev_err(&pdev->dev, "invalid number of resources\n");
  		return -EINVAL;
  	}
  
  	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  	if (unlikely(res == NULL)) {
  		dev_err(&pdev->dev, "invalid resource\n");
  		return -EINVAL;
  	}
  
  	if (pdev->dev.platform_data) {
  		hd = pdev->dev.platform_data;
  	} else {
  		hd = kzalloc(sizeof(struct heartbeat_data), GFP_KERNEL);
  		if (unlikely(!hd))
  			return -ENOMEM;
  	}
  
  	hd->base = ioremap_nocache(res->start, res->end - res->start + 1);
  	if (!unlikely(hd->base)) {
  		dev_err(&pdev->dev, "ioremap failed\n");
  
  		if (!pdev->dev.platform_data)
  			kfree(hd);
  
  		return -ENXIO;
  	}
  
  	if (!hd->nr_bits) {
  		hd->bit_pos = default_bit_pos;
  		hd->nr_bits = ARRAY_SIZE(default_bit_pos);
  	}
  
  	if (!hd->regsize)
  		hd->regsize = 8;	/* default access size */
  
  	setup_timer(&hd->timer, heartbeat_timer, (unsigned long)hd);
  	platform_set_drvdata(pdev, hd);
  
  	return mod_timer(&hd->timer, jiffies + 1);
  }
  
  static int heartbeat_drv_remove(struct platform_device *pdev)
  {
  	struct heartbeat_data *hd = platform_get_drvdata(pdev);
  
  	del_timer_sync(&hd->timer);
  	iounmap(hd->base);
  
  	platform_set_drvdata(pdev, NULL);
  
  	if (!pdev->dev.platform_data)
  		kfree(hd);
  
  	return 0;
  }
  
  static struct platform_driver heartbeat_driver = {
  	.probe		= heartbeat_drv_probe,
  	.remove		= heartbeat_drv_remove,
  	.driver		= {
  		.name	= DRV_NAME,
  	},
  };
  
  static int __init heartbeat_init(void)
  {
  	printk(KERN_NOTICE DRV_NAME ": version %s loaded\n", DRV_VERSION);
  	return platform_driver_register(&heartbeat_driver);
  }
  
  static void __exit heartbeat_exit(void)
  {
  	platform_driver_unregister(&heartbeat_driver);
  }
  module_init(heartbeat_init);
  module_exit(heartbeat_exit);
  
  MODULE_VERSION(DRV_VERSION);
  MODULE_AUTHOR("Paul Mundt");
  MODULE_LICENSE("GPLv2");
  