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 #include <asm/heartbeat.h> 28 29 #define DRV_NAME "heartbeat" 30 #define DRV_VERSION "0.1.1" 31 32 static unsigned char default_bit_pos[] = { 0, 1, 2, 3, 4, 5, 6, 7 }; 33 34 static inline void heartbeat_toggle_bit(struct heartbeat_data *hd, 35 unsigned bit, unsigned int inverted) 36 { 37 unsigned int new; 38 39 new = (1 << hd->bit_pos[bit]); 40 if (inverted) 41 new = ~new; 42 43 switch (hd->regsize) { 44 case 32: 45 iowrite32(new, hd->base); 46 break; 47 case 16: 48 iowrite16(new, hd->base); 49 break; 50 default: 51 iowrite8(new, hd->base); 52 break; 53 } 54 } 55 56 static void heartbeat_timer(unsigned long data) 57 { 58 struct heartbeat_data *hd = (struct heartbeat_data *)data; 59 static unsigned bit = 0, up = 1; 60 61 heartbeat_toggle_bit(hd, bit, hd->flags & HEARTBEAT_INVERTED); 62 63 bit += up; 64 if ((bit == 0) || (bit == (hd->nr_bits)-1)) 65 up = -up; 66 67 mod_timer(&hd->timer, jiffies + (110 - ((300 << FSHIFT) / 68 ((avenrun[0] / 5) + (3 << FSHIFT))))); 69 } 70 71 static int heartbeat_drv_probe(struct platform_device *pdev) 72 { 73 struct resource *res; 74 struct heartbeat_data *hd; 75 76 if (unlikely(pdev->num_resources != 1)) { 77 dev_err(&pdev->dev, "invalid number of resources\n"); 78 return -EINVAL; 79 } 80 81 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 82 if (unlikely(res == NULL)) { 83 dev_err(&pdev->dev, "invalid resource\n"); 84 return -EINVAL; 85 } 86 87 if (pdev->dev.platform_data) { 88 hd = pdev->dev.platform_data; 89 } else { 90 hd = kzalloc(sizeof(struct heartbeat_data), GFP_KERNEL); 91 if (unlikely(!hd)) 92 return -ENOMEM; 93 } 94 95 hd->base = ioremap_nocache(res->start, res->end - res->start + 1); 96 if (!unlikely(hd->base)) { 97 dev_err(&pdev->dev, "ioremap failed\n"); 98 99 if (!pdev->dev.platform_data) 100 kfree(hd); 101 102 return -ENXIO; 103 } 104 105 if (!hd->nr_bits) { 106 hd->bit_pos = default_bit_pos; 107 hd->nr_bits = ARRAY_SIZE(default_bit_pos); 108 } 109 110 if (!hd->regsize) 111 hd->regsize = 8; /* default access size */ 112 113 setup_timer(&hd->timer, heartbeat_timer, (unsigned long)hd); 114 platform_set_drvdata(pdev, hd); 115 116 return mod_timer(&hd->timer, jiffies + 1); 117 } 118 119 static int heartbeat_drv_remove(struct platform_device *pdev) 120 { 121 struct heartbeat_data *hd = platform_get_drvdata(pdev); 122 123 del_timer_sync(&hd->timer); 124 iounmap(hd->base); 125 126 platform_set_drvdata(pdev, NULL); 127 128 if (!pdev->dev.platform_data) 129 kfree(hd); 130 131 return 0; 132 } 133 134 static struct platform_driver heartbeat_driver = { 135 .probe = heartbeat_drv_probe, 136 .remove = heartbeat_drv_remove, 137 .driver = { 138 .name = DRV_NAME, 139 }, 140 }; 141 142 static int __init heartbeat_init(void) 143 { 144 printk(KERN_NOTICE DRV_NAME ": version %s loaded\n", DRV_VERSION); 145 return platform_driver_register(&heartbeat_driver); 146 } 147 148 static void __exit heartbeat_exit(void) 149 { 150 platform_driver_unregister(&heartbeat_driver); 151 } 152 module_init(heartbeat_init); 153 module_exit(heartbeat_exit); 154 155 MODULE_VERSION(DRV_VERSION); 156 MODULE_AUTHOR("Paul Mundt"); 157 MODULE_LICENSE("GPLv2"); 158