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/timer.h> 25 #include <linux/io.h> 26 #include <linux/slab.h> 27 #include <asm/heartbeat.h> 28 29 #define DRV_NAME "heartbeat" 30 #define DRV_VERSION "0.1.2" 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 new &= hd->mask; 44 45 switch (hd->regsize) { 46 case 32: 47 new |= ioread32(hd->base) & ~hd->mask; 48 iowrite32(new, hd->base); 49 break; 50 case 16: 51 new |= ioread16(hd->base) & ~hd->mask; 52 iowrite16(new, hd->base); 53 break; 54 default: 55 new |= ioread8(hd->base) & ~hd->mask; 56 iowrite8(new, hd->base); 57 break; 58 } 59 } 60 61 static void heartbeat_timer(unsigned long data) 62 { 63 struct heartbeat_data *hd = (struct heartbeat_data *)data; 64 static unsigned bit = 0, up = 1; 65 66 heartbeat_toggle_bit(hd, bit, hd->flags & HEARTBEAT_INVERTED); 67 68 bit += up; 69 if ((bit == 0) || (bit == (hd->nr_bits)-1)) 70 up = -up; 71 72 mod_timer(&hd->timer, jiffies + (110 - ((300 << FSHIFT) / 73 ((avenrun[0] / 5) + (3 << FSHIFT))))); 74 } 75 76 static int heartbeat_drv_probe(struct platform_device *pdev) 77 { 78 struct resource *res; 79 struct heartbeat_data *hd; 80 int i; 81 82 if (unlikely(pdev->num_resources != 1)) { 83 dev_err(&pdev->dev, "invalid number of resources\n"); 84 return -EINVAL; 85 } 86 87 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 88 if (unlikely(res == NULL)) { 89 dev_err(&pdev->dev, "invalid resource\n"); 90 return -EINVAL; 91 } 92 93 if (pdev->dev.platform_data) { 94 hd = pdev->dev.platform_data; 95 } else { 96 hd = kzalloc(sizeof(struct heartbeat_data), GFP_KERNEL); 97 if (unlikely(!hd)) 98 return -ENOMEM; 99 } 100 101 hd->base = ioremap_nocache(res->start, resource_size(res)); 102 if (unlikely(!hd->base)) { 103 dev_err(&pdev->dev, "ioremap failed\n"); 104 105 if (!pdev->dev.platform_data) 106 kfree(hd); 107 108 return -ENXIO; 109 } 110 111 if (!hd->nr_bits) { 112 hd->bit_pos = default_bit_pos; 113 hd->nr_bits = ARRAY_SIZE(default_bit_pos); 114 } 115 116 hd->mask = 0; 117 for (i = 0; i < hd->nr_bits; i++) 118 hd->mask |= (1 << hd->bit_pos[i]); 119 120 if (!hd->regsize) { 121 switch (res->flags & IORESOURCE_MEM_TYPE_MASK) { 122 case IORESOURCE_MEM_32BIT: 123 hd->regsize = 32; 124 break; 125 case IORESOURCE_MEM_16BIT: 126 hd->regsize = 16; 127 break; 128 case IORESOURCE_MEM_8BIT: 129 default: 130 hd->regsize = 8; 131 break; 132 } 133 } 134 135 setup_timer(&hd->timer, heartbeat_timer, (unsigned long)hd); 136 platform_set_drvdata(pdev, hd); 137 138 return mod_timer(&hd->timer, jiffies + 1); 139 } 140 141 static struct platform_driver heartbeat_driver = { 142 .probe = heartbeat_drv_probe, 143 .driver = { 144 .name = DRV_NAME, 145 .suppress_bind_attrs = true, 146 }, 147 }; 148 149 static int __init heartbeat_init(void) 150 { 151 printk(KERN_NOTICE DRV_NAME ": version %s loaded\n", DRV_VERSION); 152 return platform_driver_register(&heartbeat_driver); 153 } 154 device_initcall(heartbeat_init); 155