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); 156