1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Generic heartbeat driver for regular LED banks 4 * 5 * Copyright (C) 2007 - 2010 Paul Mundt 6 * 7 * Most SH reference boards include a number of individual LEDs that can 8 * be independently controlled (either via a pre-defined hardware 9 * function or via the LED class, if desired -- the hardware tends to 10 * encapsulate some of the same "triggers" that the LED class supports, 11 * so there's not too much value in it). 12 * 13 * Additionally, most of these boards also have a LED bank that we've 14 * traditionally used for strobing the load average. This use case is 15 * handled by this driver, rather than giving each LED bit position its 16 * own struct device. 17 */ 18 #include <linux/init.h> 19 #include <linux/platform_device.h> 20 #include <linux/sched.h> 21 #include <linux/sched/loadavg.h> 22 #include <linux/timer.h> 23 #include <linux/io.h> 24 #include <linux/slab.h> 25 #include <asm/heartbeat.h> 26 27 #define DRV_NAME "heartbeat" 28 #define DRV_VERSION "0.1.2" 29 30 static unsigned char default_bit_pos[] = { 0, 1, 2, 3, 4, 5, 6, 7 }; 31 32 static inline void heartbeat_toggle_bit(struct heartbeat_data *hd, 33 unsigned bit, unsigned int inverted) 34 { 35 unsigned int new; 36 37 new = (1 << hd->bit_pos[bit]); 38 if (inverted) 39 new = ~new; 40 41 new &= hd->mask; 42 43 switch (hd->regsize) { 44 case 32: 45 new |= ioread32(hd->base) & ~hd->mask; 46 iowrite32(new, hd->base); 47 break; 48 case 16: 49 new |= ioread16(hd->base) & ~hd->mask; 50 iowrite16(new, hd->base); 51 break; 52 default: 53 new |= ioread8(hd->base) & ~hd->mask; 54 iowrite8(new, hd->base); 55 break; 56 } 57 } 58 59 static void heartbeat_timer(struct timer_list *t) 60 { 61 struct heartbeat_data *hd = from_timer(hd, t, timer); 62 static unsigned bit = 0, up = 1; 63 64 heartbeat_toggle_bit(hd, bit, hd->flags & HEARTBEAT_INVERTED); 65 66 bit += up; 67 if ((bit == 0) || (bit == (hd->nr_bits)-1)) 68 up = -up; 69 70 mod_timer(&hd->timer, jiffies + (110 - ((300 << FSHIFT) / 71 ((avenrun[0] / 5) + (3 << FSHIFT))))); 72 } 73 74 static int heartbeat_drv_probe(struct platform_device *pdev) 75 { 76 struct resource *res; 77 struct heartbeat_data *hd; 78 int i; 79 80 if (unlikely(pdev->num_resources != 1)) { 81 dev_err(&pdev->dev, "invalid number of resources\n"); 82 return -EINVAL; 83 } 84 85 res = platform_get_resource(pdev, IORESOURCE_MEM, 0); 86 if (unlikely(res == NULL)) { 87 dev_err(&pdev->dev, "invalid resource\n"); 88 return -EINVAL; 89 } 90 91 if (pdev->dev.platform_data) { 92 hd = pdev->dev.platform_data; 93 } else { 94 hd = kzalloc(sizeof(struct heartbeat_data), GFP_KERNEL); 95 if (unlikely(!hd)) 96 return -ENOMEM; 97 } 98 99 hd->base = ioremap(res->start, resource_size(res)); 100 if (unlikely(!hd->base)) { 101 dev_err(&pdev->dev, "ioremap failed\n"); 102 103 if (!pdev->dev.platform_data) 104 kfree(hd); 105 106 return -ENXIO; 107 } 108 109 if (!hd->nr_bits) { 110 hd->bit_pos = default_bit_pos; 111 hd->nr_bits = ARRAY_SIZE(default_bit_pos); 112 } 113 114 hd->mask = 0; 115 for (i = 0; i < hd->nr_bits; i++) 116 hd->mask |= (1 << hd->bit_pos[i]); 117 118 if (!hd->regsize) { 119 switch (res->flags & IORESOURCE_MEM_TYPE_MASK) { 120 case IORESOURCE_MEM_32BIT: 121 hd->regsize = 32; 122 break; 123 case IORESOURCE_MEM_16BIT: 124 hd->regsize = 16; 125 break; 126 case IORESOURCE_MEM_8BIT: 127 default: 128 hd->regsize = 8; 129 break; 130 } 131 } 132 133 timer_setup(&hd->timer, heartbeat_timer, 0); 134 platform_set_drvdata(pdev, hd); 135 136 return mod_timer(&hd->timer, jiffies + 1); 137 } 138 139 static struct platform_driver heartbeat_driver = { 140 .probe = heartbeat_drv_probe, 141 .driver = { 142 .name = DRV_NAME, 143 .suppress_bind_attrs = true, 144 }, 145 }; 146 147 static int __init heartbeat_init(void) 148 { 149 printk(KERN_NOTICE DRV_NAME ": version %s loaded\n", DRV_VERSION); 150 return platform_driver_register(&heartbeat_driver); 151 } 152 device_initcall(heartbeat_init); 153