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, inverted: hd->flags & HEARTBEAT_INVERTED); |
65 | |
66 | bit += up; |
67 | if ((bit == 0) || (bit == (hd->nr_bits)-1)) |
68 | up = -up; |
69 | |
70 | mod_timer(timer: &hd->timer, expires: 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(offset: res->start, size: 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(objp: 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, data: hd); |
135 | |
136 | return mod_timer(timer: &hd->timer, expires: 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 | |