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
30static unsigned char default_bit_pos[] = { 0, 1, 2, 3, 4, 5, 6, 7 };
31
32static 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
59static 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
74static 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
139static struct platform_driver heartbeat_driver = {
140	.probe		= heartbeat_drv_probe,
141	.driver		= {
142		.name			= DRV_NAME,
143		.suppress_bind_attrs	= true,
144	},
145};
146
147static 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}
152device_initcall(heartbeat_init);
153