1// SPDX-License-Identifier: GPL-2.0
2/* power.c: Power management driver.
3 *
4 * Copyright (C) 1999, 2007, 2008 David S. Miller (davem@davemloft.net)
5 */
6
7#include <linux/kernel.h>
8#include <linux/export.h>
9#include <linux/init.h>
10#include <linux/interrupt.h>
11#include <linux/reboot.h>
12#include <linux/of.h>
13#include <linux/platform_device.h>
14
15#include <asm/prom.h>
16#include <asm/io.h>
17
18static void __iomem *power_reg;
19
20static irqreturn_t power_handler(int irq, void *dev_id)
21{
22	orderly_poweroff(true);
23
24	/* FIXME: Check registers for status... */
25	return IRQ_HANDLED;
26}
27
28static int has_button_interrupt(unsigned int irq, struct device_node *dp)
29{
30	if (irq == 0xffffffff)
31		return 0;
32	if (!of_property_read_bool(dp, "button"))
33		return 0;
34
35	return 1;
36}
37
38static int power_probe(struct platform_device *op)
39{
40	struct resource *res = &op->resource[0];
41	unsigned int irq = op->archdata.irqs[0];
42
43	power_reg = of_ioremap(res, 0, 0x4, "power");
44
45	printk(KERN_INFO "%pOFn: Control reg at %llx\n",
46	       op->dev.of_node, res->start);
47
48	if (has_button_interrupt(irq, op->dev.of_node)) {
49		if (request_irq(irq,
50				power_handler, 0, "power", NULL) < 0)
51			printk(KERN_ERR "power: Cannot setup IRQ handler.\n");
52	}
53
54	return 0;
55}
56
57static const struct of_device_id power_match[] = {
58	{
59		.name = "power",
60	},
61	{},
62};
63
64static struct platform_driver power_driver = {
65	.probe		= power_probe,
66	.driver = {
67		.name = "power",
68		.of_match_table = power_match,
69	},
70};
71
72builtin_platform_driver(power_driver);
73