1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * Servergy CTS-1000 Setup
4 *
5 * Maintained by Ben Collins <ben.c@servergy.com>
6 *
7 * Copyright 2012 by Servergy, Inc.
8 */
9
10#define pr_fmt(fmt) "gpio-halt: " fmt
11
12#include <linux/err.h>
13#include <linux/platform_device.h>
14#include <linux/device.h>
15#include <linux/gpio/consumer.h>
16#include <linux/module.h>
17#include <linux/of_irq.h>
18#include <linux/workqueue.h>
19#include <linux/reboot.h>
20#include <linux/interrupt.h>
21
22#include <asm/machdep.h>
23
24static struct gpio_desc *halt_gpio;
25static int halt_irq;
26
27static const struct of_device_id child_match[] = {
28	{
29		.compatible = "sgy,gpio-halt",
30	},
31	{},
32};
33
34static void gpio_halt_wfn(struct work_struct *work)
35{
36	/* Likely wont return */
37	orderly_poweroff(true);
38}
39static DECLARE_WORK(gpio_halt_wq, gpio_halt_wfn);
40
41static void __noreturn gpio_halt_cb(void)
42{
43	pr_info("triggering GPIO.\n");
44
45	/* Probably wont return */
46	gpiod_set_value(halt_gpio, 1);
47
48	panic("Halt failed\n");
49}
50
51/* This IRQ means someone pressed the power button and it is waiting for us
52 * to handle the shutdown/poweroff. */
53static irqreturn_t gpio_halt_irq(int irq, void *__data)
54{
55	struct platform_device *pdev = __data;
56
57	dev_info(&pdev->dev, "scheduling shutdown due to power button IRQ\n");
58	schedule_work(&gpio_halt_wq);
59
60        return IRQ_HANDLED;
61};
62
63static int __gpio_halt_probe(struct platform_device *pdev,
64			     struct device_node *halt_node)
65{
66	int err;
67
68	halt_gpio = fwnode_gpiod_get_index(of_fwnode_handle(halt_node),
69					   NULL, 0, GPIOD_OUT_LOW, "gpio-halt");
70	err = PTR_ERR_OR_ZERO(halt_gpio);
71	if (err) {
72		dev_err(&pdev->dev, "failed to request halt GPIO: %d\n", err);
73		return err;
74	}
75
76	/* Now get the IRQ which tells us when the power button is hit */
77	halt_irq = irq_of_parse_and_map(halt_node, 0);
78	err = request_irq(halt_irq, gpio_halt_irq,
79			  IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING,
80			  "gpio-halt", pdev);
81	if (err) {
82		dev_err(&pdev->dev, "failed to request IRQ %d: %d\n",
83			halt_irq, err);
84		gpiod_put(halt_gpio);
85		halt_gpio = NULL;
86		return err;
87	}
88
89	/* Register our halt function */
90	ppc_md.halt = gpio_halt_cb;
91	pm_power_off = gpio_halt_cb;
92
93	dev_info(&pdev->dev, "registered halt GPIO, irq: %d\n", halt_irq);
94
95	return 0;
96}
97
98static int gpio_halt_probe(struct platform_device *pdev)
99{
100	struct device_node *halt_node;
101	int ret;
102
103	if (!pdev->dev.of_node)
104		return -ENODEV;
105
106	/* If there's no matching child, this isn't really an error */
107	halt_node = of_find_matching_node(pdev->dev.of_node, child_match);
108	if (!halt_node)
109		return -ENODEV;
110
111	ret = __gpio_halt_probe(pdev, halt_node);
112	of_node_put(halt_node);
113
114	return ret;
115}
116
117static int gpio_halt_remove(struct platform_device *pdev)
118{
119	free_irq(halt_irq, pdev);
120	cancel_work_sync(&gpio_halt_wq);
121
122	ppc_md.halt = NULL;
123	pm_power_off = NULL;
124
125	gpiod_put(halt_gpio);
126	halt_gpio = NULL;
127
128	return 0;
129}
130
131static const struct of_device_id gpio_halt_match[] = {
132	/* We match on the gpio bus itself and scan the children since they
133	 * wont be matched against us. We know the bus wont match until it
134	 * has been registered too. */
135	{
136		.compatible = "fsl,qoriq-gpio",
137	},
138	{},
139};
140MODULE_DEVICE_TABLE(of, gpio_halt_match);
141
142static struct platform_driver gpio_halt_driver = {
143	.driver = {
144		.name		= "gpio-halt",
145		.of_match_table = gpio_halt_match,
146	},
147	.probe		= gpio_halt_probe,
148	.remove		= gpio_halt_remove,
149};
150
151module_platform_driver(gpio_halt_driver);
152
153MODULE_DESCRIPTION("Driver to support GPIO triggered system halt for Servergy CTS-1000 Systems.");
154MODULE_VERSION("1.0");
155MODULE_AUTHOR("Ben Collins <ben.c@servergy.com>");
156MODULE_LICENSE("GPL");
157