1/*
2 * Servergy CTS-1000 Setup
3 *
4 * Maintained by Ben Collins <ben.c@servergy.com>
5 *
6 * Copyright 2012 by Servergy, Inc.
7 *
8 * This program is free software; you can redistribute  it and/or modify it
9 * under  the terms of  the GNU General  Public License as published by the
10 * Free Software Foundation;  either version 2 of the  License, or (at your
11 * option) any later version.
12 */
13
14#include <linux/platform_device.h>
15#include <linux/device.h>
16#include <linux/module.h>
17#include <linux/of_gpio.h>
18#include <linux/of_irq.h>
19#include <linux/workqueue.h>
20#include <linux/reboot.h>
21#include <linux/interrupt.h>
22
23#include <asm/machdep.h>
24
25static struct device_node *halt_node;
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 gpio_halt_cb(void)
42{
43	enum of_gpio_flags flags;
44	int trigger, gpio;
45
46	if (!halt_node)
47		return;
48
49	gpio = of_get_gpio_flags(halt_node, 0, &flags);
50
51	if (!gpio_is_valid(gpio))
52		return;
53
54	trigger = (flags == OF_GPIO_ACTIVE_LOW);
55
56	printk(KERN_INFO "gpio-halt: triggering GPIO.\n");
57
58	/* Probably wont return */
59	gpio_set_value(gpio, trigger);
60}
61
62/* This IRQ means someone pressed the power button and it is waiting for us
63 * to handle the shutdown/poweroff. */
64static irqreturn_t gpio_halt_irq(int irq, void *__data)
65{
66	printk(KERN_INFO "gpio-halt: shutdown due to power button IRQ.\n");
67	schedule_work(&gpio_halt_wq);
68
69        return IRQ_HANDLED;
70};
71
72static int gpio_halt_probe(struct platform_device *pdev)
73{
74	enum of_gpio_flags flags;
75	struct device_node *node = pdev->dev.of_node;
76	int gpio, err, irq;
77	int trigger;
78
79	if (!node)
80		return -ENODEV;
81
82	/* If there's no matching child, this isn't really an error */
83	halt_node = of_find_matching_node(node, child_match);
84	if (!halt_node)
85		return 0;
86
87	/* Technically we could just read the first one, but punish
88	 * DT writers for invalid form. */
89	if (of_gpio_count(halt_node) != 1)
90		return -EINVAL;
91
92	/* Get the gpio number relative to the dynamic base. */
93	gpio = of_get_gpio_flags(halt_node, 0, &flags);
94	if (!gpio_is_valid(gpio))
95		return -EINVAL;
96
97	err = gpio_request(gpio, "gpio-halt");
98	if (err) {
99		printk(KERN_ERR "gpio-halt: error requesting GPIO %d.\n",
100		       gpio);
101		halt_node = NULL;
102		return err;
103	}
104
105	trigger = (flags == OF_GPIO_ACTIVE_LOW);
106
107	gpio_direction_output(gpio, !trigger);
108
109	/* Now get the IRQ which tells us when the power button is hit */
110	irq = irq_of_parse_and_map(halt_node, 0);
111	err = request_irq(irq, gpio_halt_irq, IRQF_TRIGGER_RISING |
112			  IRQF_TRIGGER_FALLING, "gpio-halt", halt_node);
113	if (err) {
114		printk(KERN_ERR "gpio-halt: error requesting IRQ %d for "
115		       "GPIO %d.\n", irq, gpio);
116		gpio_free(gpio);
117		halt_node = NULL;
118		return err;
119	}
120
121	/* Register our halt function */
122	ppc_md.halt = gpio_halt_cb;
123	pm_power_off = gpio_halt_cb;
124
125	printk(KERN_INFO "gpio-halt: registered GPIO %d (%d trigger, %d"
126	       " irq).\n", gpio, trigger, irq);
127
128	return 0;
129}
130
131static int gpio_halt_remove(struct platform_device *pdev)
132{
133	if (halt_node) {
134		int gpio = of_get_gpio(halt_node, 0);
135		int irq = irq_of_parse_and_map(halt_node, 0);
136
137		free_irq(irq, halt_node);
138
139		ppc_md.halt = NULL;
140		pm_power_off = NULL;
141
142		gpio_free(gpio);
143
144		halt_node = NULL;
145	}
146
147	return 0;
148}
149
150static const struct of_device_id gpio_halt_match[] = {
151	/* We match on the gpio bus itself and scan the children since they
152	 * wont be matched against us. We know the bus wont match until it
153	 * has been registered too. */
154	{
155		.compatible = "fsl,qoriq-gpio",
156	},
157	{},
158};
159MODULE_DEVICE_TABLE(of, gpio_halt_match);
160
161static struct platform_driver gpio_halt_driver = {
162	.driver = {
163		.name		= "gpio-halt",
164		.of_match_table = gpio_halt_match,
165	},
166	.probe		= gpio_halt_probe,
167	.remove		= gpio_halt_remove,
168};
169
170module_platform_driver(gpio_halt_driver);
171
172MODULE_DESCRIPTION("Driver to support GPIO triggered system halt for Servergy CTS-1000 Systems.");
173MODULE_VERSION("1.0");
174MODULE_AUTHOR("Ben Collins <ben.c@servergy.com>");
175MODULE_LICENSE("GPL");
176