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 
25 static struct device_node *halt_node;
26 
27 static const struct of_device_id child_match[] = {
28 	{
29 		.compatible = "sgy,gpio-halt",
30 	},
31 	{},
32 };
33 
34 static void gpio_halt_wfn(struct work_struct *work)
35 {
36 	/* Likely wont return */
37 	orderly_poweroff(true);
38 }
39 static DECLARE_WORK(gpio_halt_wq, gpio_halt_wfn);
40 
41 static 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. */
64 static 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 
72 static 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 
131 static 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 
150 static 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 };
159 MODULE_DEVICE_TABLE(of, gpio_halt_match);
160 
161 static 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 
170 module_platform_driver(gpio_halt_driver);
171 
172 MODULE_DESCRIPTION("Driver to support GPIO triggered system halt for Servergy CTS-1000 Systems.");
173 MODULE_VERSION("1.0");
174 MODULE_AUTHOR("Ben Collins <ben.c@servergy.com>");
175 MODULE_LICENSE("GPL");
176