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Benjamin Collins5611fe42012-12-17 04:19:28 +00001/*
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/init.h>
18#include <linux/of_gpio.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 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 __devinit 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 ppc_md.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 __devexit 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 ppc_md.power_off = NULL;
141
142 gpio_free(gpio);
143
144 halt_node = NULL;
145 }
146
147 return 0;
148}
149
150static 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 .owner = THIS_MODULE,
165 .of_match_table = gpio_halt_match,
166 },
167 .probe = gpio_halt_probe,
168 .remove = __devexit_p(gpio_halt_remove),
169};
170
171module_platform_driver(gpio_halt_driver);
172
173MODULE_DESCRIPTION("Driver to support GPIO triggered system halt for Servergy CTS-1000 Systems.");
174MODULE_VERSION("1.0");
175MODULE_AUTHOR("Ben Collins <ben.c@servergy.com>");
176MODULE_LICENSE("GPL");