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 #include <linux/platform_device.h>
11 #include <linux/device.h>
12 #include <linux/module.h>
13 #include <linux/of_gpio.h>
14 #include <linux/of_irq.h>
15 #include <linux/workqueue.h>
16 #include <linux/reboot.h>
17 #include <linux/interrupt.h>
18
19 #include <asm/machdep.h>
20
21 static struct device_node *halt_node;
22
23 static const struct of_device_id child_match[] = {
24 {
25 .compatible = "sgy,gpio-halt",
26 },
27 {},
28 };
29
gpio_halt_wfn(struct work_struct * work)30 static void gpio_halt_wfn(struct work_struct *work)
31 {
32 /* Likely wont return */
33 orderly_poweroff(true);
34 }
35 static DECLARE_WORK(gpio_halt_wq, gpio_halt_wfn);
36
gpio_halt_cb(void)37 static void __noreturn gpio_halt_cb(void)
38 {
39 enum of_gpio_flags flags;
40 int trigger, gpio;
41
42 if (!halt_node)
43 panic("No reset GPIO information was provided in DT\n");
44
45 gpio = of_get_gpio_flags(halt_node, 0, &flags);
46
47 if (!gpio_is_valid(gpio))
48 panic("Provided GPIO is invalid\n");
49
50 trigger = (flags == OF_GPIO_ACTIVE_LOW);
51
52 printk(KERN_INFO "gpio-halt: triggering GPIO.\n");
53
54 /* Probably wont return */
55 gpio_set_value(gpio, trigger);
56
57 panic("Halt failed\n");
58 }
59
60 /* This IRQ means someone pressed the power button and it is waiting for us
61 * to handle the shutdown/poweroff. */
gpio_halt_irq(int irq,void * __data)62 static irqreturn_t gpio_halt_irq(int irq, void *__data)
63 {
64 printk(KERN_INFO "gpio-halt: shutdown due to power button IRQ.\n");
65 schedule_work(&gpio_halt_wq);
66
67 return IRQ_HANDLED;
68 };
69
gpio_halt_probe(struct platform_device * pdev)70 static int gpio_halt_probe(struct platform_device *pdev)
71 {
72 enum of_gpio_flags flags;
73 struct device_node *node = pdev->dev.of_node;
74 int gpio, err, irq;
75 int trigger;
76
77 if (!node)
78 return -ENODEV;
79
80 /* If there's no matching child, this isn't really an error */
81 halt_node = of_find_matching_node(node, child_match);
82 if (!halt_node)
83 return 0;
84
85 /* Technically we could just read the first one, but punish
86 * DT writers for invalid form. */
87 if (of_gpio_count(halt_node) != 1)
88 return -EINVAL;
89
90 /* Get the gpio number relative to the dynamic base. */
91 gpio = of_get_gpio_flags(halt_node, 0, &flags);
92 if (!gpio_is_valid(gpio))
93 return -EINVAL;
94
95 err = gpio_request(gpio, "gpio-halt");
96 if (err) {
97 printk(KERN_ERR "gpio-halt: error requesting GPIO %d.\n",
98 gpio);
99 halt_node = NULL;
100 return err;
101 }
102
103 trigger = (flags == OF_GPIO_ACTIVE_LOW);
104
105 gpio_direction_output(gpio, !trigger);
106
107 /* Now get the IRQ which tells us when the power button is hit */
108 irq = irq_of_parse_and_map(halt_node, 0);
109 err = request_irq(irq, gpio_halt_irq, IRQF_TRIGGER_RISING |
110 IRQF_TRIGGER_FALLING, "gpio-halt", halt_node);
111 if (err) {
112 printk(KERN_ERR "gpio-halt: error requesting IRQ %d for "
113 "GPIO %d.\n", irq, gpio);
114 gpio_free(gpio);
115 halt_node = NULL;
116 return err;
117 }
118
119 /* Register our halt function */
120 ppc_md.halt = gpio_halt_cb;
121 pm_power_off = gpio_halt_cb;
122
123 printk(KERN_INFO "gpio-halt: registered GPIO %d (%d trigger, %d"
124 " irq).\n", gpio, trigger, irq);
125
126 return 0;
127 }
128
gpio_halt_remove(struct platform_device * pdev)129 static int gpio_halt_remove(struct platform_device *pdev)
130 {
131 if (halt_node) {
132 int gpio = of_get_gpio(halt_node, 0);
133 int irq = irq_of_parse_and_map(halt_node, 0);
134
135 free_irq(irq, halt_node);
136
137 ppc_md.halt = NULL;
138 pm_power_off = NULL;
139
140 gpio_free(gpio);
141
142 halt_node = NULL;
143 }
144
145 return 0;
146 }
147
148 static const struct of_device_id gpio_halt_match[] = {
149 /* We match on the gpio bus itself and scan the children since they
150 * wont be matched against us. We know the bus wont match until it
151 * has been registered too. */
152 {
153 .compatible = "fsl,qoriq-gpio",
154 },
155 {},
156 };
157 MODULE_DEVICE_TABLE(of, gpio_halt_match);
158
159 static struct platform_driver gpio_halt_driver = {
160 .driver = {
161 .name = "gpio-halt",
162 .of_match_table = gpio_halt_match,
163 },
164 .probe = gpio_halt_probe,
165 .remove = gpio_halt_remove,
166 };
167
168 module_platform_driver(gpio_halt_driver);
169
170 MODULE_DESCRIPTION("Driver to support GPIO triggered system halt for Servergy CTS-1000 Systems.");
171 MODULE_VERSION("1.0");
172 MODULE_AUTHOR("Ben Collins <ben.c@servergy.com>");
173 MODULE_LICENSE("GPL");
174