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
24 static struct gpio_desc *halt_gpio;
25 static int halt_irq;
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 __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. */
53 static 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
63 static 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
98 static 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
117 static void 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
129 static const struct of_device_id gpio_halt_match[] = {
130 /* We match on the gpio bus itself and scan the children since they
131 * wont be matched against us. We know the bus wont match until it
132 * has been registered too. */
133 {
134 .compatible = "fsl,qoriq-gpio",
135 },
136 {},
137 };
138 MODULE_DEVICE_TABLE(of, gpio_halt_match);
139
140 static struct platform_driver gpio_halt_driver = {
141 .driver = {
142 .name = "gpio-halt",
143 .of_match_table = gpio_halt_match,
144 },
145 .probe = gpio_halt_probe,
146 .remove_new = gpio_halt_remove,
147 };
148
149 module_platform_driver(gpio_halt_driver);
150
151 MODULE_DESCRIPTION("Driver to support GPIO triggered system halt for Servergy CTS-1000 Systems.");
152 MODULE_VERSION("1.0");
153 MODULE_AUTHOR("Ben Collins <ben.c@servergy.com>");
154 MODULE_LICENSE("GPL");
155
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