sgy_cts1000.c

  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
 24static struct gpio_desc *halt_gpio;
 25static int halt_irq;
 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 __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. */
 53static 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
 63static 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
 98static 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
117static 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
129static 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};
138MODULE_DEVICE_TABLE(of, gpio_halt_match);
139
140static 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		= gpio_halt_remove,
147};
148
149module_platform_driver(gpio_halt_driver);
150
151MODULE_DESCRIPTION("Driver to support GPIO triggered system halt for Servergy CTS-1000 Systems.");
152MODULE_VERSION("1.0");
153MODULE_AUTHOR("Ben Collins <ben.c@servergy.com>");
154MODULE_LICENSE("GPL");