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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* Servergy CTS-1000 Setup
*
* Maintained by Ben Collins <ben.c@servergy.com>
*
* Copyright 2012 by Servergy, Inc.
*/
#include <linux/platform_device.h>
#include <linux/device.h>
#include <linux/module.h>
#include <linux/of_gpio.h>
#include <linux/of_irq.h>
#include <linux/workqueue.h>
#include <linux/reboot.h>
#include <linux/interrupt.h>
#include <asm/machdep.h>
static struct device_node *halt_node;
static const struct of_device_id child_match[] = {
{
.compatible = "sgy,gpio-halt",
},
{},
};
static void gpio_halt_wfn(struct work_struct *work)
{
/* Likely wont return */
orderly_poweroff(true);
}
static DECLARE_WORK(gpio_halt_wq, gpio_halt_wfn);
static void __noreturn gpio_halt_cb(void)
{
enum of_gpio_flags flags;
int trigger, gpio;
if (!halt_node)
panic("No reset GPIO information was provided in DT\n");
gpio = of_get_gpio_flags(halt_node, 0, &flags);
if (!gpio_is_valid(gpio))
panic("Provided GPIO is invalid\n");
trigger = (flags == OF_GPIO_ACTIVE_LOW);
printk(KERN_INFO "gpio-halt: triggering GPIO.\n");
/* Probably wont return */
gpio_set_value(gpio, trigger);
panic("Halt failed\n");
}
/* This IRQ means someone pressed the power button and it is waiting for us
* to handle the shutdown/poweroff. */
static irqreturn_t gpio_halt_irq(int irq, void *__data)
{
printk(KERN_INFO "gpio-halt: shutdown due to power button IRQ.\n");
schedule_work(&gpio_halt_wq);
return IRQ_HANDLED;
};
static int gpio_halt_probe(struct platform_device *pdev)
{
enum of_gpio_flags flags;
struct device_node *node = pdev->dev.of_node;
struct device_node *child_node;
int gpio, err, irq;
int trigger;
if (!node)
return -ENODEV;
/* If there's no matching child, this isn't really an error */
child_node = of_find_matching_node(node, child_match);
if (!child_node)
return 0;
/* Technically we could just read the first one, but punish
* DT writers for invalid form. */
if (of_gpio_count(child_node) != 1) {
err = -EINVAL;
goto err_put;
}
/* Get the gpio number relative to the dynamic base. */
gpio = of_get_gpio_flags(child_node, 0, &flags);
if (!gpio_is_valid(gpio)) {
err = -EINVAL;
goto err_put;
}
err = gpio_request(gpio, "gpio-halt");
if (err) {
printk(KERN_ERR "gpio-halt: error requesting GPIO %d.\n",
gpio);
goto err_put;
}
trigger = (flags == OF_GPIO_ACTIVE_LOW);
gpio_direction_output(gpio, !trigger);
/* Now get the IRQ which tells us when the power button is hit */
irq = irq_of_parse_and_map(child_node, 0);
err = request_irq(irq, gpio_halt_irq, IRQF_TRIGGER_RISING |
IRQF_TRIGGER_FALLING, "gpio-halt", child_node);
if (err) {
printk(KERN_ERR "gpio-halt: error requesting IRQ %d for "
"GPIO %d.\n", irq, gpio);
gpio_free(gpio);
goto err_put;
}
/* Register our halt function */
ppc_md.halt = gpio_halt_cb;
pm_power_off = gpio_halt_cb;
printk(KERN_INFO "gpio-halt: registered GPIO %d (%d trigger, %d"
" irq).\n", gpio, trigger, irq);
halt_node = child_node;
return 0;
err_put:
of_node_put(child_node);
return err;
}
static int gpio_halt_remove(struct platform_device *pdev)
{
if (halt_node) {
int gpio = of_get_gpio(halt_node, 0);
int irq = irq_of_parse_and_map(halt_node, 0);
free_irq(irq, halt_node);
ppc_md.halt = NULL;
pm_power_off = NULL;
gpio_free(gpio);
of_node_put(halt_node);
halt_node = NULL;
}
return 0;
}
static const struct of_device_id gpio_halt_match[] = {
/* We match on the gpio bus itself and scan the children since they
* wont be matched against us. We know the bus wont match until it
* has been registered too. */
{
.compatible = "fsl,qoriq-gpio",
},
{},
};
MODULE_DEVICE_TABLE(of, gpio_halt_match);
static struct platform_driver gpio_halt_driver = {
.driver = {
.name = "gpio-halt",
.of_match_table = gpio_halt_match,
},
.probe = gpio_halt_probe,
.remove = gpio_halt_remove,
};
module_platform_driver(gpio_halt_driver);
MODULE_DESCRIPTION("Driver to support GPIO triggered system halt for Servergy CTS-1000 Systems.");
MODULE_VERSION("1.0");
MODULE_AUTHOR("Ben Collins <ben.c@servergy.com>");
MODULE_LICENSE("GPL");
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