drivers/parisc/power.c

1 /* SPDX-License-Identifier: GPL-2.0-or-later */
3  * HP PARISC soft power switch driver
5  * Copyright (c) 2001-2023 Helge Deller <deller@gmx.de>
8  *  Support of the soft power switch button may be enabled or disabled at
9  *  runtime through the "/proc/sys/kernel/power" procfs entry.
28 /* how often should the power button be polled ? */
31 /* how long does the power button needs to be down until we react ? */
64 	/* wait until the button was pressed for 1 second */  in process_shutdown()
79 /* main power switch task struct */
82 /* filename in /proc which can be used to enable/disable the power switch */
83 #define SYSCTL_FILENAME	"sys/kernel/power"
85 /* soft power switch enabled/disabled */
88 /* main kernel thread worker. It polls the button state */
104 			 * Non-Gecko-style machines:  in kpowerswd()
105 			 * Check the power switch status which is read from the  in kpowerswd()
107 			 * Bit 31 ("the lowest bit) is the status of the power switch.  in kpowerswd()
108 			 * This bit is "1" if the button is NOT pressed.  in kpowerswd()
114 			 * the power switch status is stored in Bit 0 ("the highest bit")  in kpowerswd()
117 			 * the button has been released again.  in kpowerswd()
156  * be executed any longer. This function then re-enables
157  * the soft-power switch and allows the user to switch off
165 	/* re-enable the soft-power switch */  in parisc_panic_event()
175 /* qemu soft power-off function */
179 	gsc_writel(0, (unsigned long) data->cb_data);  in qemu_power_off()
194 	/* enable the soft power switch if possible */  in power_init()
199 		soft_power_reg = -1UL;  in power_init()
202 	case 0:		printk(KERN_INFO DRIVER_NAME ": Gecko-style soft power switch enabled.\n");  in power_init()
205 	case -1UL:	printk(KERN_INFO DRIVER_NAME ": Soft power switch support not available.\n");  in power_init()
206 			return -ENODEV;  in power_init()
208 	default:	printk(KERN_INFO DRIVER_NAME ": Soft power switch at 0x%08lx enabled.\n",  in power_init()
222 		return -EIO;  in power_init()
247 MODULE_DESCRIPTION("Soft power switch driver");