diff options
| -rw-r--r-- | drivers/acpi/Kconfig | 24 | ||||
| -rw-r--r-- | drivers/acpi/Makefile | 1 | ||||
| -rw-r--r-- | drivers/acpi/tiny-power-button.c | 46 |
3 files changed, 71 insertions, 0 deletions
diff --git a/drivers/acpi/Kconfig b/drivers/acpi/Kconfig index cc57bab146b5..ce2730d61a8f 100644 --- a/drivers/acpi/Kconfig +++ b/drivers/acpi/Kconfig @@ -190,6 +190,30 @@ config ACPI_BUTTON To compile this driver as a module, choose M here: the module will be called button. +config ACPI_TINY_POWER_BUTTON + tristate "Tiny Power Button Driver" + depends on !ACPI_BUTTON + help + This driver provides a tiny alternative to the ACPI Button driver. + The tiny power button driver only handles the power button. Rather + than notifying userspace via the input layer or a netlink event, this + driver directly signals the init process to shut down. + + This driver is particularly suitable for cloud and VM environments, + which use a simulated power button to initiate a controlled poweroff, + but which may not want to run a separate userspace daemon to process + input events. + +config ACPI_TINY_POWER_BUTTON_SIGNAL + int "Tiny Power Button Signal" + depends on ACPI_TINY_POWER_BUTTON + default 38 + help + Default signal to send to init in response to the power button. + + Likely values here include 38 (SIGRTMIN+4) to power off, or 2 + (SIGINT) to simulate Ctrl+Alt+Del. + config ACPI_VIDEO tristate "Video" depends on X86 && BACKLIGHT_CLASS_DEVICE diff --git a/drivers/acpi/Makefile b/drivers/acpi/Makefile index 33fdaf67454e..e81e1ebbfb32 100644 --- a/drivers/acpi/Makefile +++ b/drivers/acpi/Makefile @@ -71,6 +71,7 @@ obj-$(CONFIG_ACPI_IPMI) += acpi_ipmi.o obj-$(CONFIG_ACPI_AC) += ac.o obj-$(CONFIG_ACPI_BUTTON) += button.o +obj-$(CONFIG_ACPI_TINY_POWER_BUTTON) += tiny-power-button.o obj-$(CONFIG_ACPI_FAN) += fan.o obj-$(CONFIG_ACPI_VIDEO) += video.o obj-$(CONFIG_ACPI_TAD) += acpi_tad.o diff --git a/drivers/acpi/tiny-power-button.c b/drivers/acpi/tiny-power-button.c new file mode 100644 index 000000000000..6273d73c0b59 --- /dev/null +++ b/drivers/acpi/tiny-power-button.c @@ -0,0 +1,46 @@ +// SPDX-License-Identifier: GPL-2.0-or-later +#include <linux/module.h> +#include <linux/sched/signal.h> +#include <linux/acpi.h> +#include <acpi/button.h> + +ACPI_MODULE_NAME("tiny-power-button"); +MODULE_AUTHOR("Josh Triplett"); +MODULE_DESCRIPTION("ACPI Tiny Power Button Driver"); +MODULE_LICENSE("GPL"); + +static int power_signal __read_mostly = CONFIG_ACPI_TINY_POWER_BUTTON_SIGNAL; +module_param(power_signal, int, 0644); +MODULE_PARM_DESC(power_signal, "Power button sends this signal to init"); + +static const struct acpi_device_id tiny_power_button_device_ids[] = { + { ACPI_BUTTON_HID_POWER, 0 }, + { ACPI_BUTTON_HID_POWERF, 0 }, + { "", 0 }, +}; +MODULE_DEVICE_TABLE(acpi, tiny_power_button_device_ids); + +static int acpi_noop_add_remove(struct acpi_device *device) +{ + return 0; +} + +static void acpi_tiny_power_button_notify(struct acpi_device *device, u32 event) +{ + kill_cad_pid(power_signal, 1); +} + +static struct acpi_driver acpi_tiny_power_button_driver = { + .name = "tiny-power-button", + .class = "tiny-power-button", + .ids = tiny_power_button_device_ids, + .ops = { + .add = acpi_noop_add_remove, + .remove = acpi_noop_add_remove, + .notify = acpi_tiny_power_button_notify, + }, +}; + +module_driver(acpi_tiny_power_button_driver, + acpi_bus_register_driver, + acpi_bus_unregister_driver); |