Unverified Commit 93064e15 authored by Stefan Binding's avatar Stefan Binding Committed by Mark Brown
Browse files

ACPI: utils: Add api to read _SUB from ACPI 



Add a wrapper function to read the _SUB string from ACPI.

Signed-off-by: default avatarStefan Binding <sbinding@opensource.cirrus.com>
Acked-by: default avatarRafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20220707151037.3901050-2-sbinding@opensource.cirrus.com


Signed-off-by: default avatarMark Brown <broonie@kernel.org>
parent 7fb72b7b

drivers/acpi/utils.c

+38 −0
Original line number Diff line number Diff line
@@ -291,6 +291,44 @@ int acpi_get_local_address(acpi_handle handle, u32 *addr) 
}

EXPORT_SYMBOL(acpi_get_local_address);



#define ACPI_MAX_SUB_BUF_SIZE	9



const char *acpi_get_subsystem_id(acpi_handle handle)

{

	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };

	union acpi_object *obj;

	acpi_status status;

	const char *sub;

	size_t len;



	status = acpi_evaluate_object(handle, METHOD_NAME__SUB, NULL, &buffer);

	if (ACPI_FAILURE(status)) {

		acpi_handle_debug(handle, "Reading ACPI _SUB failed: %#x\n", status);

		return ERR_PTR(-ENODATA);

	}



	obj = buffer.pointer;

	if (obj->type == ACPI_TYPE_STRING) {

		len = strlen(obj->string.pointer);

		if (len < ACPI_MAX_SUB_BUF_SIZE && len > 0) {

			sub = kstrdup(obj->string.pointer, GFP_KERNEL);

			if (!sub)

				sub = ERR_PTR(-ENOMEM);

		} else {

			acpi_handle_err(handle, "ACPI _SUB Length %zu is Invalid\n", len);

			sub = ERR_PTR(-ENODATA);

		}

	} else {

		acpi_handle_warn(handle, "Warning ACPI _SUB did not return a string\n");

		sub = ERR_PTR(-ENODATA);

	}



	acpi_os_free(buffer.pointer);



	return sub;

}

EXPORT_SYMBOL_GPL(acpi_get_subsystem_id);



acpi_status

acpi_evaluate_reference(acpi_handle handle,

			acpi_string pathname,

include/linux/acpi.h

+6 −0
Original line number Diff line number Diff line
@@ -762,6 +762,7 @@ static inline u64 acpi_arch_get_root_pointer(void) 
#endif



int acpi_get_local_address(acpi_handle handle, u32 *addr);

const char *acpi_get_subsystem_id(acpi_handle handle);



#else	/* !CONFIG_ACPI */
@@ -1023,6 +1024,11 @@ static inline int acpi_get_local_address(acpi_handle handle, u32 *addr) 
	return -ENODEV;

}



static inline const char *acpi_get_subsystem_id(acpi_handle handle)

{

	return ERR_PTR(-ENODEV);

}



static inline int acpi_register_wakeup_handler(int wake_irq,

	bool (*wakeup)(void *context), void *context)

{