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ACPI: utils: Add api to read _SUB from ACPI 

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

Signed-off-by: Stefan Binding <sbinding@opensource.cirrus.com>
Acked-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/20220707151037.3901050-2-sbinding@opensource.cirrus.com
Signed-off-by: Mark Brown <broonie@kernel.org>
This commit is contained in:
Stefan Binding 2022-07-07 16:10:36 +01:00 committed by Mark Brown
parent 7fb72b7bf1
commit 93064e15c8
No known key found for this signature in database
GPG Key ID: 24D68B725D5487D0
2 changed files with 44 additions and 0 deletions
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38
drivers/acpi/utils.c
View File

@ -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,

6
include/linux/acpi.h
View File

@ -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)
{