Other parts of the kernel may use constraints information to make
decisions on what power state to put a device into.
Signed-off-by: Mario Limonciello <mario.limonciello@xxxxxxx>
---
v12->v13:
* Drop checking for enabled, just return constraints
v11->v12:
* Use for_each_lpi_constraint instead
* use CONFIG_SUSPEND instead of CONFIG_ACPI_SLEEP
v9->v10:
* split from other patches
* kerneldoc fixes
* move debug statement to this function
---
drivers/acpi/x86/s2idle.c | 24 ++++++++++++++++++++++++
include/linux/acpi.h | 6 ++++++
2 files changed, 30 insertions(+)
diff --git a/drivers/acpi/x86/s2idle.c b/drivers/acpi/x86/s2idle.c
index 1aa3cd5677bd8..dd961f3a60577 100644
--- a/drivers/acpi/x86/s2idle.c
+++ b/drivers/acpi/x86/s2idle.c
@@ -299,6 +299,30 @@ static void lpi_device_get_constraints(void)
ACPI_FREE(out_obj);
}
+/**
+ * acpi_get_lps0_constraint - get any LPS0 constraint for a device
+ * @dev: device to get constraints for
+ *
+ * Returns:
+ * - the value for constraint.
+ * - Otherwise, -ENODEV.
+ */
+int acpi_get_lps0_constraint(struct device *dev)
+{
+ struct lpi_constraints *entry;
+
+ for_each_lpi_constraint(entry) {
+ if (!device_match_acpi_handle(dev, entry->handle))
+ continue;
+ acpi_handle_debug(entry->handle,
+ "ACPI device constraint: %d\n", entry->min_dstate);
+ return entry->min_dstate;
+ }
+ dev_dbg(dev, "No ACPI device constraint specified\n");
+
+ return -ENODEV;
+}
+
static void lpi_check_constraints(void)
{
struct lpi_constraints *entry;
diff --git a/include/linux/acpi.h b/include/linux/acpi.h
index f1552c04a2856..6745535444c76 100644
--- a/include/linux/acpi.h
+++ b/include/linux/acpi.h
@@ -1109,6 +1109,12 @@ struct acpi_s2idle_dev_ops {
};
int acpi_register_lps0_dev(struct acpi_s2idle_dev_ops *arg);
void acpi_unregister_lps0_dev(struct acpi_s2idle_dev_ops *arg);
+int acpi_get_lps0_constraint(struct device *dev);
+#else /* CONFIG_SUSPEND && CONFIG_X86 */
+static inline int acpi_get_lps0_constraint(struct device *dev)
+{
+ return -ENODEV;
+}
#endif /* CONFIG_SUSPEND && CONFIG_X86 */
#ifndef CONFIG_IA64
void arch_reserve_mem_area(acpi_physical_address addr, size_t size);
--
2.34.1
