soundwire: intel: add support for jack detection in clock stop mode

When system is suspended in clock stop mode on intel platforms, both
master and slave are in clock stop mode and soundwire bus is taken
over by a special hardware. The bus message for jack event is processed
by this special hardware, which will tigger a interrupt to ACPI system
and resume audio pci device. Then audio pci driver will resume soundwire
master and slave, transfer bus ownership to master, finally slave
will report jack event to master and codec driver is triggered to
check jack status.

Signed-off-by: Rander Wang <rander.wang@intel.com>

drivers/soundwire/intel.c

@@ -401,6 +401,44 @@ static void intel_shim_wake(struct sdw_intel *sdw, bool wake_enable)
 	}
 }
 
+void sdw_intel_process_wakeen_event(struct sdw_intel_ctx *ctx)
+{
+	struct sdw_intel_link_res *link;
+	struct sdw_master_device *md;
+	struct sdw_slave *slave;
+	struct sdw_bus *bus;
+
+	list_for_each_entry(link, &ctx->link_list, list) {
+		struct sdw_intel *sdw;
+		u16 wake_sts;
+
+		md = link->md;
+		bus = &link->cdns->bus;
+		sdw = cdns_to_intel(link->cdns);
+		wake_sts = intel_readw(sdw->link_res->shim, SDW_SHIM_WAKESTS);
+
+		/* disable WAKEEN interrupt ASAP to prevent interrupt flood */
+		intel_shim_wake(sdw, false);
+
+		if (!(wake_sts & BIT(sdw->instance)))
+			continue;
+
+		/*
+		 * wake up master and slave so that slave can notify master
+		 * the wakeen event and let codec driver check codec status
+		 */
+		list_for_each_entry(slave, &bus->slaves, node) {
+			if (slave->prop.wake_capable) {
+				if (slave->status != SDW_SLAVE_ATTACHED)
+					continue;
+
+				pm_request_resume(&slave->dev);
+			}
+		}
+	}
+}
+EXPORT_SYMBOL(sdw_intel_process_wakeen_event);
+
 static int intel_link_power_down(struct sdw_intel *sdw)
 {
 	int link_control, spa_mask, cpa_mask, ret;

include/linux/soundwire/sdw_intel.h

@@ -122,6 +122,8 @@ struct sdw_intel_res {
 int sdw_intel_acpi_scan(acpi_handle *parent_handle,
 			struct sdw_intel_acpi_info *info);
 
+void sdw_intel_process_wakeen_event(struct sdw_intel_ctx *ctx);
+
 struct sdw_intel_ctx *
 sdw_intel_probe(struct sdw_intel_res *res);