soundwire: cadence: add status in dev_dbg 'State change' log

The existing debug log only mentions a state change, without providing
any details. For integration and stress-tests, it's helpful to see in
the dmesg log the reason for the state change.

The value is intended for power users and isn't converted as
human-readable values. But for the record each device has a 4-bit
status:

BIT(0): Unattached
BIT(1): Attached
BIT(2): Alert
BIT(3): Reserved (should not happen)

Example:

[  121.891288] intel-sdw intel-sdw.0: Slave status change: 0x2

<< this shows a Device0 Attached

[  121.891295] soundwire sdw-master-0: Slave attached, programming device number
[  121.891629] soundwire sdw-master-0: SDW Slave Addr: 30025d071101
[  121.891632] soundwire sdw-master-0: SDW Slave class_id 1, part_id 711, mfg_id 25d, unique_id 0, version 3
[  121.892011] intel-sdw intel-sdw.0: Msg ignored for Slave 0
[  121.892013] soundwire sdw-master-0: No more devices to enumerate
[  121.892200] intel-sdw intel-sdw.0: Slave status change: 0x21

<< this shows the device now Attached as Device1 and Unattached as
Device0, i.e. a successful enumeration.
Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@linux.intel.com>
Link: https://lore.kernel.org/r/20210115053738.22630-3-yung-chuan.liao@linux.intel.comSigned-off-by: Vinod Koul <vkoul@kernel.org>

drivers/soundwire/cadence_master.c

@@ -734,21 +734,18 @@ static void cdns_read_response(struct sdw_cdns *cdns)
 }
 
 static int cdns_update_slave_status(struct sdw_cdns *cdns,
-				    u32 slave0, u32 slave1)
+				    u64 slave_intstat)
 {
 	enum sdw_slave_status status[SDW_MAX_DEVICES + 1];
 	bool is_slave = false;
-	u64 slave;
 	u32 mask;
 	int i, set_status;
 
-	/* combine the two status */
-	slave = ((u64)slave1 << 32) | slave0;
 	memset(status, 0, sizeof(status));
 
 	for (i = 0; i <= SDW_MAX_DEVICES; i++) {
-		mask = (slave >> (i * CDNS_MCP_SLAVE_STATUS_NUM)) &
-				CDNS_MCP_SLAVE_STATUS_BITS;
+		mask = (slave_intstat >> (i * CDNS_MCP_SLAVE_STATUS_NUM)) &
+			CDNS_MCP_SLAVE_STATUS_BITS;
 		if (!mask)
 			continue;
 
@@ -918,13 +915,17 @@ static void cdns_update_slave_status_work(struct work_struct *work)
 	struct sdw_cdns *cdns =
 		container_of(work, struct sdw_cdns, work);
 	u32 slave0, slave1;
-
-	dev_dbg_ratelimited(cdns->dev, "Slave status change\n");
+	u64 slave_intstat;
 
 	slave0 = cdns_readl(cdns, CDNS_MCP_SLAVE_INTSTAT0);
 	slave1 = cdns_readl(cdns, CDNS_MCP_SLAVE_INTSTAT1);
 
-	cdns_update_slave_status(cdns, slave0, slave1);
+	/* combine the two status */
+	slave_intstat = ((u64)slave1 << 32) | slave0;
+
+	dev_dbg_ratelimited(cdns->dev, "Slave status change: 0x%llx\n", slave_intstat);
+
+	cdns_update_slave_status(cdns, slave_intstat);
 	cdns_writel(cdns, CDNS_MCP_SLAVE_INTSTAT0, slave0);
 	cdns_writel(cdns, CDNS_MCP_SLAVE_INTSTAT1, slave1);