[PATCH] soundwire: qcom: Check device status before reading devid

[Srinivas Kandagatla]

As per hardware datasheet its recommended that we check the device
status before reading devid assigned by auto-enumeration.

Without this patch we see SoundWire devices with invalid enumeration
addresses on the bus.

Cc: stable at vger.kernel.org
Fixes: a6e6581942ca ("soundwire: qcom: add auto enumeration support")
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla at linaro.org>
---
 drivers/soundwire/qcom.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c
index dbf793e7e5d7..9df970eeca45 100644
--- a/drivers/soundwire/qcom.c
+++ b/drivers/soundwire/qcom.c
@@ -480,6 +480,10 @@ static int qcom_swrm_enumerate(struct sdw_bus *bus)
 	char *buf1 = (char *)&val1, *buf2 = (char *)&val2;
 
 	for (i = 1; i <= SDW_MAX_DEVICES; i++) {
+		/* do not continue if the status is Not Present  */
+		if (!ctrl->status[i])
+			continue;
+
 		/*SCP_Devid5 - Devid 4*/
 		ctrl->reg_read(ctrl, SWRM_ENUMERATOR_SLAVE_DEV_ID_1(i), &val1);
 
-- 
2.25.1