soundwire: qcom: Check device status before reading devid

commit aa1262ca66957183ea1fb32a067e145b995f3744 upstream.

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@vger.kernel.org
Fixes: a6e6581942ca ("soundwire: qcom: add auto enumeration support")
Signed-off-by: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>
Link: https://lore.kernel.org/r/20220706095644.5852-1-srinivas.kandagatla@linaro.org
Signed-off-by: Vinod Koul <vkoul@kernel.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/soundwire/qcom.c b/drivers/soundwire/qcom.c
index f595582..2adc0a7 100644 (file)
--- a/drivers/soundwire/qcom.c
+++ b/drivers/soundwire/qcom.c
@@ -451,6 +451,10 @@ 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);