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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org,
        Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
        Vinod Koul <vkoul@kernel.org>
Subject: [PATCH 5.18 0098/1095] soundwire: qcom: Check device status before reading devid
Date:   Mon, 15 Aug 2022 19:51:37 +0200
Message-Id: <20220815180433.612111006@linuxfoundation.org>
In-Reply-To: <20220815180429.240518113@linuxfoundation.org>
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From: Srinivas Kandagatla <srinivas.kandagatla@linaro.org>

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>
---
 drivers/soundwire/qcom.c |    4 ++++
 1 file changed, 4 insertions(+)

--- a/drivers/soundwire/qcom.c
+++ b/drivers/soundwire/qcom.c
@@ -471,6 +471,10 @@ static int qcom_swrm_enumerate(struct sd
 	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);