linux-kernel - [PATCH 2/7] soundwire: bus: filter-out unwanted interrupt reports

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Date:   Tue, 18 Aug 2020 22:06:51 +0800
From:   Bard Liao <yung-chuan.liao@...ux.intel.com>
To:     alsa-devel@...a-project.org, vkoul@...nel.org
Cc:     vinod.koul@...aro.org, linux-kernel@...r.kernel.org, tiwai@...e.de,
        broonie@...nel.org, gregkh@...uxfoundation.org, jank@...ence.com,
        srinivas.kandagatla@...aro.org, rander.wang@...ux.intel.com,
        ranjani.sridharan@...ux.intel.com, hui.wang@...onical.com,
        pierre-louis.bossart@...ux.intel.com, sanyog.r.kale@...el.com,
        mengdong.lin@...el.com, bard.liao@...el.com
Subject: [PATCH 2/7] soundwire: bus: filter-out unwanted interrupt reports

From: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>

Unlike the traditional usage, in the SoundWire specification the
interrupt masks only gate the propagation of an interrupt condition to
the PING frame status. They do not gate the changes of the INT_STAT
registers, which will happen regardless of the mask settings. See
Figure 116 of the SoundWire 1.2 specification for an in-depth
description of the interrupt model.

When the bus driver reads the SCP_INT1_STAT register, it will retrieve
all the interrupt status, including for the mask fields that were not
explicitly set. For example, even if the PARITY mask is not set, the
PARITY error status will be reported if an implementation-defined
interrupt for jack detection is enabled and occurs.

Filtering undesired interrupt reports and handling has to be
implemented in software. This patch enables this filtering for the
INT1_IMPL_DEF, PARITY and BUS_CLASH interrupt sources.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.bossart@...ux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehmanen@...ux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovetski@...ux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.liao@...ux.intel.com>
---
 drivers/soundwire/bus.c | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index 3b6a87bc254e..9e5bcd0dd115 100644
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -1394,12 +1394,14 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave)
 		 * interrupt
 		 */
 		if (buf & SDW_SCP_INT1_PARITY) {
-			dev_err(&slave->dev, "Parity error detected\n");
+			if (slave->prop.scp_int1_mask & SDW_SCP_INT1_PARITY)
+				dev_err(&slave->dev, "Parity error detected\n");
 			clear |= SDW_SCP_INT1_PARITY;
 		}
 
 		if (buf & SDW_SCP_INT1_BUS_CLASH) {
-			dev_err(&slave->dev, "Bus clash error detected\n");
+			if (slave->prop.scp_int1_mask & SDW_SCP_INT1_BUS_CLASH)
+				dev_err(&slave->dev, "Bus clash detected\n");
 			clear |= SDW_SCP_INT1_BUS_CLASH;
 		}
 
@@ -1411,9 +1413,11 @@ static int sdw_handle_slave_alerts(struct sdw_slave *slave)
 		 */
 
 		if (buf & SDW_SCP_INT1_IMPL_DEF) {
-			dev_dbg(&slave->dev, "Slave impl defined interrupt\n");
+			if (slave->prop.scp_int1_mask & SDW_SCP_INT1_IMPL_DEF) {
+				dev_dbg(&slave->dev, "Slave impl defined interrupt\n");
+				slave_notify = true;
+			}
 			clear |= SDW_SCP_INT1_IMPL_DEF;
-			slave_notify = true;
 		}
 
 		/* Check port 0 - 3 interrupts */
-- 
2.17.1