[PATCH 4/7] soundwire: bus: use quirk to filter out invalid parity errors

[Bard Liao]

From: Pierre-Louis Bossart <pierre-louis.boss...@linux.intel.com>

If a Slave device reports with a quirk that its initial parity check
may be incorrect, filter it but keep the parity checks active in
steady state.

Signed-off-by: Pierre-Louis Bossart <pierre-louis.boss...@linux.intel.com>
Reviewed-by: Kai Vehmanen <kai.vehma...@linux.intel.com>
Reviewed-by: Guennadi Liakhovetski <guennadi.liakhovet...@linux.intel.com>
Signed-off-by: Bard Liao <yung-chuan.l...@linux.intel.com>
---
 drivers/soundwire/bus.c       | 8 +++++++-
 include/linux/soundwire/sdw.h | 4 ++++
 2 files changed, 11 insertions(+), 1 deletion(-)

diff --git a/drivers/soundwire/bus.c b/drivers/soundwire/bus.c
index cddf39e3adfc..869290a8db40 100644
--- a/drivers/soundwire/bus.c
+++ b/drivers/soundwire/bus.c
@@ -1362,6 +1362,8 @@ static int sdw_handle_slave_alerts(struct sdw_slave 
*slave)
        unsigned long port;
        bool slave_notify = false;
        u8 buf, buf2[2], _buf, _buf2[2];
+       bool parity_check;
+       bool parity_quirk;
 
        sdw_modify_slave_status(slave, SDW_SLAVE_ALERT);
 
@@ -1394,7 +1396,11 @@ static int sdw_handle_slave_alerts(struct sdw_slave 
*slave)
                 * interrupt
                 */
                if (buf & SDW_SCP_INT1_PARITY) {
-                       if (slave->prop.scp_int1_mask & SDW_SCP_INT1_PARITY)
+                       parity_check = slave->prop.scp_int1_mask & 
SDW_SCP_INT1_PARITY;
+                       parity_quirk = !slave->first_interrupt_done &&
+                               (slave->prop.quirks & 
SDW_SLAVE_QUIRKS_INVALID_INITIAL_PARITY);
+
+                       if (parity_check && !parity_quirk)
                                dev_err(&slave->dev, "Parity error detected\n");
                        clear |= SDW_SCP_INT1_PARITY;
                }
diff --git a/include/linux/soundwire/sdw.h b/include/linux/soundwire/sdw.h
index 3550ab530c43..19bec6e4bbb6 100644
--- a/include/linux/soundwire/sdw.h
+++ b/include/linux/soundwire/sdw.h
@@ -356,6 +356,7 @@ struct sdw_dpn_prop {
  * @src_dpn_prop: Source Data Port N properties
  * @sink_dpn_prop: Sink Data Port N properties
  * @scp_int1_mask: SCP_INT1_MASK desired settings
+ * @quirks: bitmask identifying deltas from the MIPI specification
  */
 struct sdw_slave_prop {
        u32 mipi_revision;
@@ -378,8 +379,11 @@ struct sdw_slave_prop {
        struct sdw_dpn_prop *src_dpn_prop;
        struct sdw_dpn_prop *sink_dpn_prop;
        u8 scp_int1_mask;
+       u32 quirks;
 };
 
+#define SDW_SLAVE_QUIRKS_INVALID_INITIAL_PARITY        BIT(0)
+
 /**
  * struct sdw_master_prop - Master properties
  * @revision: MIPI spec version of the implementation
-- 
2.17.1