Transfer size of zero means a request to do an address-only
transfer. Since the HW support this, we probably shouldn't be just
ignoring such requests. While at it allow DP_AUX_I2C_MOT flag to pass
through, since it is supported by the HW as well.
Signed-off-by: Andrey Smirnov <andrew.smirnov@xxxxxxxxx>
Cc: Andrzej Hajda <a.hajda@xxxxxxxxxxx>
Cc: Laurent Pinchart <Laurent.pinchart@xxxxxxxxxxxxxxxx>
Cc: Tomi Valkeinen <tomi.valkeinen@xxxxxx>
Cc: Andrey Gusakov <andrey.gusakov@xxxxxxxxxxxxxxxxxx>
Cc: Philipp Zabel <p.zabel@xxxxxxxxxxxxxx>
Cc: Cory Tusar <cory.tusar@xxxxxxxx>
Cc: Chris Healy <cphealy@xxxxxxxxx>
Cc: Lucas Stach <l.stach@xxxxxxxxxxxxxx>
Cc: dri-devel@xxxxxxxxxxxxxxxxxxxxx
Cc: linux-kernel@xxxxxxxxxxxxxxx
---
drivers/gpu/drm/bridge/tc358767.c | 30 +++++++++++++++++++++++-------
1 file changed, 23 insertions(+), 7 deletions(-)
diff --git a/drivers/gpu/drm/bridge/tc358767.c b/drivers/gpu/drm/bridge/tc358767.c
index 7d0fbb12195b..4bb9b15e1324 100644
--- a/drivers/gpu/drm/bridge/tc358767.c
+++ b/drivers/gpu/drm/bridge/tc358767.c
@@ -145,6 +145,8 @@
/* AUX channel */
#define DP0_AUXCFG0 0x0660
+#define DP0_AUXCFG0_BSIZE GENMASK(11, 8)
+#define DP0_AUXCFG0_ADDR_ONLY BIT(4)
#define DP0_AUXCFG1 0x0664
#define AUX_RX_FILTER_EN BIT(16)
@@ -327,6 +329,18 @@ static int tc_aux_read_data(struct tc_data *tc, void *data, size_t size)
return size;
}
+static u32 tc_auxcfg0(struct drm_dp_aux_msg *msg, size_t size)
+{
+ u32 auxcfg0 = msg->request;
+
+ if (size)
+ auxcfg0 |= FIELD_PREP(DP0_AUXCFG0_BSIZE, size - 1);
+ else
+ auxcfg0 |= DP0_AUXCFG0_ADDR_ONLY;
+
+ return auxcfg0;
+}
+
static ssize_t tc_aux_transfer(struct drm_dp_aux *aux,
struct drm_dp_aux_msg *msg)
{
@@ -336,9 +350,6 @@ static ssize_t tc_aux_transfer(struct drm_dp_aux *aux,
u32 auxstatus;
int ret;
- if (size == 0)
- return 0;
-
ret = tc_aux_wait_busy(tc, 100);
if (ret)
return ret;
@@ -362,8 +373,7 @@ static ssize_t tc_aux_transfer(struct drm_dp_aux *aux,
if (ret)
return ret;
/* Start transfer */
- ret = regmap_write(tc->regmap, DP0_AUXCFG0,
- ((size - 1) << 8) | request);
+ ret = regmap_write(tc->regmap, DP0_AUXCFG0, tc_auxcfg0(msg, size));
if (ret)
return ret;
@@ -377,8 +387,14 @@ static ssize_t tc_aux_transfer(struct drm_dp_aux *aux,
if (auxstatus & AUX_TIMEOUT)
return -ETIMEDOUT;
-
- size = FIELD_GET(AUX_BYTES, auxstatus);
+ /*
+ * For some reason address-only DP_AUX_I2C_WRITE (MOT), still
+ * reports 1 byte transferred in its status. To deal we that
+ * we ignore aux_bytes field if we know that this was an
+ * address-only transfer
+ */
+ if (size)
+ size = FIELD_GET(AUX_BYTES, auxstatus);
msg->reply = FIELD_GET(AUX_STATUS, auxstatus);
switch (request) {
--
2.21.0
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