We should be setting the drm_dp_aux_msg::reply field if a NACK or a
SHORT reply happens. Update the error bit handling logic in
ti_sn_aux_transfer() to handle these cases and notify upper layers that
such errors have happened. This helps the retry logic understand that a
timeout has happened, or to shorten the read length if the panel isn't
able to handle the longest read possible.
Cc: Douglas Anderson <dianders@xxxxxxxxxxxx>
Cc: Laurent Pinchart <Laurent.pinchart@xxxxxxxxxxxxxxxx>
Cc: Jonas Karlman <jonas@xxxxxxxxx>
Cc: Jernej Skrabec <jernej.skrabec@xxxxxxxx>
Cc: Sean Paul <seanpaul@xxxxxxxxxxxx>
Signed-off-by: Stephen Boyd <swboyd@xxxxxxxxxxxx>
---
drivers/gpu/drm/bridge/ti-sn65dsi86.c | 31 +++++++++++++++++++++++----
1 file changed, 27 insertions(+), 4 deletions(-)
diff --git a/drivers/gpu/drm/bridge/ti-sn65dsi86.c b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
index 6b6e98ca2881..19737bc01b8f 100644
--- a/drivers/gpu/drm/bridge/ti-sn65dsi86.c
+++ b/drivers/gpu/drm/bridge/ti-sn65dsi86.c
@@ -878,6 +878,7 @@ static ssize_t ti_sn_aux_transfer(struct drm_dp_aux *aux,
case DP_AUX_NATIVE_READ:
case DP_AUX_I2C_READ:
regmap_write(pdata->regmap, SN_AUX_CMD_REG, request_val);
+ msg->reply = 0; /* Assume it's good */
break;
default:
return -EINVAL;
@@ -909,10 +910,32 @@ static ssize_t ti_sn_aux_transfer(struct drm_dp_aux *aux,
ret = regmap_read(pdata->regmap, SN_AUX_CMD_STATUS_REG, &val);
if (ret)
return ret;
- else if ((val & AUX_IRQ_STATUS_NAT_I2C_FAIL)
- || (val & AUX_IRQ_STATUS_AUX_RPLY_TOUT)
- || (val & AUX_IRQ_STATUS_AUX_SHORT))
- return -ENXIO;
+
+ if (val & AUX_IRQ_STATUS_AUX_RPLY_TOUT) {
+ /*
+ * The hardware tried the message seven times per the DP spec
+ * but it hit a timeout. We ignore defers here because they're
+ * handled in hardware.
+ */
+ return -ETIMEDOUT;
+ }
+ if (val & AUX_IRQ_STATUS_AUX_SHORT) {
+ ret = regmap_read(pdata->regmap, SN_AUX_LENGTH_REG, &len);
+ if (ret)
+ return ret;
+ } else if (val & AUX_IRQ_STATUS_NAT_I2C_FAIL) {
+ switch (request) {
+ case DP_AUX_I2C_WRITE:
+ case DP_AUX_I2C_READ:
+ msg->reply |= DP_AUX_I2C_REPLY_NACK;
+ break;
+ case DP_AUX_NATIVE_READ:
+ case DP_AUX_NATIVE_WRITE:
+ msg->reply |= DP_AUX_NATIVE_REPLY_NACK;
+ break;
+ }
+ return 0;
+ }
if (request == DP_AUX_NATIVE_WRITE || request == DP_AUX_I2C_WRITE ||
len == 0)
--
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