drm/i915: support address only i2c-over-aux transactions
To support bare address requests used by the drm dp helpers.
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c
index a0dad1a..d2a5588 100644
--- a/drivers/gpu/drm/i915/intel_dp.c
+++ b/drivers/gpu/drm/i915/intel_dp.c
@@ -575,7 +575,8 @@
return ret;
}
-#define HEADER_SIZE 4
+#define BARE_ADDRESS_SIZE 3
+#define HEADER_SIZE (BARE_ADDRESS_SIZE + 1)
static ssize_t
intel_dp_aux_transfer(struct drm_dp_aux *aux, struct drm_dp_aux_msg *msg)
{
@@ -592,7 +593,7 @@
switch (msg->request & ~DP_AUX_I2C_MOT) {
case DP_AUX_NATIVE_WRITE:
case DP_AUX_I2C_WRITE:
- txsize = HEADER_SIZE + msg->size;
+ txsize = msg->size ? HEADER_SIZE + msg->size : BARE_ADDRESS_SIZE;
rxsize = 1;
if (WARN_ON(txsize > 20))
@@ -611,7 +612,7 @@
case DP_AUX_NATIVE_READ:
case DP_AUX_I2C_READ:
- txsize = HEADER_SIZE;
+ txsize = msg->size ? HEADER_SIZE : BARE_ADDRESS_SIZE;
rxsize = msg->size + 1;
if (WARN_ON(rxsize > 20))