Commit 19423ba7 authored by Jianqun Xu's avatar Jianqun Xu Committed by Archit Taneja

drm/bridge: analogix_dp: return error if transfer none byte

Reference from drm_dp_aux description (about transfer):
Upon success, the implementation should return the number of payload bytes
that were transferred, or a negative error-code on failure. Helpers
propagate errors from the .transfer() function, with the exception of
the -EBUSY error, which causes a transaction to be retried. On a short,
helpers will return -EPROTO to make it simpler to check for failure.

The analogix_dp_transfer will return num_transferred, but if there is none
byte been transferred, the return value will be 0, which means success, we
should return error-code if transfer none byte.

for (retry = 0; retry < 32; retry++) {
	err = aux->transfer(aux, &msg);
	if (err < 0) {
		if (err == -EBUSY)
			continue;

		goto unlock;
	}
}

Cc: zain wang <wzz@rock-chips.com>
Reviewed-by: default avatarSean Paul <seanpaul@chromium.org>
Signed-off-by: default avatarJianqun Xu <jay.xu@rock-chips.com>
Signed-off-by: default avatarArchit Taneja <architt@codeaurora.org>
Link: http://patchwork.freedesktop.org/patch/msgid/1479255219-7243-1-git-send-email-jay.xu@rock-chips.com
parent b9876d50
...@@ -1162,5 +1162,5 @@ ssize_t analogix_dp_transfer(struct analogix_dp_device *dp, ...@@ -1162,5 +1162,5 @@ ssize_t analogix_dp_transfer(struct analogix_dp_device *dp,
(msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_NATIVE_READ) (msg->request & ~DP_AUX_I2C_MOT) == DP_AUX_NATIVE_READ)
msg->reply = DP_AUX_NATIVE_REPLY_ACK; msg->reply = DP_AUX_NATIVE_REPLY_ACK;
return num_transferred; return num_transferred > 0 ? num_transferred : -EBUSY;
} }
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