platform/chrome: cros_ec_lightbar: Use cros_ec_cmd_xfer_status helper

This patch makes use of cros_ec_cmd_xfer_status() instead of
cros_ec_cmd_xfer(). It allows us to remove some redundand code. In this
case, though, we are changing a bit the behaviour because of returning
-EINVAL on protocol error we propagate the error return for
cros_ec_cmd_xfer_status() function, but I think it will be fine, even
more clear as we don't mask the Linux error code.
Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com>
Tested-by: Prashant Malani <pmalani@chromium.org>

drivers/platform/chrome/cros_ec_lightbar.c

@@ -116,7 +116,7 @@ static int get_lightbar_version(struct cros_ec_dev *ec,
 
 	param = (struct ec_params_lightbar *)msg->data;
 	param->cmd = LIGHTBAR_CMD_VERSION;
-	ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
+	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
 	if (ret < 0) {
 		ret = 0;
 		goto exit;
@@ -193,15 +193,10 @@ static ssize_t brightness_store(struct device *dev,
 	if (ret)
 		goto exit;
 
-	ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
+	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
 	if (ret < 0)
 		goto exit;
 
-	if (msg->result != EC_RES_SUCCESS) {
-		ret = -EINVAL;
-		goto exit;
-	}
-
 	ret = count;
 exit:
 	kfree(msg);
@@ -258,13 +253,10 @@ static ssize_t led_rgb_store(struct device *dev, struct device_attribute *attr,
 					goto exit;
 			}
 
-			ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
+			ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
 			if (ret < 0)
 				goto exit;
 
-			if (msg->result != EC_RES_SUCCESS)
-				goto exit;
-
 			i = 0;
 			ok = 1;
 		}
@@ -305,14 +297,13 @@ static ssize_t sequence_show(struct device *dev,
 	if (ret)
 		goto exit;
 
-	ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
-	if (ret < 0)
-		goto exit;
-
-	if (msg->result != EC_RES_SUCCESS) {
+	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
+	if (ret == -EPROTO) {
 		ret = scnprintf(buf, PAGE_SIZE,
 				"ERROR: EC returned %d\n", msg->result);
 		goto exit;
+	} else if (ret < 0) {
+		goto exit;
 	}
 
 	resp = (struct ec_response_lightbar *)msg->data;
@@ -344,13 +335,10 @@ static int lb_send_empty_cmd(struct cros_ec_dev *ec, uint8_t cmd)
 	if (ret)
 		goto error;
 
-	ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
+	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
 	if (ret < 0)
 		goto error;
-	if (msg->result != EC_RES_SUCCESS) {
-		ret = -EINVAL;
-		goto error;
-	}
+
 	ret = 0;
 error:
 	kfree(msg);
@@ -377,13 +365,10 @@ static int lb_manual_suspend_ctrl(struct cros_ec_dev *ec, uint8_t enable)
 	if (ret)
 		goto error;
 
-	ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
+	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
 	if (ret < 0)
 		goto error;
-	if (msg->result != EC_RES_SUCCESS) {
-		ret = -EINVAL;
-		goto error;
-	}
+
 	ret = 0;
 error:
 	kfree(msg);
@@ -425,15 +410,10 @@ static ssize_t sequence_store(struct device *dev, struct device_attribute *attr,
 	if (ret)
 		goto exit;
 
-	ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
+	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
 	if (ret < 0)
 		goto exit;
 
-	if (msg->result != EC_RES_SUCCESS) {
-		ret = -EINVAL;
-		goto exit;
-	}
-
 	ret = count;
 exit:
 	kfree(msg);
@@ -487,13 +467,9 @@ static ssize_t program_store(struct device *dev, struct device_attribute *attr,
 	 */
 	msg->outsize = count + extra_bytes;
 
-	ret = cros_ec_cmd_xfer(ec->ec_dev, msg);
+	ret = cros_ec_cmd_xfer_status(ec->ec_dev, msg);
 	if (ret < 0)
 		goto exit;
-	if (msg->result != EC_RES_SUCCESS) {
-		ret = -EINVAL;
-		goto exit;
-	}
 
 	ret = count;
 exit: