drm/udl: Various improvements to the connector

Add style fixes, better error handling and reporting, and minor
clean-up changes to the connector code before moving the code to
the rest of the modesetting pipeline.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Javier Martinez Canillas <javierm@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20221006095355.23579-5-tzimmermann@suse.de

drivers/gpu/drm/udl/udl_connector.c

@@ -15,56 +15,64 @@
 #include "udl_connector.h"
 #include "udl_drv.h"
 
-static int udl_get_edid_block(void *data, u8 *buf, unsigned int block,
-			       size_t len)
+static int udl_get_edid_block(void *data, u8 *buf, unsigned int block, size_t len)
 {
-	int ret, i;
-	u8 *read_buff;
 	struct udl_device *udl = data;
+	struct drm_device *dev = &udl->drm;
 	struct usb_device *udev = udl_to_usb_device(udl);
+	u8 *read_buff;
+	int ret;
+	size_t i;
 
 	read_buff = kmalloc(2, GFP_KERNEL);
 	if (!read_buff)
-		return -1;
+		return -ENOMEM;
 
 	for (i = 0; i < len; i++) {
 		int bval = (i + block * EDID_LENGTH) << 8;
+
 		ret = usb_control_msg(udev, usb_rcvctrlpipe(udev, 0),
 				      0x02, (0x80 | (0x02 << 5)), bval,
 				      0xA1, read_buff, 2, USB_CTRL_GET_TIMEOUT);
-		if (ret < 1) {
-			DRM_ERROR("Read EDID byte %d failed err %x\n", i, ret);
-			kfree(read_buff);
-			return -1;
+		if (ret < 0) {
+			drm_err(dev, "Read EDID byte %zu failed err %x\n", i, ret);
+			goto err_kfree;
+		} else if (ret < 1) {
+			ret = -EIO;
+			drm_err(dev, "Read EDID byte %zu failed\n", i);
+			goto err_kfree;
 		}
+
 		buf[i] = read_buff[1];
 	}
 
 	kfree(read_buff);
+
 	return 0;
+
+err_kfree:
+	kfree(read_buff);
+	return ret;
 }
 
-static int udl_get_modes(struct drm_connector *connector)
+static int udl_connector_helper_get_modes(struct drm_connector *connector)
 {
 	struct udl_connector *udl_connector = to_udl_connector(connector);
 
 	drm_connector_update_edid_property(connector, udl_connector->edid);
 	if (udl_connector->edid)
 		return drm_add_edid_modes(connector, udl_connector->edid);
+
 	return 0;
 }
 
-static enum drm_connector_status
-udl_detect(struct drm_connector *connector, bool force)
+static enum drm_connector_status udl_connector_detect(struct drm_connector *connector, bool force)
 {
 	struct udl_device *udl = to_udl(connector->dev);
 	struct udl_connector *udl_connector = to_udl_connector(connector);
 
-	/* cleanup previous edid */
-	if (udl_connector->edid != NULL) {
+	/* cleanup previous EDID */
 	kfree(udl_connector->edid);
-		udl_connector->edid = NULL;
-	}
 
 	udl_connector->edid = drm_do_get_edid(connector, udl_get_edid_block, udl);
 	if (!udl_connector->edid)
@@ -79,16 +87,16 @@ static void udl_connector_destroy(struct drm_connector *connector)
 
 	drm_connector_cleanup(connector);
 	kfree(udl_connector->edid);
-	kfree(connector);
+	kfree(udl_connector);
 }
 
 static const struct drm_connector_helper_funcs udl_connector_helper_funcs = {
-	.get_modes = udl_get_modes,
+	.get_modes = udl_connector_helper_get_modes,
 };
 
 static const struct drm_connector_funcs udl_connector_funcs = {
 	.reset = drm_atomic_helper_connector_reset,
-	.detect = udl_detect,
+	.detect = udl_connector_detect,
 	.fill_modes = drm_helper_probe_single_connector_modes,
 	.destroy = udl_connector_destroy,
 	.atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
@@ -99,18 +107,26 @@ struct drm_connector *udl_connector_init(struct drm_device *dev)
 {
 	struct udl_connector *udl_connector;
 	struct drm_connector *connector;
+	int ret;
 
 	udl_connector = kzalloc(sizeof(*udl_connector), GFP_KERNEL);
 	if (!udl_connector)
 		return ERR_PTR(-ENOMEM);
 
 	connector = &udl_connector->connector;
-	drm_connector_init(dev, connector, &udl_connector_funcs,
-			   DRM_MODE_CONNECTOR_VGA);
+	ret = drm_connector_init(dev, connector, &udl_connector_funcs, DRM_MODE_CONNECTOR_VGA);
+	if (ret)
+		goto err_kfree;
+
 	drm_connector_helper_add(connector, &udl_connector_helper_funcs);
 
 	connector->polled = DRM_CONNECTOR_POLL_HPD |
-		DRM_CONNECTOR_POLL_CONNECT | DRM_CONNECTOR_POLL_DISCONNECT;
+			    DRM_CONNECTOR_POLL_CONNECT |
+			    DRM_CONNECTOR_POLL_DISCONNECT;
 
 	return connector;
+
+err_kfree:
+	kfree(udl_connector);
+	return ERR_PTR(ret);
 }