drm/probe-helper: Add drm_connector_helper_get_modes_fixed()

Add drm_connector_helper_get_modes_fixed(), which duplicates a single
display mode for a connector. Convert drivers.

v2:
	* rename 'static' and 'hw' to 'fixed' everywhere
	* fix typo 'there' to 'their' (Sam)
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20220905141648.22013-2-tzimmermann@suse.de

drivers/gpu/drm/drm_mipi_dbi.c

@@ -415,26 +415,8 @@ EXPORT_SYMBOL(mipi_dbi_pipe_disable);
 static int mipi_dbi_connector_get_modes(struct drm_connector *connector)
 {
 	struct mipi_dbi_dev *dbidev = drm_to_mipi_dbi_dev(connector->dev);
-	struct drm_display_mode *mode;
 
-	mode = drm_mode_duplicate(connector->dev, &dbidev->mode);
-	if (!mode) {
-		DRM_ERROR("Failed to duplicate mode\n");
-		return 0;
-	}
-
-	if (mode->name[0] == '\0')
-		drm_mode_set_name(mode);
-
-	mode->type |= DRM_MODE_TYPE_PREFERRED;
-	drm_mode_probed_add(connector, mode);
-
-	if (mode->width_mm) {
-		connector->display_info.width_mm = mode->width_mm;
-		connector->display_info.height_mm = mode->height_mm;
-	}
-
-	return 1;
+	return drm_connector_helper_get_modes_fixed(connector, &dbidev->mode);
 }
 
 static const struct drm_connector_helper_funcs mipi_dbi_connector_hfuncs = {

drivers/gpu/drm/drm_probe_helper.c

@@ -1050,6 +1050,46 @@ int drm_connector_helper_get_modes_from_ddc(struct drm_connector *connector)
 }
 EXPORT_SYMBOL(drm_connector_helper_get_modes_from_ddc);
 
+/**
+ * drm_connector_helper_get_modes_fixed - Duplicates a display mode for a connector
+ * @connector: the connector
+ * @fixed_mode: the display hardware's mode
+ *
+ * This function duplicates a display modes for a connector. Drivers for hardware
+ * that only supports a single fixed mode can use this function in their connector's
+ * get_modes helper.
+ *
+ * Returns:
+ * The number of created modes.
+ */
+int drm_connector_helper_get_modes_fixed(struct drm_connector *connector,
+					 const struct drm_display_mode *fixed_mode)
+{
+	struct drm_device *dev = connector->dev;
+	struct drm_display_mode *mode;
+
+	mode = drm_mode_duplicate(dev, fixed_mode);
+	if (!mode) {
+		drm_err(dev, "Failed to duplicate mode " DRM_MODE_FMT "\n",
+			DRM_MODE_ARG(fixed_mode));
+		return 0;
+	}
+
+	if (mode->name[0] == '\0')
+		drm_mode_set_name(mode);
+
+	mode->type |= DRM_MODE_TYPE_PREFERRED;
+	drm_mode_probed_add(connector, mode);
+
+	if (mode->width_mm)
+		connector->display_info.width_mm = mode->width_mm;
+	if (mode->height_mm)
+		connector->display_info.height_mm = mode->height_mm;
+
+	return 1;
+}
+EXPORT_SYMBOL(drm_connector_helper_get_modes_fixed);
+
 /**
  * drm_connector_helper_get_modes - Read EDID and update connector.
  * @connector: The connector

drivers/gpu/drm/tiny/repaper.c

@@ -839,22 +839,8 @@ static const struct drm_simple_display_pipe_funcs repaper_pipe_funcs = {
 static int repaper_connector_get_modes(struct drm_connector *connector)
 {
 	struct repaper_epd *epd = drm_to_epd(connector->dev);
-	struct drm_display_mode *mode;
 
-	mode = drm_mode_duplicate(connector->dev, epd->mode);
-	if (!mode) {
-		DRM_ERROR("Failed to duplicate mode\n");
-		return 0;
-	}
-
-	drm_mode_set_name(mode);
-	mode->type |= DRM_MODE_TYPE_PREFERRED;
-	drm_mode_probed_add(connector, mode);
-
-	connector->display_info.width_mm = mode->width_mm;
-	connector->display_info.height_mm = mode->height_mm;
-
-	return 1;
+	return drm_connector_helper_get_modes_fixed(connector, epd->mode);
 }
 
 static const struct drm_connector_helper_funcs repaper_connector_hfuncs = {

drivers/gpu/drm/tiny/simpledrm.c

@@ -620,24 +620,8 @@ static const struct drm_encoder_funcs simpledrm_encoder_funcs = {
 static int simpledrm_connector_helper_get_modes(struct drm_connector *connector)
 {
 	struct simpledrm_device *sdev = simpledrm_device_of_dev(connector->dev);
-	struct drm_display_mode *mode;
 
-	mode = drm_mode_duplicate(connector->dev, &sdev->mode);
-	if (!mode)
-		return 0;
-
-	if (mode->name[0] == '\0')
-		drm_mode_set_name(mode);
-
-	mode->type |= DRM_MODE_TYPE_PREFERRED;
-	drm_mode_probed_add(connector, mode);
-
-	if (mode->width_mm)
-		connector->display_info.width_mm = mode->width_mm;
-	if (mode->height_mm)
-		connector->display_info.height_mm = mode->height_mm;
-
-	return 1;
+	return drm_connector_helper_get_modes_fixed(connector, &sdev->mode);
 }
 
 static const struct drm_connector_helper_funcs simpledrm_connector_helper_funcs = {

include/drm/drm_probe_helper.h

@@ -7,6 +7,7 @@
 
 struct drm_connector;
 struct drm_device;
+struct drm_display_mode;
 struct drm_modeset_acquire_ctx;
 
 int drm_helper_probe_single_connector_modes(struct drm_connector
@@ -27,6 +28,8 @@ void drm_kms_helper_poll_enable(struct drm_device *dev);
 bool drm_kms_helper_is_poll_worker(void);
 
 int drm_connector_helper_get_modes_from_ddc(struct drm_connector *connector);
+int drm_connector_helper_get_modes_fixed(struct drm_connector *connector,
+					 const struct drm_display_mode *fixed_mode);
 int drm_connector_helper_get_modes(struct drm_connector *connector);
 
 #endif