drm: add backwards compatibility support for drm_kms_helper.edid_firmware

Add drm_kms_helper.edid_firmware module parameter with param ops hooks
to set drm.edid_firmware instead, for backwards compatibility.
Suggested-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Cc: Abdiel Janulgue <abdiel.janulgue@linux.intel.com>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Acked-by: Dave Airlie <airlied@gmail.com>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20170918182003.22238-2-jani.nikula@intel.com

drivers/gpu/drm/drm_edid_load.c

@@ -31,6 +31,22 @@ module_param_string(edid_firmware, edid_firmware, sizeof(edid_firmware), 0644);
 MODULE_PARM_DESC(edid_firmware, "Do not probe monitor, use specified EDID blob "
 	"from built-in data or /lib/firmware instead. ");
 
+/* Use only for backward compatibility with drm_kms_helper.edid_firmware */
+int __drm_set_edid_firmware_path(const char *path)
+{
+	scnprintf(edid_firmware, sizeof(edid_firmware), "%s", path);
+
+	return 0;
+}
+EXPORT_SYMBOL(__drm_set_edid_firmware_path);
+
+/* Use only for backward compatibility with drm_kms_helper.edid_firmware */
+int __drm_get_edid_firmware_path(char *buf, size_t bufsize)
+{
+	return scnprintf(buf, bufsize, "%s", edid_firmware);
+}
+EXPORT_SYMBOL(__drm_get_edid_firmware_path);
+
 #define GENERIC_EDIDS 6
 static const char * const generic_edid_name[GENERIC_EDIDS] = {
 	"edid/800x600.bin",

drivers/gpu/drm/drm_kms_helper_common.c

@@ -26,6 +26,7 @@
  */
 
 #include <linux/module.h>
+#include <drm/drmP.h>
 
 #include "drm_crtc_helper_internal.h"
 
@@ -33,6 +34,33 @@ MODULE_AUTHOR("David Airlie, Jesse Barnes");
 MODULE_DESCRIPTION("DRM KMS helper");
 MODULE_LICENSE("GPL and additional rights");
 
+#if IS_ENABLED(CONFIG_DRM_LOAD_EDID_FIRMWARE)
+
+/* Backward compatibility for drm_kms_helper.edid_firmware */
+static int edid_firmware_set(const char *val, const struct kernel_param *kp)
+{
+	DRM_NOTE("drm_kms_firmware.edid_firmware is deprecated, please use drm.edid_firmware intead.\n");
+
+	return __drm_set_edid_firmware_path(val);
+}
+
+static int edid_firmware_get(char *buffer, const struct kernel_param *kp)
+{
+	return __drm_get_edid_firmware_path(buffer, PAGE_SIZE);
+}
+
+static const struct kernel_param_ops edid_firmware_ops = {
+	.set = edid_firmware_set,
+	.get = edid_firmware_get,
+};
+
+module_param_cb(edid_firmware, &edid_firmware_ops, NULL, 0644);
+__MODULE_PARM_TYPE(edid_firmware, "charp");
+MODULE_PARM_DESC(edid_firmware,
+		 "DEPRECATED. Use drm.edid_firmware module parameter instead.");
+
+#endif
+
 static int __init drm_kms_helper_init(void)
 {
 	int ret;

include/drm/drm_edid.h

@@ -341,6 +341,8 @@ int drm_av_sync_delay(struct drm_connector *connector,
 
 #ifdef CONFIG_DRM_LOAD_EDID_FIRMWARE
 struct edid *drm_load_edid_firmware(struct drm_connector *connector);
+int __drm_set_edid_firmware_path(const char *path);
+int __drm_get_edid_firmware_path(char *buf, size_t bufsize);
 #else
 static inline struct edid *
 drm_load_edid_firmware(struct drm_connector *connector)