drm/i915: extract intel_dsi_dcs_backlight.h from intel_drv.h

It used to be handy that we only had a couple of headers, but over time
intel_drv.h has become unwieldy. Extract declarations to a separate
header file corresponding to the implementation module, clarifying the
modularity of the driver.

Ensure the new header is self-contained, and do so with minimal further
includes, using forward declarations as needed. Include the new header
only where needed, and sort the modified include directives while at it
and as needed.

No functional changes.
Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/f35fc2ba76d7dd5886d304ad690a6f9078a56ecd.1556540890.git.jani.nikula@intel.com

drivers/gpu/drm/i915/Makefile.header-test

@@ -29,6 +29,7 @@ header_test := \
 	intel_dpll_mgr.h \
 	intel_drv.h \
 	intel_dsi.h \
+	intel_dsi_dcs_backlight.h \
 	intel_dvo.h \
 	intel_dvo_dev.h \
 	intel_fbc.h \

drivers/gpu/drm/i915/intel_drv.h

@@ -1766,9 +1766,6 @@ unsigned int i9xx_plane_max_stride(struct intel_plane *plane,
 				   u32 pixel_format, u64 modifier,
 				   unsigned int rotation);
 
-/* intel_dsi_dcs_backlight.c */
-int intel_dsi_dcs_init_backlight_funcs(struct intel_connector *intel_connector);
-
 /* intel_runtime_pm.c */
 void intel_runtime_pm_init_early(struct drm_i915_private *dev_priv);
 int intel_power_domains_init(struct drm_i915_private *);

drivers/gpu/drm/i915/intel_dsi_dcs_backlight.c

@@ -23,11 +23,13 @@
  * Author: Deepak M <m.deepak at intel.com>
  */
 
+#include <drm/drm_mipi_dsi.h>
+#include <video/mipi_display.h>
+
+#include "i915_drv.h"
 #include "intel_drv.h"
 #include "intel_dsi.h"
-#include "i915_drv.h"
-#include <video/mipi_display.h>
-#include <drm/drm_mipi_dsi.h>
+#include "intel_dsi_dcs_backlight.h"
 
 #define CONTROL_DISPLAY_BCTRL		(1 << 5)
 #define CONTROL_DISPLAY_DD		(1 << 3)

drivers/gpu/drm/i915/intel_dsi_dcs_backlight.h

+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2019 Intel Corporation
+ */
+
+#ifndef __INTEL_DSI_DCS_BACKLIGHT_H__
+#define __INTEL_DSI_DCS_BACKLIGHT_H__
+
+struct intel_connector;
+
+int intel_dsi_dcs_init_backlight_funcs(struct intel_connector *intel_connector);
+
+#endif /* __INTEL_DSI_DCS_BACKLIGHT_H__ */

drivers/gpu/drm/i915/intel_panel.c

@@ -37,6 +37,7 @@
 #include "intel_connector.h"
 #include "intel_dp_aux_backlight.h"
 #include "intel_drv.h"
+#include "intel_dsi_dcs_backlight.h"
 #include "intel_panel.h"
 
 #define CRC_PMIC_PWM_PERIOD_NS	21333