drm/i915: extract intel_acpi.h from i915_drv.h

It used to be handy that we only had a couple of headers, but over time
i915_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/9bc1317a67df0b9d019eca5b36f474b76a1cad26.1556809195.git.jani.nikula@intel.com

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

@@ -13,6 +13,7 @@ header_test := \
 	i915_reg.h \
 	i915_scheduler_types.h \
 	i915_timeline_types.h \
+	intel_acpi.h \
 	intel_atomic.h \
 	intel_atomic_plane.h \
 	intel_audio.h \

drivers/gpu/drm/i915/i915_drv.c

@@ -57,6 +57,7 @@
 #include "i915_query.h"
 #include "i915_trace.h"
 #include "i915_vgpu.h"
+#include "intel_acpi.h"
 #include "intel_audio.h"
 #include "intel_cdclk.h"
 #include "intel_csr.h"

drivers/gpu/drm/i915/i915_drv.h

@@ -3264,15 +3264,6 @@ static inline bool intel_gmbus_is_forced_bit(struct i2c_adapter *adapter)
 }
 extern void intel_i2c_reset(struct drm_i915_private *dev_priv);
 
-/* intel_acpi.c */
-#ifdef CONFIG_ACPI
-extern void intel_register_dsm_handler(void);
-extern void intel_unregister_dsm_handler(void);
-#else
-static inline void intel_register_dsm_handler(void) { return; }
-static inline void intel_unregister_dsm_handler(void) { return; }
-#endif /* CONFIG_ACPI */
-
 /* intel_device_info.c */
 static inline struct intel_device_info *
 mkwrite_device_info(struct drm_i915_private *dev_priv)

drivers/gpu/drm/i915/intel_acpi.c

@@ -4,9 +4,12 @@
  *
  * _DSM related code stolen from nouveau_acpi.c.
  */
+
 #include <linux/pci.h>
 #include <linux/acpi.h>
+
 #include "i915_drv.h"
+#include "intel_acpi.h"
 
 #define INTEL_DSM_REVISION_ID 1 /* For Calpella anyway... */
 #define INTEL_DSM_FN_PLATFORM_MUX_INFO 1 /* No args */

drivers/gpu/drm/i915/intel_acpi.h

@@ -0,0 +1,17 @@
+/* SPDX-License-Identifier: MIT */
+/*
+ * Copyright © 2019 Intel Corporation
+ */
+
+#ifndef __INTEL_ACPI_H__
+#define __INTEL_ACPI_H__
+
+#ifdef CONFIG_ACPI
+void intel_register_dsm_handler(void);
+void intel_unregister_dsm_handler(void);
+#else
+static inline void intel_register_dsm_handler(void) { return; }
+static inline void intel_unregister_dsm_handler(void) { return; }
+#endif /* CONFIG_ACPI */
+
+#endif /* __INTEL_ACPI_H__ */

drivers/gpu/drm/i915/intel_display.c

@@ -47,6 +47,7 @@
 #include "i915_drv.h"
 #include "i915_gem_clflush.h"
 #include "i915_trace.h"
+#include "intel_acpi.h"
 #include "intel_atomic.h"
 #include "intel_atomic_plane.h"
 #include "intel_color.h"