drm/ast: Move DDC code to ast_ddc.{c,h}

Rename ast_i2c.c to ast_ddc.c and move its interface into the
new header ast_ddc.h. Update all include statements as necessary
and change the adapter name to 'AST DDC bus'.

This avoids including I2C headers in the driver's main header file,
which doesn't need them. Renaming files to _ddc indicates that the
code is about the DDC. I2C is really just the underlying bus here.
Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Reviewed-by: Sui Jingfeng <sui.jingfeng@linux.dev>
Reviewed-by: Jocelyn Falempe <jfalempe@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240325200855.21150-6-tzimmermann@suse.de

drivers/gpu/drm/ast/Makefile

@@ -3,6 +3,14 @@
 # Makefile for the drm device driver.  This driver provides support for the
 # Direct Rendering Infrastructure (DRI) in XFree86 4.1.0 and higher.
 
-ast-y := ast_drv.o ast_i2c.o ast_main.o ast_mm.o ast_mode.o ast_post.o ast_dp501.o ast_dp.o
+ast-y := \
+	ast_ddc.o \
+	ast_dp501.o \
+	ast_dp.o \
+	ast_drv.o \
+	ast_main.o \
+	ast_mm.o \
+	ast_mode.o \
+	ast_post.o
 
 obj-$(CONFIG_DRM_AST) := ast.o

drivers/gpu/drm/ast/ast_i2c.c → drivers/gpu/drm/ast/ast_ddc.c

@@ -24,6 +24,7 @@
 #include <drm/drm_managed.h>
 #include <drm/drm_print.h>
 
+#include "ast_ddc.h"
 #include "ast_drv.h"
 
 static void ast_i2c_setsda(void *i2c_priv, int data)
@@ -122,8 +123,7 @@ struct ast_i2c_chan *ast_i2c_create(struct drm_device *dev)
 	i2c->adapter.dev.parent = dev->dev;
 	i2c->dev = dev;
 	i2c_set_adapdata(&i2c->adapter, i2c);
-	snprintf(i2c->adapter.name, sizeof(i2c->adapter.name),
-		 "AST i2c bit bus");
+	snprintf(i2c->adapter.name, sizeof(i2c->adapter.name), "AST DDC bus");
 	i2c->adapter.algo_data = &i2c->bit;
 
 	i2c->bit.udelay = 20;

drivers/gpu/drm/ast/ast_ddc.h

+/* SPDX-License-Identifier: MIT */
+
+#ifndef __AST_DDC_H__
+#define __AST_DDC_H__
+
+#include <linux/i2c.h>
+#include <linux/i2c-algo-bit.h>
+
+struct drm_device;
+
+struct ast_i2c_chan {
+	struct i2c_adapter adapter;
+	struct drm_device *dev;
+	struct i2c_algo_bit_data bit;
+};
+
+struct ast_i2c_chan *ast_i2c_create(struct drm_device *dev);
+
+#endif

drivers/gpu/drm/ast/ast_drv.h

@@ -28,8 +28,6 @@
 #ifndef __AST_DRV_H__
 #define __AST_DRV_H__
 
-#include <linux/i2c.h>
-#include <linux/i2c-algo-bit.h>
 #include <linux/io.h>
 #include <linux/types.h>
 
@@ -149,15 +147,9 @@ static inline struct ast_plane *to_ast_plane(struct drm_plane *plane)
 }
 
 /*
- * Connector with i2c channel
+ * BMC
  */
 
-struct ast_i2c_chan {
-	struct i2c_adapter adapter;
-	struct drm_device *dev;
-	struct i2c_algo_bit_data bit;
-};
-
 struct ast_bmc_connector {
 	struct drm_connector base;
 	struct drm_connector *physical_connector;
@@ -476,9 +468,6 @@ bool ast_dp501_read_edid(struct drm_device *dev, u8 *ediddata);
 u8 ast_get_dp501_max_clk(struct drm_device *dev);
 void ast_init_3rdtx(struct drm_device *dev);
 
-/* ast_i2c.c */
-struct ast_i2c_chan *ast_i2c_create(struct drm_device *dev);
-
 /* aspeed DP */
 bool ast_astdp_is_connected(struct ast_device *ast);
 int ast_astdp_read_edid(struct drm_device *dev, u8 *ediddata);

drivers/gpu/drm/ast/ast_mode.c

@@ -46,6 +46,7 @@
 #include <drm/drm_probe_helper.h>
 #include <drm/drm_simple_kms_helper.h>
 
+#include "ast_ddc.h"
 #include "ast_drv.h"
 #include "ast_tables.h"