video: fbdev: ssd1307fb: Extract ssd1307fb_set_{col,page}_range()

Extract the code to set the column and page ranges into two helper
functions.
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Acked-by: Sam Ravnborg <sam@ravnborg.org>
Signed-off-by: Sam Ravnborg <sam@ravnborg.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20210727134730.3765898-4-geert@linux-m68k.org

drivers/video/fbdev/ssd1307fb.c

@@ -152,6 +152,40 @@ static inline int ssd1307fb_write_cmd(struct i2c_client *client, u8 cmd)
 	return ret;
 }
 
+static int ssd1307fb_set_col_range(struct ssd1307fb_par *par, u8 col_start,
+				   u8 cols)
+{
+	u8 col_end = col_start + cols - 1;
+	int ret;
+
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COL_RANGE);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client, col_start);
+	if (ret < 0)
+		return ret;
+
+	return ssd1307fb_write_cmd(par->client, col_end);
+}
+
+static int ssd1307fb_set_page_range(struct ssd1307fb_par *par, u8 page_start,
+				    u8 pages)
+{
+	u8 page_end = page_start + pages - 1;
+	int ret;
+
+	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PAGE_RANGE);
+	if (ret < 0)
+		return ret;
+
+	ret = ssd1307fb_write_cmd(par->client, page_start);
+	if (ret < 0)
+		return ret;
+
+	return ssd1307fb_write_cmd(par->client, page_end);
+}
+
 static int ssd1307fb_update_display(struct ssd1307fb_par *par)
 {
 	struct ssd1307fb_array *array;
@@ -462,30 +496,13 @@ static int ssd1307fb_init(struct ssd1307fb_par *par)
 		return ret;
 
 	/* Set column range */
-	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_COL_RANGE);
-	if (ret < 0)
-		return ret;
-
-	ret = ssd1307fb_write_cmd(par->client, par->col_offset);
-	if (ret < 0)
-		return ret;
-
-	ret = ssd1307fb_write_cmd(par->client, par->col_offset + par->width - 1);
+	ret = ssd1307fb_set_col_range(par, par->col_offset, par->width);
 	if (ret < 0)
 		return ret;
 
 	/* Set page range */
-	ret = ssd1307fb_write_cmd(par->client, SSD1307FB_SET_PAGE_RANGE);
-	if (ret < 0)
-		return ret;
-
-	ret = ssd1307fb_write_cmd(par->client, par->page_offset);
-	if (ret < 0)
-		return ret;
-
-	ret = ssd1307fb_write_cmd(par->client,
-				  par->page_offset +
-				  DIV_ROUND_UP(par->height, 8) - 1);
+	ret = ssd1307fb_set_page_range(par, par->page_offset,
+				       DIV_ROUND_UP(par->height, 8));
 	if (ret < 0)
 		return ret;