fbdev: sh_mobile_hdmi: add support for more precise HDMI clock configuration

The HDMI clock has to be reconfigured for different video modes. However, the
precision of the supplying SoC clock on SH-Mobile systems is often
insufficient. This patch allows to additionally reconfigure the parent clock
to achieve the optimal HDMI clock frequency, in case this is supported by the
platform.

Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
diff --git a/include/video/sh_mobile_hdmi.h b/include/video/sh_mobile_hdmi.h
index 1e1aa54..b569329 100644
--- a/include/video/sh_mobile_hdmi.h
+++ b/include/video/sh_mobile_hdmi.h
@@ -13,6 +13,7 @@
 
 struct sh_mobile_lcdc_chan_cfg;
 struct device;
+struct clk;
 
 /*
  * flags format
@@ -33,6 +34,8 @@
 	struct sh_mobile_lcdc_chan_cfg	*lcd_chan;
 	struct device			*lcd_dev;
 	unsigned int			 flags;
+	long (*clk_optimize_parent)(unsigned long target, unsigned long *best_freq,
+				    unsigned long *parent_freq);
 };
 
 #endif