OMAPDSS: DISPC: add new clock calculation code

Add new way to iterate over DISPC clock divisors. dispc_div_calc()
provides a generic way to go over all the divisors, within given pixel
clock range. dispc_div_calc() will call a callback function for each
divider set, making the function reusable for all use cases.

Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
diff --git a/drivers/video/omap2/dss/dss.h b/drivers/video/omap2/dss/dss.h
index 610c8e5..0ff41dd 100644
--- a/drivers/video/omap2/dss/dss.h
+++ b/drivers/video/omap2/dss/dss.h
@@ -376,6 +376,12 @@
 void dispc_enable_gamma_table(bool enable);
 void dispc_set_loadmode(enum omap_dss_load_mode mode);
 
+typedef bool (*dispc_div_calc_func)(int lckd, int pckd, unsigned long lck,
+		unsigned long pck, void *data);
+bool dispc_div_calc(unsigned long dispc,
+		unsigned long pck_min, unsigned long pck_max,
+		dispc_div_calc_func func, void *data);
+
 bool dispc_mgr_timings_ok(enum omap_channel channel,
 		const struct omap_video_timings *timings);
 unsigned long dispc_fclk_rate(void);