video: da8xx-fb: reset LCDC only if functional clock changes with DVFS

LCDC functional clock may or may not be derived from CPU/MPU DPLL,
For example,
AM335x => Separate independent DPLL for LCDC
Davinci => Same DPLL as MPU

So, on platforms where LCDC functional clock is not derived from CPU/MPU
PLL it is not required to reset LCDC module as its functional clock does
not change with DVFS.

This patch adds check to do reset only if functional clock changes
between pre and post notifier callbacks with DVFS.

Signed-off-by: Manjunathappa, Prakash <prakash.pm@ti.com>
Signed-off-by: Florian Tobias Schandinat <FlorianSchandinat@gmx.de>

diff --git a/drivers/video/da8xx-fb.c b/drivers/video/da8xx-fb.c
index 29577bf1f559070044ee2c9f50d300d86745f78e..9ecc30744c6a765e994a6fd15c7d3ac708037f93 100644 (file)
--- a/drivers/video/da8xx-fb.c
+++ b/drivers/video/da8xx-fb.c
@@ -161,6 +161,7 @@ struct da8xx_fb_par {
        int                     vsync_timeout;
 #ifdef CONFIG_CPU_FREQ
        struct notifier_block   freq_transition;
+       unsigned int            lcd_fck_rate;
 #endif
        void (*panel_power_ctrl)(int);
 };
@@ -840,11 +841,13 @@ static int lcd_da8xx_cpufreq_transition(struct notifier_block *nb,
        struct da8xx_fb_par *par;
 
        par = container_of(nb, struct da8xx_fb_par, freq_transition);
-       if (val == CPUFREQ_PRECHANGE) {
-               lcd_disable_raster();
-       } else if (val == CPUFREQ_POSTCHANGE) {
-               lcd_calc_clk_divider(par);
-               lcd_enable_raster();
+       if (val == CPUFREQ_POSTCHANGE) {
+               if (par->lcd_fck_rate != clk_get_rate(par->lcdc_clk)) {
+                       par->lcd_fck_rate = clk_get_rate(par->lcdc_clk);
+                       lcd_disable_raster();
+                       lcd_calc_clk_divider(par);
+                       lcd_enable_raster();
+               }
        }
 
        return 0;
@@ -1137,6 +1140,9 @@ static int __devinit fb_probe(struct platform_device *device)
 
        par = da8xx_fb_info->par;
        par->lcdc_clk = fb_clk;
+#ifdef CONFIG_CPU_FREQ
+       par->lcd_fck_rate = clk_get_rate(fb_clk);
+#endif
        par->pxl_clk = lcdc_info->pxl_clk;
        if (fb_pdata->panel_power_ctrl) {
                par->panel_power_ctrl = fb_pdata->panel_power_ctrl;