OMAPDSS: PLL: add dss_pll_wait_reset_done()

Add a helper function to wait until the PLL's reset is done.
Signed-off-by: NTomi Valkeinen <tomi.valkeinen@ti.com>

drivers/video/fbdev/omap2/dss/dss.h

@@ -453,5 +453,6 @@ int dss_pll_write_config_type_a(struct dss_pll *pll,
 		const struct dss_pll_clock_info *cinfo);
 int dss_pll_write_config_type_b(struct dss_pll *pll,
 		const struct dss_pll_clock_info *cinfo);
+int dss_pll_wait_reset_done(struct dss_pll *pll);
 
 #endif

drivers/video/fbdev/omap2/dss/pll.c

@@ -222,6 +222,16 @@ static int wait_for_bit_change(void __iomem *reg, int bitnum, int value)
 	return !value;
 }
 
+int dss_pll_wait_reset_done(struct dss_pll *pll)
+{
+	void __iomem *base = pll->base;
+
+	if (wait_for_bit_change(base + PLL_STATUS, 0, 1) != 1)
+		return -ETIMEDOUT;
+	else
+		return 0;
+}
+
 static int dss_wait_hsdiv_ack(struct dss_pll *pll, u32 hsdiv_ack_mask)
 {
 	int t = 100;