ble: ap807: improve PLL configuration sequence

Update PLL configuration according to HW team guidelines.

Change-Id: I23cac4fb4a638e7416965a5399ce6947e08d0711
Signed-off-by: Alex Leibovich <alexl@marvell.com>

drivers/marvell/ap807_clocks_init.c

@@ -39,14 +39,29 @@
 #define AP807_CPU_PLL_PARAM(cluster)	AP807_CPU_PLL_CTRL(cluster)
 #define AP807_CPU_PLL_CFG(cluster)	(AP807_CPU_PLL_CTRL(cluster) + 0x4)
 #define AP807_CPU_PLL_CFG_BYPASS_MODE	(0x1)
+#define AP807_CPU_PLL_FRC_DSCHG		(0x2)
 #define AP807_CPU_PLL_CFG_USE_REG_FILE	(0x1 << 9)
 
 static void pll_set_freq(unsigned int freq_val)
 {
 	int i;
 
+	if (freq_val != PLL_FREQ_2200)
+		return;
+
 	for (i = 0 ; i < AP807_CLUSTER_NUM ; i++) {
+		/* Set parameter of cluster i PLL to 2.2GHz */
 		mmio_write_32(AP807_CPU_PLL_PARAM(i), freq_val);
+		/* Set apll_lpf_frc_dschg - Control
+		 * voltage of internal VCO is discharged
+		 */
+		mmio_write_32(AP807_CPU_PLL_CFG(i),
+				AP807_CPU_PLL_FRC_DSCHG);
+		/* Set use_rf_conf  load PLL parameter from register */
+		mmio_write_32(AP807_CPU_PLL_CFG(i),
+				AP807_CPU_PLL_FRC_DSCHG |
+				AP807_CPU_PLL_CFG_USE_REG_FILE);
+		/* Un-set apll_lpf_frc_dschg */
 		mmio_write_32(AP807_CPU_PLL_CFG(i),
 			      AP807_CPU_PLL_CFG_USE_REG_FILE);
 	}