mx5 clocks: Fix get_periph_clk()

In the case periph_clk comes from periph_apm_clk, the latter is selected by the
CCM.CBCMR.periph_apm_sel mux, which can source the lp_apm clock from its
input ♯2. get_periph_clk() returned 0 instead of the lp_apm clock frequency in
this case.

Signed-off-by: Benoît Thébaudeau <benoit.thebaudeau@advansee.com>
Cc: Stefano Babic <sbabic@denx.de>

arch/arm/cpu/armv7/mx5/clock.c

@@ -239,6 +239,26 @@ static u32 get_fpm(void)
 }
 #endif
 
+/*
+ * This function returns the low power audio clock.
+ */
+static u32 get_lp_apm(void)
+{
+	u32 ret_val = 0;
+	u32 ccsr = readl(&mxc_ccm->ccsr);
+
+	if (ccsr & MXC_CCM_CCSR_LP_APM)
+#if defined(CONFIG_MX51)
+		ret_val = get_fpm();
+#elif defined(CONFIG_MX53)
+		ret_val = decode_pll(mxc_plls[PLL4_CLOCK], MXC_HCLK);
+#endif
+	else
+		ret_val = MXC_HCLK;
+
+	return ret_val;
+}
+
 /*
  * Get mcu main rate
  */
@@ -267,6 +287,8 @@ u32 get_periph_clk(void)
 		return decode_pll(mxc_plls[PLL1_CLOCK], MXC_HCLK);
 	case 1:
 		return decode_pll(mxc_plls[PLL3_CLOCK], MXC_HCLK);
+	case 2:
+		return get_lp_apm();
 	default:
 		return 0;
 	}
@@ -335,26 +357,6 @@ static u32 get_uart_clk(void)
 	return freq;
 }
 
-/*
- * This function returns the low power audio clock.
- */
-static u32 get_lp_apm(void)
-{
-	u32 ret_val = 0;
-	u32 ccsr = readl(&mxc_ccm->ccsr);
-
-	if (ccsr & MXC_CCM_CCSR_LP_APM)
-#if defined(CONFIG_MX51)
-		ret_val = get_fpm();
-#elif defined(CONFIG_MX53)
-		ret_val = decode_pll(mxc_plls[PLL4_CLOCK], MXC_HCLK);
-#endif
-	else
-		ret_val = MXC_HCLK;
-
-	return ret_val;
-}
-
 /*
  * get cspi clock rate.
  */