Enable LPIT for rt118x devices

1. Configure clock source for lpit3 for imxrt118x devices
2. Support lpit in clock driver

Signed-off-by: Felix Wang <fei.wang_3@nxp.com>

Author: FelixWang47831

drivers/clock_control/clock_control_mcux_ccm_rev2.c

@@ -256,7 +256,25 @@ static int mcux_ccm_get_subsys_rate(const struct device *dev,
 		clock_root = kCLOCK_Root_Bus + instance;
 		break;
 #endif
-
+#ifdef CONFIG_COUNTER_MCUX_LPIT
+#if defined(CONFIG_SOC_SERIES_IMXRT118X)
+	case IMX_CCM_LPIT_CLK:
+		switch (instance) {
+		case 0:
+			clock_root = kCLOCK_Root_Bus_Aon;
+			break;
+		case 1:
+			clock_root = kCLOCK_Root_Bus_Wakeup;
+			break;
+		case 2:
+			clock_root = kCLOCK_Root_Lpit3;
+			break;
+		default:
+			return -EINVAL;
+		}
+		break;
+#endif
+#endif
 #ifdef CONFIG_ADC_MCUX_LPADC
 	case IMX_CCM_LPADC1_CLK:
 		clock_root = kCLOCK_Root_Adc1 + instance;

include/zephyr/dt-bindings/clock/imx_ccm_rev2.h

@@ -149,6 +149,12 @@
 #define IMX_CCM_I3C1_CLK               0x2200UL
 #define IMX_CCM_I3C2_CLK               0x2201UL
 
+/* LPIT */
+#define IMX_CCM_LPIT_CLK                0x2300UL
+#define IMX_CCM_LPIT1_CLK               0x2300UL
+#define IMX_CCM_LPIT2_CLK               0x2301UL
+#define IMX_CCM_LPIT3_CLK               0x2302UL
+
 /* QTMR */
 #define IMX_CCM_QTMR_CLK               0x6000UL
 #define IMX_CCM_QTMR1_CLK              0x6000UL

soc/nxp/imxrt/imxrt118x/soc.c

@@ -596,6 +596,15 @@ __weak void clock_init(void)
 
 #endif /* CONFIG_IMX_USDHC */
 
+#ifdef CONFIG_COUNTER_MCUX_LPIT
+#if DT_NODE_HAS_STATUS(DT_NODELABEL(lpit3), okay)
+	/* Configure LPIT3 using SysPll3Div2 */
+	rootCfg.mux = kCLOCK_LPIT3_ClockRoot_MuxSysPll3Div2;
+	rootCfg.div = 3;
+	CLOCK_SetRootClock(kCLOCK_Root_Lpit3, &rootCfg);
+#endif
+#endif /* CONFIG_COUNTER_MCUX_LPIT */
+
 	/* Keep core clock ungated during WFI */
 	CCM->LPCG[1].LPM0 = 0x33333333;
 	CCM->LPCG[1].LPM1 = 0x33333333;