RTC is not updating in RZ/G2L. RTC has no clock.

Dear Team,

                In our custom board based on rzg2l RTC is not updating as it does not produce 32768 khz which it is supposed to do. It sets time but not updating. But in the development board we found that there is clock and it is updating. We are using the same pmic raa215300 but in the custom board is on/off version pmic ie, RAA215300A2GNP#HA1 and in evaluation module RAA215300A2GNP#HA0 Long Push button type. These are bascally same pmic  other than on/off vs long push button. it is connected to i2c3 as shown in below.

&i2c3 {
	pinctrl-0 = <&i2c3_pins>;
	pinctrl-names = "default";
	clock-frequency = <400000>;

	status = "okay";

	pmic: raa215300@12 {
		compatible = "renesas,raa215300";
		reg = <0x12>;

	rtc: isl1208@6f {
		compatible = "isil,isl1208";
		reg = <0x6f>;

why  clock is updating in evaluation module but not in custom board? Please help