The RAVB module on Gen4 have no gPTP clock as part of the RAVB module itself, instead it relies on an external system wide gPTP clock. The gPTP clock is shared with RTSN on V4H and RSWITCH on S4. Add an optional phandle so that the RAVB driver can find and use the gPTP clock. Ideally this should have been a mandatory property but for backward compatible it is optional. The RAVB module is capable of functioning without it, but can in such cases not provided PTP functionality. Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se> Reviewed-by: Sergey Shtylyov <sergei.shtylyov@gmail.com> Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com> Link: https://patch.msgid.link/20260921175037.4084310-10-niklas.soderlund+renesas@ragnatech.se Signed-off-by: Jakub Kicinski <kuba@kernel.org>