is it enough to pass jee main to get seat in iit

Nope. First you need to clear MAINS than you need to clear JEE Advance with a good rank in order to get into IIT.
Clearing only MAINS will not help you to get into any IIT.
there will be a cutoff mark in Jee mains test which would be considered as the eligibility to sit in Jee Advanced exam….For Admission to IITS,only JEE ADVANCED marks will be considered….also one should score 75% or be in top 20 percentile in one's corresponding board exam.
but you can try for other prestigious colleges and university which consider mains marks for admission like nits ,iiits
and other private universities like thapar ,bits mesra etc also for that also you requires good rank in mains from next year you can give mains two times this is a good news for all the jee aspirants rest i will suggest you if you missed this time you can try for next time also