“Inna’s themes are harvest, offering, protection, promises and justice. Her symbols are yams and harvested foods. In Nigeria, Inna ensures an abundant yam harvest for the Yam Festival, as well as good crops for farmers who honor Her. During the summer months, She appears as a protectress who oversees our lands, homes, promises and all matters of justice. Oaths taken in Inna’s name are totally binding.
Around the end of June, nearly every group in Nigeria celebrates the New Yam Festival with offerings to the Goddess and a feast of yams. This is a sacred crop here and eating yams today will purify your body and spirit. If you can’t find yams, try sweet potatoes instead, sprinkling them with a little brown sugar to ensure sweet rewards for your diligent efforts. To get the wheels of justice turning a little faster, forego the sugar and eat the potatoes steaming hot (heat represents motivating energy).
People traditionally practice yam divination today. You can try this yourself using any potato. Cut it in half the long way, then toss the two sides in the air while praying for Inna’s insight. If one lands face up and the other face down, it is a good sign for your family or the entire community in which you live. The coming year will be filled with Inna’s abundance and equity. To increase the meaning in this system, draw two personally significant symbolsin the potao and see if either comes up!”
(Patricia Telesco, “365 Goddess: a daily guide to the magic and inspiration of the goddess”.)
I could find no information on Inna other than that She is an African Goddess of Justice.  I found one Goddess by the name of Aha-Njoku (also called the “Lady of Yams), worshipped by the Igbo people of Nigeria, who oversees the growth and harvesting of yams and the women who care for them.  Perhaps a minor local deity or spirit? Or Perhaps somehow related to Goddess Ala?
Wikipedia, “Ahia Njoku“.