The iphone chip is the A-series chip, which is independently developed by Apple.
On January 9, 2007, Steve Jobs introduced the first iPhone at Apple's annual Conference for Worldwide Software Developers 2007 at the Maesconi Convention Center in San Francisco. The two initial models, a 4GB version priced at 499 and an 8GB version priced at 599, went on sale in the United States at 6pm local time on June 29, 2007, with hundreds of Apple fans lining up outside Apple stores nationwide to get their hands on them. Due to the recent launch of the iPhone triggered a boom and sales response, some media hailed as God mobile phone.
The chips in Apple's phones are the A-series. Apple developed its own processor chip for the iPhone. It's currently the top chip. It works perfectly with the Apple system.