On Tue, 2018-12-11 at 21:29 +0100, Wolfram Sang wrote: > > + - ch-offset: base reg offset for multi-user. > > What is "multi-user"? Why can't you add this offset to the reg-property > directly? > Thanks for your comment. There are 3 channel in one MT8183 I3C controller, and every channel can be used as an I2C controller. Take the following diagram as example: If use I3C channels as I2C bus, 1. CH-A/B/C offset are different; 2. If use CH-B or CH-A as I2C, they must config registers which's address are in CH-A. ____________________________________ | ________ | | | |<--- offset:0x00 | | | CH-A | | | |________| | | | |<--- offset:0x100 | | | CH-B | | | |________| | | | |<--- offset:0x200 | | | CH-C | | | |________| | |____________________________________| one I3C controller Because of CH-B/CH-C depend on CH-A's register, it can't add offset to reg-property directly. MT8183 doesn't need to support muti-user according to the latest project information, and I'll remove this feature from patches. > > + - mediatek,share-i3c: i3c controller can share i2c function. > > Please explain in more detail? Is this an I3C controller? > Yes, it is a i3c controller, and it is compatible with i2c. I only use the feature of i2c, so I need a flag to do some extra settings.