[PATCH v2 0/3] ARM: mediatek: Add driver for Mediatek I2C controller

[wsa@the-dreams.de (Wolfram Sang)]

> MTK I2C HW has some limitation.
> 1. If the i2c_msg number is more than one, STOP will be issued instead of
> RS(Repeat Start) between each message.
> 
> 2. Mediatek I2C controller support WRRD(write then read) mode, in WRRD
> mode the Repeat Start will be issued between 2 messages.
> In this driver if 2 messages is first write then read, the driver will
> combine 2 messages using Write-Read mode so the RS will be issued between
> the 2 messages.
> Ex: W/R/R, driver will combine first W/R and then R.
> 
> 3. Due to HW limitation, in this version the max transfer data length is 255
> in one message.

This looks to me more like an SMBUS controller instead of I2C. Maybe you
should populate smbus_xfer rather than master_xfer?

> MT8135 and MT6589 can control I2C pins on PMIC(MT6397) by setting the i2c
> registers in MT8135 side.

I still didn't get this, even after reading the mail thread of old
series. Can someone maybe draw me a nice ASCII picture showing the setup
which is going on here?

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