i.MX6UL - I2C1 and UART4 pin conflict?

[jsopenrb]

Using kernel 4.4, I cannot get I2C1 and UART4 working together on i.MX6UL EVK. As soon as UART4 is enabled in device tree, I2C1 stops working. I2C1 is working correctly both in kernel with UART4 disabled and in u-boot.

Device tree config:

MX6UL_PAD_CSI_MCLK__I2C1_SDA 0x4001b8b1

MX6UL_PAD_CSI_PIXCLK__I2C1_SCL 0x4001b8b1

MX6UL_PAD_UART4_TX_DATA__UART4_DCE_TX 0x1f0b1

MX6UL_PAD_UART4_RX_DATA__UART4_DCE_RX 0x1f0b1

[jsopenrb]

Hi igor, thanks for your replay.

Indeed, EVK uses UART4 pins for I2C1, but that's not what I'm trying to achieve. I want to use UART4 pins for UART and CSI_MCLK/CSI_PIXCLK for I2C1. According to docs this should be possible, but it looks like there's some extra configuration missing somewhere, daisy chain config perhaps? There's some info on UART7/8 usage, maybe something similar is required:

How-To use UART7/8 on i.MX6UL

[igorpadykov]

Hi J

4.4 kernel is not officially supported yet, could you try with latest official 3.14.52 release

Board Support Packages (29)

L3.14.52_1.1.0_MX6QDLSOLO (REV L3.14.52_1.1.0)

http://www.nxp.com/products/microcontrollers-and-processors/arm-processors/i.mx-applications-process...

~igor

[igorpadykov]

Hi J

seems you are right as UART4 signals are used as I2C for sensors on EVK schematic:

Schematics (1)

MCIMX6UL-EVK_DESIGNFILES

Design files, including hardware schematics, Gerbers, and OrCAD files. (REV 0)

http://www.nxp.com/products/sensors/gyroscopes/i.mx6ultralite-evaluation-kit:MCIMX6UL-EVK?fpsp=1&tab...

Best regards

igor

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