Hello,
I am currently using yocto for the VAR-SOM-MX8M-MINI which uses the freescale imx8mm-var-som.dts file. In this file, the I2C2 SDA and SCL signals are defined with an input_val of 0x400001c3. However, referencing the IOMUXC_SW_PAD_CTL_PAD_I2C2_SCL register defined in the i.MX 8M Mini Applications Processor
Reference Manual (Rev 2.8/19), only bits 0-8 are valid.
My question is, why is bit 30 set in the DTS file? Is there a conflict with the documentation?
Solved! Go to Solution.
Hello,
Sorry I made a mistake about this, I misinterpreted your question, for pad configuration you should take a look to the devicetree documentation general and chips specific:
As per documentation (fsl,imx-pinctrl) is the following:
Bits used for CONFIG:
NO_PAD_CTL(1 << 31): indicate this pin does not need config.
SION(1 << 30): Software Input On Field.
Force the selected mux mode input path no matter of MUX_MODE functionality.
By default the input path is determined by functionality of the selected
mux mode (regular).
As for the first 9 bits, yes you're correct you may look to the Reference Manual for pad configuration.
Sorry for the confusion,
Best regards,
Aldo.
Hello,
This comes from the I2C binding, from the documentation available here:
https://source.codeaurora.org/external/imx/linux-imx/tree/Documentation/devicetree/bindings/i2c/i2c....
I2C_TEN_BIT_ADDRESS (1 << 31)
I2C_OWN_SLAVE_ADDRESS (1 << 30)
In this case would mean I2C is a 7 bit address and the I2C own slave address.
Hope this helps,
Best regards,
Aldo.
Thanks Aldo for your quick response!
Given this new information, am I still correct in thinking that the first 9-bits of this value still come from the i.MX 8M Mini Applications Processor Reference Manual as shown below?
In the future, how should I know which bits come from the reference manual, and which bits are defined by the device bindings?
Hello,
Sorry I made a mistake about this, I misinterpreted your question, for pad configuration you should take a look to the devicetree documentation general and chips specific:
As per documentation (fsl,imx-pinctrl) is the following:
Bits used for CONFIG:
NO_PAD_CTL(1 << 31): indicate this pin does not need config.
SION(1 << 30): Software Input On Field.
Force the selected mux mode input path no matter of MUX_MODE functionality.
By default the input path is determined by functionality of the selected
mux mode (regular).
As for the first 9 bits, yes you're correct you may look to the Reference Manual for pad configuration.
Sorry for the confusion,
Best regards,
Aldo.