i.MX8M Mini Device Tree

oprata — Sat, 06 Feb 2021 01:36:22 GMT

Hello Folks!

I am trying to understand the device tree file of imx8mmevk board because I intend to make a change in the imx8mm-evk.dts file. At the file "fsl,imx8mm-pinctrl.txt" I saw that "fsl,pins" field has the format <PIN_FUNC_ID CONFIG>. The PIN_FUNC_ID field, I found at imx8mm-pinfunc.h file and the CONFIG field I found at "i.MX8M Mini Applications Processor Reference Manual, Rev. 2, 08/2019" document.

From "i.MX8M Mini Applications Processor Reference Manual, Rev. 2, 08/2019" document the CONFIG value has 9 bits. Like the example below

pinctrl_csi_rst: csi_rst_grp {
fsl,pins = <
MX8MM_IOMUXC_GPIO1_IO06_GPIO1_IO6 0x19
MX8MM_IOMUXC_GPIO1_IO14_CCMSRCGPCMIX_CLKO1 0x59
>;
};

pinctrl_ir_recv: ir-recv {
fsl,pins = <
MX8MM_IOMUXC_GPIO1_IO13_GPIO1_IO13 0x4f
>;
};

I would like to understand why the I2C pins doesn't use the same syntax of the other pins. Look the example below

pinctrl_i2c1: i2c1grp {
fsl,pins = <
MX8MM_IOMUXC_I2C1_SCL_I2C1_SCL 0x400001c3
MX8MM_IOMUXC_I2C1_SDA_I2C1_SDA 0x400001c3
>;
};

pinctrl_i2c2: i2c2grp {
fsl,pins = <
MX8MM_IOMUXC_I2C2_SCL_I2C2_SCL 0x400001c3
MX8MM_IOMUXC_I2C2_SDA_I2C2_SDA 0x400001c3
>;
};

pinctrl_i2c3: i2c3grp {
fsl,pins = <
MX8MM_IOMUXC_I2C3_SCL_I2C3_SCL 0x400001c3
MX8MM_IOMUXC_I2C3_SDA_I2C3_SDA 0x400001c3
>;
};

Does anybody can explain why I2C pin doesn't use the same form of the other pins at the device tree file?

Thanks in advance.

Re: i.MX8M Mini Device Tree

igorpadykov — Sat, 06 Feb 2021 04:26:42 GMT

Hi oprata

for i2c it is necessary to set SION bit, described in sect.8.2.3.3 SW Loopback through SION bit

i.MX 8M Mini Applications Processor Reference Manual

In device tree : "SION(1 << 30): Software Input On Field."

https://source.codeaurora.org/external/imx/linux-imx/tree/Documentation/devicetree/bindings/pinctrl/fsl,imx-pinctrl.txt?h=imx_5.4.70_2.3.0

Best regards
igor

i.MX Processorsのトピックi.MX8M Mini Device Tree

i.MX8M Mini Device Tree

Re: i.MX8M Mini Device Tree