Processors forum

Hi Wilson,

Do you have any issues with the other I2C buses?

Thanks,

Neehar

In my case, i2cdetect -r -y 0, i2cdetect -r -y 1 and i2cdetect -r -y 2 work normally. I get dump from them with no arbitration lost problem.

root@j721s2-evm:~# i2cdetect -r -y 0
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:                         -- -- -- -- -- -- -- --
10: -- -- -- 13 14 -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- 48 49 4a 4b 4c 4d 4e 4f
50: -- -- -- -- -- -- -- -- 58 59 5a 5b -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

root@j721s2-evm:~# i2cdetect -r -y 1
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:                         -- -- -- -- -- -- -- --
10: -- -- 12 -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- 48 -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

root@j721s2-evm:~# i2cdetect -r -y 2
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:                         -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

- Wilson

Hi Wilson,

Thanks for this information.

Can you provide the dts file where the pinmux is done? 

Thanks,

Neehar

Hi, Neehar,

Post main_i2c1 related DT below for reference.

1. kernel/arch/arm64/boot/dts/ti/k3-j721s2-common-proc-board.dts

&main_i2c0 {
    ...
};

&main_i2c1 {
	status = "okay";
	pinctrl-names = "default";
	pinctrl-0 = <&main_i2c1_pins_default>;
	clock-frequency = <400000>;
};

2. kernel/arch/arm64/boot/dts/ti/k3-j721s2-som-p0.dtsi

&main_pmx0 {
    ...
	
	main_i2c1_pins_default: main-i2c1-pins-default {
		pinctrl-single,pins = <
			J721S2_IOPAD(0x020, PIN_INPUT_PULLUP, 12) /* (AA23) I2C1_SCL */
			J721S2_IOPAD(0x024, PIN_INPUT_PULLUP, 12) /* (Y28) I2C1_SDA */
		>;
	};	
};

&main_i2c0 {
    ...
};

&main_i2c1 {
	status = "okay";
	pinctrl-names = "default";
	pinctrl-0 = <&main_i2c1_pins_default>;
	clock-frequency = <400000>;
};

&main_mcan16 {
	status = "disabled";
};

3. kernel/arch/arm64/boot/dts/ti/k3-j721s2-main.dtsi

	main_i2c1: i2c@2010000 {
		compatible = "ti,j721e-i2c", "ti,omap4-i2c";
		reg = <0x00 0x02010000 0x00 0x100>;
		interrupts = <GIC_SPI 201 IRQ_TYPE_LEVEL_HIGH>;
		#address-cells = <1>;
		#size-cells = <0>;
		clocks = <&k3_clks 215 1>;
		clock-names = "fck";
		power-domains = <&k3_pds 215 TI_SCI_PD_EXCLUSIVE>;
		status = "disabled";
	};

4. kernel/arch/arm64/boot/dts/ti/k3-j721s2-vision-apps.dtso

&main_i2c1 {
    status = "okay";
};

5. u-boot/arch/arm/dts/k3-j721s2-common-proc-board.dts

&main_i2c0 {
	...
};

&main_i2c1 {
	status = "okay";
};

6. u-boot/arch/arm/dts/k3-j721s2-main.dtsi

	main_i2c1: i2c@2010000 {
		compatible = "ti,j721e-i2c", "ti,omap4-i2c";
		reg = <0x00 0x02010000 0x00 0x100>;
		interrupts = <GIC_SPI 201 IRQ_TYPE_LEVEL_HIGH>;
		#address-cells = <1>;
		#size-cells = <0>;
		clocks = <&k3_clks 215 1>;
		clock-names = "fck";
		power-domains = <&k3_pds 215 TI_SCI_PD_EXCLUSIVE>;
	};

7. u-boot/arch/arm/dts/k3-j721s2-som-p0.dtsi

&main_i2c1 {
	pinctrl-names = "default";
	pinctrl-0 = <&main_i2c1_pins_default>;
	clock-frequency = <400000>;
};

&main_mcan16 {
	status = "disabled"; 
};

8. u-boot/arch/arm/dts/k3-j721s2-common-proc-board-u-boot.dtsi

	aliases {
        ...
		i2c0 = &wkup_i2c0;
		i2c1 = &mcu_i2c0;
		i2c2 = &main_i2c0;
		i2c3 = &main_i2c1;
        ...
	};

After power on, I also get these msgs:

[ 18.541707] platform mux-controller1: deferred probe pending
[ 18.547380] platform mux-controller0: deferred probe pending
[ 18.553037] platform 2910000.pcie: deferred probe pending
[ 18.558433] platform 4a00000.dss: deferred probe pending

- Wilson

Hi Wilson,

What devices do you have connected on the main_i2c1 bus? There may be an issue with timeout when communicating with the slave device.

Thanks,
Neehar

Hi, Neehar,

It's MAX96717. However, at this moment, as posted above, we have not declared any client device under main_i2c1 in the device tree yet. We suppose to get result from i2c1 similar to one from i2c0, don't we? For example,

root@j721s2-evm:~# i2cdetect -r -y 3
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:                         -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --

- Wilson

Hi Wilson,

Yes, this behavior should be expected. Are you using a custom board or J721S2 EVM?

Thanks,

Neehar

Hi, Neehar,

Yes. I am.

- Wilson

Hi Wilson,

Can you ensure balls AA23 and Y28 are not used elsewhere that may be causing conflicts? Or test by programming to a different ball such as AB26 and AD26. 
Thanks,

Neehar

Hi, Neehar,

Search for AA23 pinmux settings in the board-support/ sub-directory:

wilson@virtual-pc:~/tda4vl_9.2/tda4vl_linux_9.2$ grep -r "J721S2_IOPAD(0x020, " --include=k3-j721s2*.dts*
board-support/ti-u-boot-2023.04+gitAUTOINC+f9b966c674/arch/arm/dts/k3-j721s2-som-p0.dtsi:                    J721S2_IOPAD(0x020, PIN_INPUT_PULLUP, 12) /* (AA23) I2C1_SCL */
board-support/ti-linux-kernel-6.1.80+gitAUTOINC+2e423244f8-ti/arch/arm64/boot/dts/ti/k3-j721s2-common-proc-board.dts:                        J721S2_IOPAD(0x020, PIN_INPUT_PULLUP, 12) /* (AA23) I2C1_SCL */
wilson@virtual-pc:~/tda4vl_9.2/tda4vl_linux_9.2$ grep -r "J721S2_IOPAD(0x20, " --include=k3-j721s2*.dts*
wilson@virtual-pc:~/tda4vl_9.2/tda4vl_linux_9.2$

Search for Y28 pinmux settings in the board-support/ sub-directory:

wilson@virtual-pc:~tda4vl_9.2/tda4vl_linux_9.2$ grep -r "J721S2_IOPAD(0x024," --include=k3-j721s2*.dts*
board-support/ti-u-boot-2023.04+gitAUTOINC+f9b966c674/arch/arm/dts/k3-j721s2-som-p0.dtsi:                    J721S2_IOPAD(0x024, PIN_INPUT_PULLUP, 12) /* (Y28) I2C1_SDA */
board-support/ti-linux-kernel-6.1.80+gitAUTOINC+2e423244f8-ti/arch/arm64/boot/dts/ti/k3-j721s2-common-proc-board.dts:                        J721S2_IOPAD(0x024, PIN_INPUT_PULLUP, 12) /* (Y28) I2C1_SDA */
wilson@virtual-pc:~/tda4vl_9.2/tda4vl_linux_9.2$ grep -r "J721S2_IOPAD(0x24," --include=k3-j721s2*.dts*
wilson@virtual-pc:~/tda4vl_9.2/tda4vl_linux_9.2$

There is no conflict with any other pinmux defined.

root@j721s2-evm:~# i2cdetect -l
i2c-0   i2c             OMAP I2C adapter                        I2C adapter
i2c-1   i2c             OMAP I2C adapter                        I2C adapter
i2c-2   i2c             OMAP I2C adapter                        I2C adapter
i2c-3   i2c             OMAP I2C adapter                        I2C adapter
root@j721s2-evm:~# i2cdetect -r -y 3
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:                         [ 1835.028702] omap_i2c 2010000.i2c: Arbitration lost
-- [ 1836.044699] omap_i2c 2010000.i2c: controller timed out

- Wilson

Hi Wilson,

Thanks for this information. Let me look into this and get back to you tomorrow.
Thanks,

Neehar

Hi Wilson,

Can you elaborate what the issue was?
Thanks,

Neehar