Camera'a reset-gpios not found via IO expander

[khang.l4es]

Dear All,

Could someone give me an example of configuring an IO Expander ( TCA6408, TCA8539, …) as output to be used in a sensor node’s reset-gpios property, please ?

For example :
Define outputs :

  i2c@3180000 {
    tca6408_21: tca6408@21 {
      compatible = "ti,tca6408";
      gpio-controller;
      #gpio-cells = <2>;
      reg = <0x21>;
      vcc-supply = <&en_vdd_cam>;

      // TODO : Configure inputs & outputs  
    };
   };

Use outputs as value of reset-gpios property :

  i2c@3180000 {
        imx219_z@10 {
          ...
          reset-gpios = <&tca6408_21 0 GPIO_ACTIVE_HIGH>;
          ...
        };
        imx219_y@10 {
          ...
          reset-gpios = <&tca6408_21 1 GPIO_ACTIVE_HIGH>;
          ...
        };
  };

I’ve got following error be only doing as above :
imx219 10-001f: reset-gpios not found

Thanks in advance,
K.

[JerryChang]

hello khang.l4es,

so, you’re going to enable TCA6408 multiplexer,
had you already configure those GPIO definition? you should see reference driver to have implementation.
for example,

        i2c@3180000 {
                tca6408_21: tca6408@21 {
                        compatible = "ti,tca6408";
                        gpio-controller;
                        #gpio-cells = <2>;
                        reg = <0x21>;
                        vcc-supply = <&p2822_vdd_1v8_cvb>;
                        tca6408_21_outlow {
                                gpio-hog;
                                gpios = <0 0 1 0 ...>;
                                output-low;
                                label = "tca6408_21_outlow_0",
                                        "tca6408_21_outlow_1",
                                        ...

                        tca6408_21_outhigh {
                                status = "disabled";
                        };
                        tca6408_21_input {
                                status = "disabled";
                        };

...
                        i2c@2 {
                                ov5693_c@36 {
                                        pwdn-gpios = <&tca6408_21 0 GPIO_ACTIVE_HIGH>;
                                        reset-gpios = <&tca6408_21 1 GPIO_ACTIVE_HIGH>;
                                        ...

[JerryChang]

@JerryChang

gpios = <0 0 1 0 ...>;

to add-on,
<0 0>, the 1st 0 is GPIO definition, the 2nd 0 is the default state.
this example, define two GPIOs, both of them configure low by default.

[khang.l4es]

HI @JerryChang ,
Thanks for your reply. It is clear for me about defining gpio inputs as well as outputs low and high. I’m specially interested in reset-gpios definition which is not recognized. I would like to know why

 i2c@2 {
 }

is there and should it be inside

tca6408_21: tca6408@21 {

};

Also, in case if the camera sensor is plugged into different i2c bus, what would happen, please ?

Many thanks,
K.

[JerryChang]

@khang.l4es

 i2c@2 {
 }

i2c@2 this may not necessary for your use-case, it’s recap from the reference drivers,
it’s a six camera module to share the i2c bus (0x36) with pca9548. it muxes i2c address by using i2c@0 to i2c@5.
for example, $L4T_Sources/r32.6.1/Linux_for_Tegra/source/public/hardware/nvidia/platform/t19x/galen/kernel-dts/common/tegra194-p2822-0000-camera-e3333-a00.dtsi

please replace that with the actual sensor i2c address if you’re having camera modules define without mux.
thanks

[khang.l4es]

Hi @JerryChang ,

Thanks again for your reply. I would like to make a little bit clearer the case without i2c mux. For example, if my sensor is hooked to a different i2c bus saying i2c@3160000, How should I replace the above i2c@2 node ? Could i2c@3160000 be inside tca6408@21 and same level of tca6408_21_outlow, tca6408_21_outhigh, tca6408_21_input, etc?

        i2c@3180000 {
                tca6408_21: tca6408@21 { // Begin of tca6408_21
                        compatible = "ti,tca6408";
                        gpio-controller;
                        #gpio-cells = <2>;
                        reg = <0x21>;
                        vcc-supply = <&p2822_vdd_1v8_cvb>;
                        tca6408_21_outlow {
                                gpio-hog;
                                gpios = <0 0 1 0 ...>;
                                output-low;
                                label = "tca6408_21_outlow_0",
                                        "tca6408_21_outlow_1",
                                        ...

                        tca6408_21_outhigh {
                                status = "disabled";
                        };
                        tca6408_21_input {
                                status = "disabled";
                        };

                        i2c@3160000 {
                                ov5693_c@36 {
                                        pwdn-gpios = <&tca6408_21 0 GPIO_ACTIVE_HIGH>;
                                        reset-gpios = <&tca6408_21 1 GPIO_ACTIVE_HIGH>;
                                        ...
                                };
                        };  // End of i2c@3160000 

                 };  // End of tca6408_21: tca6408@21

        }; // End of   i2c@3180000

Or should i2c@3160000 be same level as i2c@3180000, please ?

And should we list out the gpios’ indexes (0 and 1 for example) :

                                gpios = <0 0 1 0 ...>;

that later will be used in

                                        pwdn-gpios = <&tca6408_21 0 GPIO_ACTIVE_HIGH>;
                                        reset-gpios = <&tca6408_21 1 GPIO_ACTIVE_HIGH>;

Thanks,
Khang

[JerryChang]

hello khang.l4es,

you should define i2c@3160000 to be same level as i2c@3180000,
here’s hierarchy in the above reference driver,

        i2c@3180000 {
                tca6408@21 {...}
                tca9548@77 {
                        i2c@0 {...}
                        i2c@1 {...}
                        i2c@2 {...}
                        ...

@khang.l4es

And should we list out the gpios’ indexes (0 and 1 for example) :

yes.

[khang.l4es]

Hi @JerryChang ,

The provided example , $L4T_Sources/r32.6.1/Linux_for_Tegra/source/public/hardware/nvidia/platform/t19x/galen/kernel-dts/common/tegra194-p2822-0000-camera-e3333-a00.dtsi is quite clear. I just have some small doubts :

1. Should we list out all of the GPIOs’ indexes or just one(s) we use? For example, if the reset-gpios is for my sensor is on output #7, then which one below is correct :

 gpios = <0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0>;

or

 gpios = <7 0>;

2. The reset-gpios of my sensor is active-low i.e a low level (0V) on that gpio will cause the reset. Therefore, do I need to define inversely :

                       tca6408_21_outlow {
                               status = "disabled";
                       };

                       tca6408_21_outhigh {
                               gpio-hog;
                               gpios = <7 0>; // Or  gpios = <0 0 1 0 2 0 3 0 4 0 5 0 6 0 7 0>;
                               output-high;
                               label = "tca6408_21_outhigh_7;
                       };
                       tca6408_21_input {
                               status = "disabled";
                       };

and

                                        reset-gpios = <&tca6408_21 7 GPIO_ACTIVE_LOW>;

Thanks alot,
Khang

[JerryChang]

hi khang.l4es,

1. you don’t need to list all of the GPIOs’ indexes, please just specify the ones you would like to use.
2. it looks the correct init gpio state settings.