Standard devicetree connectors for boards

[Mani-Sadhasivam]

Is your feature request related to a problem? Please describe.
For the boards belonging to a standard form factor like 96Boards, it would be nice to have a dedicated devicetree connector which can expose the available peripherals like GPIO, I2C, SPI in a generic way so that the sample applications can run on any board adhering to the standard.

Describe the solution you'd like
This could be achieved by having a below devicetree node in board dts:

        96b-ls-con {
                compatible = "96b-ls-con";
                i2c0 = &i2c0;
                uart0 = &uart0;

                gpioa: gpioa {
                        gpios = <&gpio0 1 0>;
                        label = "GPIO-A";
                };
                gpiob: gpiob {
                        gpios = <&gpio0 2 0>;
                        label = "GPIO-B";
                };
        };

Then the applications can make use of the definitions like DT_96B_LS_CON_GPIOA_GPIO_CONTROLLER, DT_96B_LS_CON_GPIOA_GPIO_PIN etc...

For achieving the above solution, a separate connector binding needs to be created and it shall include all possible peripherals.

Describe alternatives you've considered
There is already a concept of shields exist in Zephyr but it is limited to the expansion connectors and specifically not able to handle individual gpio's.

[mike-scott]

There is a bit of discussion about supporting GPIOs for headers (and shields) on this example PR: #14057

[erwango]

@Mani-Sadhasivam, I've created #15637 that aims at solving this issue

[erwango]

@Mani-Sadhasivam, can you check #15861 and comment of solving your querry?

[galak]

@Mani-Sadhasivam any update on this?

[Mani-Sadhasivam]

Will check #15861 soon.

[Mani-Sadhasivam]

@erwango I think this satisfies my requirement. This is what I tried:

/ {
        lscon_96b: connector {
                compatible = "96b-lscon-30pin";
                #gpio-cells = <2>;
                gpio-map = <13 0 &gpioa 8 0>,   /* GPIO-A */
                           <14 0 &gpiob 3 0>,   /* GPIO-B */
                           <16 0 &gpiob 5 0>,   /* GPIO-D */
                           <17 0 &gpioa 13 0>,  /* GPIO-E */
                           <18 0 &gpioa 14 0>,  /* GPIO-F */
                           <19 0 &gpioa 12 0>,  /* GPIO-G */
                           <20 0 &gpiob 4 0>;   /* GPIO-H */
        };
};

lscon_96b_i2c0: &i2c1 {};
lscon_96b_uart0: &usart1 {};

NOTE Devicetree spec doesn't allow the node label to start with a number, so I can't use 96b_lscon.

And I have the following define in the generated_dts_board.conf
DT_INST_0_96B_LSCON_30PIN=1

Now, I'm just curious if you have any sample application for testing/validating this!

[erwango]

Now, I'm just curious if you have any sample application for testing/validating this!

@Mani-Sadhasivam, ASAFAIK no spevcific test, but indirectly new version of gpio_basic_api would help you to do that.

[erwango]

@Mani-Sadhasivam, can we close the ticket then ?