Enable one wire (w1) drivers on TorizonCore to comunicate with DS2401 IC

Thank you @lucas_a.tx for your reply.

We built a custom linux image to verify the kernel options and also to test the device tree. After a whole lot of testing we finally got it to work.

@jeremias.tx we can confirm that these are the right options we need.

CONFIG_W1
CONFIG_W1_GPIO
CONFIG_W1_SLAVE_SMEM

Please go ahead and put in the request to have these kernel options enabled by default on TorizonCore.

Regarding the device tree we found that for the w1-gpio driver to work properly the third cell of the gpios property of the master node, which corresponds to gpio flag bitfield, needs to be set to GPIO_OPEN_DRAIN. So the working device tree extract looks like this:

/ {
	&iomuxc {
		pinctrl_onewire: onewiregrp {
			fsl,pins = <
				MX6QDL_PAD_NANDF_D6__GPIO2_IO06	0x4001b8b1
			>;
		};
	};

	onewire {
			compatible = "w1-gpio";
			gpios = <&gpio2 6 GPIO_OPEN_DRAIN>;
			linux,open-drain;
			pinctrl-names = "default";
			pinctrl-0 = <&pinctrl_onewire>;
			status = "okay";
	};
};

Best regards,
Martin.