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Registered: ‎09-06-2019

Pinctrl usage and groups

Hi I've been trying to configure a device tree for some SPI devices and have come questions regarding pinctrl usage. I've read through https://xilinx-wiki.atlassian.net/wiki/spaces/A/pages/18842152/ZynqMP+Linux+Pin+Controller+Driver

From https://github.com/Xilinx/linux-xlnx/blob/master/Documentation/devicetree/bindings/pinctrl/xlnx%2Czynqmp-pinctrl.txt 

How are group values assigned? Are these linked to real pins within the ultrascale or are they just names we can arbitrability assign to pin groups. In the following example: 

			pinctrl_uart1_default: uart1-default {
				mux {
					groups = "uart0_4_grp";
					function = "uart0";
				};

				conf {
					groups = "uart0_4_grp";
					slew-rate = <SLEW_RATE_SLOW>;
					io-standard = <IO_STANDARD_LVCMOS18>;
				};

				conf-rx {
					pins = "MIO18";
					bias-high-impedance;
				};

				conf-tx {
					pins = "MIO19";
					bias-disable;
					schmitt-cmos = <PIN_INPUT_TYPE_CMOS>;
				};
			};

If I replaced:

uart0_4_grp

with: 

uart0_1_grp

That should effect any functionality of the hardware and just reassigns just a label to that particular pin control config for the uart?

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