I’m trying to add a new ethernet device to an existing stm32mp1 board, but i’m a bit lost in the device tree section.
What i found so far:
In the board.dts file, i could find the pins which connects to the ethernet phy:
&pinctrl {
ethernet0_rgmii_pins: rgmii-0 {
pins1 {
pinmux = <STM32_PINMUX('G', 4, AF11)>, /* ETH_RGMII_GTX_CLK */
<STM32_PINMUX('B', 12, AF11)>, /* ETH_RGMII_TXD0 */
<STM32_PINMUX('G', 14, AF11)>, /* ETH_RGMII_TXD1 */
<STM32_PINMUX('C', 2, AF11)>, /* ETH_RGMII_TXD2 */
<STM32_PINMUX('E', 2, AF11)>, /* ETH_RGMII_TXD3 */
<STM32_PINMUX('G', 11, AF11)>, /* ETH_RGMII_TX_CTL */
<STM32_PINMUX('C', 1, AF11)>; /* ETH_MDC */
bias-disable;
drive-push-pull;
slew-rate = <2>;
};
pins2 {
pinmux = <STM32_PINMUX('A', 2, AF11)>; /* ETH_MDIO */
bias-disable;
drive-push-pull;
slew-rate = <0>;
};
pins3 {
pinmux = <STM32_PINMUX('C', 4, AF11)>, /* ETH_RGMII_RXD0 */
<STM32_PINMUX('C', 5, AF11)>, /* ETH_RGMII_RXD1 */
<STM32_PINMUX('H', 6, AF11)>, /* ETH_RGMII_RXD2 */
<STM32_PINMUX('H', 7, AF11)>, /* ETH_RGMII_RXD3 */
<STM32_PINMUX('A', 1, AF11)>, /* ETH_RGMII_RX_CLK */
<STM32_PINMUX('A', 7, AF11)>; /* ETH_RGMII_RX_CTL */
bias-disable;
};
};
};
ðernet0 {
status = "okay";
pinctrl-0 = <ðernet0_rmii_pins>;
pinctrl-names = "default";
phy-mode = "rgmii";
phy-handle = <&phy0>;
st,eth_clk_sel = <1>;
max-speed = <1000>;
clock-names = "stmmaceth", "mac-clk-tx", "mac-clk-rx", "eth-ck", "syscfg-clk", "ethstp";
clocks = <&rcc ETHMAC>, <&rcc ETHTX>, <&rcc ETHRX>, <&rcc ETHCK_K>, <&rcc SYSCFG>, <&rcc ETHSTP>;
mdio0 {
#address-cells = <1>;
#size-cells = <0>;
compatible = "snps,dwmac-mdio";
phy0: ethernet-phy@0 {
reg = <0>;
ti,rx-internal-delay = <DP83867_RGMIIDCTL_2_25_NS>;
ti,tx-internal-delay = <DP83867_RGMIIDCTL_2_75_NS>;
ti,fifo-depth = <DP83867_PHYCR_FIFO_DEPTH_4_B_NIB>;
ti,dp83867-rxctrl-strap-quirk;
};
};
};
For example in the pins1 section the following pins are connected:
pinmux = <STM32_PINMUX('G', 4, AF11)>, /* ETH_RGMII_GTX_CLK */
<STM32_PINMUX('B', 12, AF11)>, /* ETH_RGMII_TXD0 */
<STM32_PINMUX('G', 14, AF11)>, /* ETH_RGMII_TXD1 */
<STM32_PINMUX('C', 2, AF11)>, /* ETH_RGMII_TXD2 */
<STM32_PINMUX('E', 2, AF11)>, /* ETH_RGMII_TXD3 */
<STM32_PINMUX('G', 11, AF11)>, /* ETH_RGMII_TX_CTL */
<STM32_PINMUX('C', 1, AF11)>; /* ETH_MDC */
But how and where is the order defined? How is it passed later to the phy device driver? What if i change the phy from rgmii to rmii? Then the number of pins reduce, but in what order do i have to place the pins?
Sadly i just can’t find any documentation to it, maybe someone can help me out here.
Thanks.
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Author: hberg539