drivers: ethernet: stm32: add support for DT pinctrl

Add support for configuring Ethernet pins using DT pinctrl entries. Note
that F1 series pinctrl support is not handled as the driver does not
support F1.

Signed-off-by: Gerard Marull-Paretas <gerard@teslabs.com>

drivers/ethernet/eth_stm32_hal.c

@@ -26,6 +26,7 @@ LOG_MODULE_REGISTER(LOG_MODULE_NAME);
 #include <sys/printk.h>
 #include <drivers/clock_control.h>
 #include <drivers/clock_control/stm32_clock_control.h>
+#include <pinmux/stm32/pinmux_stm32.h>
 
 #include "eth.h"
 #include "eth_stm32_hal_priv.h"
@@ -654,6 +655,14 @@ static int eth_initialize(const struct device *dev)
 		return -EIO;
 	}
 
+	/* configure pinmux */
+	ret = stm32_dt_pinctrl_configure(cfg->pinctrl, cfg->pinctrl_len,
+					 (uint32_t)dev_data->heth.Instance);
+	if (ret < 0) {
+		LOG_ERR("Could not configure ethernet pins");
+		return ret;
+	}
+
 	heth = &dev_data->heth;
 
 #if defined(CONFIG_ETH_STM32_HAL_RANDOM_MAC)
@@ -852,6 +861,8 @@ static void eth0_irq_config(void)
 	irq_enable(DT_INST_IRQN(0));
 }
 
+static const struct soc_gpio_pinctrl eth0_pins[] = ST_STM32_DT_INST_PINCTRL(0, 0);
+
 static const struct eth_stm32_hal_dev_cfg eth0_config = {
 	.config_func = eth0_irq_config,
 	.pclken = {.bus = DT_INST_CLOCKS_CELL_BY_NAME(0, stmmaceth, bus),
@@ -864,6 +875,8 @@ static const struct eth_stm32_hal_dev_cfg eth0_config = {
 	.pclken_ptp = {.bus = DT_INST_CLOCKS_CELL_BY_NAME(0, mac_clk_ptp, bus),
 		       .enr = DT_INST_CLOCKS_CELL_BY_NAME(0, mac_clk_ptp, bits)},
 #endif /* !CONFIG_SOC_SERIES_STM32H7X */
+	.pinctrl = eth0_pins,
+	.pinctrl_len = ARRAY_SIZE(eth0_pins),
 };
 
 static struct eth_stm32_hal_dev_data eth0_data = {

drivers/ethernet/eth_stm32_hal_priv.h

@@ -29,6 +29,8 @@ struct eth_stm32_hal_dev_cfg {
 #if !defined(CONFIG_SOC_SERIES_STM32H7X)
 	struct stm32_pclken pclken_ptp;
 #endif /* !defined(CONFIG_SOC_SERIES_STM32H7X) */
+	const struct soc_gpio_pinctrl *pinctrl;
+	size_t pinctrl_len;
 };
 
 /* Device run time data */

dts/bindings/ethernet/st,stm32-ethernet.yaml

@@ -16,3 +16,12 @@ properties:
       required: true
     clock-names:
       required: true
+
+    pinctrl-0:
+      type: phandles
+      required: false
+      description: |
+        GPIO pin configuration for Ethernet signals. We expect that the phandles
+        will reference pinctrl nodes, e.g.
+
+           pinctrl-0 = <&eth_ref_clk_pa1 &eth_mdio_pa2 ...>;