drivers: mdio: add support for NXP S32 NETC EMDIO

Introduce NXP S32 NETC External MDIO controller driver. Driver supports
a single instance, as current support is based on NXP S32Z/E SoCs.

Signed-off-by: Manuel Arguelles <manuel.arguelles@nxp.com>

drivers/mdio/CMakeLists.txt

@@ -5,3 +5,4 @@ zephyr_library()
 zephyr_library_sources_ifdef(CONFIG_MDIO_SHELL		mdio_shell.c)
 zephyr_library_sources_ifdef(CONFIG_MDIO_ATMEL_SAM	mdio_sam.c)
 zephyr_library_sources_ifdef(CONFIG_MDIO_ESP32		mdio_esp32.c)
+zephyr_library_sources_ifdef(CONFIG_MDIO_NXP_S32_NETC	mdio_nxp_s32_netc.c)

drivers/mdio/Kconfig

@@ -27,6 +27,7 @@ config MDIO_SHELL
 # overridden (by defining symbols in multiple locations)
 source "drivers/mdio/Kconfig.esp32"
 source "drivers/mdio/Kconfig.sam"
+source "drivers/mdio/Kconfig.nxp_s32"
 
 config MDIO_INIT_PRIORITY
 	int "Init priority"

drivers/mdio/Kconfig.nxp_s32

@@ -0,0 +1,10 @@
+# Copyright 2022 NXP
+# SPDX-License-Identifier: Apache-2.0
+
+config MDIO_NXP_S32_NETC
+	bool "NXP S32 NETC External MDIO driver"
+	default y
+	depends on DT_HAS_NXP_S32_NETC_EMDIO_ENABLED
+	select NOCACHE_MEMORY
+	help
+	  Enable NETC External MDIO Controller driver for NXP S32 SoCs.

drivers/mdio/mdio_nxp_s32_netc.c

@@ -0,0 +1,110 @@
+/*
+ * Copyright 2022 NXP
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#include <zephyr/kernel.h>
+#include <zephyr/drivers/mdio.h>
+#include <zephyr/drivers/pinctrl.h>
+#include <zephyr/logging/log.h>
+LOG_MODULE_REGISTER(nxp_s32_emdio, CONFIG_MDIO_LOG_LEVEL);
+
+#include <Netc_EthSwt_Ip.h>
+
+#define MDIO_NODE	DT_NODELABEL(emdio)
+#define NETC_SWT_IDX	0
+
+struct nxp_s32_mdio_config {
+	int protocol;
+	const struct pinctrl_dev_config *pincfg;
+};
+
+struct nxp_s32_mdio_data {
+	struct k_mutex rw_mutex;
+};
+
+static int nxp_s32_mdio_read(const struct device *dev, uint8_t prtad,
+			     uint8_t devad, uint16_t *regval)
+{
+	const struct nxp_s32_mdio_config *const cfg = dev->config;
+	struct nxp_s32_mdio_data *data = dev->data;
+	Std_ReturnType status;
+
+	if (cfg->protocol != CLAUSE_22) {
+		LOG_ERR("Unsupported protocol");
+		return -ENOTSUP;
+	}
+
+	k_mutex_lock(&data->rw_mutex, K_FOREVER);
+	status = Netc_EthSwt_Ip_ReadTrcvRegister(NETC_SWT_IDX, prtad, devad, regval);
+	k_mutex_unlock(&data->rw_mutex);
+
+	return status == E_OK ? 0 : -EIO;
+}
+
+static int nxp_s32_mdio_write(const struct device *dev, uint8_t prtad,
+			      uint8_t devad, uint16_t regval)
+{
+	const struct nxp_s32_mdio_config *const cfg = dev->config;
+	struct nxp_s32_mdio_data *data = dev->data;
+	Std_ReturnType status;
+
+	if (cfg->protocol != CLAUSE_22) {
+		LOG_ERR("Unsupported protocol");
+		return -ENOTSUP;
+	}
+
+	k_mutex_lock(&data->rw_mutex, K_FOREVER);
+	status = Netc_EthSwt_Ip_WriteTrcvRegister(NETC_SWT_IDX, prtad, devad, regval);
+	k_mutex_unlock(&data->rw_mutex);
+
+	return status == E_OK ? 0 : -EIO;
+}
+
+static int nxp_s32_mdio_initialize(const struct device *dev)
+{
+	struct nxp_s32_mdio_data *data = dev->data;
+	const struct nxp_s32_mdio_config *cfg = dev->config;
+	int err;
+
+	err = pinctrl_apply_state(cfg->pincfg, PINCTRL_STATE_DEFAULT);
+	if (err != 0) {
+		return err;
+	}
+
+	k_mutex_init(&data->rw_mutex);
+
+	return 0;
+}
+
+static void nxp_s32_mdio_noop(const struct device *dev)
+{
+	/* intentionally left empty */
+}
+
+static const struct mdio_driver_api nxp_s32_mdio_api = {
+	.read = nxp_s32_mdio_read,
+	.write = nxp_s32_mdio_write,
+	/* NETC does not support enabling/disabling EMDIO controller independently */
+	.bus_enable = nxp_s32_mdio_noop,
+	.bus_disable = nxp_s32_mdio_noop,
+};
+
+PINCTRL_DT_DEFINE(MDIO_NODE);
+
+static struct nxp_s32_mdio_data nxp_s32_mdio0_data;
+
+static const struct nxp_s32_mdio_config nxp_s32_mdio0_cfg = {
+	.protocol = DT_ENUM_IDX(MDIO_NODE, protocol),
+	.pincfg = PINCTRL_DT_DEV_CONFIG_GET(MDIO_NODE),
+};
+
+DEVICE_DT_DEFINE(MDIO_NODE,
+		 &nxp_s32_mdio_initialize,
+		 NULL,
+		 &nxp_s32_mdio0_data,
+		 &nxp_s32_mdio0_cfg,
+		 POST_KERNEL,
+		 CONFIG_MDIO_INIT_PRIORITY,
+		 &nxp_s32_mdio_api);

drivers/mdio/mdio_shell.c

@@ -18,6 +18,8 @@ LOG_MODULE_REGISTER(mdio_shell, CONFIG_LOG_DEFAULT_LEVEL);
 #define DT_DRV_COMPAT atmel_sam_mdio
 #elif DT_HAS_COMPAT_STATUS_OKAY(espressif_esp32_mdio)
 #define DT_DRV_COMPAT espressif_esp32_mdio
+#elif DT_HAS_COMPAT_STATUS_OKAY(nxp_s32_netc_emdio)
+#define DT_DRV_COMPAT nxp_s32_netc_emdio
 #else
 #error "No known devicetree compatible match for MDIO shell"
 #endif

dts/bindings/mdio/nxp,s32-netc-emdio.yaml

@@ -0,0 +1,18 @@
+# Copyright 2022 NXP
+# SPDX-License-Identifier: Apache-2.0
+
+description: NXP S32 NETC External MDIO controller
+
+compatible: "nxp,s32-netc-emdio"
+
+include: [mdio-controller.yaml, pinctrl-device.yaml]
+
+properties:
+  reg:
+    required: true
+
+  pinctrl-0:
+    required: true
+
+  pinctrl-names:
+    required: true