drivers: mdio: Add ESP32 MDIO driver

The MDIO driver is required to for ESP32 Ethernet

Signed-off-by: Grant Ramsay <grant.ramsay@hotmail.com>

drivers/mdio/CMakeLists.txt

@@ -4,3 +4,4 @@ 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)

drivers/mdio/Kconfig

@@ -25,6 +25,7 @@ config MDIO_SHELL
 
 # Include these first so that any properties (e.g. defaults) below can be
 # overridden (by defining symbols in multiple locations)
+source "drivers/mdio/Kconfig.esp32"
 source "drivers/mdio/Kconfig.sam"
 
 config MDIO_INIT_PRIORITY

drivers/mdio/Kconfig.esp32

@@ -0,0 +1,9 @@
+# Copyright (c) 2022 Grant Ramsay <grant.ramsay@hotmail.com>
+# SPDX-License-Identifier: Apache-2.0
+
+config MDIO_ESP32
+	bool "ESP32 MDIO driver"
+	depends on SOC_ESP32
+	default y
+	help
+	  Enable ESP32 MCU Family MDIO driver.

drivers/mdio/mdio_esp32.c

@@ -0,0 +1,162 @@
+/*
+ * Copyright (c) 2022 Grant Ramsay <grant.ramsay@hotmail.com>
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT espressif_esp32_mdio
+
+#include <soc.h>
+#include <zephyr/drivers/clock_control.h>
+#include <zephyr/drivers/mdio.h>
+#include <zephyr/drivers/pinctrl.h>
+#include <zephyr/logging/log.h>
+
+#include <esp_mac.h>
+#include <hal/emac_hal.h>
+#include <hal/emac_ll.h>
+
+LOG_MODULE_REGISTER(mdio_esp32, CONFIG_MDIO_LOG_LEVEL);
+
+#define PHY_OPERATION_TIMEOUT_US 1000
+
+struct mdio_esp32_dev_data {
+	struct k_sem sem;
+	emac_hal_context_t hal;
+};
+
+struct mdio_esp32_dev_config {
+	const struct pinctrl_dev_config *pcfg;
+};
+
+static int mdio_transfer(const struct device *dev, uint8_t prtad, uint8_t devad,
+			 bool write, uint16_t data_in, uint16_t *data_out)
+{
+	struct mdio_esp32_dev_data *const dev_data = dev->data;
+
+	k_sem_take(&dev_data->sem, K_FOREVER);
+
+	if (emac_ll_is_mii_busy(dev_data->hal.mac_regs)) {
+		LOG_ERR("phy busy");
+		k_sem_give(&dev_data->sem);
+		return -EBUSY;
+	}
+
+	if (write) {
+		emac_ll_set_phy_data(dev_data->hal.mac_regs, data_in);
+	}
+	emac_hal_set_phy_cmd(&dev_data->hal, prtad, devad, write);
+
+	/* Poll until operation complete */
+	bool success = false;
+
+	for (uint32_t t_us = 0; t_us < PHY_OPERATION_TIMEOUT_US; t_us += 100) {
+		k_sleep(K_USEC(100));
+		if (!emac_ll_is_mii_busy(dev_data->hal.mac_regs)) {
+			success = true;
+			break;
+		}
+	}
+	if (!success) {
+		LOG_ERR("phy timeout");
+		k_sem_give(&dev_data->sem);
+		return -ETIMEDOUT;
+	}
+
+	if (!write && data_out != NULL) {
+		*data_out = emac_ll_get_phy_data(dev_data->hal.mac_regs);
+	}
+
+	k_sem_give(&dev_data->sem);
+
+	return 0;
+}
+
+static int mdio_esp32_read(const struct device *dev, uint8_t prtad, uint8_t devad,
+			 uint16_t *data)
+{
+	return mdio_transfer(dev, prtad, devad, false, 0, data);
+
+}
+
+static int mdio_esp32_write(const struct device *dev, uint8_t prtad,
+			  uint8_t devad, uint16_t data)
+{
+	return mdio_transfer(dev, prtad, devad, true, data, NULL);
+}
+
+static void mdio_esp32_bus_enable(const struct device *dev)
+{
+	ARG_UNUSED(dev);
+}
+
+static void mdio_esp32_bus_disable(const struct device *dev)
+{
+	ARG_UNUSED(dev);
+}
+
+static int mdio_esp32_initialize(const struct device *dev)
+{
+	const struct mdio_esp32_dev_config *const cfg = dev->config;
+	struct mdio_esp32_dev_data *const dev_data = dev->data;
+	int res;
+
+	k_sem_init(&dev_data->sem, 1, 1);
+
+	res = pinctrl_apply_state(cfg->pcfg, PINCTRL_STATE_DEFAULT);
+	if (res != 0) {
+		goto err;
+	}
+
+	const struct device *clock_dev =
+		DEVICE_DT_GET(DT_CLOCKS_CTLR(DT_NODELABEL(mdio)));
+	clock_control_subsys_t clock_subsys =
+		(clock_control_subsys_t)DT_CLOCKS_CELL(DT_NODELABEL(mdio), offset);
+
+	res = clock_control_on(clock_dev, clock_subsys);
+	if (res != 0) {
+		goto err;
+	}
+
+	/* Only the mac registers are required for MDIO */
+	dev_data->hal.mac_regs = &EMAC_MAC;
+
+	/* Init MDIO clock */
+	emac_hal_set_csr_clock_range(&dev_data->hal, esp_clk_apb_freq());
+
+	return 0;
+
+err:
+	return res;
+}
+
+static const struct mdio_driver_api mdio_esp32_driver_api = {
+	.read = mdio_esp32_read,
+	.write = mdio_esp32_write,
+	.bus_enable = mdio_esp32_bus_enable,
+	.bus_disable = mdio_esp32_bus_disable,
+};
+
+#define MDIO_ESP32_CONFIG(n)						\
+static const struct mdio_esp32_dev_config mdio_esp32_dev_config_##n = {	\
+	.pcfg = PINCTRL_DT_INST_DEV_CONFIG_GET(n),			\
+};
+
+#define MDIO_ESP32_PROTOCOL_ASSERT(n)					\
+	BUILD_ASSERT(DT_INST_ENUM_IDX(n, protocol) == CLAUSE_22,	\
+		     "ESP32 MDIO only supports CLAUSE_22 protocol")
+
+#define MDIO_ESP32_DEVICE(n)						\
+	MDIO_ESP32_PROTOCOL_ASSERT(n);					\
+	PINCTRL_DT_INST_DEFINE(n);					\
+	MDIO_ESP32_CONFIG(n);						\
+	static struct mdio_esp32_dev_data mdio_esp32_dev_data##n;	\
+	DEVICE_DT_INST_DEFINE(n,					\
+			      &mdio_esp32_initialize,			\
+			      NULL,					\
+			      &mdio_esp32_dev_data##n,			\
+			      &mdio_esp32_dev_config_##n, POST_KERNEL,	\
+			      CONFIG_MDIO_INIT_PRIORITY,		\
+			      &mdio_esp32_driver_api);
+
+DT_INST_FOREACH_STATUS_OKAY(MDIO_ESP32_DEVICE)

drivers/mdio/mdio_shell.c

@@ -14,7 +14,15 @@
 #include <zephyr/logging/log.h>
 LOG_MODULE_REGISTER(mdio_shell, CONFIG_LOG_DEFAULT_LEVEL);
 
-#define MDIO_NODE_ID DT_COMPAT_GET_ANY_STATUS_OKAY(atmel_sam_mdio)
+#if DT_HAS_COMPAT_STATUS_OKAY(atmel_sam_mdio)
+#define DT_DRV_COMPAT atmel_sam_mdio
+#elif DT_HAS_COMPAT_STATUS_OKAY(espressif_esp32_mdio)
+#define DT_DRV_COMPAT espressif_esp32_mdio
+#else
+#error "No known devicetree compatible match for MDIO shell"
+#endif
+
+#define MDIO_NODE_ID DT_COMPAT_GET_ANY_STATUS_OKAY(DT_DRV_COMPAT)
 
 /*
  * Scan the entire 5-bit address space of the MDIO bus

dts/bindings/mdio/espressif,esp32-mdio.yaml

@@ -0,0 +1,10 @@
+# Copyright (c) 2022 Grant Ramsay <grant.ramsay@hotmail.com>
+# SPDX-License-Identifier: Apache-2.0
+
+description: ESP32 MDIO Driver node
+
+compatible: "espressif,esp32-mdio"
+
+include:
+    - name: mdio-controller.yaml
+    - name: pinctrl-device.yaml

dts/xtensa/espressif/esp32.dtsi

@@ -42,6 +42,13 @@
 		status = "disabled";
 	};
 
+	mdio: mdio {
+		compatible = "espressif,esp32-mdio";
+		protocol = "clause 22";
+		clocks = <&rtc ESP32_EMAC_MODULE>;
+		status = "disabled";
+	};
+
 	pinctrl: pin-controller {
 		compatible = "espressif,esp32-pinctrl";
 		status = "okay";