drivers: mdio: add Atmel SAM MDIO driver

MDIO driver for ATSAM platform with Ethernet.

Signed-off-by: Arvin Farahmand <arvinf@ip-logix.com>

drivers/mdio/CMakeLists.txt

@@ -1,3 +1,5 @@
 # SPDX-License-Identifier: Apache-2.0
 
 zephyr_library()
+
+zephyr_library_sources_ifdef(CONFIG_MDIO_ATMEL_SAM		mdio_sam.c)

drivers/mdio/Kconfig

@@ -15,6 +15,7 @@ if MDIO
 
 # Include these first so that any properties (e.g. defaults) below can be
 # overridden (by defining symbols in multiple locations)
+source "drivers/mdio/Kconfig.sam"
 
 config MDIO_INIT_PRIORITY
 	int "Init priority"

drivers/mdio/Kconfig.sam

@@ -0,0 +1,9 @@
+# Copyright (c) 2021 IP-Logix Inc.
+# SPDX-License-Identifier: Apache-2.0
+
+config MDIO_ATMEL_SAM
+	bool "Atmel SAM MDIO driver"
+	depends on ETH_SAM_GMAC
+	default y
+	help
+	  Enable Atmel SAM MCU Family MDIO driver.

drivers/mdio/mdio_sam.c

@@ -0,0 +1,148 @@
+/*
+ * Copyright (c) 2021 IP-Logix Inc.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#define DT_DRV_COMPAT atmel_sam_mdio
+
+#include <errno.h>
+#include <device.h>
+#include <init.h>
+#include <soc.h>
+#include <drivers/mdio.h>
+
+#include <logging/log.h>
+LOG_MODULE_REGISTER(mdio_sam, CONFIG_MDIO_LOG_LEVEL);
+
+/* GMAC */
+#ifdef CONFIG_SOC_FAMILY_SAM0
+#define GMAC_MAN        MAN.reg
+#define GMAC_NSR        NSR.reg
+#define GMAC_NCR        NCR.reg
+#endif
+
+struct mdio_sam_dev_data {
+	struct k_sem sem;
+};
+
+struct mdio_sam_dev_config {
+	Gmac * const regs;
+	int protocol;
+};
+
+#define DEV_NAME(dev) ((dev)->name)
+#define DEV_DATA(dev) ((struct mdio_sam_dev_data *const)(dev)->data)
+#define DEV_CFG(dev) \
+	((const struct mdio_sam_dev_config *const)(dev)->config)
+
+static int mdio_transfer(const struct device *dev, uint8_t prtad, uint8_t devad,
+			 uint8_t rw, uint16_t data_in, uint16_t *data_out)
+{
+	const struct mdio_sam_dev_config *const cfg = DEV_CFG(dev);
+	struct mdio_sam_dev_data *const data = DEV_DATA(dev);
+	int timeout = 50;
+
+	k_sem_take(&data->sem, K_FOREVER);
+
+	/* Write mdio transaction */
+	if (cfg->protocol == CLAUSE_45) {
+		cfg->regs->GMAC_MAN = (GMAC_MAN_OP(rw ? 0x2 : 0x3))
+				    |  GMAC_MAN_WTN(0x02)
+				    |  GMAC_MAN_PHYA(prtad)
+				    |  GMAC_MAN_REGA(devad)
+				    |  GMAC_MAN_DATA(data_in);
+
+	} else if (cfg->protocol == CLAUSE_22) {
+		cfg->regs->GMAC_MAN =  GMAC_MAN_CLTTO
+				    | (GMAC_MAN_OP(rw ? 0x2 : 0x1))
+				    |  GMAC_MAN_WTN(0x02)
+				    |  GMAC_MAN_PHYA(prtad)
+				    |  GMAC_MAN_REGA(devad)
+				    |  GMAC_MAN_DATA(data_in);
+
+	} else {
+		LOG_ERR("Unsupported protocol");
+	}
+
+	/* Wait until done */
+	while (!(cfg->regs->GMAC_NSR & GMAC_NSR_IDLE)) {
+		if (timeout-- == 0U) {
+			LOG_ERR("transfer timedout %s", DEV_NAME(dev));
+			k_sem_give(&data->sem);
+
+			return -ETIMEDOUT;
+		}
+
+		k_sleep(K_MSEC(5));
+	}
+
+	if (data_out) {
+		*data_out = cfg->regs->GMAC_MAN & GMAC_MAN_DATA_Msk;
+	}
+
+	k_sem_give(&data->sem);
+
+	return 0;
+}
+
+static int mdio_sam_read(const struct device *dev, uint8_t prtad, uint8_t devad,
+			 uint16_t *data)
+{
+	return mdio_transfer(dev, prtad, devad, 1, 0, data);
+}
+
+static int mdio_sam_write(const struct device *dev, uint8_t prtad,
+			  uint8_t devad, uint16_t data)
+{
+	return mdio_transfer(dev, prtad, devad, 0, data, NULL);
+}
+
+static void mdio_sam_bus_enable(const struct device *dev)
+{
+	const struct mdio_sam_dev_config *const cfg = DEV_CFG(dev);
+
+	cfg->regs->GMAC_NCR |= GMAC_NCR_MPE;
+}
+
+static void mdio_sam_bus_disable(const struct device *dev)
+{
+	const struct mdio_sam_dev_config *const cfg = DEV_CFG(dev);
+
+	cfg->regs->GMAC_NCR &= ~GMAC_NCR_MPE;
+}
+
+static int mdio_sam_initialize(const struct device *dev)
+{
+	struct mdio_sam_dev_data *const data = DEV_DATA(dev);
+
+	k_sem_init(&data->sem, 1, 1);
+
+	return 0;
+}
+
+static const struct mdio_driver_api mdio_sam_driver_api = {
+	.read = mdio_sam_read,
+	.write = mdio_sam_write,
+	.bus_enable = mdio_sam_bus_enable,
+	.bus_disable = mdio_sam_bus_disable,
+};
+
+#define MDIO_SAM_CONFIG(n)						\
+static const struct mdio_sam_dev_config mdio_sam_dev_config_##n = {	\
+	.regs = (Gmac *)DT_REG_ADDR(DT_PARENT(DT_DRV_INST(n))),		\
+	.protocol = DT_ENUM_IDX(DT_DRV_INST(n), protocol),		\
+};
+
+#define MDIO_SAM_DEVICE(n)						\
+	MDIO_SAM_CONFIG(n);						\
+	static struct mdio_sam_dev_data mdio_sam_dev_data##n;		\
+	DEVICE_DT_INST_DEFINE(n,					\
+			      &mdio_sam_initialize,			\
+			      NULL,					\
+			      &mdio_sam_dev_data##n,			\
+			      &mdio_sam_dev_config_##n, POST_KERNEL,	\
+			      CONFIG_MDIO_INIT_PRIORITY,		\
+			      &mdio_sam_driver_api);
+
+DT_INST_FOREACH_STATUS_OKAY(MDIO_SAM_DEVICE)

dts/bindings/mdio/atmel,sam-mdio.yaml

@@ -0,0 +1,18 @@
+# Copyright (c) 2021 IP-Logix Inc.
+# SPDX-License-Identifier: Apache-2.0
+
+description: Atmel SAM Family MDIO Driver node
+
+compatible: "atmel,sam-mdio"
+
+include: mdio-controller.yaml
+
+properties:
+    pinctrl-0:
+      type: phandles
+      required: false
+      description: |
+        PIO pin configuration for MDC, and MDIO signals.
+
+        For example the GMAC on SAME7x would be
+          pinctrl-0 = <&pd8a_gmac_gmdc &pd9a_gmac_gmdio>;