drivers: ethernet: vsc8541: Use 16-bit values for MDIO access

The internal register read/write functions used uint32_t for the values
even though the registers are only 16 bits wide, resulting in a bunch of
casting. Change the internal functions to use uint16_t and wrap them for
the external read/write API which uses uint32_t.

Signed-off-by: Robert Hancock <robert.hancock@calian.com>

Author: robhancocksed

drivers/ethernet/phy/phy_microchip_vsc8541.c

@@ -110,8 +110,8 @@ struct mc_vsc8541_data {
 	uint8_t link_monitor_thread_stack[STACK_SIZE];
 };
 
-static int phy_mc_vsc8541_read(const struct device *dev, uint16_t reg_addr, uint32_t *data);
-static int phy_mc_vsc8541_write(const struct device *dev, uint16_t reg_addr, uint32_t data);
+static int phy_mc_vsc8541_read(const struct device *dev, uint16_t reg_addr, uint16_t *data);
+static int phy_mc_vsc8541_write(const struct device *dev, uint16_t reg_addr, uint16_t data);
 static void phy_mc_vsc8541_link_monitor(void *arg1, void *arg2, void *arg3);
 
 #if CONFIG_PHY_VERIFY_DEVICE_IDENTIFICATION
@@ -123,11 +123,11 @@ static int phy_mc_vsc8541_verify_phy_id(const struct device *dev)
 	uint16_t phy_id_1;
 	uint16_t phy_id_2;
 
-	if (0 != phy_mc_vsc8541_read(dev, PHY_REG_PAGE0_ID1, (uint32_t *)&phy_id_1)) {
+	if (0 != phy_mc_vsc8541_read(dev, PHY_REG_PAGE0_ID1, &phy_id_1)) {
 		return -EINVAL;
 	}
 
-	if (0 != phy_mc_vsc8541_read(dev, PHY_REG_PAGE0_ID2, (uint32_t *)&phy_id_2)) {
+	if (0 != phy_mc_vsc8541_read(dev, PHY_REG_PAGE0_ID2, &phy_id_2)) {
 		return -EINVAL;
 	}
 
@@ -216,7 +216,7 @@ static int phy_mc_vsc8541_reset(const struct device *dev)
 	}
 
 	/* wait for phy finished software reset */
-	uint32_t reg = 0;
+	uint16_t reg = 0;
 
 	do {
 		phy_mc_vsc8541_read(dev, PHY_REG_PAGE0_BMCR, &reg);
@@ -271,10 +271,10 @@ static int phy_mc_vsc8541_reset(const struct device *dev)
 static int phy_mc_vsc8541_get_speed(const struct device *dev, struct phy_link_state *state)
 {
 	int ret;
-	uint32_t status;
-	uint32_t link10_status;
-	uint32_t link100_status;
-	uint32_t link1000_status;
+	uint16_t status;
+	uint16_t link10_status;
+	uint16_t link100_status;
+	uint16_t link1000_status;
 
 	ret = phy_mc_vsc8541_read(dev, PHY_REG_PAGE0_BMSR, &status);
 	if (ret) {
@@ -361,8 +361,8 @@ static int phy_mc_vsc8541_init(const struct device *dev)
 static int phy_mc_vsc8541_get_link(const struct device *dev, struct phy_link_state *state)
 {
 	int ret;
-	uint32_t reg_sr;
-	uint32_t reg_cr;
+	uint16_t reg_sr;
+	uint16_t reg_cr;
 
 	ret = phy_mc_vsc8541_read(dev, PHY_REG_PAGE0_BMSR, &reg_sr);
 	if (ret) {
@@ -470,7 +470,7 @@ void phy_mc_vsc8541_link_monitor(void *arg1, void *arg2, void *arg3)
  * - to speed up, we store the last used page and only swap page if needed
  *
  */
-static int phy_mc_vsc8541_read(const struct device *dev, uint16_t reg_addr, uint32_t *data)
+static int phy_mc_vsc8541_read(const struct device *dev, uint16_t reg_addr, uint16_t *data)
 {
 	const struct mc_vsc8541_config *cfg = dev->config;
 	struct mc_vsc8541_data *dev_data = dev->data;
@@ -479,7 +479,7 @@ static int phy_mc_vsc8541_read(const struct device *dev, uint16_t reg_addr, uint
 	*data = 0U;
 
 	/* decode page */
-	uint32_t page = reg_addr >> 8;
+	uint16_t page = reg_addr >> 8;
 
 	/* mask out lower byte */
 	reg_addr &= 0x00ff;
@@ -488,7 +488,7 @@ static int phy_mc_vsc8541_read(const struct device *dev, uint16_t reg_addr, uint
 
 	/* select page, given by register upper byte */
 	if (dev_data->active_page != page) {
-		ret = mdio_write(cfg->mdio_dev, cfg->addr, PHY_REG_PAGE_SELECTOR, (uint16_t)page);
+		ret = mdio_write(cfg->mdio_dev, cfg->addr, PHY_REG_PAGE_SELECTOR, page);
 		if (ret) {
 			mdio_bus_disable(cfg->mdio_dev);
 			return ret;
@@ -497,7 +497,7 @@ static int phy_mc_vsc8541_read(const struct device *dev, uint16_t reg_addr, uint
 	}
 
 	/* select register, given by register lower byte */
-	ret = mdio_read(cfg->mdio_dev, cfg->addr, reg_addr, (uint16_t *)data);
+	ret = mdio_read(cfg->mdio_dev, cfg->addr, reg_addr, data);
 	mdio_bus_disable(cfg->mdio_dev);
 	if (ret) {
 		return ret;
@@ -506,6 +506,15 @@ static int phy_mc_vsc8541_read(const struct device *dev, uint16_t reg_addr, uint
 	return 0;
 }
 
+/**
+ * @brief Reading of phy register content at given address via mdio interface
+ * For external API using uint32_t as data type
+ */
+static int phy_mc_vsc8541_read_ext(const struct device *dev, uint16_t reg_addr, uint32_t *data)
+{
+	return phy_mc_vsc8541_read(dev, reg_addr, (uint16_t *)data);
+}
+
 /**
  * @brief Writing of new value to phy register at given address via mdio interface
  *
@@ -514,14 +523,14 @@ static int phy_mc_vsc8541_read(const struct device *dev, uint16_t reg_addr, uint
  * - to speed up, we store the last used page and only swap page if needed
  *
  */
-static int phy_mc_vsc8541_write(const struct device *dev, uint16_t reg_addr, uint32_t data)
+static int phy_mc_vsc8541_write(const struct device *dev, uint16_t reg_addr, uint16_t data)
 {
 	const struct mc_vsc8541_config *cfg = dev->config;
 	struct mc_vsc8541_data *dev_data = dev->data;
 	int ret;
 
 	/* decode page */
-	uint32_t page = reg_addr >> 8;
+	uint16_t page = reg_addr >> 8;
 
 	/* mask out lower byte */
 	reg_addr &= 0x00ff;
@@ -539,7 +548,7 @@ static int phy_mc_vsc8541_write(const struct device *dev, uint16_t reg_addr, uin
 	}
 
 	/* write register, given by lower byte */
-	ret = mdio_write(cfg->mdio_dev, cfg->addr, reg_addr, (uint16_t)data);
+	ret = mdio_write(cfg->mdio_dev, cfg->addr, reg_addr, data);
 	mdio_bus_disable(cfg->mdio_dev);
 	if (ret) {
 		return ret;
@@ -548,12 +557,17 @@ static int phy_mc_vsc8541_write(const struct device *dev, uint16_t reg_addr, uin
 	return 0;
 }
 
+static int phy_mc_vsc8541_write_ext(const struct device *dev, uint16_t reg_addr, uint32_t data)
+{
+	return phy_mc_vsc8541_write(dev, reg_addr, (uint16_t)data);
+}
+
 static DEVICE_API(ethphy, mc_vsc8541_phy_api) = {
 	.get_link = phy_mc_vsc8541_get_link,
 	.cfg_link = phy_mc_vsc8541_cfg_link,
 	.link_cb_set = phy_mc_vsc8541_link_cb_set,
-	.read = phy_mc_vsc8541_read,
-	.write = phy_mc_vsc8541_write,
+	.read = phy_mc_vsc8541_read_ext,
+	.write = phy_mc_vsc8541_write_ext,
 };
 
 #if DT_ANY_INST_HAS_PROP_STATUS_OKAY(reset_gpios)