On Tue, Jan 20, 2026 at 11:13:50AM +0000, Yao Zi wrote:

On Tue, Jan 20, 2026 at 12:36:08PM +0800, Inochi Amaoto wrote:

quoted

Adds Spacemit dwmac driver support on the Spacemit K3 SoC.

Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
---
 drivers/net/ethernet/stmicro/stmmac/Kconfig   |  12 +
 drivers/net/ethernet/stmicro/stmmac/Makefile  |   1 +
 .../ethernet/stmicro/stmmac/dwmac-spacemit.c  | 224 ++++++++++++++++++
 3 files changed, 237 insertions(+)
 create mode 100644 drivers/net/ethernet/stmicro/stmmac/dwmac-spacemit.c

...

quoted

diff --git a/drivers/net/ethernet/stmicro/stmmac/dwmac-spacemit.c b/drivers/net/ethernet/stmicro/stmmac/dwmac-spacemit.c
new file mode 100644
index 000000000000..72744e60d02a
--- /dev/null
+++ b/drivers/net/ethernet/stmicro/stmmac/dwmac-spacemit.c

@@ -0,0 +1,224 @@
+// SPDX-License-Identifier: GPL-2.0+
+/*
+ * Spacemit DWMAC platform driver
+ *
+ * Copyright (C) 2026 Inochi Amaoto <inochiama@gmail.com>
+ */
+
+#include <linux/clk.h>
+#include <linux/mfd/syscon.h>
+#include <linux/math.h>

These are the only two headers listed out-of-order. Is this intended?

I will fix this.

quoted

+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>

...

quoted

+static int spacemit_dwmac_detected_delay_value(unsigned int delay,
+					       unsigned int *config)
+{
+	int i;
+	int code, best_code = 0;
+	unsigned int best_delay = 0;
+	unsigned int best_config = 0;
+
+	if (delay == 0)
+		return 0;
+
+	for (i = 0; i < ARRAY_SIZE(k3_delay_step_10x); i++) {
+		unsigned int step = k3_delay_step_10x[i];
+
+		for (code = 1; code <= MAX_DLINE_DELAY_CODE; code++) {
+			/*
+			 * Note K3 require a specific factor for calculate
+			 * the delay, in this scenario it is 0.9. So the
+			 * formula is code * step / 10 * 0.9
+			 */
+			unsigned int tmp = code * step * 9 / 10 / 10;
+
+			if (abs(tmp - delay) < abs(best_delay - delay)) {
+				best_code = code;
+				best_delay = tmp;
+				best_config = i;
+			}

Is the inner loop really necessary? Could it be replaced by

	this_code = DIV_ROUND_CLOSEST(delay * 10 * 10, step * 9);
	this_delay = this_code * step * 9 / 10 / 10;

Then comparing abs(this_delay - delay) and abs(best_delay - delay)?

This is a good idea, thanks.

quoted

+		}
+	}
+
+	*config = best_config;
+
+	return best_code;
+}

...

quoted

+static int spacemit_dwmac_update_ifconfig(struct plat_stmmacenet_data *plat_dat,
+					  struct stmmac_resources *stmmac_res,
+					  struct regmap *apmu,
+					  unsigned int ctrl_offset)
+{
+	unsigned int mask = PHY_INTF_MII | PHY_INTF_RGMII | WAKE_IRQ_EN;
+	unsigned int val = 0;
+
+	switch (plat_dat->phy_interface) {
+	case PHY_INTERFACE_MODE_MII:
+		val |= PHY_INTF_MII;
+		break;

The OR operation seems unnecessary and could be replaced with an
assignment. Same for PHY_INTERFACE_MODE_RGMII's case.

That's tree, an assignment is better than the OR operation, I will
change this in the next version.

quoted

+
+	case PHY_INTERFACE_MODE_RMII:
+		break;
+
+	case PHY_INTERFACE_MODE_RGMII:
+	case PHY_INTERFACE_MODE_RGMII_ID:
+	case PHY_INTERFACE_MODE_RGMII_RXID:
+	case PHY_INTERFACE_MODE_RGMII_TXID:
+		val |= PHY_INTF_RGMII;
+		break;
+
+	default:
+		return -EOPNOTSUPP;
+	}

...

quoted

+static int spacemit_dwmac_probe(struct platform_device *pdev)
+{

...

quoted

+	of_property_read_u32(pdev->dev.of_node, "tx-internal-delay-ps", &tx_delay);
+	of_property_read_u32(pdev->dev.of_node, "rx-internal-delay-ps", &rx_delay);

According to of.h, of_property_read_u32, which in turn calls
of_property_read_u32_array, could fail with -ENODATA if there's no value
associated with the property. Should the case be handled?

Regards,
Yao Zi