[PATCH 0/3] soc: realtek: Add Realtek DHC I/O level detector support

[PATCH 0/3] soc: realtek: Add Realtek DHC I/O level detector support

[Yu-Chun Lin]

Hi all,

This patch series introduces support for the Realtek DHC I/O level detector.

The Realtek DHC I/O level detector is a hardware block responsible for
detecting the I/O signaling levels (1.8V or 3.3V) of various IP blocks
such as RGMII, SDIO, eMMC, CSI, SD, UART1, and AIO.

The driver reads the hardware registers to determine the current I/O voltage
levels. Based on these detection results, it dynamically selects and applies
the appropriate pinctrl states to ensure the correct pad configurations are
used for each interface.

Thanks,
Yu-Chun

Tzuyi Chang (2):
  dt-bindings: soc: realtek: Add Realtek DHC I/O level detector
  soc: realtek: Add driver for DHC I/O level detector

Yu-Chun Lin (1):
  arm64: dts: realtek: Add I/O level detector

 .../realtek/realtek,rtd1625-io-detect.yaml    |  77 +++++++++
 MAINTAINERS                                   |   1 +
 arch/arm64/boot/dts/realtek/kent-pinctrl.dtsi | 108 +++++++++++++
 arch/arm64/boot/dts/realtek/kent.dtsi         |  28 ++++
 drivers/soc/Kconfig                           |   1 +
 drivers/soc/Makefile                          |   1 +
 drivers/soc/realtek/Kconfig                   |  21 +++
 drivers/soc/realtek/Makefile                  |   2 +
 drivers/soc/realtek/rtd-io-detect.c           | 152 ++++++++++++++++++
 9 files changed, 391 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/soc/realtek/realtek,rtd1625-io-detect.yaml
 create mode 100644 arch/arm64/boot/dts/realtek/kent-pinctrl.dtsi
 create mode 100644 drivers/soc/realtek/Kconfig
 create mode 100644 drivers/soc/realtek/Makefile
 create mode 100644 drivers/soc/realtek/rtd-io-detect.c

-- 
2.43.0

[PATCH 1/3] dt-bindings: soc: realtek: Add Realtek DHC I/O level detector

[Yu-Chun Lin]

From: Tzuyi Chang <tychang@realtek.com>

Add device tree binding documentation for the Realtek DHC I/O level
detector.

This hardware block is responsible for detecting the I/O signaling
levels (e.g., 1.8V or 3.3V) of various interfaces (RGMII, SDIO, eMMC,
etc.) and applying the corresponding pad configurations via pinctrl
states.

Signed-off-by: Tzuyi Chang <tychang@realtek.com>
Signed-off-by: Yu-Chun Lin <eleanor.lin@realtek.com>
---
 .../realtek/realtek,rtd1625-io-detect.yaml    | 77 +++++++++++++++++++
 1 file changed, 77 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/soc/realtek/realtek,rtd1625-io-detect.yaml

diff --git a/Documentation/devicetree/bindings/soc/realtek/realtek,rtd1625-io-detect.yaml b/Documentation/devicetree/bindings/soc/realtek/realtek,rtd1625-io-detect.yaml
new file mode 100644
index 000000000000..badf27212dfd
--- /dev/null
+++ b/Documentation/devicetree/bindings/soc/realtek/realtek,rtd1625-io-detect.yaml
@@ -0,0 +1,77 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+# Copyright 2026 Realtek Semiconductor Corporation
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/soc/realtek/realtek,rtd1625-io-detect.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Realtek DHC I/O Level Detector
+
+maintainers:
+  - Tzuyi Chang <tychang@realtek.com>
+
+description: |
+  The Realtek DHC I/O Level Detector is a hardware block that detects I/O
+  signaling levels (such as 1.8V or 3.3V) to determine the correct pad
+  configurations for specific IP blocks.
+
+properties:
+  compatible:
+    const: realtek,rtd1625-io-detect
+
+  pinctrl-names:
+    items:
+      - const: rgmii_1v8
+      - const: rgmii_3v3
+      - const: sdio_1v8
+      - const: sdio_3v3
+      - const: csi_1v8
+      - const: csi_3v3
+      - const: sd_1v8
+      - const: sd_3v3
+      - const: uart1_1v8
+      - const: uart1_3v3
+      - const: aio_1v8
+      - const: aio_3v3
+      - const: emmc_1v8
+      - const: emmc_3v3
+
+  realtek,iso-pinctrl:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      Pinctrl phandle containing I/O detection registers.
+
+required:
+  - compatible
+  - pinctrl-names
+  - realtek,iso-pinctrl
+
+additionalProperties: false
+
+examples:
+  - |
+    io-detect {
+        compatible = "realtek,rtd1625-io-detect";
+        pinctrl-names = "rgmii_1v8", "rgmii_3v3",
+                        "sdio_1v8", "sdio_3v3",
+                        "csi_1v8", "csi_3v3",
+                        "sd_1v8", "sd_3v3",
+                        "uart1_1v8", "uart1_3v3",
+                        "aio_1v8", "aio_3v3",
+                        "emmc_1v8", "emmc_3v3";
+        pinctrl-0 = <&rgmii_vsel_1v8_pins>;
+        pinctrl-1 = <&rgmii_vsel_3v3_pins>;
+        pinctrl-2 = <&sdio_vsel_1v8_pins>;
+        pinctrl-3 = <&sdio_vsel_3v3_pins>;
+        pinctrl-4 = <&csi_vsel_1v8_pins>;
+        pinctrl-5 = <&csi_vsel_3v3_pins>;
+        pinctrl-6 = <&sd_vsel_1v8_pins>;
+        pinctrl-7 = <&sd_vsel_3v3_pins>;
+        pinctrl-8 = <&uart1_vsel_1v8_pins>;
+        pinctrl-9 = <&uart1_vsel_3v3_pins>;
+        pinctrl-10 = <&aio_vsel_1v8_pins>;
+        pinctrl-11 = <&aio_vsel_3v3_pins>;
+        pinctrl-12 = <&emmc_vsel_1v8_pins>;
+        pinctrl-13 = <&emmc_vsel_3v3_pins>;
+        realtek,iso-pinctrl = <&iso_pinctrl>;
+    };
-- 
2.43.0

[PATCH 2/3] soc: realtek: Add driver for DHC I/O level detector

[Yu-Chun Lin]

From: Tzuyi Chang <tychang@realtek.com>

Add driver support for the Realtek DHC I/O level detector.

The driver reads hardware registers to determine the current I/O voltage
levels (e.g., 1.8V or 3.3V) for specific IP blocks. Based on the
detection results, it selects and applies the appropriate pinctrl states
to ensure the correct pad configurations are used.

Signed-off-by: Tzuyi Chang <tychang@realtek.com>
Signed-off-by: Yu-Chun Lin <eleanor.lin@realtek.com>
---
 MAINTAINERS                         |   1 +
 drivers/soc/Kconfig                 |   1 +
 drivers/soc/Makefile                |   1 +
 drivers/soc/realtek/Kconfig         |  21 ++++
 drivers/soc/realtek/Makefile        |   2 +
 drivers/soc/realtek/rtd-io-detect.c | 152 ++++++++++++++++++++++++++++
 6 files changed, 178 insertions(+)
 create mode 100644 drivers/soc/realtek/Kconfig
 create mode 100644 drivers/soc/realtek/Makefile
 create mode 100644 drivers/soc/realtek/rtd-io-detect.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 9ec290e38b44..6121eb4f904e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3379,6 +3379,7 @@ F:	arch/arm/boot/dts/realtek/
 F:	arch/arm/mach-realtek/
 F:	arch/arm64/boot/dts/realtek/
 F:	drivers/pinctrl/realtek/
+F:	drivers/soc/realtek/
 
 ARM/RISC-V/RENESAS ARCHITECTURE
 M:	Geert Uytterhoeven <geert+renesas@glider.be>
diff --git a/drivers/soc/Kconfig b/drivers/soc/Kconfig
index a2d65adffb80..d63b9d4dc042 100644
--- a/drivers/soc/Kconfig
+++ b/drivers/soc/Kconfig
@@ -20,6 +20,7 @@ source "drivers/soc/microchip/Kconfig"
 source "drivers/soc/nuvoton/Kconfig"
 source "drivers/soc/pxa/Kconfig"
 source "drivers/soc/qcom/Kconfig"
+source "drivers/soc/realtek/Kconfig"
 source "drivers/soc/renesas/Kconfig"
 source "drivers/soc/rockchip/Kconfig"
 source "drivers/soc/samsung/Kconfig"
diff --git a/drivers/soc/Makefile b/drivers/soc/Makefile
index c9e689080ceb..8678b1001183 100644
--- a/drivers/soc/Makefile
+++ b/drivers/soc/Makefile
@@ -26,6 +26,7 @@ obj-y				+= nuvoton/
 obj-y				+= pxa/
 obj-y				+= amlogic/
 obj-y				+= qcom/
+obj-y				+= realtek/
 obj-y				+= renesas/
 obj-y				+= rockchip/
 obj-$(CONFIG_SOC_SAMSUNG)	+= samsung/
diff --git a/drivers/soc/realtek/Kconfig b/drivers/soc/realtek/Kconfig
new file mode 100644
index 000000000000..4c5796c7f9f7
--- /dev/null
+++ b/drivers/soc/realtek/Kconfig
@@ -0,0 +1,21 @@
+# SPDX-License-Identifier: GPL-2.0-only
+#
+# Realtek SoC drivers
+#
+menu "Realtek SoC drivers"
+        depends on ARCH_REALTEK || COMPILE_TEST
+
+config RTD_IO_LEVEL_DETECT
+	tristate "Realtek DHC I/O Level Detector"
+	depends on PINCTRL_RTD
+	select MFD_SYSCON
+	default ARCH_REALTEK
+	help
+	  Enable support for the Realtek DHC I/O level detector.
+
+	  This driver handles the auto-detection of I/O signaling levels
+	  (such as 1.8V and 3.3V) and dynamically configures the pad states
+	  for specific IP blocks.
+
+endmenu
+
diff --git a/drivers/soc/realtek/Makefile b/drivers/soc/realtek/Makefile
new file mode 100644
index 000000000000..c307e5bdb52d
--- /dev/null
+++ b/drivers/soc/realtek/Makefile
@@ -0,0 +1,2 @@
+# SPDX-License-Identifier: GPL-2.0-only
+obj-$(CONFIG_RTD_IO_LEVEL_DETECT) += rtd-io-detect.o
diff --git a/drivers/soc/realtek/rtd-io-detect.c b/drivers/soc/realtek/rtd-io-detect.c
new file mode 100644
index 000000000000..84ef8ea23cb5
--- /dev/null
+++ b/drivers/soc/realtek/rtd-io-detect.c
@@ -0,0 +1,152 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Realtek DHC I/O Level Detect driver
+ *
+ * Copyright (c) 2026 Realtek Semiconductor Corp.
+ */
+
+#include <linux/mfd/syscon.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/pinctrl/consumer.h>
+#include <linux/platform_device.h>
+#include <linux/property.h>
+#include <linux/regmap.h>
+
+struct rtd_io_detect_desc_info {
+	const char *name;
+	const char *state_1v8;
+	const char *state_3v3;
+	unsigned int reg_offset;
+	unsigned int en_offset;
+	unsigned int status_offset;
+};
+
+struct rtd_io_detect_descs {
+	const struct rtd_io_detect_desc_info *info;
+	int num_descs;
+};
+
+struct rtd_io_detect_data {
+	const struct rtd_io_detect_descs *descs;
+	struct regmap *base;
+	struct device *dev;
+};
+
+#define RTD_IO_DETECT_DESC(_name, _reg_off, _en_off, _st_off) \
+	{ \
+		.name = #_name, \
+		.state_1v8 = #_name "_1v8", \
+		.state_3v3 = #_name "_3v3", \
+		.reg_offset = _reg_off, \
+		.en_offset = _en_off, \
+		.status_offset = _st_off, \
+	}
+
+static const struct rtd_io_detect_desc_info rtd1625_io_detect_desc[] = {
+	RTD_IO_DETECT_DESC(rgmii, 0x1a0, 8, 1),
+	RTD_IO_DETECT_DESC(sd, 0x1a0, 9, 2),
+	RTD_IO_DETECT_DESC(csi, 0x1a0, 10, 3),
+	RTD_IO_DETECT_DESC(sdio, 0x1a0, 11, 4),
+	RTD_IO_DETECT_DESC(uart1, 0x1a0, 12, 5),
+	RTD_IO_DETECT_DESC(aio, 0x1a0, 13, 6),
+	RTD_IO_DETECT_DESC(emmc, 0x1a0, 14, 7),
+};
+
+static const struct rtd_io_detect_descs rtd1625_io_detect_descs = {
+	.info = rtd1625_io_detect_desc,
+	.num_descs = ARRAY_SIZE(rtd1625_io_detect_desc),
+};
+
+static void detect_io_set(struct pinctrl *pinctrl,
+			  const struct rtd_io_detect_desc_info *desc,
+			  struct rtd_io_detect_data *data)
+{
+	struct pinctrl_state *state_1v8;
+	struct pinctrl_state *state_3v3;
+	unsigned int val;
+	int ret;
+
+	state_1v8 = pinctrl_lookup_state(pinctrl, desc->state_1v8);
+	if (IS_ERR(state_1v8)) {
+		dev_err(data->dev, "Failed to lookup %s state: %ld\n",
+			desc->state_1v8, PTR_ERR(state_1v8));
+		return;
+	}
+
+	state_3v3 = pinctrl_lookup_state(pinctrl, desc->state_3v3);
+	if (IS_ERR(state_3v3)) {
+		dev_err(data->dev, "Failed to lookup %s state: %ld\n",
+			desc->state_3v3, PTR_ERR(state_3v3));
+		return;
+	}
+
+	regmap_update_bits(data->base, desc->reg_offset,
+			   BIT(desc->en_offset), BIT(desc->en_offset));
+
+	regmap_read(data->base, desc->reg_offset, &val);
+
+	ret = pinctrl_select_state(pinctrl,
+				   (val & BIT(desc->status_offset)) ? state_3v3 : state_1v8);
+	if (ret)
+		dev_err(data->dev, "Failed to select pinctrl state\n");
+}
+
+static int rtd_io_detect_probe(struct platform_device *pdev)
+{
+	struct rtd_io_detect_data *data;
+	struct device *dev = &pdev->dev;
+	struct device_node *pinctrl_np;
+	struct pinctrl *pinctrl;
+	int i;
+
+	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+
+	pinctrl_np = of_parse_phandle(dev->of_node, "realtek,iso-pinctrl", 0);
+	if (!pinctrl_np) {
+		dev_err(dev, "Failed to find ISO pinctrl node\n");
+		return -ENODEV;
+	}
+
+	data->base = device_node_to_regmap(pinctrl_np);
+	of_node_put(pinctrl_np);
+
+	if (IS_ERR(data->base))
+		return dev_err_probe(dev, PTR_ERR(data->base), "Failed to get regmap\n");
+
+	data->descs = device_get_match_data(dev);
+	if (!data->descs)
+		return -EINVAL;
+
+	pinctrl = devm_pinctrl_get(dev);
+	if (IS_ERR(pinctrl))
+		return dev_err_probe(dev, PTR_ERR(pinctrl), "Failed to get pinctrl\n");
+
+	data->dev = dev;
+
+	for (i = 0; i < data->descs->num_descs; i++)
+		detect_io_set(pinctrl, &data->descs->info[i], data);
+
+	return 0;
+}
+
+static const struct of_device_id rtd_io_detect_of_matches[] = {
+	{ .compatible = "realtek,rtd1625-io-detect", .data = &rtd1625_io_detect_descs },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, rtd_io_detect_of_matches);
+
+static struct platform_driver rtd_io_detect_driver = {
+	.driver = {
+		.name = "rtd_io_level_detect",
+		.of_match_table = rtd_io_detect_of_matches,
+	},
+	.probe = rtd_io_detect_probe,
+};
+module_platform_driver(rtd_io_detect_driver);
+
+MODULE_DESCRIPTION("Realtek DHC SoC I/O Level Detect driver");
+MODULE_LICENSE("GPL");
+
-- 
2.43.0

[PATCH 3/3] arm64: dts: realtek: Add I/O level detector

[Yu-Chun Lin]

Add io-level-detector node with pinctrl configurations for 1.8V/3.3V
voltage selection on RGMII, SDIO, CSI, SD, UART1, AIO, and eMMC.

Signed-off-by: Yu-Chun Lin <eleanor.lin@realtek.com>
---
This patch depends on this pinctrl node patch [1].
[1] https://git.kernel.org/pub/scm/linux/kernel/git/soc/soc.git/commit/?id=50d92732d10e
---
 arch/arm64/boot/dts/realtek/kent-pinctrl.dtsi | 108 ++++++++++++++++++
 arch/arm64/boot/dts/realtek/kent.dtsi         |  28 +++++
 2 files changed, 136 insertions(+)
 create mode 100644 arch/arm64/boot/dts/realtek/kent-pinctrl.dtsi

diff --git a/arch/arm64/boot/dts/realtek/kent-pinctrl.dtsi b/arch/arm64/boot/dts/realtek/kent-pinctrl.dtsi
new file mode 100644
index 000000000000..ec7e33034b96
--- /dev/null
+++ b/arch/arm64/boot/dts/realtek/kent-pinctrl.dtsi
@@ -0,0 +1,108 @@
+// SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
+/*
+ * Copyright (c) 2022-2026 Realtek Semiconductor Corp.
+ */
+
+&iso_pinctrl {
+	aio_vsel_1v8_pins: aio-vsel-1v8-pins {
+		pins = "gpio_98", "gpio_99", "gpio_100", "gpio_101", "gpio_102", "gpio_103",
+		       "gpio_104", "gpio_105", "gpio_106", "gpio_107", "gpio_108", "gpio_109",
+		       "gpio_110", "gpio_111", "gpio_112";
+		power-source = <0>;
+		input-threshold-voltage-microvolt = <1800000>;
+	};
+
+	aio_vsel_3v3_pins: aio-vsel-3v3-pins {
+		pins = "gpio_98", "gpio_99", "gpio_100", "gpio_101", "gpio_102", "gpio_103",
+		       "gpio_104", "gpio_105", "gpio_106", "gpio_107", "gpio_108", "gpio_109",
+		       "gpio_110", "gpio_111", "gpio_112";
+		power-source = <1>;
+		input-threshold-voltage-microvolt = <3300000>;
+	};
+
+	csi_vsel_1v8_pins: csi-vsel-1v8-pins {
+		pins = "csi_vdsel";
+		function = "csi_1v8";
+	};
+
+	csi_vsel_3v3_pins: csi-vsel-3v3-pins {
+		pins = "csi_vdsel";
+		function = "csi_3v3";
+	};
+
+	rgmii_vsel_1v8_pins: rgmii-vsel-1v8-pins {
+		pins = "rgmii_vdsel";
+		function = "rgmii_1v8";
+	};
+
+	rgmii_vsel_3v3_pins: rgmii-vsel-3v3-pins {
+		pins = "rgmii_vdsel";
+		function = "rgmii_3v3";
+	};
+
+	sdio_vsel_1v8_pins: sdio-vsel-1v8-pins {
+		pins = "gpio_45", "gpio_46", "gpio_47", "gpio_48", "gpio_49", "gpio_50";
+		power-source = <0>;
+	};
+
+	sdio_vsel_3v3_pins: sdio-vsel-3v3-pins {
+		pins = "gpio_45", "gpio_46", "gpio_47", "gpio_48", "gpio_49", "gpio_50";
+		power-source = <1>;
+	};
+
+	uart1_vsel_1v8_pins: uart1-vsel-1v8-pins {
+		pins = "gpio_8", "gpio_9", "gpio_10", "gpio_11";
+		power-source = <0>;
+		input-threshold-voltage-microvolt = <1800000>;
+	};
+
+	uart1_vsel_3v3_pins: uart1-vsel-3v3-pins {
+		pins = "gpio_8", "gpio_9", "gpio_10", "gpio_11";
+		power-source = <1>;
+		input-threshold-voltage-microvolt = <3300000>;
+	};
+};
+
+&main2_pinctrl {
+	emmc_vsel_1v8_pins: emmc-vsel-1v8-pins {
+		pins = "emmc_rst_n",
+			"emmc_dd_sb",
+			"emmc_clk",
+			"emmc_cmd",
+			"emmc_data_0",
+			"emmc_data_1",
+			"emmc_data_2",
+			"emmc_data_3",
+			"emmc_data_4",
+			"emmc_data_5",
+			"emmc_data_6",
+			"emmc_data_7";
+		power-source = <0>;
+	};
+
+	emmc_vsel_3v3_pins: emmc-vsel-3v3-pins {
+		pins = "emmc_rst_n",
+			"emmc_dd_sb",
+			"emmc_clk",
+			"emmc_cmd",
+			"emmc_data_0",
+			"emmc_data_1",
+			"emmc_data_2",
+			"emmc_data_3",
+			"emmc_data_4",
+			"emmc_data_5",
+			"emmc_data_6",
+			"emmc_data_7";
+		power-source = <1>;
+	};
+
+	sd_vsel_1v8_pins: sd-vsel-1v8-pins {
+		pins = "gpio_40", "gpio_41", "hif_clk", "hif_data", "hif_en", "hif_rdy";
+		power-source = <0>;
+	};
+
+	sd_vsel_3v3_pins: sd-vsel-3v3-pins {
+		pins = "gpio_40", "gpio_41", "hif_clk", "hif_data", "hif_en", "hif_rdy";
+		power-source = <1>;
+	};
+};
diff --git a/arch/arm64/boot/dts/realtek/kent.dtsi b/arch/arm64/boot/dts/realtek/kent.dtsi
index 8d4293cd4c03..f18b975c3593 100644
--- a/arch/arm64/boot/dts/realtek/kent.dtsi
+++ b/arch/arm64/boot/dts/realtek/kent.dtsi
@@ -125,6 +125,32 @@ psci: psci {
 		method = "smc";
 	};
 
+	io_level_detector: io-level-detector {
+		compatible = "realtek,rtd1625-io-detect";
+		pinctrl-names = "rgmii_1v8", "rgmii_3v3",
+				"sdio_1v8", "sdio_3v3",
+				"csi_1v8", "csi_3v3",
+				"sd_1v8", "sd_3v3",
+				"uart1_1v8", "uart1_3v3",
+				"aio_1v8", "aio_3v3",
+				"emmc_1v8", "emmc_3v3";
+		pinctrl-0 = <&rgmii_vsel_1v8_pins>;
+		pinctrl-1 = <&rgmii_vsel_3v3_pins>;
+		pinctrl-2 = <&sdio_vsel_1v8_pins>;
+		pinctrl-3 = <&sdio_vsel_3v3_pins>;
+		pinctrl-4 = <&csi_vsel_1v8_pins>;
+		pinctrl-5 = <&csi_vsel_3v3_pins>;
+		pinctrl-6 = <&sd_vsel_1v8_pins>;
+		pinctrl-7 = <&sd_vsel_3v3_pins>;
+		pinctrl-8 = <&uart1_vsel_1v8_pins>;
+		pinctrl-9 = <&uart1_vsel_3v3_pins>;
+		pinctrl-10 = <&aio_vsel_1v8_pins>;
+		pinctrl-11 = <&aio_vsel_3v3_pins>;
+		pinctrl-12 = <&emmc_vsel_1v8_pins>;
+		pinctrl-13 = <&emmc_vsel_3v3_pins>;
+		realtek,iso-pinctrl = <&iso_pinctrl>;
+	};
+
 	soc@0 {
 		compatible = "simple-bus";
 		ranges = <0x0 0x0 0x0 0x40000>, /* boot code */
@@ -184,3 +210,5 @@ gic: interrupt-controller@ff100000 {
 		};
 	};
 };
+
+#include "kent-pinctrl.dtsi"
-- 
2.43.0

Re: [PATCH 1/3] dt-bindings: soc: realtek: Add Realtek DHC I/O level detector

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [High] The binding models a software routine as a virtual hardware node, improperly hijacking pin control from disjoint peripherals.
--

commit fcf36e305148fab2c941a519260634bf6fcea792
Author: Tzuyi Chang <tychang@realtek.com>

dt-bindings: soc: realtek: Add Realtek DHC I/O level detector

This commit adds device tree binding documentation for the Realtek DHC
I/O level detector. The block detects I/O signaling levels and applies
pad configurations via pinctrl states.

> diff --git a/Documentation/devicetree/bindings/soc/realtek/realtek,rtd1625-io-detect.yaml b/Documentation/devicetree/bindings/soc/realtek/realtek,rtd1625-io-detect.yaml
> new file mode 100644
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/soc/realtek/realtek,rtd1625-io-detect.yaml

[ ... ]

> +properties:
> +  compatible:
> +    const: realtek,rtd1625-io-detect
> +
> +  pinctrl-names:
> +    items:
> +      - const: rgmii_1v8
> +      - const: rgmii_3v3
> +      - const: sdio_1v8
> +      - const: sdio_3v3
> +      - const: csi_1v8
> +      - const: csi_3v3
> +      - const: sd_1v8
> +      - const: sd_3v3
> +      - const: uart1_1v8
> +      - const: uart1_3v3
> +      - const: aio_1v8
> +      - const: aio_3v3
> +      - const: emmc_1v8
> +      - const: emmc_3v3

[Severity: High]
Does this centralized approach prevent the actual peripheral drivers from
managing their own pins dynamically?

For example, MMC/SDHCI drivers typically need to switch between 1.8V and
3.3V pinctrl states during UHS enumeration. By statically claiming all
these disjoint states (RGMII, SDIO, eMMC, etc.) in a single node, does
this strip the individual peripheral drivers of their pin ownership and
break standard subsystem-level pin management?

> +
> +  realtek,iso-pinctrl:
> +    $ref: /schemas/types.yaml#/definitions/phandle
> +    description:
> +      Pinctrl phandle containing I/O detection registers.

[Severity: High]
Does this binding describe a software routine rather than actual
hardware topology?

Since there is no reg property and the node accesses registers via the
realtek,iso-pinctrl phandle, this appears to model a virtual device node.
Device tree principles typically require describing hardware topology.

Could the I/O detection logic be modeled within the actual pinctrl
hardware node or peripheral nodes instead?

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260604111821.975624-1-eleanor.lin@realtek.com?part=1

Re: [PATCH 2/3] soc: realtek: Add driver for DHC I/O level detector

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 2 potential issue(s) to consider:
- [High] Ignored return values from regmap operations lead to uninitialized stack variable usage and potential hardware misconfiguration.
- [Low] Unnecessary dynamic memory allocation for probe-only data structure.
--

commit c604ce13442f04b606b3ba51b12003236c8a3ba6
Author: Tzuyi Chang <tychang@realtek.com>

soc: realtek: Add driver for DHC I/O level detector

Add driver support for the Realtek DHC I/O level detector. The driver reads
hardware registers to determine the current I/O voltage levels (e.g., 1.8V
or 3.3V) for specific IP blocks and configures pinctrl states.

> diff --git a/drivers/soc/realtek/rtd-io-detect.c b/drivers/soc/realtek/rtd-io-detect.c
> new file mode 100644
> index 0000000000000..84ef8ea23cb5c
> --- /dev/null
> +++ b/drivers/soc/realtek/rtd-io-detect.c

[ ... ]

> +static void detect_io_set(struct pinctrl *pinctrl,
> +			  const struct rtd_io_detect_desc_info *desc,
> +			  struct rtd_io_detect_data *data)
> +{
> +	struct pinctrl_state *state_1v8;
> +	struct pinctrl_state *state_3v3;
> +	unsigned int val;
> +	int ret;

[ ... ]

> +	regmap_update_bits(data->base, desc->reg_offset,
> +			   BIT(desc->en_offset), BIT(desc->en_offset));
> +
> +	regmap_read(data->base, desc->reg_offset, &val);
> +
> +	ret = pinctrl_select_state(pinctrl,
> +				   (val & BIT(desc->status_offset)) ? state_3v3 : state_1v8);

[Severity: High]
If regmap_update_bits() or regmap_read() fail here, won't val remain
uninitialized?

Since val is used immediately after to select the voltage state, could this
cause the hardware to be misconfigured by applying 3.3V to a 1.8V pad if
it evaluates a garbage stack value?

> +	if (ret)
> +		dev_err(data->dev, "Failed to select pinctrl state\n");
> +}
> +
> +static int rtd_io_detect_probe(struct platform_device *pdev)
> +{
> +	struct rtd_io_detect_data *data;
> +	struct device *dev = &pdev->dev;
> +	struct device_node *pinctrl_np;
> +	struct pinctrl *pinctrl;
> +	int i;
> +
> +	data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;

[Severity: Low]
Does this structure need to be dynamically allocated and tied to the
device lifetime with devm_kzalloc()?

It looks like struct rtd_io_detect_data is only used locally within
rtd_io_detect_probe() to pass arguments into detect_io_set(). Since it is
never saved via platform_set_drvdata() or used in other callbacks, could it
just be allocated on the stack to save memory?

> +
> +	pinctrl_np = of_parse_phandle(dev->of_node, "realtek,iso-pinctrl", 0);
> +	if (!pinctrl_np) {
> +		dev_err(dev, "Failed to find ISO pinctrl node\n");

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260604111821.975624-1-eleanor.lin@realtek.com?part=2

Re: [PATCH 3/3] arm64: dts: realtek: Add I/O level detector

[sashiko-bot]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Device tree compilation fails due to undefined labels `iso_pinctrl` and `main2_pinctrl`.
--

commit 3280d12b516149efbcad054728b0302fe3fcc602
Author: Yu-Chun Lin <eleanor.lin@realtek.com>

arm64: dts: realtek: Add I/O level detector

Add io-level-detector node with pinctrl configurations for 1.8V/3.3V
voltage selection on RGMII, SDIO, CSI, SD, UART1, AIO, and eMMC.

> diff --git a/arch/arm64/boot/dts/realtek/kent-pinctrl.dtsi b/arch/arm64/boot/dts/realtek/kent-pinctrl.dtsi
> new file mode 100644
> index 0000000000000..ec7e33034b967
> --- /dev/null
> +++ b/arch/arm64/boot/dts/realtek/kent-pinctrl.dtsi
> @@ -0,0 +1,108 @@
> +// SPDX-License-Identifier: (GPL-2.0-or-later OR BSD-2-Clause)
> +/*
> + * Copyright (c) 2022-2026 Realtek Semiconductor Corp.
> + */
> +
> +&iso_pinctrl {

[Severity: Low]
Are the labels iso_pinctrl and main2_pinctrl defined anywhere in the device
tree sources?

It appears this causes a DTC compilation error due to using an undefined
label as an overlay target.

> +	aio_vsel_1v8_pins: aio-vsel-1v8-pins {

[ ... ]

> +	uart1_vsel_3v3_pins: uart1-vsel-3v3-pins {
> +		pins = "gpio_8", "gpio_9", "gpio_10", "gpio_11";
> +		power-source = <1>;
> +		input-threshold-voltage-microvolt = <3300000>;
> +	};
> +};
> +
> +&main2_pinctrl {

[Severity: Low]
Does this node also cause a DTC compilation error due to main2_pinctrl being
undefined?

> +	emmc_vsel_1v8_pins: emmc-vsel-1v8-pins {

[ ... ]

> diff --git a/arch/arm64/boot/dts/realtek/kent.dtsi b/arch/arm64/boot/dts/realtek/kent.dtsi
> index ae006ce244205..54e7e2e1cb53d 100644
> --- a/arch/arm64/boot/dts/realtek/kent.dtsi
> +++ b/arch/arm64/boot/dts/realtek/kent.dtsi

[ ... ]

> @@ -125,6 +125,32 @@ psci: psci {
>  		method = "smc";
>  	};
>  
> +	io_level_detector: io-level-detector {
> +		compatible = "realtek,rtd1625-io-detect";

[ ... ]

> +		pinctrl-12 = <&emmc_vsel_1v8_pins>;
> +		pinctrl-13 = <&emmc_vsel_3v3_pins>;
> +		realtek,iso-pinctrl = <&iso_pinctrl>;

[Severity: Low]
Will this phandle reference cause a compilation failure since iso_pinctrl
appears to be undefined?

> +	};

-- 
Sashiko AI review · https://sashiko.dev/#/patchset/20260604111821.975624-1-eleanor.lin@realtek.com?part=3

Re: [PATCH 1/3] dt-bindings: soc: realtek: Add Realtek DHC I/O level detector

[Krzysztof Kozlowski]

On 04/06/2026 13:18, Yu-Chun Lin wrote:
> From: Tzuyi Chang <tychang@realtek.com>
> 
> Add device tree binding documentation for the Realtek DHC I/O level
> detector.
> 
> This hardware block is responsible for detecting the I/O signaling
> levels (e.g., 1.8V or 3.3V) of various interfaces (RGMII, SDIO, eMMC,
> etc.) and applying the corresponding pad configurations via pinctrl
> states.
> 
> Signed-off-by: Tzuyi Chang <tychang@realtek.com>
> Signed-off-by: Yu-Chun Lin <eleanor.lin@realtek.com>
> ---
>  .../realtek/realtek,rtd1625-io-detect.yaml    | 77 +++++++++++++++++++
>  1 file changed, 77 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/soc/realtek/realtek,rtd1625-io-detect.yaml
> 
> diff --git a/Documentation/devicetree/bindings/soc/realtek/realtek,rtd1625-io-detect.yaml b/Documentation/devicetree/bindings/soc/realtek/realtek,rtd1625-io-detect.yaml
> new file mode 100644
> index 000000000000..badf27212dfd
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/soc/realtek/realtek,rtd1625-io-detect.yaml
> @@ -0,0 +1,77 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +# Copyright 2026 Realtek Semiconductor Corporation
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/soc/realtek/realtek,rtd1625-io-detect.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Realtek DHC I/O Level Detector
> +
> +maintainers:
> +  - Tzuyi Chang <tychang@realtek.com>
> +
> +description: |

Drop |

> +  The Realtek DHC I/O Level Detector is a hardware block that detects I/O
> +  signaling levels (such as 1.8V or 3.3V) to determine the correct pad
> +  configurations for specific IP blocks.
> +
> +properties:
> +  compatible:
> +    const: realtek,rtd1625-io-detect
> +

No resources here, so does not look like a real device, but driver
instantiation.


> +  pinctrl-names:
> +    items:
> +      - const: rgmii_1v8
> +      - const: rgmii_3v3
> +      - const: sdio_1v8
> +      - const: sdio_3v3
> +      - const: csi_1v8
> +      - const: csi_3v3
> +      - const: sd_1v8
> +      - const: sd_3v3
> +      - const: uart1_1v8
> +      - const: uart1_3v3
> +      - const: aio_1v8
> +      - const: aio_3v3
> +      - const: emmc_1v8
> +      - const: emmc_3v3
> +
> +  realtek,iso-pinctrl:
> +    $ref: /schemas/types.yaml#/definitions/phandle
> +    description:
> +      Pinctrl phandle containing I/O detection registers.

MMIO registers are in 'reg' property.


> +
> +required:
> +  - compatible
> +  - pinctrl-names
> +  - realtek,iso-pinctrl
Best regards,
Krzysztof