diff --git a/sound/soc/codecs/Kconfig b/sound/soc/codecs/Kconfig
index 7092842480ef..b095eba9d634 100644
--- a/sound/soc/codecs/Kconfig
+++ b/sound/soc/codecs/Kconfig
@@ -1545,6 +1545,11 @@ config SND_SOC_RL6231
 	default m if SND_SOC_RT1305=m
 	default m if SND_SOC_RT1308=m
 
+config SND_SOC_RT_SDW_COMMON
+	tristate
+	default y if SND_SOC_RT721_SDCA_SDW=y
+	default m if SND_SOC_RT721_SDCA_SDW=m
+
 config SND_SOC_RL6347A
 	tristate
 	default y if SND_SOC_RT274=y
diff --git a/sound/soc/codecs/Makefile b/sound/soc/codecs/Makefile
index 54cbc3feae32..4497b2e30cd3 100644
--- a/sound/soc/codecs/Makefile
+++ b/sound/soc/codecs/Makefile
@@ -216,6 +216,7 @@ snd-soc-rk3308-y := rk3308_codec.o
 snd-soc-rk3328-y := rk3328_codec.o
 snd-soc-rk817-y := rk817_codec.o
 snd-soc-rl6231-y := rl6231.o
+snd-soc-rt-sdw-common-y := rt-sdw-common.o
 snd-soc-rl6347a-y := rl6347a.o
 snd-soc-rt1011-y := rt1011.o
 snd-soc-rt1015-y := rt1015.o
@@ -618,6 +619,7 @@ obj-$(CONFIG_SND_SOC_RK3308)	+= snd-soc-rk3308.o
 obj-$(CONFIG_SND_SOC_RK3328)	+= snd-soc-rk3328.o
 obj-$(CONFIG_SND_SOC_RK817)	+= snd-soc-rk817.o
 obj-$(CONFIG_SND_SOC_RL6231)	+= snd-soc-rl6231.o
+obj-$(CONFIG_SND_SOC_RT_SDW_COMMON)	+= snd-soc-rt-sdw-common.o
 obj-$(CONFIG_SND_SOC_RL6347A)	+= snd-soc-rl6347a.o
 obj-$(CONFIG_SND_SOC_RT1011)	+= snd-soc-rt1011.o
 obj-$(CONFIG_SND_SOC_RT1015)	+= snd-soc-rt1015.o
diff --git a/sound/soc/codecs/rt-sdw-common.c b/sound/soc/codecs/rt-sdw-common.c
new file mode 100644
index 000000000000..9ed0e9855699
--- /dev/null
+++ b/sound/soc/codecs/rt-sdw-common.c
@@ -0,0 +1,238 @@
+// SPDX-License-Identifier: GPL-2.0-only
+//
+// rt-sdw-common.c
+//
+// Copyright(c) 2024 Realtek Semiconductor Corp.
+//
+
+/*
+ * This file defines common functions used with Realtek soundwire codecs.
+ */
+
+#include <linux/module.h>
+#include <linux/regmap.h>
+#include <linux/bitops.h>
+#include <linux/soundwire/sdw_registers.h>
+#include <sound/jack.h>
+
+#include "rt-sdw-common.h"
+
+/**
+ * rt_sdca_index_write - Write a value to Realtek defined register.
+ *
+ * @map: map for setting.
+ * @nid: Realtek-defined ID.
+ * @reg: register.
+ * @value: value.
+ *
+ * A value of zero will be returned on success, a negative errno will
+ * be returned in error cases.
+ */
+int rt_sdca_index_write(struct regmap *map, unsigned int nid,
+	unsigned int reg, unsigned int value)
+{
+	unsigned int addr = (nid << 20) | reg;
+	int ret;
+
+	ret = regmap_write(map, addr, value);
+	if (ret < 0)
+		pr_err("Failed to set value: %06x <= %04x ret=%d\n",
+			addr, value, ret);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(rt_sdca_index_write);
+
+/**
+ * rt_sdca_index_read - Read value from Realtek defined register.
+ *
+ * @map: map for setting.
+ * @nid: Realtek-defined ID.
+ * @reg: register.
+ * @value: value.
+ *
+ * A value of zero will be returned on success, a negative errno will
+ * be returned in error cases.
+ */
+int rt_sdca_index_read(struct regmap *map, unsigned int nid,
+	unsigned int reg, unsigned int *value)
+{
+	unsigned int addr = (nid << 20) | reg;
+	int ret;
+
+	ret = regmap_read(map, addr, value);
+	if (ret < 0)
+		pr_err("Failed to get value: %06x => %04x ret=%d\n",
+			addr, *value, ret);
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(rt_sdca_index_read);
+
+/**
+ * rt_sdca_index_update_bits - Update value on Realtek defined register.
+ *
+ * @map: map for setting.
+ * @nid: Realtek-defined ID.
+ * @reg: register.
+ * @mask: Bitmask to change
+ * @value: New value for bitmask
+ *
+ * A value of zero will be returned on success, a negative errno will
+ * be returned in error cases.
+ */
+
+int rt_sdca_index_update_bits(struct regmap *map,
+	unsigned int nid, unsigned int reg, unsigned int mask, unsigned int val)
+{
+	unsigned int tmp;
+	int ret;
+
+	ret = rt_sdca_index_read(map, nid, reg, &tmp);
+	if (ret < 0)
+		return ret;
+
+	set_mask_bits(&tmp, mask, val);
+	return rt_sdca_index_write(map, nid, reg, tmp);
+}
+EXPORT_SYMBOL_GPL(rt_sdca_index_update_bits);
+
+/**
+ * rt_sdca_btn_type - Decision of button type.
+ *
+ * @buffer: UMP message buffer.
+ *
+ * A button type will be returned regarding to buffer,
+ * it returns zero if buffer cannot be recognized.
+ */
+int rt_sdca_btn_type(unsigned char *buffer)
+{
+	u8 btn_type = 0;
+	int ret;
+
+	btn_type |= buffer[0] & 0xf;
+	btn_type |= (buffer[0] >> 4) & 0xf;
+	btn_type |= buffer[1] & 0xf;
+	btn_type |= (buffer[1] >> 4) & 0xf;
+
+	if (btn_type & BIT(0))
+		ret |= SND_JACK_BTN_2;
+	if (btn_type & BIT(1))
+		ret |= SND_JACK_BTN_3;
+	if (btn_type & BIT(2))
+		ret |= SND_JACK_BTN_0;
+	if (btn_type & BIT(3))
+		ret |= SND_JACK_BTN_1;
+
+	return ret;
+}
+EXPORT_SYMBOL_GPL(rt_sdca_btn_type);
+
+/**
+ * rt_sdca_headset_detect - Headset jack type detection.
+ *
+ * @map: map for setting.
+ * @entity_id: SDCA entity ID.
+ *
+ * A headset jack type will be returned, a negative errno will
+ * be returned in error cases.
+ */
+int rt_sdca_headset_detect(struct regmap *map, unsigned int entity_id)
+{
+	unsigned int det_mode, jack_type;
+	int ret;
+
+	/* get detected_mode */
+	ret = regmap_read(map, SDW_SDCA_CTL(SDCA_NUM_JACK_CODEC, entity_id,
+			RT_SDCA_CTL_DETECTED_MODE, 0), &det_mode);
+
+	if (ret < 0)
+		goto io_error;
+
+	switch (det_mode) {
+	case 0x00:
+		jack_type = 0;
+		break;
+	case 0x03:
+		jack_type = SND_JACK_HEADPHONE;
+		break;
+	case 0x05:
+		jack_type = SND_JACK_HEADSET;
+		break;
+	}
+
+	/* write selected_mode */
+	if (det_mode) {
+		ret = regmap_write(map, SDW_SDCA_CTL(SDCA_NUM_JACK_CODEC, entity_id,
+				RT_SDCA_CTL_SELECTED_MODE, 0), det_mode);
+		if (ret < 0)
+			goto io_error;
+	}
+
+	return jack_type;
+
+io_error:
+	pr_err_ratelimited("IO error in %s, ret %d\n", __func__, ret);
+	return ret;
+}
+EXPORT_SYMBOL_GPL(rt_sdca_headset_detect);
+
+/**
+ * rt_sdca_button_detect - Read UMP message and decide button type.
+ *
+ * @map: map for setting.
+ * @entity_id: SDCA entity ID.
+ * @hid_buf_addr: HID buffer address.
+ * @hid_id: Report ID for HID.
+ *
+ * A button type will be returned regarding to buffer,
+ * it returns zero if buffer cannot be recognized.
+ */
+int rt_sdca_button_detect(struct regmap *map, unsigned int entity_id,
+	unsigned int hid_buf_addr, unsigned int hid_id)
+{
+	unsigned int btn_type = 0, offset, idx, val, owner;
+	unsigned char buf[3];
+	int ret;
+
+	/* get current UMP message owner */
+	ret = regmap_read(map, SDW_SDCA_CTL(SDCA_NUM_HID, entity_id,
+			RT_SDCA_CTL_HIDTX_CURRENT_OWNER, 0), &owner);
+	if (ret < 0)
+		return 0;
+
+	/* if owner is device then there is no button event from device */
+	if (owner == 1)
+		return 0;
+
+	/* read UMP message offset */
+	ret = regmap_read(map, SDW_SDCA_CTL(SDCA_NUM_HID, entity_id,
+			RT_SDCA_CTL_HIDTX_MESSAGE_OFFSET, 0), &offset);
+	if (ret < 0)
+		goto _end_btn_det_;
+
+	for (idx = 0; idx < sizeof(buf); idx++) {
+		ret = regmap_read(map, hid_buf_addr + offset + idx, &val);
+		if (ret < 0)
+			goto _end_btn_det_;
+		buf[idx] = val & 0xff;
+	}
+	/* Report ID for HID */
+	if (buf[0] == hid_id)
+		btn_type = rt_sdca_btn_type(&buf[1]);
+
+_end_btn_det_:
+	/* Host is owner, so set back to device */
+	if (owner == 0)
+		/* set owner to device */
+		regmap_write(map,
+			SDW_SDCA_CTL(SDCA_NUM_HID, entity_id,
+				RT_SDCA_CTL_HIDTX_CURRENT_OWNER, 0), 0x01);
+
+	return btn_type;
+}
+EXPORT_SYMBOL_GPL(rt_sdca_button_detect);
+
+MODULE_DESCRIPTION("Realtek soundwire common functions");
+MODULE_AUTHOR("jack yu <jack.yu@realtek.com>");
+MODULE_LICENSE("GPL");
diff --git a/sound/soc/codecs/rt-sdw-common.h b/sound/soc/codecs/rt-sdw-common.h
new file mode 100644
index 000000000000..4759516feb38
--- /dev/null
+++ b/sound/soc/codecs/rt-sdw-common.h
@@ -0,0 +1,66 @@
+/* SPDX-License-Identifier: GPL-2.0-only */
+//
+// rt-sdw-common.h
+//
+// Copyright(c) 2024 Realtek Semiconductor Corp.
+//
+
+/*
+ * This file defines common functions used with Realtek soundwire codecs.
+ */
+
+#ifndef __RT_SDW_COMMON_H__
+#define __RT_SDW_COMMON_H__
+
+#define SDCA_NUM_JACK_CODEC			0x01
+#define SDCA_NUM_MIC_ARRAY			0x02
+#define SDCA_NUM_HID				0x03
+#define SDCA_NUM_AMP				0x04
+#define RT_SDCA_CTL_SELECTED_MODE		0x01
+#define RT_SDCA_CTL_DETECTED_MODE		0x02
+#define RT_SDCA_CTL_HIDTX_CURRENT_OWNER		0x10
+#define RT_SDCA_CTL_HIDTX_MESSAGE_OFFSET	0x12
+
+struct rt_sdca_dmic_kctrl_priv {
+	unsigned int reg_base;
+	unsigned int count;
+	unsigned int max;
+	unsigned int invert;
+};
+
+#define RT_SDCA_PR_VALUE(xreg_base, xcount, xmax, xinvert) \
+	((unsigned long)&(struct rt_sdca_dmic_kctrl_priv) \
+		{.reg_base = xreg_base, .count = xcount, .max = xmax, \
+		.invert = xinvert})
+
+#define RT_SDCA_FU_CTRL(xname, reg_base, xmax, xinvert, xcount, \
+	xinfo, xget, xput) \
+{	.iface = SNDRV_CTL_ELEM_IFACE_MIXER, .name = (xname), \
+	.info = xinfo, \
+	.get = xget, \
+	.put = xput, \
+	.private_value = RT_SDCA_PR_VALUE(reg_base, xcount, xmax, xinvert)}
+
+#define RT_SDCA_EXT_TLV(xname, reg_base, xhandler_get,\
+	 xhandler_put, xcount, xmax, tlv_array, xinfo) \
+{	.iface = SNDRV_CTL_ELEM_IFACE_MIXER, .name = (xname), \
+	.access = SNDRV_CTL_ELEM_ACCESS_TLV_READ | \
+		 SNDRV_CTL_ELEM_ACCESS_READWRITE, \
+	.tlv.p = (tlv_array), \
+	.info = xinfo, \
+	.get = xhandler_get, .put = xhandler_put, \
+	.private_value = RT_SDCA_PR_VALUE(reg_base, xcount, xmax, 0) }
+
+
+int rt_sdca_index_write(struct regmap *map, unsigned int nid,
+	unsigned int reg, unsigned int value);
+int rt_sdca_index_read(struct regmap *map, unsigned int nid,
+	unsigned int reg, unsigned int *value);
+int rt_sdca_index_update_bits(struct regmap *map,
+	unsigned int nid, unsigned int reg, unsigned int mask, unsigned int val);
+int rt_sdca_btn_type(unsigned char *buffer);
+int rt_sdca_headset_detect(struct regmap *map, unsigned int entity_id);
+int rt_sdca_button_detect(struct regmap *map, unsigned int entity_id,
+	unsigned int hid_buf_addr, unsigned int hid_id);
+
+#endif /* __RT_SDW_COMMON_H__ */
