* [PATCH v4 1/2] dt-bindings: usb: Add ITE IT8851/IT8853 Type-C PD controllers
2026-07-17 9:59 [PATCH v4 0/2] usb: typec: ucsi: Add ITE IT8851/IT8853 support Amber Kao
@ 2026-07-17 9:59 ` Amber Kao
2026-07-17 9:59 ` [PATCH v4 2/2] usb: typec: ucsi: Add ITE IT8851/IT8853 Type-C PD controller driver Amber Kao
1 sibling, 0 replies; 4+ messages in thread
From: Amber Kao @ 2026-07-17 9:59 UTC (permalink / raw)
To: Jeson Yang, Yaode Fang, Greg Kroah-Hartman, Rob Herring,
Krzysztof Kozlowski, Conor Dooley, Heikki Krogerus
Cc: linux-usb, devicetree, linux-kernel, Amber Kao, Bling Chiang,
Eric Su, Doreen Lin
Add device tree binding for the ITE IT8851 and IT8853 I2C-based USB
Type-C Power Delivery controllers.
The IT8851 supports one Type-C port; the IT8853 is the two-port variant
sharing the same interface.
Add a MAINTAINERS entry for the binding.
Cc: Yaode Fang <Yaode.Fang@ite.com.tw>
Cc: Jeson Yang <jeson.yang@ite.com.tw>
Cc: Bling Chiang <Bling.Chiang@ite.com.tw>
Cc: Eric Su <Eric.Su@ite.com.tw>
Cc: Doreen Lin <doreen.lin@ite.com.tw>
Signed-off-by: Amber Kao <amber.kao@ite.com.tw>
---
.../devicetree/bindings/usb/ite,it8851.yaml | 142 +++++++++++++++++++++
MAINTAINERS | 8 ++
2 files changed, 150 insertions(+)
diff --git a/Documentation/devicetree/bindings/usb/ite,it8851.yaml b/Documentation/devicetree/bindings/usb/ite,it8851.yaml
new file mode 100644
index 000000000000..97c1e5490518
--- /dev/null
+++ b/Documentation/devicetree/bindings/usb/ite,it8851.yaml
@@ -0,0 +1,142 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/usb/ite,it8851.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: ITE IT8851/IT8853 USB Type-C Power Delivery Controller
+
+maintainers:
+ - Jeson Yang <jeson.yang@ite.com.tw>
+
+description:
+ The ITE IT8851 is an I2C-based USB Type-C Power Delivery (PD) controller
+ supporting one Type-C port.
+ The IT8853 is the two-port variant sharing the same programming interface.
+
+properties:
+ compatible:
+ enum:
+ - ite,it8851
+ - ite,it8853
+
+ reg:
+ maxItems: 1
+
+ interrupts:
+ maxItems: 1
+
+ wakeup-source: true
+
+ '#address-cells':
+ const: 1
+
+ '#size-cells':
+ const: 0
+
+patternProperties:
+ "^connector@[01]$":
+ $ref: /schemas/connector/usb-connector.yaml#
+ unevaluatedProperties: false
+
+required:
+ - compatible
+ - reg
+ - interrupts
+
+allOf:
+ - if:
+ properties:
+ compatible:
+ contains:
+ const: ite,it8851
+ then:
+ properties:
+ connector@1: false
+
+unevaluatedProperties: false
+
+examples:
+ - |
+ #include <dt-bindings/interrupt-controller/irq.h>
+
+ i2c {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ typec@40 {
+ compatible = "ite,it8853";
+ reg = <0x40>;
+ interrupts-extended = <&tlmm 129 IRQ_TYPE_EDGE_FALLING>;
+ wakeup-source;
+
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ connector@0 {
+ compatible = "usb-c-connector";
+ reg = <0>;
+ label = "USB-C-0";
+ power-role = "dual";
+ data-role = "dual";
+
+ ports {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ port@0 {
+ reg = <0>;
+ endpoint {
+ remote-endpoint = <&eud_con>;
+ };
+ };
+
+ port@1 {
+ reg = <1>;
+ endpoint {
+ remote-endpoint = <&redriver_ss_out>;
+ };
+ };
+
+ port@2 {
+ reg = <2>;
+ endpoint {
+ remote-endpoint = <&fsa4480_sbu_mux>;
+ };
+ };
+ };
+ };
+
+ connector@1 {
+ compatible = "usb-c-connector";
+ reg = <1>;
+ label = "USB-C-1";
+ power-role = "dual";
+ data-role = "dual";
+
+ ports {
+ #address-cells = <1>;
+ #size-cells = <0>;
+
+ port@0 {
+ reg = <0>;
+ endpoint {
+ remote-endpoint = <&usb1_hs_con>;
+ };
+ };
+ port@1 {
+ reg = <1>;
+ endpoint {
+ remote-endpoint = <&redriver1_ss_out>;
+ };
+ };
+ port@2 {
+ reg = <2>;
+ endpoint {
+ remote-endpoint = <&sbu_mux1>;
+ };
+ };
+ };
+ };
+ };
+ };
diff --git a/MAINTAINERS b/MAINTAINERS
index 461a3eed6129..ec0eeea79b9e 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13720,6 +13720,14 @@ T: git https://gitlab.freedesktop.org/drm/misc/kernel.git
F: Documentation/devicetree/bindings/display/bridge/ite,it66121.yaml
F: drivers/gpu/drm/bridge/ite-it66121.c
+ITE IT8851 TYPE-C PD CONTROLLER DRIVER
+M: Amber Kao <amber.kao@ite.com.tw>
+R: Jeson Yang <jeson.yang@ite.com.tw>
+R: Yaode Fang <Yaode.Fang@ite.com.tw>
+L: linux-usb@vger.kernel.org
+S: Maintained
+F: Documentation/devicetree/bindings/usb/ite,it8851.yaml
+
IVTV VIDEO4LINUX DRIVER
M: Andy Walls <awalls@md.metrocast.net>
L: linux-media@vger.kernel.org
--
2.53.0
^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH v4 2/2] usb: typec: ucsi: Add ITE IT8851/IT8853 Type-C PD controller driver
2026-07-17 9:59 [PATCH v4 0/2] usb: typec: ucsi: Add ITE IT8851/IT8853 support Amber Kao
2026-07-17 9:59 ` [PATCH v4 1/2] dt-bindings: usb: Add ITE IT8851/IT8853 Type-C PD controllers Amber Kao
@ 2026-07-17 9:59 ` Amber Kao
2026-07-17 10:12 ` sashiko-bot
1 sibling, 1 reply; 4+ messages in thread
From: Amber Kao @ 2026-07-17 9:59 UTC (permalink / raw)
To: Jeson Yang, Yaode Fang, Greg Kroah-Hartman, Rob Herring,
Krzysztof Kozlowski, Conor Dooley, Heikki Krogerus
Cc: linux-usb, devicetree, linux-kernel, Amber Kao, Bling Chiang,
Eric Su, Doreen Lin
Add a UCSI driver for the ITE IT8851 and IT8853 I2C-based USB Type-C
Power Delivery controllers.
The controller signals UCSI through a shared interrupt line; events are
read and acknowledged via vendor-specific registers, and
UCSI events are forwarded to the UCSI core.
Add the driver file to the MAINTAINERS entry.
Cc: Yaode Fang <Yaode.Fang@ite.com.tw>
Cc: Jeson Yang <jeson.yang@ite.com.tw>
Cc: Bling Chiang <Bling.Chiang@ite.com.tw>
Cc: Eric Su <Eric.Su@ite.com.tw>
Cc: Doreen Lin <doreen.lin@ite.com.tw>
Signed-off-by: Amber Kao <amber.kao@ite.com.tw>
---
MAINTAINERS | 1 +
drivers/usb/typec/ucsi/Kconfig | 10 +
drivers/usb/typec/ucsi/Makefile | 1 +
drivers/usb/typec/ucsi/ucsi_itepd.c | 381 ++++++++++++++++++++++++++++++++++++
4 files changed, 393 insertions(+)
diff --git a/MAINTAINERS b/MAINTAINERS
index ec0eeea79b9e..1e76e299e6c3 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13727,6 +13727,7 @@ R: Yaode Fang <Yaode.Fang@ite.com.tw>
L: linux-usb@vger.kernel.org
S: Maintained
F: Documentation/devicetree/bindings/usb/ite,it8851.yaml
+F: drivers/usb/typec/ucsi/ucsi_itepd.c
IVTV VIDEO4LINUX DRIVER
M: Andy Walls <awalls@md.metrocast.net>
diff --git a/drivers/usb/typec/ucsi/Kconfig b/drivers/usb/typec/ucsi/Kconfig
index 87dd992a4b9e..0f10dac9b34b 100644
--- a/drivers/usb/typec/ucsi/Kconfig
+++ b/drivers/usb/typec/ucsi/Kconfig
@@ -104,4 +104,14 @@ config UCSI_HUAWEI_GAOKUN
To compile the driver as a module, choose M here: the module will be
called ucsi_huawei_gaokun.
+config UCSI_ITEPD
+ tristate "UCSI Interface Driver for ITE IT8851/IT8853"
+ depends on I2C
+ help
+ This driver enables UCSI support on platforms that expose an
+ ITE IT8851/IT8853 Type-C Power Delivery controller over an I2C interface.
+
+ To compile the driver as a module, choose M here: the module
+ will be called ucsi_itepd.
+
endif
diff --git a/drivers/usb/typec/ucsi/Makefile b/drivers/usb/typec/ucsi/Makefile
index c7e38bf01350..0903a1fd486b 100644
--- a/drivers/usb/typec/ucsi/Makefile
+++ b/drivers/usb/typec/ucsi/Makefile
@@ -28,3 +28,4 @@ obj-$(CONFIG_UCSI_PMIC_GLINK) += ucsi_glink.o
obj-$(CONFIG_CROS_EC_UCSI) += cros_ec_ucsi.o
obj-$(CONFIG_UCSI_LENOVO_YOGA_C630) += ucsi_yoga_c630.o
obj-$(CONFIG_UCSI_HUAWEI_GAOKUN) += ucsi_huawei_gaokun.o
+obj-$(CONFIG_UCSI_ITEPD) += ucsi_itepd.o
diff --git a/drivers/usb/typec/ucsi/ucsi_itepd.c b/drivers/usb/typec/ucsi/ucsi_itepd.c
new file mode 100644
index 000000000000..ceaadb0b3fef
--- /dev/null
+++ b/drivers/usb/typec/ucsi/ucsi_itepd.c
@@ -0,0 +1,381 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2025-2026, ITE. All Rights Reserved
+ *
+ */
+#include <linux/bits.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/mutex.h>
+#include <linux/slab.h>
+#include <linux/unaligned.h>
+
+#include "ucsi.h"
+
+#define ITEPD_UCSI_VERSION_REG 0x80
+#define ITEPD_UCSI_CCI_REG 0x84
+#define ITEPD_UCSI_MSG_IN_REG 0x88
+#define ITEPD_UCSI_CONTROL_REG 0x98
+
+#define ITEPD_VENDOR_WC_INT 0xbc
+#define ITEPD_VENDOR_INT 0xbd
+#define ITEPD_ALERT_VDM_EVENT BIT(0)
+#define ITEPD_ALERT_UCSI_EVENT BIT(1)
+
+#define ITEPD_MSG_IN_MAX_LEN 0x28
+
+#define ITEPD_EVENT_NONE 0
+#define ITEPD_EVENT_UCSI 1
+#define ITEPD_EVENT_VDM 2
+
+struct itepd {
+ struct i2c_client *client;
+ struct ucsi *ucsi;
+ struct mutex i2c_lock; /* Serializes I2C accesses */
+ struct mutex event_lock; /* Serializes event processing (IRQ vs poll) */
+ struct mutex received_lock; /* Protects cci and msg_in */
+ u8 msg_in[ITEPD_MSG_IN_MAX_LEN];
+ u32 cci;
+};
+
+static u8 ucsi_itepd_get_len(u32 cci)
+{
+ if (cci & UCSI_CCI_COMMAND_COMPLETE)
+ return UCSI_CCI_LENGTH(cci);
+ return 0;
+}
+
+static int itepd_read_reg(struct itepd *itepd, u8 reg, void *data, u32 len)
+{
+ struct i2c_client *client = itepd->client;
+ struct i2c_msg msg[2];
+ u8 *tx_buf, *rx_buf;
+ int ret;
+
+ tx_buf = kzalloc(1, GFP_KERNEL);
+ if (!tx_buf)
+ return -ENOMEM;
+
+ rx_buf = kzalloc(len, GFP_KERNEL);
+ if (!rx_buf) {
+ kfree(tx_buf);
+ return -ENOMEM;
+ }
+
+ tx_buf[0] = reg;
+
+ msg[0].addr = client->addr;
+ msg[0].flags = 0;
+ msg[0].len = 1;
+ msg[0].buf = tx_buf;
+
+ msg[1].addr = client->addr;
+ msg[1].flags = I2C_M_RD;
+ msg[1].len = len;
+ msg[1].buf = rx_buf;
+
+ mutex_lock(&itepd->i2c_lock);
+ ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
+ mutex_unlock(&itepd->i2c_lock);
+ if (ret < 0) {
+ dev_err_ratelimited(&client->dev, "reg 0x%02x read failed: %d\n",
+ reg, ret);
+ goto out_free;
+ }
+ if (ret != ARRAY_SIZE(msg)) {
+ ret = -EIO;
+ goto out_free;
+ }
+
+ memcpy(data, rx_buf, len);
+ ret = 0;
+
+out_free:
+ kfree(rx_buf);
+ kfree(tx_buf);
+ return ret;
+}
+
+static int itepd_write_reg(struct itepd *itepd, u8 reg, const void *data, u32 len)
+{
+ struct i2c_client *client = itepd->client;
+ struct i2c_msg msg[1];
+ u8 *tx_buf;
+ int ret;
+
+ tx_buf = kzalloc(len + 1, GFP_KERNEL);
+ if (!tx_buf)
+ return -ENOMEM;
+
+ tx_buf[0] = reg;
+ memcpy(tx_buf + 1, data, len);
+
+ msg[0].addr = client->addr;
+ msg[0].flags = 0;
+ msg[0].len = len + 1;
+ msg[0].buf = tx_buf;
+
+ mutex_lock(&itepd->i2c_lock);
+ ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
+ mutex_unlock(&itepd->i2c_lock);
+ if (ret < 0) {
+ dev_err_ratelimited(&client->dev, "reg 0x%02x write failed: %d\n",
+ reg, ret);
+ goto out_free;
+ }
+ if (ret != ARRAY_SIZE(msg)) {
+ ret = -EIO;
+ goto out_free;
+ }
+
+ ret = 0;
+
+out_free:
+ kfree(tx_buf);
+ return ret;
+}
+
+static int itepd_process_event(struct itepd *itepd, u32 *cci)
+{
+ u8 msg_in[ITEPD_MSG_IN_MAX_LEN] = {};
+ __le32 le_cci;
+ u8 event, ack;
+ u8 len = 0;
+ int ret;
+
+ mutex_lock(&itepd->event_lock);
+
+ ret = itepd_read_reg(itepd, ITEPD_VENDOR_INT, &event, sizeof(event));
+ if (ret)
+ goto out_unlock;
+
+ event &= ITEPD_ALERT_VDM_EVENT | ITEPD_ALERT_UCSI_EVENT;
+ if (!event) {
+ mutex_lock(&itepd->received_lock);
+ *cci = itepd->cci;
+ mutex_unlock(&itepd->received_lock);
+ ret = ITEPD_EVENT_NONE;
+ goto out_unlock;
+ }
+
+ if (event & ITEPD_ALERT_UCSI_EVENT) {
+ ret = itepd_read_reg(itepd, ITEPD_UCSI_CCI_REG, &le_cci,
+ sizeof(le_cci));
+ if (ret)
+ goto out_unlock;
+
+ *cci = le32_to_cpu(le_cci);
+ len = min_t(u8, ucsi_itepd_get_len(*cci), sizeof(msg_in));
+ if (len) {
+ ret = itepd_read_reg(itepd, ITEPD_UCSI_MSG_IN_REG,
+ msg_in, len);
+ if (ret)
+ goto out_unlock;
+ }
+ }
+
+ ack = event;
+ ret = itepd_write_reg(itepd, ITEPD_VENDOR_WC_INT, &ack, sizeof(ack));
+ if (ret)
+ goto out_unlock;
+
+ if (event & ITEPD_ALERT_UCSI_EVENT) {
+ mutex_lock(&itepd->received_lock);
+ itepd->cci = *cci;
+ memset(itepd->msg_in, 0, sizeof(itepd->msg_in));
+ memcpy(itepd->msg_in, msg_in, len);
+ mutex_unlock(&itepd->received_lock);
+ ret = ITEPD_EVENT_UCSI;
+ } else {
+ mutex_lock(&itepd->received_lock);
+ *cci = itepd->cci;
+ mutex_unlock(&itepd->received_lock);
+ ret = ITEPD_EVENT_VDM;
+ }
+
+out_unlock:
+ mutex_unlock(&itepd->event_lock);
+ return ret;
+}
+
+static int ucsi_itepd_read_version(struct ucsi *ucsi, u16 *version)
+{
+ struct itepd *itepd = ucsi_get_drvdata(ucsi);
+ __le16 le_version;
+ int ret;
+
+ ret = itepd_read_reg(itepd, ITEPD_UCSI_VERSION_REG, &le_version,
+ sizeof(le_version));
+ if (ret)
+ return ret;
+
+ *version = le16_to_cpu(le_version);
+
+ return 0;
+}
+
+static int ucsi_itepd_read_cci(struct ucsi *ucsi, u32 *cci)
+{
+ struct itepd *itepd = ucsi_get_drvdata(ucsi);
+
+ mutex_lock(&itepd->received_lock);
+ *cci = itepd->cci;
+ mutex_unlock(&itepd->received_lock);
+
+ return 0;
+}
+
+static int ucsi_itepd_poll_cci(struct ucsi *ucsi, u32 *cci)
+{
+ struct itepd *itepd = ucsi_get_drvdata(ucsi);
+ int ret;
+
+ ret = itepd_process_event(itepd, cci);
+ return ret < 0 ? ret : 0;
+}
+
+static int ucsi_itepd_read_message_in(struct ucsi *ucsi, void *val, size_t val_len)
+{
+ struct itepd *itepd = ucsi_get_drvdata(ucsi);
+
+ mutex_lock(&itepd->received_lock);
+ memcpy(val, itepd->msg_in, min(val_len, sizeof(itepd->msg_in)));
+ mutex_unlock(&itepd->received_lock);
+
+ return 0;
+}
+
+static int ucsi_itepd_async_control(struct ucsi *ucsi, u64 command)
+{
+ struct itepd *itepd = ucsi_get_drvdata(ucsi);
+ __le64 le_cmd = cpu_to_le64(command);
+
+ if (UCSI_COMMAND(command) == UCSI_PPM_RESET) {
+ mutex_lock(&itepd->received_lock);
+ itepd->cci = 0;
+ mutex_unlock(&itepd->received_lock);
+ }
+
+ return itepd_write_reg(itepd, ITEPD_UCSI_CONTROL_REG, &le_cmd,
+ sizeof(le_cmd));
+}
+
+static const struct ucsi_operations ucsi_itepd_ops = {
+ .read_version = ucsi_itepd_read_version,
+ .read_cci = ucsi_itepd_read_cci,
+ .poll_cci = ucsi_itepd_poll_cci,
+ .read_message_in = ucsi_itepd_read_message_in,
+ .sync_control = ucsi_sync_control_common,
+ .async_control = ucsi_itepd_async_control,
+};
+
+static irqreturn_t itepd_irq_process(struct itepd *itepd)
+{
+ u32 cci;
+ int ret;
+
+ ret = itepd_process_event(itepd, &cci);
+ if (ret < 0 || ret == ITEPD_EVENT_NONE)
+ return IRQ_NONE;
+
+ if (ret == ITEPD_EVENT_UCSI)
+ ucsi_notify_common(itepd->ucsi, cci);
+
+ return IRQ_HANDLED;
+}
+
+static irqreturn_t itepd_irq_thread_fn(int irq, void *data)
+{
+ struct itepd *itepd = data;
+
+ return itepd_irq_process(itepd);
+}
+
+static int itepd_probe(struct i2c_client *client)
+{
+ struct device *dev = &client->dev;
+ struct itepd *itepd;
+ u32 cci;
+ int ret;
+
+ if (client->irq <= 0)
+ return dev_err_probe(dev, -ENODEV, "no IRQ provided\n");
+
+ itepd = devm_kzalloc(dev, sizeof(*itepd), GFP_KERNEL);
+ if (!itepd)
+ return -ENOMEM;
+
+ itepd->client = client;
+ mutex_init(&itepd->i2c_lock);
+ mutex_init(&itepd->event_lock);
+ mutex_init(&itepd->received_lock);
+ i2c_set_clientdata(client, itepd);
+
+ itepd->ucsi = ucsi_create(dev, &ucsi_itepd_ops);
+ if (IS_ERR(itepd->ucsi))
+ return PTR_ERR(itepd->ucsi);
+
+ ucsi_set_drvdata(itepd->ucsi, itepd);
+
+ ret = request_threaded_irq(client->irq, NULL, itepd_irq_thread_fn,
+ IRQF_ONESHOT, dev_name(dev), itepd);
+ if (ret) {
+ dev_err(dev, "request_threaded_irq failed - %d\n", ret);
+ goto out_ucsi_destroy;
+ }
+
+ itepd_process_event(itepd, &cci);
+
+ ret = ucsi_register(itepd->ucsi);
+ if (ret) {
+ dev_err(dev, "failed to register UCSI: %d\n", ret);
+ goto out_free_irq;
+ }
+
+ return 0;
+
+out_free_irq:
+ free_irq(client->irq, itepd);
+out_ucsi_destroy:
+ ucsi_destroy(itepd->ucsi);
+ return ret;
+}
+
+static void itepd_remove(struct i2c_client *client)
+{
+ struct itepd *itepd = i2c_get_clientdata(client);
+
+ ucsi_unregister(itepd->ucsi);
+ free_irq(client->irq, itepd);
+ ucsi_destroy(itepd->ucsi);
+}
+
+static const struct of_device_id itepd_of_match_table[] = {
+ { .compatible = "ite,it8851" },
+ { .compatible = "ite,it8853" },
+ {}
+};
+MODULE_DEVICE_TABLE(of, itepd_of_match_table);
+
+static const struct i2c_device_id itepd_id_table[] = {
+ { "ucsi_itepd", 0 },
+ {}
+};
+MODULE_DEVICE_TABLE(i2c, itepd_id_table);
+
+static struct i2c_driver itepd_driver = {
+ .driver = {
+ .name = "ucsi_itepd",
+ .of_match_table = itepd_of_match_table,
+ },
+ .probe = itepd_probe,
+ .remove = itepd_remove,
+ .id_table = itepd_id_table,
+};
+module_i2c_driver(itepd_driver);
+
+MODULE_AUTHOR("Jeson Yang <jeson.yang@ite.com.tw>");
+MODULE_DESCRIPTION("UCSI driver for ITE IT8851 and IT8853 Type-C PD controllers");
+MODULE_LICENSE("GPL");
--
2.53.0
^ permalink raw reply related [flat|nested] 4+ messages in thread