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[5.198.68.184]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-439fe22529csm21876575f8f.31.2026.03.13.18.32.11 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 13 Mar 2026 18:32:11 -0700 (PDT) From: Edward Blair To: linux-i2c@vger.kernel.org, linux-usb@vger.kernel.org Cc: heikki.krogerus@linux.intel.com, gregkh@linuxfoundation.org, wsa+renesas@sang-engineering.com, westeri@kernel.org, linux-acpi@vger.kernel.org, linux-kernel@vger.kernel.org, Edward Blair Subject: [PATCH 2/2] usb: typec: ucsi: add ITE885x I2C transport driver Date: Sat, 14 Mar 2026 01:31:56 +0000 Message-ID: <20260314013157.7181-3-edward.blair@gmail.com> X-Mailer: git-send-email 2.53.0 In-Reply-To: <20260314013157.7181-1-edward.blair@gmail.com> References: <20260314013157.7181-1-edward.blair@gmail.com> Precedence: bulk X-Mailing-List: linux-usb@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Add a UCSI transport driver for ITE8853/ITE8800-ITE8805 USB Type-C controllers, commonly found on ASUS Z690/Z790/X670E motherboards. These controllers implement the UCSI protocol over I2C with ITE-proprietary register offsets and dedicated interrupt registers: - CCI at 0x84, MESSAGE_IN at 0x88, CONTROL at 0x98 - INT_STATUS at 0xBD, INT_ACK at 0xBC - GPIO interrupt (level-triggered, active-low) The ITE8853 does not accept PPM_RESET over I2C (the Windows driver handles it internally), so the driver intercepts this command and returns a synthetic reset-complete response. Tested on ASUS ROG Strix Z790-E Gaming WiFi with ITE8853 at I2C address 0x40 on the DesignWare I2C controller. Signed-off-by: Edward Blair --- drivers/usb/typec/ucsi/Kconfig | 11 ++ drivers/usb/typec/ucsi/Makefile | 1 + drivers/usb/typec/ucsi/ucsi_ite.c | 285 ++++++++++++++++++++++++++++++ 3 files changed, 297 insertions(+) create mode 100644 drivers/usb/typec/ucsi/ucsi_ite.c diff --git a/drivers/usb/typec/ucsi/Kconfig b/drivers/usb/typec/ucsi/Kconfig index 87dd992a4..455272b5a 100644 --- a/drivers/usb/typec/ucsi/Kconfig +++ b/drivers/usb/typec/ucsi/Kconfig @@ -104,4 +104,15 @@ config UCSI_HUAWEI_GAOKUN To compile the driver as a module, choose M here: the module will be called ucsi_huawei_gaokun. +config UCSI_ITE + tristate "UCSI Interface Driver for ITE885x" + depends on I2C + help + This driver enables UCSI support on platforms that expose an ITE8853 + or ITE8800-ITE8805 USB Type-C controller over I2C, commonly found + on ASUS Z690/Z790/X670E motherboards. + + To compile the driver as a module, choose M here: the module will be + called ucsi_ite. + endif diff --git a/drivers/usb/typec/ucsi/Makefile b/drivers/usb/typec/ucsi/Makefile index c7e38bf01..9bc1d6bbb 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_ITE) += ucsi_ite.o diff --git a/drivers/usb/typec/ucsi/ucsi_ite.c b/drivers/usb/typec/ucsi/ucsi_ite.c new file mode 100644 index 000000000..400b844a1 --- /dev/null +++ b/drivers/usb/typec/ucsi/ucsi_ite.c @@ -0,0 +1,285 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * UCSI I2C transport driver for ITE885x USB-C controllers + * + * ITE8853/ITE8800-ITE8805 are UCSI-compliant USB-C controllers found on + * ASUS Z690/Z790/X670E motherboards. They communicate via I2C with + * ITE-proprietary register offsets and interrupt registers. + * + * Note: Some BIOS implementations declare both MSFT8000 (generic UCSI) and + * ITE8853 (vendor-specific) ACPI devices at the same I2C address. The i2c + * core skips the generic device when a vendor-specific sibling exists, + * allowing this driver to bind to the ITE8853 client with proper IRQ. + */ + +#include +#include +#include +#include + +#include "ucsi.h" + +/* ITE-specific I2C register offsets */ +#define ITE_REG_CCI 0x84 +#define ITE_REG_MESSAGE_IN 0x88 +#define ITE_REG_CONTROL 0x98 +#define ITE_REG_INT_ACK 0xbc +#define ITE_REG_INT_STATUS 0xbd + +/* INT_STATUS register bits */ +#define ITE_INT_VENDOR_ALERT BIT(0) +#define ITE_INT_CCI BIT(1) + +/* INT_ACK register values */ +#define ITE_ACK_VENDOR 0x01 +#define ITE_ACK_CCI 0x02 + +struct ucsi_ite { + struct device *dev; + struct i2c_client *client; + struct ucsi *ucsi; +}; + +static int ucsi_ite_read(struct ucsi_ite *ite, u8 reg, void *val, size_t len) +{ + struct i2c_msg msgs[] = { + { + .addr = ite->client->addr, + .flags = 0, + .len = 1, + .buf = ®, + }, + { + .addr = ite->client->addr, + .flags = I2C_M_RD, + .len = len, + .buf = val, + }, + }; + int ret; + + ret = i2c_transfer(ite->client->adapter, msgs, ARRAY_SIZE(msgs)); + if (ret != ARRAY_SIZE(msgs)) { + dev_err(ite->dev, "i2c read 0x%02x failed: %d\n", reg, ret); + return ret < 0 ? ret : -EIO; + } + + return 0; +} + +static int ucsi_ite_write(struct ucsi_ite *ite, u8 reg, const void *val, + size_t len) +{ + struct i2c_msg msg = { + .addr = ite->client->addr, + .flags = 0, + }; + u8 *buf; + int ret; + + buf = kmalloc(len + 1, GFP_KERNEL); + if (!buf) + return -ENOMEM; + + buf[0] = reg; + memcpy(&buf[1], val, len); + msg.len = len + 1; + msg.buf = buf; + + ret = i2c_transfer(ite->client->adapter, &msg, 1); + kfree(buf); + if (ret != 1) { + dev_err(ite->dev, "i2c write 0x%02x failed: %d\n", reg, ret); + return ret < 0 ? ret : -EIO; + } + + return 0; +} + +static int ucsi_ite_read_version(struct ucsi *ucsi, u16 *version) +{ + /* + * The ITE8853 does not expose a UCSI VERSION register over I2C. + * The Windows driver never reads it. Report UCSI 1.0. + */ + *version = UCSI_VERSION_1_0; + return 0; +} + +static int ucsi_ite_read_cci(struct ucsi *ucsi, u32 *cci) +{ + struct ucsi_ite *ite = ucsi_get_drvdata(ucsi); + + return ucsi_ite_read(ite, ITE_REG_CCI, cci, sizeof(*cci)); +} + +static int ucsi_ite_read_message_in(struct ucsi *ucsi, void *val, size_t len) +{ + struct ucsi_ite *ite = ucsi_get_drvdata(ucsi); + + return ucsi_ite_read(ite, ITE_REG_MESSAGE_IN, val, len); +} + +static int ucsi_ite_async_control(struct ucsi *ucsi, u64 command) +{ + struct ucsi_ite *ite = ucsi_get_drvdata(ucsi); + + return ucsi_ite_write(ite, ITE_REG_CONTROL, &command, sizeof(command)); +} + +static int ucsi_ite_sync_control(struct ucsi *ucsi, u64 command, u32 *cci, + void *data, size_t size) +{ + /* + * The ITE8853 handles PPM_RESET internally and does not accept it + * over I2C — the Windows driver never sends it. Fake a successful + * reset so the UCSI core can proceed with initialization. + */ + if ((command & 0xff) == UCSI_PPM_RESET) { + if (cci) + *cci = UCSI_CCI_RESET_COMPLETE; + return 0; + } + + return ucsi_sync_control_common(ucsi, command, cci, data, size); +} + +static const struct ucsi_operations ucsi_ite_ops = { + .read_version = ucsi_ite_read_version, + .read_cci = ucsi_ite_read_cci, + .poll_cci = ucsi_ite_read_cci, + .read_message_in = ucsi_ite_read_message_in, + .sync_control = ucsi_ite_sync_control, + .async_control = ucsi_ite_async_control, +}; + +static irqreturn_t ucsi_ite_irq(int irq, void *data) +{ + struct ucsi_ite *ite = data; + u8 status; + u32 cci; + u8 ack; + int ret; + + ret = ucsi_ite_read(ite, ITE_REG_INT_STATUS, &status, sizeof(status)); + if (ret) + return IRQ_NONE; + + if (!(status & (ITE_INT_CCI | ITE_INT_VENDOR_ALERT))) + return IRQ_NONE; + + if (status & ITE_INT_CCI) { + ack = ITE_ACK_CCI; + ucsi_ite_write(ite, ITE_REG_INT_ACK, &ack, sizeof(ack)); + + ret = ucsi_ite_read(ite, ITE_REG_CCI, &cci, sizeof(cci)); + if (!ret) + ucsi_notify_common(ite->ucsi, cci); + } + + if (status & ITE_INT_VENDOR_ALERT) { + ack = ITE_ACK_VENDOR; + ucsi_ite_write(ite, ITE_REG_INT_ACK, &ack, sizeof(ack)); + } + + return IRQ_HANDLED; +} + +static int ucsi_ite_probe(struct i2c_client *client) +{ + struct device *dev = &client->dev; + struct ucsi_ite *ite; + int ret; + + ite = devm_kzalloc(dev, sizeof(*ite), GFP_KERNEL); + if (!ite) + return -ENOMEM; + + ite->dev = dev; + ite->client = client; + i2c_set_clientdata(client, ite); + + ite->ucsi = ucsi_create(dev, &ucsi_ite_ops); + if (IS_ERR(ite->ucsi)) + return PTR_ERR(ite->ucsi); + + ucsi_set_drvdata(ite->ucsi, ite); + + ret = request_threaded_irq(client->irq, NULL, ucsi_ite_irq, + IRQF_ONESHOT, dev_name(dev), ite); + if (ret) { + dev_err(dev, "failed to request IRQ: %d\n", ret); + goto err_destroy; + } + + ret = ucsi_register(ite->ucsi); + if (ret) { + dev_err(dev, "failed to register UCSI: %d\n", ret); + goto err_free_irq; + } + + return 0; + +err_free_irq: + free_irq(client->irq, ite); +err_destroy: + ucsi_destroy(ite->ucsi); + return ret; +} + +static void ucsi_ite_remove(struct i2c_client *client) +{ + struct ucsi_ite *ite = i2c_get_clientdata(client); + + ucsi_unregister(ite->ucsi); + free_irq(client->irq, ite); + ucsi_destroy(ite->ucsi); +} + +static int ucsi_ite_suspend(struct device *dev) +{ + struct ucsi_ite *ite = dev_get_drvdata(dev); + + disable_irq(ite->client->irq); + + return 0; +} + +static int ucsi_ite_resume(struct device *dev) +{ + struct ucsi_ite *ite = dev_get_drvdata(dev); + + enable_irq(ite->client->irq); + + return ucsi_resume(ite->ucsi); +} + +static DEFINE_SIMPLE_DEV_PM_OPS(ucsi_ite_pm, ucsi_ite_suspend, + ucsi_ite_resume); + +static const struct acpi_device_id ucsi_ite_acpi_ids[] = { + { "ITE8853" }, + { "ITE8800" }, + { "ITE8801" }, + { "ITE8802" }, + { "ITE8803" }, + { "ITE8804" }, + { "ITE8805" }, + { } +}; +MODULE_DEVICE_TABLE(acpi, ucsi_ite_acpi_ids); + +static struct i2c_driver ucsi_ite_driver = { + .driver = { + .name = "ucsi_ite", + .acpi_match_table = ucsi_ite_acpi_ids, + .pm = pm_sleep_ptr(&ucsi_ite_pm), + }, + .probe = ucsi_ite_probe, + .remove = ucsi_ite_remove, +}; +module_i2c_driver(ucsi_ite_driver); + +MODULE_AUTHOR("Edward Blair "); +MODULE_DESCRIPTION("UCSI I2C transport driver for ITE885x USB-C controllers"); +MODULE_LICENSE("GPL"); -- 2.53.0