[PATCH v3 0/1] mfd: nct6694: Refactor transport layer and add HIF (eSPI) support

From: a0282524688

Date: Tue Apr 21 2026 - 23:53:26 EST


From: Ming Yu <a0282524688@xxxxxxxxx>

The Nuvoton NCT6694 is a peripheral expander that provides GPIO, I2C,
CAN-FD, Watchdog, HWMON, PWM, and RTC sub-devices. Currently, the
driver only supports USB as the host transport interface.

This series refactors the NCT6694 MFD core to support multiple transport
backends and adds a new Host Interface (HIF) transport driver that
communicates over eSPI using Super-I/O shared memory.

Changes since version 2:
- Restore per-device IDA and mfd_add_hotplug_devices()/PLATFORM_DEVID_AUTO
to avoid child device ID conflicts with multiple NCT6694 chips.
- Validate irq_find_mapping() return value before dispatching IRQs.
- Check superio_enter() return value in nct6694_irq_init().

Changes since version 1:
- Reworked the Super-I/O access helpers.

Ming Yu (1):
mfd: Add Host Interface (HIF) support for Nuvoton NCT6694

MAINTAINERS | 1 +
drivers/mfd/Kconfig | 47 ++-
drivers/mfd/Makefile | 3 +-
drivers/mfd/nct6694-hif.c | 663 ++++++++++++++++++++++++++++++++++++
drivers/mfd/nct6694.c | 111 ++++--
include/linux/mfd/nct6694.h | 54 +--
6 files changed, 813 insertions(+), 66 deletions(-)
create mode 100644 drivers/mfd/nct6694-hif.c

--
2.34.1