[PATCH v4 0/3] Load cros_ec_ucsi from OF and ACPI definitions

Jameson Thies
2025-10-13T20:34:15Z

The ChromeOS UCSI driver (cros_ec_ucsi) currently gets added as
subdevice of cros_ec_dev. But without it being defined by an ACPI
node or in the OF device tree, the typec connectors are not correctly
associated with other part of the device tree. This series updates the
cros_ec_ucsi driver to load based on device definitions in ACPI and OF.
It also changes the cros_ec_dev driver to block adding cros_ec_ucsi
as a subdevice if it is defined in the device tree.

For context, I initially sent out this series for review in March 2025
(https://lkml.kernel.org/20250312195951.1579682-1-jthies@google.com/).

Patch 1/3 has been updated to address comments from the initial review.
There were some open questions on patch 3/3 regarding adding MFD
children when there is no cros_ec_ucsi node and parents conditionally
checking if a child exists to create one.

The expected behavior of this series is to only add the cros_ec_ucsi
subdevice when there isn't a corresponding FW node because always adding
it would result in multiple cros_ec_ucsi devices and too many ports
being registered with the USB Type-C connector class on devices with
correctly defined FW nodes. It also does not look for a child node to
create a child. It is looking for a child of the parent EC device to
only add cros_ec_ucsi if it does not already exist as a sibling.

v4 changes:
- added comment in cros_ec_ucsi probe explaining how the parent device
depends on how the driver is loaded
- updated commit message of patch 3/3 clarifying the expected why
cros_ec_ucsi doesn't need to be added as an mfd subdevice when
an OF/ACPI node for cros_ec_ucsi is defined

v3 changes:
- adds cros-ec-ucsi compatibility string to google,cros-ec-typec.yaml
instead of defining a new binding.
- updates maintainter list in google,cros-ec-typec.yaml
- cleaned up assignments to udata->ec in cros_ec_ucsi.c
- now using acpi_dev_found() to check for ACPI node in cros_ec_dev.c

v2 changes:
- updated google,cros-ec.yaml to support typec ports defined by
google,cros-ec-ucsi.yaml. Tested with make dt_binding_check
and dtbs_check

Jameson Thies (3):
dt-bindings: chrome: Add cros-ec-ucsi compatibility to typec binding
usb: typec: cros_ec_ucsi: Load driver from OF and ACPI definitions
mfd: cros_ec: Don't add cros_ec_ucsi if it is defined in OF or ACPI

.../bindings/chrome/google,cros-ec-typec.yaml | 19 +++++++++++---
drivers/mfd/cros_ec_dev.c | 23 ++++++++++++----
drivers/usb/typec/ucsi/cros_ec_ucsi.c | 26 +++++++++++++++++--
3 files changed, 57 insertions(+), 11 deletions(-)

base-commit: 48633acccf38d706d7b368400647bb9db9caf1ae
--
2.51.0.858.gf9c4a03a3a-goog