[PATCH v1 3/3] mfd: cros_ec: Don't add cros_ec_ucsi if it is defined in OF or ACPI

Jameson Thies
2025-09-30T01:24:33Z

On devices with a UCSI PPM in the EC, check for cros_ec_ucsi to be
defined in the OF device tree or an ACPI node. If it is defined by
either OF or ACPI, it does not need to be added as a subdevice of
cros_ec_dev.

Signed-off-by: Jameson Thies <jthies@google.com>
---
drivers/mfd/cros_ec_dev.c | 40 ++++++++++++++++++++++++++++++++++-----
1 file changed, 35 insertions(+), 5 deletions(-)

diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index dc80a272726b..b0523f6541d2 100644
--- a/drivers/mfd/cros_ec_dev.c
+++ b/drivers/mfd/cros_ec_dev.c
@@ -5,6 +5,7 @@
* Copyright (C) 2014 Google, Inc.
*/

+#include <linux/acpi.h>
#include <linux/dmi.h>
#include <linux/kconfig.h>
#include <linux/mfd/core.h>
@@ -131,11 +132,6 @@ static const struct cros_feature_to_cells cros_subdevices[] = {
.mfd_cells = cros_ec_rtc_cells,
.num_cells = ARRAY_SIZE(cros_ec_rtc_cells),
},
- {
- .id = EC_FEATURE_UCSI_PPM,
- .mfd_cells = cros_ec_ucsi_cells,
- .num_cells = ARRAY_SIZE(cros_ec_ucsi_cells),
- },
{
.id = EC_FEATURE_HANG_DETECT,
.mfd_cells = cros_ec_wdt_cells,
@@ -177,6 +173,16 @@ static const struct mfd_cell cros_ec_vbc_cells[] = {
{ .name = "cros-ec-vbc", }
};

+static int ucsi_acpi_match(struct device *dev, const void *data)
+{
+ struct acpi_device_id ucsi_acpi_device_ids[] = {
+ { "GOOG0021", 0 },
+ {"", 0},
+ };
+ return !!acpi_match_device(ucsi_acpi_device_ids, dev);
+}
+
+
static void cros_ec_class_release(struct device *dev)
{
kfree(to_cros_ec_dev(dev));
@@ -264,6 +270,30 @@ static int ec_device_probe(struct platform_device *pdev)
}
}

+ /*
+ * FW nodes can load cros_ec_ucsi, but early PDC devices did not define
+ * the required nodes. On PDC systems without FW nodes for cros_ec_ucsi,
+ * the driver should be added as an mfd subdevice.
+ */
+ if (cros_ec_check_features(ec, EC_FEATURE_USB_PD) &&
+ cros_ec_check_features(ec, EC_FEATURE_UCSI_PPM)) {
+ struct device *acpi_dev = device_find_child(ec->ec_dev->dev,
+ NULL,
+ ucsi_acpi_match);
+
+ if (!!acpi_dev) {
+ put_device(acpi_dev);
+ } else if (!of_find_compatible_node(NULL, NULL,
+ "google,cros-ec-ucsi")) {
+ retval = mfd_add_hotplug_devices(
+ ec->dev, cros_ec_ucsi_cells,
+ ARRAY_SIZE(cros_ec_ucsi_cells));
+ if (retval)
+ dev_warn(ec->dev,
+ "failed to add cros_ec_ucsi: %d\n", retval);
+ }
+ }
+
/*
* UCSI provides power supply information so we don't need to separately
* load the cros_usbpd_charger driver.
--
2.51.0.570.gb178f27e6d-goog