linux-kernel - [PATCH v4 3/3] mfd: cros_ec: Don't add cros_ec

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Message-ID: <20251013203331.398517-4-jthies@google.com>
Date: Mon, 13 Oct 2025 20:33:27 +0000
From: Jameson Thies <jthies@...gle.com>
To: dmitry.baryshkov@....qualcomm.com, akuchynski@...omium.org, 
	abhishekpandit@...omium.org, krzk+dt@...nel.org, robh@...nel.org, 
	bleung@...omium.org, heikki.krogerus@...ux.intel.com, ukaszb@...omium.org, 
	tzungbi@...nel.org
Cc: devicetree@...r.kernel.org, chrome-platform@...ts.linux.dev, 
	linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org, 
	Jameson Thies <jthies@...gle.com>
Subject: [PATCH v4 3/3] mfd: cros_ec: Don't add cros_ec_ucsi if it is defined
 in OF or ACPI

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 mfd. cros_ec_ucsi will load from the OF or ACPI node.

Signed-off-by: Jameson Thies <jthies@...gle.com>
Reviewed-by: Benson Leung <bleung@...omium.org>
---
 drivers/mfd/cros_ec_dev.c | 23 ++++++++++++++++++-----
 1 file changed, 18 insertions(+), 5 deletions(-)

diff --git a/drivers/mfd/cros_ec_dev.c b/drivers/mfd/cros_ec_dev.c
index dc80a272726b..1928c2ea2b8f 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,
@@ -264,6 +260,23 @@ 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) &&
+	    !acpi_dev_found("GOOG0021") &&
+	    !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.
-- 
2.51.0.858.gf9c4a03a3a-goog