[PATCH 0/4] Introduce EC driver for Snapdragon X1E based Dell XPS 13 9345

[PATCH 0/4] Introduce EC driver for Snapdragon X1E based Dell XPS 13 9345

[Aleksandrs Vinarskis]

This series adds Embedded Controller (EC) driver for Dell XPS 13 9345.
While EC appears to control most of device's peripherals, particular
driver addresses power and thermal managment issues. Key operational
principle involves initial thermistor constants configuration followed
by a periodic reporting of these onboard thermistor values from across
the motherboard to the EC. The latter then handles fan ramp-up/
ramp-down internally. Suspend/Resume must be likewise propagated to EC
for power management.

The driver was developed primarily by analyzing ACPI DSDT's _DSM and
i2c dumps of communication between SoC and EC during various stages of
operation (bootup, suspend, resume).

With EC driver in place, the following issues are addressed:
1. Fans were not properly cooling the laptop, would kick in late and
   spin lazily, resulting in heavy throttling. With EC driver fans
   start sooner and hit high RPM under heavy load.
2. Fans were not stopping once SoC temperature dropped, they would keep
   slowly spinning irrespective of suspend and/or closed lid until the
   next powercycle. With EC driver shortly after SoC temperature drops,
   thermistors temperature drops, and fans ramp-down.
3. Keyboard and touch row backlight were not turning off during
   suspend - only lid close would power off the touch row. With EC
   driver behavior matches that of Windows, suspending device with lid
   open powers off the peripherals.

As thermistor readout depends on pmic's ADCs, this series introduces
EC driver and its schema, adds missing ADC to hamoa-pmics, and finally
adds thermistor and EC nodes to x1e80100-dell-xps13-9345.dts.

Additional findings:
- Max fan speed depends on Dell's power mode settings, configurable in
  BIOS or using Windows app (relies on ACPI-WMI). It appears best
  cooling performance is achieved under 'Ultra Performance' profile.
- When the said power mode is changed using Windows app, EC IRQ is
  triggered. Windows performs what appears to be thermistor contants
  readout, though its not obvious what it is used for.
- Given similarities between Dell XPS 13 series (codename 'tributo')
  and Snapdragon-based Latitude, Inspiron ('thena'), including matching
  EC address and response to suspend/resume command the EC driver can
  be likely used for both, though in-depth testing on 'thena' is
  required.

Signed-off-by: Aleksandrs Vinarskis <alex@vinarskis.com>
---
Aleksandrs Vinarskis (4):
      dt-bindings: platform: introduce EC for Dell XPS 13 9345
      platform: arm64: dell-xps-ec: new driver
      arm64: dts: qcom: hamoa-pmics: define VADC for pmk8550
      arm64: dts: qcom: x1e80100-dell-xps13-9345: introduce EC

 .../embedded-controller/dell,xps13-9345-ec.yaml    |  86 +++++++
 MAINTAINERS                                        |   6 +
 arch/arm64/boot/dts/qcom/hamoa-pmics.dtsi          |  11 +
 .../boot/dts/qcom/x1e80100-dell-xps13-9345.dts     |  91 ++++++-
 drivers/platform/arm64/Kconfig                     |  12 +
 drivers/platform/arm64/Makefile                    |   1 +
 drivers/platform/arm64/dell-xps-ec.c               | 269 +++++++++++++++++++++
 7 files changed, 474 insertions(+), 2 deletions(-)
---
base-commit: 3b058d1aeeeff27a7289529c4944291613b364e9
change-id: 20260331-dell-xps-9345-ec-e5f49d1bef61

Best regards,
-- 
Aleksandrs Vinarskis <alex@vinarskis.com>

[PATCH 1/4] dt-bindings: platform: introduce EC for Dell XPS 13 9345

[Aleksandrs Vinarskis]

Add bindings for Embedded Controller (EC) in Dell XPS 13 9345 (platform
codename 'tributo'). It may be partially or fully compatible with EC
found in Snapdragon-based Dell Latitude, Inspiron ('thena').

Signed-off-by: Aleksandrs Vinarskis <alex@vinarskis.com>
---
 .../embedded-controller/dell,xps13-9345-ec.yaml    | 86 ++++++++++++++++++++++
 MAINTAINERS                                        |  5 ++
 2 files changed, 91 insertions(+)

diff --git a/Documentation/devicetree/bindings/embedded-controller/dell,xps13-9345-ec.yaml b/Documentation/devicetree/bindings/embedded-controller/dell,xps13-9345-ec.yaml
new file mode 100644
index 0000000000000000000000000000000000000000..30dc6dcd8c9f0312fdb4eafdef96bf0ce4975798
--- /dev/null
+++ b/Documentation/devicetree/bindings/embedded-controller/dell,xps13-9345-ec.yaml
@@ -0,0 +1,86 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/embedded-controller/dell,xps13-9345-ec.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Dell XPS 13 9345 Embedded Controller
+
+maintainers:
+  - Aleksandrs Vinarskis <alex@vinarskis.com>
+
+description:
+  The Dell XPS 13 9345 has an Embedded Controller (EC) which handles thermal and power
+  management. It is communicating with SoC over multiple i2c busses. Particular driver
+  is for EC subsystem that handles fan speed control, thermal shutdown, peripherals
+  supply including trackpad, touch-row, display.
+
+properties:
+  compatible:
+    const: dell,xps13-9345-ec
+
+  reg:
+    const: 0x3b
+
+  interrupts:
+    maxItems: 1
+
+  io-channels:
+    description:
+      ADC channels connected to the 7 onboard thermistors on PMK8550.
+      EC requires frequent thermal readings of these channels to perform
+      automated fan speed control.
+    items:
+      - description: ADC channel for sys_therm0
+      - description: ADC channel for sys_therm1
+      - description: ADC channel for sys_therm2
+      - description: ADC channel for sys_therm3
+      - description: ADC channel for sys_therm4
+      - description: ADC channel for sys_therm5
+      - description: ADC channel for sys_therm6
+
+  io-channel-names:
+    items:
+      - const: sys_therm0
+      - const: sys_therm1
+      - const: sys_therm2
+      - const: sys_therm3
+      - const: sys_therm4
+      - const: sys_therm5
+      - const: sys_therm6
+
+required:
+  - compatible
+  - reg
+  - interrupts
+  - io-channels
+  - io-channel-names
+
+additionalProperties: false
+
+examples:
+  - |+
+    #include <dt-bindings/interrupt-controller/irq.h>
+    #include <dt-bindings/iio/qcom,spmi-adc7-pm8350.h>
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        embedded-controller@3b {
+            compatible = "dell,xps13-9345-ec";
+            reg = <0x3b>;
+            interrupts-extended = <&tlmm 66 IRQ_TYPE_LEVEL_LOW>;
+
+            io-channels = <&pmk8550_vadc PM8350_ADC7_GPIO3_100K_PU(1)>,
+                          <&pmk8550_vadc PM8350_ADC7_GPIO4_100K_PU(1)>,
+                          <&pmk8550_vadc PM8350_ADC7_AMUX_THM1_100K_PU(1)>,
+                          <&pmk8550_vadc PM8350_ADC7_AMUX_THM2_100K_PU(1)>,
+                          <&pmk8550_vadc PM8350_ADC7_AMUX_THM3_100K_PU(1)>,
+                          <&pmk8550_vadc PM8350_ADC7_AMUX_THM4_100K_PU(1)>,
+                          <&pmk8550_vadc PM8350_ADC7_AMUX_THM5_100K_PU(1)>;
+            io-channel-names = "sys_therm0", "sys_therm1", "sys_therm2",
+                               "sys_therm3", "sys_therm4", "sys_therm5",
+                               "sys_therm6";
+        };
+    };
+...
diff --git a/MAINTAINERS b/MAINTAINERS
index ff935e197c2153a9c52c94d6ead1df54543a36d4..fe3f2fc4fbc087d8041f97708fbb93722f7d1882 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7236,6 +7236,11 @@ S:	Maintained
 F:	Documentation/ABI/testing/sysfs-class-firmware-attributes
 F:	drivers/platform/x86/dell/dell-wmi-sysman/
 
+DELL XPS EMBEDDED CONTROLLER DRIVER
+M:	Aleksandrs Vinarskis <alex@vinarskis.com>
+S:	Maintained
+F:	Documentation/devicetree/bindings/embedded-controller/dell,xps13-9345-ec.yaml
+
 DELTA AHE-50DC FAN CONTROL MODULE DRIVER
 M:	Zev Weiss <zev@bewilderbeest.net>
 L:	linux-hwmon@vger.kernel.org

-- 
2.53.0

[PATCH 2/4] platform: arm64: dell-xps-ec: new driver

[Aleksandrs Vinarskis]

Introduce EC driver for Dell XPS 13 9345 (codename 'tributo') which may
partially of fully compatible with Snapdragon-based Dell Latitude,
Inspiron ('thena'). Primary function of this driver is unblock EC's
thermal management, specifically to provide it with necessary
information to control device fans, peripherals power.

The driver was developed primarily by analyzing ACPI DSDT's _DSM and
i2c dumps of communication between SoC and EC. Changes to Windows
driver's behavior include increasing temperature feed loop from ~50ms
to 100ms here.

While Xps's EC is rather complex and controls practically all device
peripherals including touch row's brightness and special keys such as
mic mute, these do not go over this particular i2c interface.

Not yet implemented features:
- On lid-close IRQ event is registered. Windows performs what to
  appears to be thermistor constants readout, though its not obvious
  what it used for.
- According to ACPI's _DSM there is a method to readout fans' RPM.
- Initial thermistor constants were sniffed from Windows, these can be
  likely fine tuned for better cooling performance.
- There is additional temperature reading that Windows sents to EC but
  more rare than others, likely SoC T_j / TZ98 or TZ4. This is the only
  thermal zone who's reading can exceed 115C without triggering thermal
  shutdown.
- Given similarities between 'tributo' and 'thena' platforms, including
  EC i2c address, driver can be potentially extended to support both.

Signed-off-by: Aleksandrs Vinarskis <alex@vinarskis.com>
---
 MAINTAINERS                          |   1 +
 drivers/platform/arm64/Kconfig       |  12 ++
 drivers/platform/arm64/Makefile      |   1 +
 drivers/platform/arm64/dell-xps-ec.c | 269 +++++++++++++++++++++++++++++++++++
 4 files changed, 283 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index fe3f2fc4fbc087d8041f97708fbb93722f7d1882..f82c7f6c7377d3f2ff0ae1be263d854749541f03 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -7240,6 +7240,7 @@ DELL XPS EMBEDDED CONTROLLER DRIVER
 M:	Aleksandrs Vinarskis <alex@vinarskis.com>
 S:	Maintained
 F:	Documentation/devicetree/bindings/embedded-controller/dell,xps13-9345-ec.yaml
+F:	drivers/platform/arm64/dell-xps-ec.c
 
 DELTA AHE-50DC FAN CONTROL MODULE DRIVER
 M:	Zev Weiss <zev@bewilderbeest.net>
diff --git a/drivers/platform/arm64/Kconfig b/drivers/platform/arm64/Kconfig
index 10f905d7d6bfa5fad30a0689d3a20481268c781e..0bc8f016032bb05cb3a7cc50bdf1092da04153bc 100644
--- a/drivers/platform/arm64/Kconfig
+++ b/drivers/platform/arm64/Kconfig
@@ -33,6 +33,18 @@ config EC_ACER_ASPIRE1
 	  laptop where this information is not properly exposed via the
 	  standard ACPI devices.
 
+config EC_DELL_XPS
+	tristate "Dell XPS 9345 Embedded Controller driver"
+	depends on ARCH_QCOM || COMPILE_TEST
+	depends on I2C
+	depends on IIO
+	help
+	  Driver for the Embedded Controller in the Qualcomm Snapdragon-based
+	  Dell XPS 13 9345, which handles thermal management and fan speed
+	  control.
+
+	  Say M or Y here to include this support.
+
 config EC_HUAWEI_GAOKUN
 	tristate "Huawei Matebook E Go Embedded Controller driver"
 	depends on ARCH_QCOM || COMPILE_TEST
diff --git a/drivers/platform/arm64/Makefile b/drivers/platform/arm64/Makefile
index 60c131cff6a15bb51a49c9edab95badf513ee0f6..6768dc6c2310837374e67381cfc729bed1fdaaef 100644
--- a/drivers/platform/arm64/Makefile
+++ b/drivers/platform/arm64/Makefile
@@ -6,6 +6,7 @@
 #
 
 obj-$(CONFIG_EC_ACER_ASPIRE1)	+= acer-aspire1-ec.o
+obj-$(CONFIG_EC_DELL_XPS)	+= dell-xps-ec.o
 obj-$(CONFIG_EC_HUAWEI_GAOKUN)	+= huawei-gaokun-ec.o
 obj-$(CONFIG_EC_LENOVO_YOGA_C630) += lenovo-yoga-c630.o
 obj-$(CONFIG_EC_LENOVO_THINKPAD_T14S) += lenovo-thinkpad-t14s.o
diff --git a/drivers/platform/arm64/dell-xps-ec.c b/drivers/platform/arm64/dell-xps-ec.c
new file mode 100644
index 0000000000000000000000000000000000000000..5ea8f30931d8b61acbb948d8617dde3681fb8de3
--- /dev/null
+++ b/drivers/platform/arm64/dell-xps-ec.c
@@ -0,0 +1,269 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * Copyright (c) 2026, Aleksandrs Vinarskis <alex@vinarskis.com>
+ */
+
+#include <linux/array_size.h>
+#include <linux/devm-helpers.h>
+#include <linux/device.h>
+#include <linux/i2c.h>
+#include <linux/iio/consumer.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/pm.h>
+#include <linux/workqueue.h>
+
+#define DELL_XPS_EC_SUSPEND_CMD		0xb9
+#define DELL_XPS_EC_SUSPEND_MSG_LEN	64
+
+#define DELL_XPS_EC_TEMP_CMD0		0xfb
+#define DELL_XPS_EC_TEMP_CMD1		0x20
+#define DELL_XPS_EC_TEMP_CMD3		0x02
+#define DELL_XPS_EC_TEMP_MSG_LEN	6
+#define DELL_XPS_EC_TEMP_INTERVAL_MS	100
+
+/*
+ * Format:
+ * - header/unknown (2 bytes)
+ * - per-thermistor entries (3 bytes): thermistor_id, param1, param2
+ */
+static const u8 dell_xps_ec_thermistor_profile[] = {
+	0xff, 0x54,
+	0x01, 0x00, 0x2b,	/* sys_therm0 */
+	0x02, 0x44, 0x2a,	/* sys_therm1 */
+	0x03, 0x44, 0x2b,	/* sys_therm2 */
+	0x04, 0x44, 0x28,	/* sys_therm3 */
+	0x05, 0x55, 0x2a,	/* sys_therm4 */
+	0x06, 0x44, 0x26,	/* sys_therm5 */
+	0x07, 0x44, 0x2b,	/* sys_therm6 */
+};
+
+/*
+ * Mapping from IIO channel name to EC command byte
+ */
+static const struct {
+	const char *name;
+	u8 cmd;
+} dell_xps_ec_therms[] = {
+	/* TODO: 0x01 is sent only occasionally, likely TZ98 or TZ4 */
+	{ "sys_therm0", 0x02 },
+	{ "sys_therm1", 0x03 },
+	{ "sys_therm2", 0x04 },
+	{ "sys_therm3", 0x05 },
+	{ "sys_therm4", 0x06 },
+	{ "sys_therm5", 0x07 },
+	{ "sys_therm6", 0x08 },
+};
+
+struct dell_xps_ec {
+	struct device *dev;
+	struct i2c_client *client;
+	struct iio_channel *therm_channels[ARRAY_SIZE(dell_xps_ec_therms)];
+	struct delayed_work temp_work;
+};
+
+static int dell_xps_ec_suspend_cmd(struct dell_xps_ec *ec, bool suspend)
+{
+	u8 buf[DELL_XPS_EC_SUSPEND_MSG_LEN] = {};
+	int ret;
+
+	buf[0] = DELL_XPS_EC_SUSPEND_CMD;
+	buf[1] = suspend ? 0x01 : 0x00;
+	/* bytes 2..63 remain zero */
+
+	ret = i2c_master_send(ec->client, buf, sizeof(buf));
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int dell_xps_ec_send_temp(struct dell_xps_ec *ec, u8 cmd_byte,
+				 int milli_celsius)
+{
+	u8 buf[DELL_XPS_EC_TEMP_MSG_LEN];
+	u16 deci_celsius;
+	int ret;
+
+	/* Convert milli-Celsius to deci-Celsius (Celsius * 10) */
+	deci_celsius = milli_celsius / 100;
+
+	buf[0] = DELL_XPS_EC_TEMP_CMD0;
+	buf[1] = DELL_XPS_EC_TEMP_CMD1;
+	buf[2] = cmd_byte;
+	buf[3] = DELL_XPS_EC_TEMP_CMD3;
+	buf[4] = deci_celsius & 0xff;		/* LSB */
+	buf[5] = (deci_celsius >> 8) & 0xff;	/* MSB */
+
+	ret = i2c_master_send(ec->client, buf, sizeof(buf));
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static void dell_xps_ec_temp_work_fn(struct work_struct *work)
+{
+	struct dell_xps_ec *ec = container_of(work, struct dell_xps_ec,
+					      temp_work.work);
+	int val, ret, i;
+
+	for (i = 0; i < ARRAY_SIZE(dell_xps_ec_therms); i++) {
+		if (!ec->therm_channels[i])
+			continue;
+
+		ret = iio_read_channel_processed(ec->therm_channels[i], &val);
+		if (ret < 0) {
+			dev_err_ratelimited(ec->dev,
+					    "Failed to read thermistor %s: %d\n",
+					    dell_xps_ec_therms[i].name, ret);
+			continue;
+		}
+
+		ret = dell_xps_ec_send_temp(ec, dell_xps_ec_therms[i].cmd, val);
+		if (ret < 0) {
+			dev_err_ratelimited(ec->dev,
+					    "Failed to send temp for %s: %d\n",
+					    dell_xps_ec_therms[i].name, ret);
+		}
+	}
+
+	schedule_delayed_work(&ec->temp_work,
+			      msecs_to_jiffies(DELL_XPS_EC_TEMP_INTERVAL_MS));
+}
+
+static irqreturn_t dell_xps_ec_irq_handler(int irq, void *data)
+{
+	struct dell_xps_ec *ec = data;
+
+	/*
+	 * TODO: IRQ is fired on lid-close. Follow Windows example to read out
+	 *       the thermistor thresholds and potentially fan speeds.
+	 */
+	dev_info_ratelimited(ec->dev, "IRQ triggered! (irq=%d)\n", irq);
+
+	return IRQ_HANDLED;
+}
+
+static int dell_xps_ec_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct dell_xps_ec *ec;
+	int ret, i;
+
+	ec = devm_kzalloc(dev, sizeof(*ec), GFP_KERNEL);
+	if (!ec)
+		return -ENOMEM;
+
+	ec->dev = dev;
+	ec->client = client;
+	i2c_set_clientdata(client, ec);
+
+	/* Set default thermistor profile */
+	ret = i2c_master_send(client, dell_xps_ec_thermistor_profile,
+			      sizeof(dell_xps_ec_thermistor_profile));
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "Failed to set thermistor profile\n");
+
+	/* Get IIO channels for thermistors */
+	for (i = 0; i < ARRAY_SIZE(dell_xps_ec_therms); i++) {
+		ec->therm_channels[i] = devm_iio_channel_get(dev,
+					dell_xps_ec_therms[i].name);
+		if (IS_ERR(ec->therm_channels[i])) {
+			ret = PTR_ERR(ec->therm_channels[i]);
+			ec->therm_channels[i] = NULL;
+			if (ret == -EPROBE_DEFER)
+				return ret;
+			dev_warn(dev, "Thermistor %s not available: %d\n",
+				 dell_xps_ec_therms[i].name, ret);
+		}
+	}
+
+	/* Start periodic temperature reporting */
+	ret = devm_delayed_work_autocancel(dev, &ec->temp_work,
+					   dell_xps_ec_temp_work_fn);
+	if (ret)
+		return ret;
+	schedule_delayed_work(&ec->temp_work,
+			      msecs_to_jiffies(DELL_XPS_EC_TEMP_INTERVAL_MS));
+	dev_info(dev, "Started periodic temperature reporting to EC every %d ms\n",
+		 DELL_XPS_EC_TEMP_INTERVAL_MS);
+
+	/* Request IRQ for EC events */
+	ret = devm_request_threaded_irq(dev, client->irq, NULL,
+					dell_xps_ec_irq_handler,
+					IRQF_ONESHOT, dev_name(dev), ec);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "Failed to request IRQ\n");
+
+	return 0;
+}
+
+/*
+ * Notify EC of suspend
+ *
+ * This will:
+ * - Ramp down the fans
+ * - Cut power to display/trackpad/keyboard/touch row
+ * - Periodically (?) power them back, such that wake-up source still works
+ */
+static int dell_xps_ec_suspend(struct device *dev)
+{
+	struct dell_xps_ec *ec = dev_get_drvdata(dev);
+
+	cancel_delayed_work_sync(&ec->temp_work);
+
+	return dell_xps_ec_suspend_cmd(ec, true);
+}
+
+/*
+ * Notify EC of resume
+ *
+ * This will undo the suspend actions
+ * Without the resume signal, device would wake up but be forced back into
+ * suspend by EC within seconds
+ */
+static int dell_xps_ec_resume(struct device *dev)
+{
+	struct dell_xps_ec *ec = dev_get_drvdata(dev);
+	int ret;
+
+	ret = dell_xps_ec_suspend_cmd(ec, false);
+	if (ret)
+		return ret;
+
+	schedule_delayed_work(&ec->temp_work,
+			      msecs_to_jiffies(DELL_XPS_EC_TEMP_INTERVAL_MS));
+	return 0;
+}
+
+static const struct of_device_id dell_xps_ec_of_match[] = {
+	{ .compatible = "dell,xps13-9345-ec" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, dell_xps_ec_of_match);
+
+static const struct i2c_device_id dell_xps_ec_i2c_id[] = {
+	{ "dell-xps-ec" },
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, dell_xps_ec_i2c_id);
+
+static const struct dev_pm_ops dell_xps_ec_pm_ops = {
+	SYSTEM_SLEEP_PM_OPS(dell_xps_ec_suspend, dell_xps_ec_resume)
+};
+
+static struct i2c_driver dell_xps_ec_driver = {
+	.driver = {
+		.name = "dell-xps-ec",
+		.of_match_table = dell_xps_ec_of_match,
+		.pm = &dell_xps_ec_pm_ops,
+	},
+	.probe = dell_xps_ec_probe,
+	.id_table = dell_xps_ec_i2c_id,
+};
+module_i2c_driver(dell_xps_ec_driver);
+
+MODULE_AUTHOR("Aleksandrs Vinarskis <alex@vinarskis.com>");
+MODULE_DESCRIPTION("Dell XPS 13 9345 Embedded Controller");
+MODULE_LICENSE("GPL");

-- 
2.53.0

[PATCH 3/4] arm64: dts: qcom: hamoa-pmics: define VADC for pmk8550

[Aleksandrs Vinarskis]

Follow pattern of pmk8350 to add missing pmk8550 VADC to hamoa.
Register address of 0x9000 matches example schema for spmi-adc5-gen3.

Signed-off-by: Aleksandrs Vinarskis <alex@vinarskis.com>
---
 arch/arm64/boot/dts/qcom/hamoa-pmics.dtsi | 11 +++++++++++
 1 file changed, 11 insertions(+)

diff --git a/arch/arm64/boot/dts/qcom/hamoa-pmics.dtsi b/arch/arm64/boot/dts/qcom/hamoa-pmics.dtsi
index 6a31a0adf8be472badea502a916cdbc9477e9f2b..58c0dd3ccca70bce3424f83bfd5a52b1fef35c2e 100644
--- a/arch/arm64/boot/dts/qcom/hamoa-pmics.dtsi
+++ b/arch/arm64/boot/dts/qcom/hamoa-pmics.dtsi
@@ -218,6 +218,17 @@ pon_resin: resin {
 			};
 		};
 
+		pmk8550_vadc: adc@9000 {
+			compatible = "qcom,spmi-adc5-gen3";
+			reg = <0x9000>, <0x9100>;
+			#address-cells = <1>;
+			#size-cells = <0>;
+			interrupts = <0x0 0x90 0x1 IRQ_TYPE_EDGE_RISING>,
+				     <0x0 0x91 0x1 IRQ_TYPE_EDGE_RISING>;
+			#io-channel-cells = <1>;
+			#thermal-sensor-cells = <1>;
+		};
+
 		pmk8550_rtc: rtc@6100 {
 			compatible = "qcom,pmk8350-rtc";
 			reg = <0x6100>, <0x6200>;

-- 
2.53.0

[PATCH 4/4] arm64: dts: qcom: x1e80100-dell-xps13-9345: introduce EC

[Aleksandrs Vinarskis]

Describe embedded controller, its interrupt and required thermal zones.
Add EC's reset GPIO to reserved range, as triggering it during device
operation leads to unrecoverable and unusable state.

Signed-off-by: Aleksandrs Vinarskis <alex@vinarskis.com>
---
 .../boot/dts/qcom/x1e80100-dell-xps13-9345.dts     | 91 +++++++++++++++++++++-
 1 file changed, 89 insertions(+), 2 deletions(-)

diff --git a/arch/arm64/boot/dts/qcom/x1e80100-dell-xps13-9345.dts b/arch/arm64/boot/dts/qcom/x1e80100-dell-xps13-9345.dts
index ce7b10ea89b6dcb2a4a65c114037f4c90a4b0c6d..32e7134316709f5574d43d9edd83c77fb7d23451 100644
--- a/arch/arm64/boot/dts/qcom/x1e80100-dell-xps13-9345.dts
+++ b/arch/arm64/boot/dts/qcom/x1e80100-dell-xps13-9345.dts
@@ -7,6 +7,7 @@
 /dts-v1/;
 
 #include <dt-bindings/gpio/gpio.h>
+#include <dt-bindings/iio/qcom,spmi-adc7-pm8350.h>
 #include <dt-bindings/input/gpio-keys.h>
 #include <dt-bindings/input/input.h>
 #include <dt-bindings/leds/common.h>
@@ -759,8 +760,29 @@ retimer_ss0_con_sbu_out: endpoint {
 
 &i2c5 {
 	clock-frequency = <100000>;
-	status = "disabled";
-	/* EC @0x3b */
+	status = "okay";
+
+	embedded-controller@3b {
+		compatible = "dell,xps13-9345-ec";
+		reg = <0x3b>;
+
+		interrupts-extended = <&tlmm 66 IRQ_TYPE_LEVEL_LOW>;
+
+		pinctrl-0 = <&ec_int_n_default>;
+		pinctrl-names = "default";
+
+		io-channels = <&pmk8550_vadc PM8350_ADC7_GPIO3_100K_PU(1)>,
+			      <&pmk8550_vadc PM8350_ADC7_GPIO4_100K_PU(1)>,
+			      <&pmk8550_vadc PM8350_ADC7_AMUX_THM1_100K_PU(1)>,
+			      <&pmk8550_vadc PM8350_ADC7_AMUX_THM2_100K_PU(1)>,
+			      <&pmk8550_vadc PM8350_ADC7_AMUX_THM3_100K_PU(1)>,
+			      <&pmk8550_vadc PM8350_ADC7_AMUX_THM4_100K_PU(1)>,
+			      <&pmk8550_vadc PM8350_ADC7_AMUX_THM5_100K_PU(1)>;
+
+		io-channel-names = "sys_therm0", "sys_therm1", "sys_therm2",
+				   "sys_therm3", "sys_therm4", "sys_therm5",
+				   "sys_therm6";
+	};
 };
 
 &i2c7 {
@@ -1025,6 +1047,64 @@ rtmr0_1p8_reg_en: rtmr0-1p8-reg-en-state {
 	};
 };
 
+&pmk8550_vadc {
+	/* sys_therm0, around DRAM */
+	channel@14c {
+		reg = <PM8350_ADC7_GPIO3_100K_PU(1)>;
+		qcom,hw-settle-time = <200>;
+		qcom,ratiometric;
+		label = "sys_therm0";
+	};
+
+	/* sys_therm1, around left Type-C charging controller */
+	channel@14d {
+		reg = <PM8350_ADC7_GPIO4_100K_PU(1)>;
+		qcom,hw-settle-time = <200>;
+		qcom,ratiometric;
+		label = "sys_therm1";
+	};
+
+	/* sys_therm2, around upper-left side of motherboard */
+	channel@144 {
+		reg = <PM8350_ADC7_AMUX_THM1_100K_PU(1)>;
+		qcom,hw-settle-time = <200>;
+		qcom,ratiometric;
+		label = "sys_therm2";
+	};
+
+	/* sys_therm3, around right Type-C charging controller */
+	channel@145 {
+		reg = <PM8350_ADC7_AMUX_THM2_100K_PU(1)>;
+		qcom,hw-settle-time = <200>;
+		qcom,ratiometric;
+		label = "sys_therm3";
+	};
+
+	/* sys_therm4, around SSD connector */
+	channel@146 {
+		reg = <PM8350_ADC7_AMUX_THM3_100K_PU(1)>;
+		qcom,hw-settle-time = <200>;
+		qcom,ratiometric;
+		label = "sys_therm4";
+	};
+
+	/* sys_therm5, around battery charging circuit */
+	channel@147 {
+		reg = <PM8350_ADC7_AMUX_THM4_100K_PU(1)>;
+		qcom,hw-settle-time = <200>;
+		qcom,ratiometric;
+		label = "sys_therm5";
+	};
+
+	/* sys_therm6, around keyboard */
+	channel@148 {
+		reg = <PM8350_ADC7_AMUX_THM5_100K_PU(1)>;
+		qcom,hw-settle-time = <200>;
+		qcom,ratiometric;
+		label = "sys_therm6";
+	};
+};
+
 &qupv3_0 {
 	status = "okay";
 };
@@ -1071,6 +1151,7 @@ &smb2360_1_eusb2_repeater {
 
 &tlmm {
 	gpio-reserved-ranges = <44 4>,  /* SPI11 (TPM) */
+			       <65 1>,  /* EC Reset */
 			       <76 4>,  /* SPI19 (TZ Protected) */
 			       <238 1>; /* UFS Reset */
 
@@ -1081,6 +1162,12 @@ cam_indicator_en: cam-indicator-en-state {
 		bias-disable;
 	};
 
+	ec_int_n_default: ec-int-n-state {
+		pins = "gpio66";
+		function = "gpio";
+		bias-disable;
+	};
+
 	edp_bl_en: edp-bl-en-state {
 		pins = "gpio74";
 		function = "gpio";

-- 
2.53.0

Re: [PATCH 2/4] platform: arm64: dell-xps-ec: new driver

[Konrad Dybcio]

On 4/1/26 9:33 AM, Aleksandrs Vinarskis wrote:
> Introduce EC driver for Dell XPS 13 9345 (codename 'tributo') which may
> partially of fully compatible with Snapdragon-based Dell Latitude,
> Inspiron ('thena'). Primary function of this driver is unblock EC's
> thermal management, specifically to provide it with necessary
> information to control device fans, peripherals power.

[...]

> +/*
> + * Format:
> + * - header/unknown (2 bytes)
> + * - per-thermistor entries (3 bytes): thermistor_id, param1, param2
> + */
> +static const u8 dell_xps_ec_thermistor_profile[] = {
> +	0xff, 0x54,

This is super wishful thinking, but 0x54 is ASCII 'T', perhaps for
"Thermistor" or "Temp"?

> +static int dell_xps_ec_suspend_cmd(struct dell_xps_ec *ec, bool suspend)
> +{
> +	u8 buf[DELL_XPS_EC_SUSPEND_MSG_LEN] = {};
> +	int ret;
> +
> +	buf[0] = DELL_XPS_EC_SUSPEND_CMD;
> +	buf[1] = suspend ? 0x01 : 0x00;
> +	/* bytes 2..63 remain zero */

buf[1] = suspend

(since it's a boolean argument)


[...]

> +	schedule_delayed_work(&ec->temp_work,
> +			      msecs_to_jiffies(DELL_XPS_EC_TEMP_INTERVAL_MS));
> +	dev_info(dev, "Started periodic temperature reporting to EC every %d ms\n",
> +		 DELL_XPS_EC_TEMP_INTERVAL_MS);

dev_dbg()?


> +
> +	/* Request IRQ for EC events */
> +	ret = devm_request_threaded_irq(dev, client->irq, NULL,
> +					dell_xps_ec_irq_handler,
> +					IRQF_ONESHOT, dev_name(dev), ec);
> +	if (ret < 0)
> +		return dev_err_probe(dev, ret, "Failed to request IRQ\n");
> +
> +	return 0;
> +}
> +
> +/*
> + * Notify EC of suspend
> + *
> + * This will:
> + * - Ramp down the fans
> + * - Cut power to display/trackpad/keyboard/touch row
> + * - Periodically (?) power them back, such that wake-up source still works

FWIW

https://learn.microsoft.com/en-us/windows-hardware/design/device-experiences/modern-standby-firmware-notifications

Konrad

Re: [PATCH 3/4] arm64: dts: qcom: hamoa-pmics: define VADC for pmk8550

[Konrad Dybcio]

On 4/1/26 9:33 AM, Aleksandrs Vinarskis wrote:
> Follow pattern of pmk8350 to add missing pmk8550 VADC to hamoa.
> Register address of 0x9000 matches example schema for spmi-adc5-gen3.
> 
> Signed-off-by: Aleksandrs Vinarskis <alex@vinarskis.com>
> ---
>  arch/arm64/boot/dts/qcom/hamoa-pmics.dtsi | 11 +++++++++++
>  1 file changed, 11 insertions(+)
> 
> diff --git a/arch/arm64/boot/dts/qcom/hamoa-pmics.dtsi b/arch/arm64/boot/dts/qcom/hamoa-pmics.dtsi
> index 6a31a0adf8be472badea502a916cdbc9477e9f2b..58c0dd3ccca70bce3424f83bfd5a52b1fef35c2e 100644
> --- a/arch/arm64/boot/dts/qcom/hamoa-pmics.dtsi
> +++ b/arch/arm64/boot/dts/qcom/hamoa-pmics.dtsi
> @@ -218,6 +218,17 @@ pon_resin: resin {
>  			};
>  		};
>  
> +		pmk8550_vadc: adc@9000 {
> +			compatible = "qcom,spmi-adc5-gen3";
> +			reg = <0x9000>, <0x9100>;
> +			#address-cells = <1>;
> +			#size-cells = <0>;
> +			interrupts = <0x0 0x90 0x1 IRQ_TYPE_EDGE_RISING>,
> +				     <0x0 0x91 0x1 IRQ_TYPE_EDGE_RISING>;
> +			#io-channel-cells = <1>;
> +			#thermal-sensor-cells = <1>;

You can probably add the DIE_TEMP/XO_THERM channels here directly

Konrad

Re: [PATCH 4/4] arm64: dts: qcom: x1e80100-dell-xps13-9345: introduce EC

[Konrad Dybcio]

On 4/1/26 9:33 AM, Aleksandrs Vinarskis wrote:
> Describe embedded controller, its interrupt and required thermal zones.
> Add EC's reset GPIO to reserved range, as triggering it during device
> operation leads to unrecoverable and unusable state.
> 
> Signed-off-by: Aleksandrs Vinarskis <alex@vinarskis.com>
> ---

[...]

> +		io-channels = <&pmk8550_vadc PM8350_ADC7_GPIO3_100K_PU(1)>,
> +			      <&pmk8550_vadc PM8350_ADC7_GPIO4_100K_PU(1)>,
> +			      <&pmk8550_vadc PM8350_ADC7_AMUX_THM1_100K_PU(1)>,
> +			      <&pmk8550_vadc PM8350_ADC7_AMUX_THM2_100K_PU(1)>,
> +			      <&pmk8550_vadc PM8350_ADC7_AMUX_THM3_100K_PU(1)>,
> +			      <&pmk8550_vadc PM8350_ADC7_AMUX_THM4_100K_PU(1)>,
> +			      <&pmk8550_vadc PM8350_ADC7_AMUX_THM5_100K_PU(1)>;
> +
> +		io-channel-names = "sys_therm0", "sys_therm1", "sys_therm2",
> +				   "sys_therm3", "sys_therm4", "sys_therm5",
> +				   "sys_therm6";

nit: one a line please, without a separating \n between x and x-names

[...]

> +&pmk8550_vadc {
> +	/* sys_therm0, around DRAM */

another nit: I think repeating the name set in the label in each comment
is a little excessive

[...]

>  &tlmm {
>  	gpio-reserved-ranges = <44 4>,  /* SPI11 (TPM) */
> +			       <65 1>,  /* EC Reset */

Is that a "this may not be accessed" or rather "you can, but it has dire
consequences"?

Would the EC driver/binding benefit from having a reference to that pin?

Konrad

Re: [PATCH 2/4] platform: arm64: dell-xps-ec: new driver

[Ilpo Järvinen]

On Wed, 1 Apr 2026, Aleksandrs Vinarskis wrote:

> Introduce EC driver for Dell XPS 13 9345 (codename 'tributo') which may
> partially of fully compatible with Snapdragon-based Dell Latitude,
> Inspiron ('thena'). Primary function of this driver is unblock EC's
> thermal management, specifically to provide it with necessary
> information to control device fans, peripherals power.
> 
> The driver was developed primarily by analyzing ACPI DSDT's _DSM and
> i2c dumps of communication between SoC and EC. Changes to Windows
> driver's behavior include increasing temperature feed loop from ~50ms
> to 100ms here.
> 
> While Xps's EC is rather complex and controls practically all device
> peripherals including touch row's brightness and special keys such as
> mic mute, these do not go over this particular i2c interface.
> 
> Not yet implemented features:
> - On lid-close IRQ event is registered. Windows performs what to
>   appears to be thermistor constants readout, though its not obvious
>   what it used for.
> - According to ACPI's _DSM there is a method to readout fans' RPM.
> - Initial thermistor constants were sniffed from Windows, these can be
>   likely fine tuned for better cooling performance.
> - There is additional temperature reading that Windows sents to EC but
>   more rare than others, likely SoC T_j / TZ98 or TZ4. This is the only
>   thermal zone who's reading can exceed 115C without triggering thermal
>   shutdown.
> - Given similarities between 'tributo' and 'thena' platforms, including
>   EC i2c address, driver can be potentially extended to support both.
> 
> Signed-off-by: Aleksandrs Vinarskis <alex@vinarskis.com>
> ---
>  MAINTAINERS                          |   1 +
>  drivers/platform/arm64/Kconfig       |  12 ++
>  drivers/platform/arm64/Makefile      |   1 +
>  drivers/platform/arm64/dell-xps-ec.c | 269 +++++++++++++++++++++++++++++++++++
>  4 files changed, 283 insertions(+)
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index fe3f2fc4fbc087d8041f97708fbb93722f7d1882..f82c7f6c7377d3f2ff0ae1be263d854749541f03 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -7240,6 +7240,7 @@ DELL XPS EMBEDDED CONTROLLER DRIVER
>  M:	Aleksandrs Vinarskis <alex@vinarskis.com>
>  S:	Maintained
>  F:	Documentation/devicetree/bindings/embedded-controller/dell,xps13-9345-ec.yaml
> +F:	drivers/platform/arm64/dell-xps-ec.c
>  
>  DELTA AHE-50DC FAN CONTROL MODULE DRIVER
>  M:	Zev Weiss <zev@bewilderbeest.net>
> diff --git a/drivers/platform/arm64/Kconfig b/drivers/platform/arm64/Kconfig
> index 10f905d7d6bfa5fad30a0689d3a20481268c781e..0bc8f016032bb05cb3a7cc50bdf1092da04153bc 100644
> --- a/drivers/platform/arm64/Kconfig
> +++ b/drivers/platform/arm64/Kconfig
> @@ -33,6 +33,18 @@ config EC_ACER_ASPIRE1
>  	  laptop where this information is not properly exposed via the
>  	  standard ACPI devices.
>  
> +config EC_DELL_XPS
> +	tristate "Dell XPS 9345 Embedded Controller driver"
> +	depends on ARCH_QCOM || COMPILE_TEST
> +	depends on I2C
> +	depends on IIO
> +	help
> +	  Driver for the Embedded Controller in the Qualcomm Snapdragon-based
> +	  Dell XPS 13 9345, which handles thermal management and fan speed
> +	  control.
> +
> +	  Say M or Y here to include this support.
> +
>  config EC_HUAWEI_GAOKUN
>  	tristate "Huawei Matebook E Go Embedded Controller driver"
>  	depends on ARCH_QCOM || COMPILE_TEST
> diff --git a/drivers/platform/arm64/Makefile b/drivers/platform/arm64/Makefile
> index 60c131cff6a15bb51a49c9edab95badf513ee0f6..6768dc6c2310837374e67381cfc729bed1fdaaef 100644
> --- a/drivers/platform/arm64/Makefile
> +++ b/drivers/platform/arm64/Makefile
> @@ -6,6 +6,7 @@
>  #
>  
>  obj-$(CONFIG_EC_ACER_ASPIRE1)	+= acer-aspire1-ec.o
> +obj-$(CONFIG_EC_DELL_XPS)	+= dell-xps-ec.o
>  obj-$(CONFIG_EC_HUAWEI_GAOKUN)	+= huawei-gaokun-ec.o
>  obj-$(CONFIG_EC_LENOVO_YOGA_C630) += lenovo-yoga-c630.o
>  obj-$(CONFIG_EC_LENOVO_THINKPAD_T14S) += lenovo-thinkpad-t14s.o
> diff --git a/drivers/platform/arm64/dell-xps-ec.c b/drivers/platform/arm64/dell-xps-ec.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..5ea8f30931d8b61acbb948d8617dde3681fb8de3
> --- /dev/null
> +++ b/drivers/platform/arm64/dell-xps-ec.c
> @@ -0,0 +1,269 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2026, Aleksandrs Vinarskis <alex@vinarskis.com>
> + */
> +
> +#include <linux/array_size.h>
> +#include <linux/devm-helpers.h>
> +#include <linux/device.h>
> +#include <linux/i2c.h>
> +#include <linux/iio/consumer.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/pm.h>
> +#include <linux/workqueue.h>
> +
> +#define DELL_XPS_EC_SUSPEND_CMD		0xb9
> +#define DELL_XPS_EC_SUSPEND_MSG_LEN	64
> +
> +#define DELL_XPS_EC_TEMP_CMD0		0xfb
> +#define DELL_XPS_EC_TEMP_CMD1		0x20
> +#define DELL_XPS_EC_TEMP_CMD3		0x02
> +#define DELL_XPS_EC_TEMP_MSG_LEN	6
> +#define DELL_XPS_EC_TEMP_INTERVAL_MS	100
> +
> +/*
> + * Format:
> + * - header/unknown (2 bytes)
> + * - per-thermistor entries (3 bytes): thermistor_id, param1, param2
> + */
> +static const u8 dell_xps_ec_thermistor_profile[] = {
> +	0xff, 0x54,
> +	0x01, 0x00, 0x2b,	/* sys_therm0 */
> +	0x02, 0x44, 0x2a,	/* sys_therm1 */
> +	0x03, 0x44, 0x2b,	/* sys_therm2 */
> +	0x04, 0x44, 0x28,	/* sys_therm3 */
> +	0x05, 0x55, 0x2a,	/* sys_therm4 */
> +	0x06, 0x44, 0x26,	/* sys_therm5 */
> +	0x07, 0x44, 0x2b,	/* sys_therm6 */
> +};
> +
> +/*
> + * Mapping from IIO channel name to EC command byte
> + */
> +static const struct {
> +	const char *name;
> +	u8 cmd;
> +} dell_xps_ec_therms[] = {
> +	/* TODO: 0x01 is sent only occasionally, likely TZ98 or TZ4 */
> +	{ "sys_therm0", 0x02 },
> +	{ "sys_therm1", 0x03 },
> +	{ "sys_therm2", 0x04 },
> +	{ "sys_therm3", 0x05 },
> +	{ "sys_therm4", 0x06 },
> +	{ "sys_therm5", 0x07 },
> +	{ "sys_therm6", 0x08 },
> +};
> +
> +struct dell_xps_ec {
> +	struct device *dev;
> +	struct i2c_client *client;
> +	struct iio_channel *therm_channels[ARRAY_SIZE(dell_xps_ec_therms)];
> +	struct delayed_work temp_work;
> +};
> +
> +static int dell_xps_ec_suspend_cmd(struct dell_xps_ec *ec, bool suspend)
> +{
> +	u8 buf[DELL_XPS_EC_SUSPEND_MSG_LEN] = {};
> +	int ret;
> +
> +	buf[0] = DELL_XPS_EC_SUSPEND_CMD;
> +	buf[1] = suspend ? 0x01 : 0x00;
> +	/* bytes 2..63 remain zero */
> +
> +	ret = i2c_master_send(ec->client, buf, sizeof(buf));
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int dell_xps_ec_send_temp(struct dell_xps_ec *ec, u8 cmd_byte,
> +				 int milli_celsius)
> +{
> +	u8 buf[DELL_XPS_EC_TEMP_MSG_LEN];
> +	u16 deci_celsius;
> +	int ret;
> +
> +	/* Convert milli-Celsius to deci-Celsius (Celsius * 10) */
> +	deci_celsius = milli_celsius / 100;
> +
> +	buf[0] = DELL_XPS_EC_TEMP_CMD0;
> +	buf[1] = DELL_XPS_EC_TEMP_CMD1;
> +	buf[2] = cmd_byte;
> +	buf[3] = DELL_XPS_EC_TEMP_CMD3;
> +	buf[4] = deci_celsius & 0xff;		/* LSB */
> +	buf[5] = (deci_celsius >> 8) & 0xff;	/* MSB */

This looks like a 16-bit field so it should be handled as such and with 
annotated endianness. One option would be to use a struct so you can use 
it as a field.

> +	ret = i2c_master_send(ec->client, buf, sizeof(buf));
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static void dell_xps_ec_temp_work_fn(struct work_struct *work)
> +{
> +	struct dell_xps_ec *ec = container_of(work, struct dell_xps_ec,
> +					      temp_work.work);
> +	int val, ret, i;
> +
> +	for (i = 0; i < ARRAY_SIZE(dell_xps_ec_therms); i++) {
> +		if (!ec->therm_channels[i])
> +			continue;
> +
> +		ret = iio_read_channel_processed(ec->therm_channels[i], &val);
> +		if (ret < 0) {
> +			dev_err_ratelimited(ec->dev,
> +					    "Failed to read thermistor %s: %d\n",
> +					    dell_xps_ec_therms[i].name, ret);

Add include for dev_err_ratelimited().

> +			continue;
> +		}
> +
> +		ret = dell_xps_ec_send_temp(ec, dell_xps_ec_therms[i].cmd, val);
> +		if (ret < 0) {
> +			dev_err_ratelimited(ec->dev,
> +					    "Failed to send temp for %s: %d\n",
> +					    dell_xps_ec_therms[i].name, ret);
> +		}
> +	}
> +
> +	schedule_delayed_work(&ec->temp_work,
> +			      msecs_to_jiffies(DELL_XPS_EC_TEMP_INTERVAL_MS));

Add include for msecs_to_jiffies().

> +}
> +
> +static irqreturn_t dell_xps_ec_irq_handler(int irq, void *data)
> +{
> +	struct dell_xps_ec *ec = data;
> +
> +	/*
> +	 * TODO: IRQ is fired on lid-close. Follow Windows example to read out
> +	 *       the thermistor thresholds and potentially fan speeds.
> +	 */
> +	dev_info_ratelimited(ec->dev, "IRQ triggered! (irq=%d)\n", irq);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int dell_xps_ec_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	struct dell_xps_ec *ec;
> +	int ret, i;
> +
> +	ec = devm_kzalloc(dev, sizeof(*ec), GFP_KERNEL);
> +	if (!ec)
> +		return -ENOMEM;
> +
> +	ec->dev = dev;
> +	ec->client = client;
> +	i2c_set_clientdata(client, ec);
> +
> +	/* Set default thermistor profile */
> +	ret = i2c_master_send(client, dell_xps_ec_thermistor_profile,
> +			      sizeof(dell_xps_ec_thermistor_profile));
> +	if (ret < 0)
> +		return dev_err_probe(dev, ret, "Failed to set thermistor profile\n");
> +
> +	/* Get IIO channels for thermistors */
> +	for (i = 0; i < ARRAY_SIZE(dell_xps_ec_therms); i++) {
> +		ec->therm_channels[i] = devm_iio_channel_get(dev,
> +					dell_xps_ec_therms[i].name);
> +		if (IS_ERR(ec->therm_channels[i])) {

Add include.

> +			ret = PTR_ERR(ec->therm_channels[i]);
> +			ec->therm_channels[i] = NULL;
> +			if (ret == -EPROBE_DEFER)
> +				return ret;
> +			dev_warn(dev, "Thermistor %s not available: %d\n",
> +				 dell_xps_ec_therms[i].name, ret);
> +		}
> +	}
> +
> +	/* Start periodic temperature reporting */
> +	ret = devm_delayed_work_autocancel(dev, &ec->temp_work,
> +					   dell_xps_ec_temp_work_fn);
> +	if (ret)
> +		return ret;
> +	schedule_delayed_work(&ec->temp_work,
> +			      msecs_to_jiffies(DELL_XPS_EC_TEMP_INTERVAL_MS));
> +	dev_info(dev, "Started periodic temperature reporting to EC every %d ms\n",
> +		 DELL_XPS_EC_TEMP_INTERVAL_MS);
> +
> +	/* Request IRQ for EC events */
> +	ret = devm_request_threaded_irq(dev, client->irq, NULL,
> +					dell_xps_ec_irq_handler,
> +					IRQF_ONESHOT, dev_name(dev), ec);
> +	if (ret < 0)
> +		return dev_err_probe(dev, ret, "Failed to request IRQ\n");
> +
> +	return 0;
> +}
> +
> +/*
> + * Notify EC of suspend
> + *
> + * This will:
> + * - Ramp down the fans
> + * - Cut power to display/trackpad/keyboard/touch row
> + * - Periodically (?) power them back, such that wake-up source still works
> + */
> +static int dell_xps_ec_suspend(struct device *dev)
> +{
> +	struct dell_xps_ec *ec = dev_get_drvdata(dev);
> +
> +	cancel_delayed_work_sync(&ec->temp_work);
> +
> +	return dell_xps_ec_suspend_cmd(ec, true);
> +}
> +
> +/*
> + * Notify EC of resume
> + *
> + * This will undo the suspend actions
> + * Without the resume signal, device would wake up but be forced back into
> + * suspend by EC within seconds
> + */
> +static int dell_xps_ec_resume(struct device *dev)
> +{
> +	struct dell_xps_ec *ec = dev_get_drvdata(dev);
> +	int ret;
> +
> +	ret = dell_xps_ec_suspend_cmd(ec, false);
> +	if (ret)
> +		return ret;
> +
> +	schedule_delayed_work(&ec->temp_work,
> +			      msecs_to_jiffies(DELL_XPS_EC_TEMP_INTERVAL_MS));
> +	return 0;
> +}
> +
> +static const struct of_device_id dell_xps_ec_of_match[] = {
> +	{ .compatible = "dell,xps13-9345-ec" },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, dell_xps_ec_of_match);
> +
> +static const struct i2c_device_id dell_xps_ec_i2c_id[] = {
> +	{ "dell-xps-ec" },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(i2c, dell_xps_ec_i2c_id);
> +
> +static const struct dev_pm_ops dell_xps_ec_pm_ops = {
> +	SYSTEM_SLEEP_PM_OPS(dell_xps_ec_suspend, dell_xps_ec_resume)
> +};
> +
> +static struct i2c_driver dell_xps_ec_driver = {
> +	.driver = {
> +		.name = "dell-xps-ec",
> +		.of_match_table = dell_xps_ec_of_match,
> +		.pm = &dell_xps_ec_pm_ops,
> +	},
> +	.probe = dell_xps_ec_probe,
> +	.id_table = dell_xps_ec_i2c_id,
> +};
> +module_i2c_driver(dell_xps_ec_driver);
> +
> +MODULE_AUTHOR("Aleksandrs Vinarskis <alex@vinarskis.com>");
> +MODULE_DESCRIPTION("Dell XPS 13 9345 Embedded Controller");
> +MODULE_LICENSE("GPL");
> 
> 

-- 
 i.

Re: [PATCH 2/4] platform: arm64: dell-xps-ec: new driver

[Ilpo Järvinen]

On Wed, 1 Apr 2026, Konrad Dybcio wrote:

> On 4/1/26 9:33 AM, Aleksandrs Vinarskis wrote:
> > Introduce EC driver for Dell XPS 13 9345 (codename 'tributo') which may
> > partially of fully compatible with Snapdragon-based Dell Latitude,
> > Inspiron ('thena'). Primary function of this driver is unblock EC's
> > thermal management, specifically to provide it with necessary
> > information to control device fans, peripherals power.
> 
> [...]
> 
> > +/*
> > + * Format:
> > + * - header/unknown (2 bytes)
> > + * - per-thermistor entries (3 bytes): thermistor_id, param1, param2
> > + */
> > +static const u8 dell_xps_ec_thermistor_profile[] = {
> > +	0xff, 0x54,
> 
> This is super wishful thinking, but 0x54 is ASCII 'T', perhaps for
> "Thermistor" or "Temp"?
> 
> > +static int dell_xps_ec_suspend_cmd(struct dell_xps_ec *ec, bool suspend)
> > +{
> > +	u8 buf[DELL_XPS_EC_SUSPEND_MSG_LEN] = {};
> > +	int ret;
> > +
> > +	buf[0] = DELL_XPS_EC_SUSPEND_CMD;
> > +	buf[1] = suspend ? 0x01 : 0x00;
> > +	/* bytes 2..63 remain zero */
> 
> buf[1] = suspend
> 
> (since it's a boolean argument)

I'd prefer boolean -> binary conversion is done explicitly.

-- 
 i.

Re: [PATCH 2/4] platform: arm64: dell-xps-ec: new driver

[Bjorn Andersson]

On Wed, Apr 01, 2026 at 09:33:11AM +0200, Aleksandrs Vinarskis wrote:
> Introduce EC driver for Dell XPS 13 9345 (codename 'tributo') which may
> partially of fully compatible with Snapdragon-based Dell Latitude,
> Inspiron ('thena'). Primary function of this driver is unblock EC's
> thermal management, specifically to provide it with necessary
> information to control device fans, peripherals power.
> 
> The driver was developed primarily by analyzing ACPI DSDT's _DSM and
> i2c dumps of communication between SoC and EC. Changes to Windows
> driver's behavior include increasing temperature feed loop from ~50ms
> to 100ms here.
> 
> While Xps's EC is rather complex and controls practically all device
> peripherals including touch row's brightness and special keys such as
> mic mute, these do not go over this particular i2c interface.
> 
> Not yet implemented features:
> - On lid-close IRQ event is registered. Windows performs what to
>   appears to be thermistor constants readout, though its not obvious
>   what it used for.
> - According to ACPI's _DSM there is a method to readout fans' RPM.
> - Initial thermistor constants were sniffed from Windows, these can be
>   likely fine tuned for better cooling performance.
> - There is additional temperature reading that Windows sents to EC but
>   more rare than others, likely SoC T_j / TZ98 or TZ4. This is the only
>   thermal zone who's reading can exceed 115C without triggering thermal
>   shutdown.
> - Given similarities between 'tributo' and 'thena' platforms, including
>   EC i2c address, driver can be potentially extended to support both.
> 
> Signed-off-by: Aleksandrs Vinarskis <alex@vinarskis.com>

Looks good, just some minor things below.

> ---
>  MAINTAINERS                          |   1 +
>  drivers/platform/arm64/Kconfig       |  12 ++
>  drivers/platform/arm64/Makefile      |   1 +
>  drivers/platform/arm64/dell-xps-ec.c | 269 +++++++++++++++++++++++++++++++++++
>  4 files changed, 283 insertions(+)
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index fe3f2fc4fbc087d8041f97708fbb93722f7d1882..f82c7f6c7377d3f2ff0ae1be263d854749541f03 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -7240,6 +7240,7 @@ DELL XPS EMBEDDED CONTROLLER DRIVER
>  M:	Aleksandrs Vinarskis <alex@vinarskis.com>
>  S:	Maintained
>  F:	Documentation/devicetree/bindings/embedded-controller/dell,xps13-9345-ec.yaml
> +F:	drivers/platform/arm64/dell-xps-ec.c
>  
>  DELTA AHE-50DC FAN CONTROL MODULE DRIVER
>  M:	Zev Weiss <zev@bewilderbeest.net>
> diff --git a/drivers/platform/arm64/Kconfig b/drivers/platform/arm64/Kconfig
> index 10f905d7d6bfa5fad30a0689d3a20481268c781e..0bc8f016032bb05cb3a7cc50bdf1092da04153bc 100644
> --- a/drivers/platform/arm64/Kconfig
> +++ b/drivers/platform/arm64/Kconfig
> @@ -33,6 +33,18 @@ config EC_ACER_ASPIRE1
>  	  laptop where this information is not properly exposed via the
>  	  standard ACPI devices.
>  
> +config EC_DELL_XPS
> +	tristate "Dell XPS 9345 Embedded Controller driver"
> +	depends on ARCH_QCOM || COMPILE_TEST
> +	depends on I2C
> +	depends on IIO
> +	help
> +	  Driver for the Embedded Controller in the Qualcomm Snapdragon-based
> +	  Dell XPS 13 9345, which handles thermal management and fan speed
> +	  control.
> +
> +	  Say M or Y here to include this support.
> +
>  config EC_HUAWEI_GAOKUN
>  	tristate "Huawei Matebook E Go Embedded Controller driver"
>  	depends on ARCH_QCOM || COMPILE_TEST
> diff --git a/drivers/platform/arm64/Makefile b/drivers/platform/arm64/Makefile
> index 60c131cff6a15bb51a49c9edab95badf513ee0f6..6768dc6c2310837374e67381cfc729bed1fdaaef 100644
> --- a/drivers/platform/arm64/Makefile
> +++ b/drivers/platform/arm64/Makefile
> @@ -6,6 +6,7 @@
>  #
>  
>  obj-$(CONFIG_EC_ACER_ASPIRE1)	+= acer-aspire1-ec.o
> +obj-$(CONFIG_EC_DELL_XPS)	+= dell-xps-ec.o
>  obj-$(CONFIG_EC_HUAWEI_GAOKUN)	+= huawei-gaokun-ec.o
>  obj-$(CONFIG_EC_LENOVO_YOGA_C630) += lenovo-yoga-c630.o
>  obj-$(CONFIG_EC_LENOVO_THINKPAD_T14S) += lenovo-thinkpad-t14s.o
> diff --git a/drivers/platform/arm64/dell-xps-ec.c b/drivers/platform/arm64/dell-xps-ec.c
> new file mode 100644
> index 0000000000000000000000000000000000000000..5ea8f30931d8b61acbb948d8617dde3681fb8de3
> --- /dev/null
> +++ b/drivers/platform/arm64/dell-xps-ec.c
> @@ -0,0 +1,269 @@
> +// SPDX-License-Identifier: GPL-2.0-only
> +/*
> + * Copyright (c) 2026, Aleksandrs Vinarskis <alex@vinarskis.com>
> + */
> +
> +#include <linux/array_size.h>
> +#include <linux/devm-helpers.h>
> +#include <linux/device.h>
> +#include <linux/i2c.h>
> +#include <linux/iio/consumer.h>
> +#include <linux/interrupt.h>
> +#include <linux/module.h>
> +#include <linux/pm.h>
> +#include <linux/workqueue.h>
> +
> +#define DELL_XPS_EC_SUSPEND_CMD		0xb9
> +#define DELL_XPS_EC_SUSPEND_MSG_LEN	64
> +
> +#define DELL_XPS_EC_TEMP_CMD0		0xfb
> +#define DELL_XPS_EC_TEMP_CMD1		0x20
> +#define DELL_XPS_EC_TEMP_CMD3		0x02
> +#define DELL_XPS_EC_TEMP_MSG_LEN	6
> +#define DELL_XPS_EC_TEMP_INTERVAL_MS	100

If you express this in jiffies directly, you could avoid line breaking
three of the lines referring to it below.

> +
> +/*
> + * Format:
> + * - header/unknown (2 bytes)
> + * - per-thermistor entries (3 bytes): thermistor_id, param1, param2
> + */
> +static const u8 dell_xps_ec_thermistor_profile[] = {
> +	0xff, 0x54,
> +	0x01, 0x00, 0x2b,	/* sys_therm0 */
> +	0x02, 0x44, 0x2a,	/* sys_therm1 */
> +	0x03, 0x44, 0x2b,	/* sys_therm2 */
> +	0x04, 0x44, 0x28,	/* sys_therm3 */
> +	0x05, 0x55, 0x2a,	/* sys_therm4 */
> +	0x06, 0x44, 0x26,	/* sys_therm5 */
> +	0x07, 0x44, 0x2b,	/* sys_therm6 */
> +};
> +
> +/*
> + * Mapping from IIO channel name to EC command byte
> + */
> +static const struct {
> +	const char *name;
> +	u8 cmd;
> +} dell_xps_ec_therms[] = {
> +	/* TODO: 0x01 is sent only occasionally, likely TZ98 or TZ4 */
> +	{ "sys_therm0", 0x02 },
> +	{ "sys_therm1", 0x03 },
> +	{ "sys_therm2", 0x04 },
> +	{ "sys_therm3", 0x05 },
> +	{ "sys_therm4", 0x06 },
> +	{ "sys_therm5", 0x07 },
> +	{ "sys_therm6", 0x08 },
> +};
> +
> +struct dell_xps_ec {
> +	struct device *dev;
> +	struct i2c_client *client;
> +	struct iio_channel *therm_channels[ARRAY_SIZE(dell_xps_ec_therms)];
> +	struct delayed_work temp_work;
> +};
> +
> +static int dell_xps_ec_suspend_cmd(struct dell_xps_ec *ec, bool suspend)
> +{
> +	u8 buf[DELL_XPS_EC_SUSPEND_MSG_LEN] = {};
> +	int ret;
> +
> +	buf[0] = DELL_XPS_EC_SUSPEND_CMD;
> +	buf[1] = suspend ? 0x01 : 0x00;
> +	/* bytes 2..63 remain zero */
> +
> +	ret = i2c_master_send(ec->client, buf, sizeof(buf));
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static int dell_xps_ec_send_temp(struct dell_xps_ec *ec, u8 cmd_byte,
> +				 int milli_celsius)
> +{
> +	u8 buf[DELL_XPS_EC_TEMP_MSG_LEN];
> +	u16 deci_celsius;
> +	int ret;
> +
> +	/* Convert milli-Celsius to deci-Celsius (Celsius * 10) */
> +	deci_celsius = milli_celsius / 100;
> +
> +	buf[0] = DELL_XPS_EC_TEMP_CMD0;
> +	buf[1] = DELL_XPS_EC_TEMP_CMD1;
> +	buf[2] = cmd_byte;
> +	buf[3] = DELL_XPS_EC_TEMP_CMD3;
> +	buf[4] = deci_celsius & 0xff;		/* LSB */
> +	buf[5] = (deci_celsius >> 8) & 0xff;	/* MSB */
> +
> +	ret = i2c_master_send(ec->client, buf, sizeof(buf));
> +	if (ret < 0)
> +		return ret;
> +
> +	return 0;
> +}
> +
> +static void dell_xps_ec_temp_work_fn(struct work_struct *work)
> +{
> +	struct dell_xps_ec *ec = container_of(work, struct dell_xps_ec,
> +					      temp_work.work);
> +	int val, ret, i;
> +
> +	for (i = 0; i < ARRAY_SIZE(dell_xps_ec_therms); i++) {
> +		if (!ec->therm_channels[i])
> +			continue;
> +
> +		ret = iio_read_channel_processed(ec->therm_channels[i], &val);
> +		if (ret < 0) {
> +			dev_err_ratelimited(ec->dev,
> +					    "Failed to read thermistor %s: %d\n",
> +					    dell_xps_ec_therms[i].name, ret);
> +			continue;
> +		}
> +
> +		ret = dell_xps_ec_send_temp(ec, dell_xps_ec_therms[i].cmd, val);
> +		if (ret < 0) {
> +			dev_err_ratelimited(ec->dev,
> +					    "Failed to send temp for %s: %d\n",
> +					    dell_xps_ec_therms[i].name, ret);
> +		}
> +	}
> +
> +	schedule_delayed_work(&ec->temp_work,
> +			      msecs_to_jiffies(DELL_XPS_EC_TEMP_INTERVAL_MS));
> +}
> +
> +static irqreturn_t dell_xps_ec_irq_handler(int irq, void *data)
> +{
> +	struct dell_xps_ec *ec = data;
> +
> +	/*
> +	 * TODO: IRQ is fired on lid-close. Follow Windows example to read out
> +	 *       the thermistor thresholds and potentially fan speeds.
> +	 */
> +	dev_info_ratelimited(ec->dev, "IRQ triggered! (irq=%d)\n", irq);
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int dell_xps_ec_probe(struct i2c_client *client)
> +{
> +	struct device *dev = &client->dev;
> +	struct dell_xps_ec *ec;
> +	int ret, i;
> +
> +	ec = devm_kzalloc(dev, sizeof(*ec), GFP_KERNEL);
> +	if (!ec)
> +		return -ENOMEM;
> +
> +	ec->dev = dev;
> +	ec->client = client;
> +	i2c_set_clientdata(client, ec);
> +
> +	/* Set default thermistor profile */
> +	ret = i2c_master_send(client, dell_xps_ec_thermistor_profile,
> +			      sizeof(dell_xps_ec_thermistor_profile));
> +	if (ret < 0)
> +		return dev_err_probe(dev, ret, "Failed to set thermistor profile\n");
> +
> +	/* Get IIO channels for thermistors */
> +	for (i = 0; i < ARRAY_SIZE(dell_xps_ec_therms); i++) {
> +		ec->therm_channels[i] = devm_iio_channel_get(dev,
> +					dell_xps_ec_therms[i].name);

What does checkpatch --strict think about this line wrap?

> +		if (IS_ERR(ec->therm_channels[i])) {
> +			ret = PTR_ERR(ec->therm_channels[i]);
> +			ec->therm_channels[i] = NULL;
> +			if (ret == -EPROBE_DEFER)
> +				return ret;
> +			dev_warn(dev, "Thermistor %s not available: %d\n",
> +				 dell_xps_ec_therms[i].name, ret);
> +		}
> +	}
> +
> +	/* Start periodic temperature reporting */
> +	ret = devm_delayed_work_autocancel(dev, &ec->temp_work,
> +					   dell_xps_ec_temp_work_fn);
> +	if (ret)
> +		return ret;
> +	schedule_delayed_work(&ec->temp_work,
> +			      msecs_to_jiffies(DELL_XPS_EC_TEMP_INTERVAL_MS));
> +	dev_info(dev, "Started periodic temperature reporting to EC every %d ms\n",
> +		 DELL_XPS_EC_TEMP_INTERVAL_MS);

I think dev_dbg() is sufficient here. This isn't something the user
should care about during normal operation/bootup.

Regards,
Bjorn

> +
> +	/* Request IRQ for EC events */
> +	ret = devm_request_threaded_irq(dev, client->irq, NULL,
> +					dell_xps_ec_irq_handler,
> +					IRQF_ONESHOT, dev_name(dev), ec);
> +	if (ret < 0)
> +		return dev_err_probe(dev, ret, "Failed to request IRQ\n");
> +
> +	return 0;
> +}
> +
> +/*
> + * Notify EC of suspend
> + *
> + * This will:
> + * - Ramp down the fans
> + * - Cut power to display/trackpad/keyboard/touch row
> + * - Periodically (?) power them back, such that wake-up source still works
> + */
> +static int dell_xps_ec_suspend(struct device *dev)
> +{
> +	struct dell_xps_ec *ec = dev_get_drvdata(dev);
> +
> +	cancel_delayed_work_sync(&ec->temp_work);
> +
> +	return dell_xps_ec_suspend_cmd(ec, true);
> +}
> +
> +/*
> + * Notify EC of resume
> + *
> + * This will undo the suspend actions
> + * Without the resume signal, device would wake up but be forced back into
> + * suspend by EC within seconds
> + */
> +static int dell_xps_ec_resume(struct device *dev)
> +{
> +	struct dell_xps_ec *ec = dev_get_drvdata(dev);
> +	int ret;
> +
> +	ret = dell_xps_ec_suspend_cmd(ec, false);
> +	if (ret)
> +		return ret;
> +
> +	schedule_delayed_work(&ec->temp_work,
> +			      msecs_to_jiffies(DELL_XPS_EC_TEMP_INTERVAL_MS));
> +	return 0;
> +}
> +
> +static const struct of_device_id dell_xps_ec_of_match[] = {
> +	{ .compatible = "dell,xps13-9345-ec" },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(of, dell_xps_ec_of_match);
> +
> +static const struct i2c_device_id dell_xps_ec_i2c_id[] = {
> +	{ "dell-xps-ec" },
> +	{}
> +};
> +MODULE_DEVICE_TABLE(i2c, dell_xps_ec_i2c_id);
> +
> +static const struct dev_pm_ops dell_xps_ec_pm_ops = {
> +	SYSTEM_SLEEP_PM_OPS(dell_xps_ec_suspend, dell_xps_ec_resume)
> +};
> +
> +static struct i2c_driver dell_xps_ec_driver = {
> +	.driver = {
> +		.name = "dell-xps-ec",
> +		.of_match_table = dell_xps_ec_of_match,
> +		.pm = &dell_xps_ec_pm_ops,
> +	},
> +	.probe = dell_xps_ec_probe,
> +	.id_table = dell_xps_ec_i2c_id,
> +};
> +module_i2c_driver(dell_xps_ec_driver);
> +
> +MODULE_AUTHOR("Aleksandrs Vinarskis <alex@vinarskis.com>");
> +MODULE_DESCRIPTION("Dell XPS 13 9345 Embedded Controller");
> +MODULE_LICENSE("GPL");
> 
> -- 
> 2.53.0
> 

Re: [PATCH 1/4] dt-bindings: platform: introduce EC for Dell XPS 13 9345

[Krzysztof Kozlowski]

On Wed, Apr 01, 2026 at 09:33:10AM +0200, Aleksandrs Vinarskis wrote:
> Add bindings for Embedded Controller (EC) in Dell XPS 13 9345 (platform
> codename 'tributo'). It may be partially or fully compatible with EC
> found in Snapdragon-based Dell Latitude, Inspiron ('thena').
> 
> Signed-off-by: Aleksandrs Vinarskis <alex@vinarskis.com>
> ---
>  .../embedded-controller/dell,xps13-9345-ec.yaml    | 86 ++++++++++++++++++++++
>  MAINTAINERS                                        |  5 ++
>  2 files changed, 91 insertions(+)
> 
> diff --git a/Documentation/devicetree/bindings/embedded-controller/dell,xps13-9345-ec.yaml b/Documentation/devicetree/bindings/embedded-controller/dell,xps13-9345-ec.yaml
> new file mode 100644
> index 0000000000000000000000000000000000000000..30dc6dcd8c9f0312fdb4eafdef96bf0ce4975798
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/embedded-controller/dell,xps13-9345-ec.yaml
> @@ -0,0 +1,86 @@
> +# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/embedded-controller/dell,xps13-9345-ec.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Dell XPS 13 9345 Embedded Controller
> +
> +maintainers:
> +  - Aleksandrs Vinarskis <alex@vinarskis.com>
> +
> +description:
> +  The Dell XPS 13 9345 has an Embedded Controller (EC) which handles thermal and power

Please wrap code according to the preferred limit expressed in Kernel
coding style (checkpatch is not a coding style description, but only a
tool).  However don't wrap blindly (see Kernel coding style).

> +  management. It is communicating with SoC over multiple i2c busses. Particular driver

Drop "driver" references and describe what you think EC is doing.

> +  is for EC subsystem that handles fan speed control, thermal shutdown, peripherals
> +  supply including trackpad, touch-row, display.
> +
> +properties:
> +  compatible:
> +    const: dell,xps13-9345-ec
> +
> +  reg:
> +    const: 0x3b
> +
> +  interrupts:
> +    maxItems: 1
> +
> +  io-channels:
> +    description:
> +      ADC channels connected to the 7 onboard thermistors on PMK8550.
> +      EC requires frequent thermal readings of these channels to perform
> +      automated fan speed control.
> +    items:
> +      - description: ADC channel for sys_therm0
> +      - description: ADC channel for sys_therm1
> +      - description: ADC channel for sys_therm2
> +      - description: ADC channel for sys_therm3
> +      - description: ADC channel for sys_therm4
> +      - description: ADC channel for sys_therm5
> +      - description: ADC channel for sys_therm6
> +
> +  io-channel-names:
> +    items:
> +      - const: sys_therm0
> +      - const: sys_therm1
> +      - const: sys_therm2
> +      - const: sys_therm3
> +      - const: sys_therm4
> +      - const: sys_therm5
> +      - const: sys_therm6
> +
> +required:
> +  - compatible
> +  - reg
> +  - interrupts
> +  - io-channels
> +  - io-channel-names
> +
> +additionalProperties: false
> +
> +examples:
> +  - |+

If there is going to be resend:
Drop +, I think we don't ever use it in the examples.

Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>

Best regards,
Krzysztof

Re: [PATCH 4/4] arm64: dts: qcom: x1e80100-dell-xps13-9345: introduce EC

[Aleksandrs Vinarskis]

On Wednesday, April 1st, 2026 at 11:21, Konrad Dybcio <konrad.dybcio@oss.qualcomm.com> wrote:

> On 4/1/26 9:33 AM, Aleksandrs Vinarskis wrote:
> > Describe embedded controller, its interrupt and required thermal zones.
> > Add EC's reset GPIO to reserved range, as triggering it during device
> > operation leads to unrecoverable and unusable state.
> >
> > Signed-off-by: Aleksandrs Vinarskis <alex@vinarskis.com>
> > ---
>
> [...]
>
> > +		io-channels = <&pmk8550_vadc PM8350_ADC7_GPIO3_100K_PU(1)>,
> > +			      <&pmk8550_vadc PM8350_ADC7_GPIO4_100K_PU(1)>,
> > +			      <&pmk8550_vadc PM8350_ADC7_AMUX_THM1_100K_PU(1)>,
> > +			      <&pmk8550_vadc PM8350_ADC7_AMUX_THM2_100K_PU(1)>,
> > +			      <&pmk8550_vadc PM8350_ADC7_AMUX_THM3_100K_PU(1)>,
> > +			      <&pmk8550_vadc PM8350_ADC7_AMUX_THM4_100K_PU(1)>,
> > +			      <&pmk8550_vadc PM8350_ADC7_AMUX_THM5_100K_PU(1)>;
> > +
> > +		io-channel-names = "sys_therm0", "sys_therm1", "sys_therm2",
> > +				   "sys_therm3", "sys_therm4", "sys_therm5",
> > +				   "sys_therm6";
>
> nit: one a line please, without a separating \n between x and x-names

Will drop \n. One a line as in:
io-channel-names = "sys_therm0",
                   "sys_therm1",
                   "sys_therm2",
                    ...
?

>
> [...]
>
> > +&pmk8550_vadc {
> > +	/* sys_therm0, around DRAM */
>
> another nit: I think repeating the name set in the label in each comment
> is a little excessive

Will drop,

>
> [...]
>
> >  &tlmm {
> >  	gpio-reserved-ranges = <44 4>,  /* SPI11 (TPM) */
> > +			       <65 1>,  /* EC Reset */
>
> Is that a "this may not be accessed" or rather "you can, but it has dire
> consequences"?

The latter. Triggering EC reset appears to leave it in un-initialized state.
When analyzing i2c dumps I noticed UEFI sends some data to EC prior to
Windows driver loading, I am assuming its required for EC configuration.
When resetting EC from userpsace:
- Keyboard, Trackpad, touch-row power is out. WiFi connection drops. Dell's
  UEFI allows disabling many peripherals, EC can 'veto' their resets and/or
  power supplies. It appears in default reset state it kill some/all outputs
- Holding power button does not reboot laptop, it looks as if it asserts and
  holds EC in reset until released. During this time fans spin to max speed.
- Device can be recovered only by disassembly and battery removal.

>
> Would the EC driver/binding benefit from having a reference to that pin?

It will not be used by the driver, and it would greatly inconvenience user
if triggered manually. I would make the reset pin as inaccessible as
possible, but if you say its cleaner to reference it to EC driver and just
not use it, I could do that as well.

Thanks for fast review,
Alex  

>
> Konrad
>