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");
--
2.53.0On 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.
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
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.
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