leds: flash: LM3643 dual LED flash driver

This series adds a flash LED driver for the Texas Instruments LM3643. I wrote it to support the Windows Hello NIR illuminator on my ThinkPad X9-15 Gen 1, which has a single LED connected to both current sources. The driver has also been tested by Ruslan Koreev on a ThinkPad X1 Carbon Gen 14.

On both ThinkPad models the chip is described by ACPI but has no _DSD. The original RFC asked how to supply the missing child nodes. This series includes DMI-matched software nodes for both laptop models.

1/4 DT binding
2/4 driver
3/4 DMI match table and values for the X1 Carbon
4/4 DMI entry for the X9-15 Gen 1

Changes in v3:
- dt-bindings: document the enable-gpios (HWEN), flash-gpios (STROBE) and vin-supply (IN) connections (Krzysztof Kozlowski)
- dt-bindings: drop redundant minimum: 0, use led-controller as the node name in the example and tidy formatting (Krzysztof Kozlowski)
- driver: enable the optional vin-supply and drive the optional HWEN GPIO high at probe
- driver: reject an out-of-range max-brightness rather than clamping after registration (previously LED core applied max-brightness exposing sysfs before the clamp)
- driver: allow a torch output to be switched off while the device is flashing (previously returned -EBUSY)
- driver: take the chip lock when claiming current outputs
- driver: fix indentation in lm3643_torch_get_brightness()
- 3/4, 4/4: use DMI_EXACT_MATCH for the DMI entries
- 3/4: log use of the DMI description with dev_dbg() instead of dev_info()

Changes in v2:
- Rebased onto leds/for-leds-next
- dt-bindings: make flash-max-microamp, led-max-microamp and flash-max-timeout-us required
- driver: return device to standby state when the last output is switched off (squashed fix provided by Ruslan Koreev)
- New 3/4: DMI mechanism and entry for the X1 Carbon developed by Ruslan. Plus a minor update to provide a reg property for consistency with the DT bindings.
- New 4/4: DMI entry for the X9-15 Gen 1 and update struct names to be model-specific.

v2: https://lore.kernel.org/all/[email protected]/
v1: https://lore.kernel.org/all/[email protected]/

Rillian Grant (3):
dt-bindings: leds: Document TI LM3643 dual LED flash driver
leds: flash: Add support for the TI LM3643 dual LED flash driver
leds: flash: lm3643: Describe the LED on the Lenovo ThinkPad X9-15 Gen

    1

Ruslan Koreev (1):
leds: flash: lm3643: Describe the LED of ACPI boards without LED nodes

 .../devicetree/bindings/leds/ti,lm3643.yaml   | 143 +++
 MAINTAINERS                                   |   7 +
 drivers/leds/flash/Kconfig                    |  12 +
 drivers/leds/flash/Makefile                   |   1 +
 drivers/leds/flash/leds-lm3643.c              | 929 ++++++++++++++++++
 5 files changed, 1092 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/ti,lm3643.yaml
 create mode 100644 drivers/leds/flash/leds-lm3643.c

base-commit: 05b4738b0078f7d6f154f68068a11c8a0635e9df

2.56.0

Document Texas Instruments LM3643 dual LED flash driver devicetree bindings.

---
 .../devicetree/bindings/leds/ti,lm3643.yaml   | 143 ++++++++++++++++++
 1 file changed, 143 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/leds/ti,lm3643.yaml

new file mode 100644
index 000000000000..63c5f09f3bd5
@@ -0,0 +1,143 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/leds/ti,lm3643.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Texas Instruments LM3643 1500mA dual LED Flash Driver
+
+maintainers:
+  - Rillian Grant <[email protected]>
+
+description: |
+  The LM3643 is a dual LED flash driver utilizing a synchronous boost converter
+  to provide power to two current sources.
+
+  The dual high-side current sources can be tied together to provide flash
+  currents up to 1.5A through a single LED.
+
+  Datasheet: https://www.ti.com/lit/ds/symlink/lm3643.pdf
+
+properties:
+  compatible:
+    enum:
+      - ti,lm3643
+
+  reg:
+    maxItems: 1
+
+  "#address-cells":
+    const: 1
+
+  "#size-cells":
+    const: 0
+
+  enable-gpios:
+    description: GPIO connected to the HWEN pin.
+    maxItems: 1
+
+  flash-gpios:
+    description: GPIO connected to the STROBE pin.
+    maxItems: 1
+
+  vin-supply:
+    description: Supply connected to the IN line.
+
+patternProperties:
+  "^led@[0-1]$":
+    type: object
+    $ref: common.yaml#
+    unevaluatedProperties: false
+
+    properties:
+      reg:
+        description: Index of the LED.
+        maximum: 1
+
+      led-sources:
+        minItems: 1
+        maxItems: 2
+        items:
+          maximum: 1
+
+      flash-max-microamp:
+        description: |
+          Maximum flash current through this LED. Each high-side current source
+          can provide up to 1.5A. The maximum current the boost can deliver is
+          1.5A across both sources.
+
+          Valid values for an LED connected to one source:
+            10900 - 1500000, step by 11725 (rounded down)
+          Valid values for an LED connected to both sources:
+            21800 - 1500000, step by 23450 (rounded down)
+        minimum: 10900
+        maximum: 1500000
+
+      led-max-microamp:
+        description: |
+          Maximum torch current through this LED. In torch mode each high-side
+          current source can provide up to 179mA.
+
+          Valid values for an LED connected to one source:
+            977 - 179000, step by 1400 (rounded down)
+          Valid values for an LED connected to both sources:
+            1954 - 358000, step by 2800 (rounded down)
+        minimum: 977
+        maximum: 358000
+
+      flash-max-timeout-us:
+        description:
+          The chip supports timeouts from 10ms to 100ms in increments of 10ms
+          and from 100ms to 400ms in increments of 50ms. The provided value
+          will be rounded down to a supported value.
+        minimum: 10000
+        maximum: 400000
+
+    required:
+      - reg
+      - led-sources
+      - flash-max-microamp
+      - led-max-microamp
+      - flash-max-timeout-us
+
+required:
+  - compatible
+  - reg
+  - "#address-cells"
+  - "#size-cells"
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+    #include <dt-bindings/leds/common.h>
+
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        led-controller@63 {
+            compatible = "ti,lm3643";
+            reg = <0x63>;
+
+            #address-cells = <1>;
+            #size-cells = <0>;
+
+            enable-gpios = <&gpio 42 GPIO_ACTIVE_HIGH>;
+            flash-gpios = <&gpio 43 GPIO_ACTIVE_HIGH>;
+            vin-supply = <&vreg_flash>;
+
+            led@0 {
+                reg = <0>;
+                led-sources = <0>, <1>;
+
+                function = LED_FUNCTION_FLASH;
+                color = <LED_COLOR_ID_IR>;
+
+                flash-max-microamp = <750000>;
+                led-max-microamp = <180000>;
+                flash-max-timeout-us = <150000>;
+            };
+        };
+    };

2.56.0

Best regards,
Krzysztof

The LM3643 is an I2C dual LED flash driver. Its two high-side current sources share a synchronous boost converter and each supports torch and flash modes with programmable current and flash timeout alongside fault reporting.

It also supports connecting both sources together to supply one LED with current up to the boost converter's 1.5A maximum. In that case the current will be split between each source symmetrically and the sources will be enabled and disabled at the same time.

As strobing is toggled chip-wide the driver returns -EBUSY when a sibling LED is active.

Flash timeouts do not have a constant step. The driver advertises the most granular step and rounds down to the nearest supported value.

Register behavior was taken from the datasheet (SNVS967A).

---
 MAINTAINERS                      |   7 +
 drivers/leds/flash/Kconfig       |  12 +
 drivers/leds/flash/Makefile      |   1 +
 drivers/leds/flash/leds-lm3643.c | 796 +++++++++++++++++++++++++++++++
 4 files changed, 816 insertions(+)
 create mode 100644 drivers/leds/flash/leds-lm3643.c

index a1eb0937238d..0c186a7f2648 100644
@@ -27036,6 +27036,13 @@ F:	include/linux/dma/k3-udma-glue.h
 F:	include/linux/dma/ti-cppi5.h
 X:	drivers/dma/ti/cppi41.c
 
+TEXAS INSTRUMENTS LM3643 LED FLASH DRIVER
+M:	Rillian Grant <[email protected]>
+L:	[email protected]
+S:	Maintained
+F:	Documentation/devicetree/bindings/leds/ti,lm3643.yaml
+F:	drivers/leds/flash/leds-lm3643.c
+
 TEXAS INSTRUMENTS TPS25990 HARDWARE MONITOR DRIVER
 M:	Jerome Brunet <[email protected]>
 L:	[email protected]

index 9b6dd3f1ffe8..0f0a60a902fc 100644
@@ -39,6 +39,18 @@ config LEDS_LM3601X
 	  This option enables support for the TI LM3601x family
 	  of flash, torch and indicator classes.
 
+config LEDS_LM3643
+	tristate "LED support for LM3643 dual LED flash driver"
+	depends on I2C
+	depends on V4L2_FLASH_LED_CLASS || !V4L2_FLASH_LED_CLASS
+	select REGMAP_I2C
+	help
+	  This option enables support for the Texas Instruments LM3643 dual
+	  LED flash driver.
+
+	  This driver can also be built as a module. If so, the module
+	  will be called "leds-lm3643".
+
 config LEDS_MAX77693
 	tristate "LED support for MAX77693 Flash"
 	depends on V4L2_FLASH_LED_CLASS || !V4L2_FLASH_LED_CLASS

index 44e6c1b4beb3..e2e885e02123 100644
@@ -6,6 +6,7 @@ obj-$(CONFIG_LEDS_AAT1290)	+= leds-aat1290.o
 obj-$(CONFIG_LEDS_AS3645A)	+= leds-as3645a.o
 obj-$(CONFIG_LEDS_KTD2692)	+= leds-ktd2692.o
 obj-$(CONFIG_LEDS_LM3601X)	+= leds-lm3601x.o
+obj-$(CONFIG_LEDS_LM3643)	+= leds-lm3643.o
 obj-$(CONFIG_LEDS_MAX77693)	+= leds-max77693.o
 obj-$(CONFIG_LEDS_QCOM_FLASH)	+= leds-qcom-flash.o
 obj-$(CONFIG_LEDS_RT4505)	+= leds-rt4505.o

2.56.0

Happy to switch to "leds: flash: lm3643:" across the series if there is another revision, or for the maintainer to adjust when applying.

The LM3643 datasheet specifies no delay between HWEN high and I2C ready, so I'd rather not add an arbitrary sleep.

Rillian Grant

From: Ruslan Koreev <[email protected]>

Lenovo ThinkPads enumerate the LM3643 through ACPI (HID TXNW3643) without a _DSD, so the device has no LED child nodes and the driver refuses to probe. On these laptops the chip drives the Windows Hello IR flood illuminator, with both current sources feeding a single LED, and Lenovo's Windows driver applies a fixed configuration to any LM3643 it finds.

Add a DMI table that provides that description as a software node when the firmware offers none: one IR flash LED on both outputs, with torch and flash limits well below the chip's maximums. Start with the ThinkPad X1 Carbon Gen 14.

The description is keyed by DMI instead of being applied to every TXNW3643 because the wiring is a board property: which output feeds which LED and how much current the LED tolerates cannot be read from the chip, and a wrong guess overdrives an LED. The firmware cannot be fixed from the driver side, and a per-board table is what x86-android-tablets does for devices whose ACPI tables describe nothing either. Boards with a _DSD are not affected, the fallback only runs when the device has no child nodes. The limits are conservative because the LED part is not documented; the illuminator is bright enough for face authentication at a fraction of them.

Tested on that laptop: torch through /sys/class/leds/ir:flash lights the ST VD55G1 IR camera's field of view, and the resulting frames are good enough for face authentication.

---
 drivers/leds/flash/leds-lm3643.c | 93 ++++++++++++++++++++++++++++++++
 1 file changed, 93 insertions(+)

index cbe66e90d8e1..18ac75df72e2 100644
@@ -9,6 +9,7 @@
 #include <linux/bitfield.h>
 #include <linux/bits.h>
 #include <linux/cleanup.h>
+#include <linux/dmi.h>
 #include <linux/gpio/consumer.h>
 #include <linux/i2c.h>
 #include <linux/led-class-flash.h>

@@ -691,6 +692,92 @@ static int lm3643_register_led(struct device *dev, struct lm3643 *chip,
 	return lm3643_register_v4l2(dev, led, fwnode);
 }
 
+/*
+ * Lenovo ThinkPads enumerate the chip through ACPI (HID TXNW3643) without a
+ * _DSD, so the LED is not described by firmware. On the boards below it drives
+ * the Windows Hello IR flood illuminator, with both current sources feeding a
+ * single LED. Describe that with a software node, with torch and flash limits
+ * (100 mA and 300 mA per output) well below the chip's maximums.
+ */
+static const u32 lm3643_ir_flood_sources[] = { 0, 1 };
+
+static const struct property_entry lm3643_ir_flood_props[] = {
+	PROPERTY_ENTRY_U32("reg", 0),
+	PROPERTY_ENTRY_U32_ARRAY("led-sources", lm3643_ir_flood_sources),
+	PROPERTY_ENTRY_STRING("function", LED_FUNCTION_FLASH),
+	PROPERTY_ENTRY_U32("color", LED_COLOR_ID_IR),
+	PROPERTY_ENTRY_U32("led-max-microamp", 200000),
+	PROPERTY_ENTRY_U32("flash-max-microamp", 600000),
+	PROPERTY_ENTRY_U32("flash-max-timeout-us", 100000),
+	{ }
+};
+
+static const struct software_node lm3643_ir_flood_root = {
+	.name = "lm3643",
+};
+
+static const struct software_node lm3643_ir_flood_led = {
+	.name = "led-0",
+	.parent = &lm3643_ir_flood_root,
+	.properties = lm3643_ir_flood_props,
+};
+
+static const struct software_node *lm3643_ir_flood_nodes[] = {
+	&lm3643_ir_flood_root,
+	&lm3643_ir_flood_led,
+	NULL
+};
+
+static const struct dmi_system_id lm3643_dmi_leds[] = {
+	{
+		/* Lenovo ThinkPad X1 Carbon Gen 14 */
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_EXACT_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X1 Carbon Gen 14"),
+		},
+		.driver_data = (void *)lm3643_ir_flood_nodes,
+	},
+	{ }
+};
+
+static void lm3643_remove_dmi_leds(void *data)
+{
+	struct device *dev = data;
+	const struct dmi_system_id *id = dmi_first_match(lm3643_dmi_leds);
+
+	set_secondary_fwnode(dev, NULL);
+	if (id)
+		software_node_unregister_node_group(id->driver_data);
+}
+
+static int lm3643_add_dmi_leds(struct device *dev)
+{
+	const struct dmi_system_id *id;
+	const struct software_node **nodes;
+	int ret;
+
+	if (!has_acpi_companion(dev))
+		return 0;
+
+	id = dmi_first_match(lm3643_dmi_leds);
+	if (!id)
+		return 0;
+
+	nodes = id->driver_data;
+	/* The nodes are static: a second chip on the same board cannot reuse them */
+	if (software_node_fwnode(nodes[0]))
+		return dev_err_probe(dev, -EBUSY, "LED description already in use\n");
+
+	ret = software_node_register_node_group(nodes);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to register the LED description\n");
+
+	set_secondary_fwnode(dev, software_node_fwnode(nodes[0]));
+	dev_dbg(dev, "no LED nodes in firmware, using the DMI description\n");
+
+	return devm_add_action_or_reset(dev, lm3643_remove_dmi_leds, dev);
+}
+
 static int lm3643_probe(struct i2c_client *client)
 {
 	struct device *dev = &client->dev;

@@ -701,6 +788,12 @@ static int lm3643_probe(struct i2c_client *client)
 	int ret;
 
 	count = device_get_child_node_count(dev);
+	if (!count) {
+		ret = lm3643_add_dmi_leds(dev);
+		if (ret)
+			return ret;
+		count = device_get_child_node_count(dev);
+	}
 	if (!count || count > LM3643_NUM_CHANNELS)
 		return dev_err_probe(dev, -EINVAL, "%u LED nodes found, expected 1 to %d\n",
 					 count, LM3643_NUM_CHANNELS);

2.56.0

This condition is currently unreachable. It would require two LM3643 instances on the same DMI entry.

I'd be happy to add a static mutex if preferred, or alongside any future DMI entry for a board with more than one LM3643.

Rillian Grant

Please.

Lee Jones

Andy, et al., Please see below.

Lee Jones

Hi Lee, others,

In this case the ipu-bridge needs to provide the information to the lm3643 driver via software nodes, as it already does for a number of other devices. There's no point in putting the information to the LED driver.

Presumably the ACPI device node already exists so this should be straightforward. What's also missing from the sensor then is the flash-leds property, the lens-focus handling serves as an example.

Regards,

Sakari Ailus

...

Seconding Sakari's answer, this doesn't sound like the best approach.

+1 to all the above.

With Best Regards,
Andy Shevchenko

The ThinkPad X9-15 Gen 1 enumerates the LM3643 through ACPI (HID TXNW3643) without a _DSD, like the X1 Carbon Gen 14. It drives the Windows Hello IR flood illuminator with both current sources feeding a single LED.

The flash limits were obtained from an ETW trace of the SPB class extension during a Windows Hello unlock. The Windows driver programs 304 mA per current source (code 0x19 with the LED2 override set) and a 400 ms flash timeout.

There is no vendor value for the torch limit, so use the same conservative limit as the X1 Carbon Gen 14.

Rename the X1 Carbon Gen 14 nodes after the machine now that the table has a second entry. Sources and root node remain shared.

---
 drivers/leds/flash/leds-lm3643.c | 70 +++++++++++++++++++++++++-------
 1 file changed, 55 insertions(+), 15 deletions(-)

index 18ac75df72e2..38b1dd09a1b7 100644
@@ -692,16 +692,21 @@ static int lm3643_register_led(struct device *dev, struct lm3643 *chip,
 	return lm3643_register_v4l2(dev, led, fwnode);
 }
 
-/*
- * Lenovo ThinkPads enumerate the chip through ACPI (HID TXNW3643) without a
- * _DSD, so the LED is not described by firmware. On the boards below it drives
- * the Windows Hello IR flood illuminator, with both current sources feeding a
- * single LED. Describe that with a software node, with torch and flash limits
- * (100 mA and 300 mA per output) well below the chip's maximums.
- */
 static const u32 lm3643_ir_flood_sources[] = { 0, 1 };
 
-static const struct property_entry lm3643_ir_flood_props[] = {
+static const struct software_node lm3643_ir_flood_root = {
+	.name = "lm3643",
+};
+
+/*
+ * The Lenovo ThinkPad X1 Carbon Gen 14 enumerates the chip through ACPI
+ * (HID TXNW3643) without a _DSD, so the LED is not described by firmware.
+ * On the X1 Gen 14 it drives the Windows Hello IR flood illuminator, with
+ * both current sources feeding a single LED. Describe that with a software
+ * node, with torch and flash limits (100 mA and 300 mA per output) well below
+ * the chip's maximums.
+ */
+static const struct property_entry lm3643_x1c14_props[] = {
 	PROPERTY_ENTRY_U32("reg", 0),
 	PROPERTY_ENTRY_U32_ARRAY("led-sources", lm3643_ir_flood_sources),
 	PROPERTY_ENTRY_STRING("function", LED_FUNCTION_FLASH),

@@ -712,19 +717,46 @@ static const struct property_entry lm3643_ir_flood_props[] = {
 	{ }
 };
 
-static const struct software_node lm3643_ir_flood_root = {
-	.name = "lm3643",
+static const struct software_node lm3643_x1c14_led = {
+	.name = "led-0",
+	.parent = &lm3643_ir_flood_root,
+	.properties = lm3643_x1c14_props,
+};
+
+static const struct software_node *lm3643_x1c14_nodes[] = {
+	&lm3643_ir_flood_root,
+	&lm3643_x1c14_led,
+	NULL
 };
 
-static const struct software_node lm3643_ir_flood_led = {
+/*
+ * The Lenovo ThinkPad X9-15 Gen 1 enumerates the chip through ACPI
+ * (HID TXNW3643) without a _DSD. On the X9-15 it drives the Windows Hello IR
+ * flood illuminator, with both current sources feeding a single LED. Flash
+ * maximums were obtained from an SPB class extension ETW trace of the
+ * vendor-supplied Windows driver. The torch limit is a conservative value well
+ * below the chip's maximum.
+ */
+static const struct property_entry lm3643_x9_15_props[] = {
+	PROPERTY_ENTRY_U32("reg", 0),
+	PROPERTY_ENTRY_U32_ARRAY("led-sources", lm3643_ir_flood_sources),
+	PROPERTY_ENTRY_STRING("function", LED_FUNCTION_FLASH),
+	PROPERTY_ENTRY_U32("color", LED_COLOR_ID_IR),
+	PROPERTY_ENTRY_U32("led-max-microamp", 200000),
+	PROPERTY_ENTRY_U32("flash-max-microamp", 608050),
+	PROPERTY_ENTRY_U32("flash-max-timeout-us", 400000),
+	{ }
+};
+
+static const struct software_node lm3643_x9_15_led = {
 	.name = "led-0",
 	.parent = &lm3643_ir_flood_root,
-	.properties = lm3643_ir_flood_props,
+	.properties = lm3643_x9_15_props,
 };
 
-static const struct software_node *lm3643_ir_flood_nodes[] = {
+static const struct software_node *lm3643_x9_15_nodes[] = {
 	&lm3643_ir_flood_root,
-	&lm3643_ir_flood_led,
+	&lm3643_x9_15_led,
 	NULL
 };
 

@@ -735,7 +767,15 @@ static const struct dmi_system_id lm3643_dmi_leds[] = {
 			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 			DMI_EXACT_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X1 Carbon Gen 14"),
 		},
-		.driver_data = (void *)lm3643_ir_flood_nodes,
+		.driver_data = (void *)lm3643_x1c14_nodes,
+	},
+	{
+		/* Lenovo ThinkPad X9-15 Gen 1 */
+		.matches = {
+			DMI_EXACT_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_EXACT_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X9-15 Gen 1"),
+		},
+		.driver_data = (void *)lm3643_x9_15_nodes,
 	},
 	{ }
 };

2.56.0

--- checkpatch.pl: clean (0 issues) ---

static const struct property_entry lm3643_ir_flood_props[] = {
       PROPERTY_ENTRY_U32("reg", 0),
       PROPERTY_ENTRY_U32_ARRAY("led-sources", lm3643_ir_flood_sources),
       PROPERTY_ENTRY_STRING("function", LED_FUNCTION_FLASH),
       PROPERTY_ENTRY_U32("color", LED_COLOR_ID_IR),
       PROPERTY_ENTRY_U32("led-max-microamp", 200000),
       PROPERTY_ENTRY_U32("flash-max-microamp", 600000),
       PROPERTY_ENTRY_U32("flash-max-timeout-us", 100000),
       { }
};

Lee Jones

Hi Lee,

We can share the board-description code in ipu-bridge and add flash-leds, as Sakari and Andy suggested, while keeping per-board current settings.

Lenovo's packages set IRFlashLedIntensity=30 for the X1 [1] and 40 for the X9 [2]. With both outputs using the same current setting, these convert to nominal totals of 467350 uA and 608050 uA respectively. The X9 result matches Rillian's trace; the X1 result is from static analysis, with live Windows behavior still unverified.

My earlier claim that Windows applies a fixed configuration to any LM3643 was too broad: the sensor configuration affects the current request.

Both default paths configure a 400 ms controller timeout. Actual mode, pulse duration and continuous-torch limits remain unverified, so these are candidate operating settings rather than established LED limits.

Rillian, could you share the relevant SPB trace, including mode, current and timeout writes, together with the installed driver version?

[1] https://download.lenovo.com/pccbbs/mobiles/n4oce17w.html
[2] https://download.lenovo.com/pccbbs/mobiles/n4cim20w.html

Ruslan

Hi Ruslan,

Driver versions: the X9-15 Gen 1 values are from the Windows install on my machine. The X1 Carbon Gen 14 values are from the current package on Lenovo's support site.

X9-15 Gen 1:
- lm3643.inf/.sys 70.26100.2.18321 (02/20/2025)
- IR sensor: HM1092, hm1092.inf 70.26100.2.18321
- FlashLEDsIntensity = 0x3C64 (lm3643.inf)
- IRFlashLedIntensity = 40 (hm1092.inf)

X1 Carbon Gen 14:
- lm3643.inf 71.26100.10.21060 (08/05/2026) however lm3643.sys contradicts with 71.26100.23.21060
- IR sensor: VD55G1, TBE0020A1.inf 71.26100.10.21060
- FlashLEDsIntensity = 0x3C64 (lm3643.inf)
- IRFlashLedIntensity = 30 (TBE0020A1.inf)

Both lm3643.inf files bind ACPI\TXNW3643 and ACPI\INT347D. Apart from the version, they differ only in where DeviceCharacteristics/Security are written. The registry on the X9 matches the INF defaults.

Before I submitted the DMI software node patch, I had seen that the Carbon had a different driver version and a different IRFlashLedIntensity. That is why I didn't reuse its values for the X9.

I traced Microsoft-Windows-SPB-ClassExtension (analytic) during a Windows Hello face unlock on the X9. Every write to the LM3643 is preceded by a read of the same register. Register decodes are from SNVS967A.

Start of the session (once, after the controller entered D0):
R 0x0A=00 R 0x0B=00 R 0x01=03 R 0x0C=02
R 0x07=09 -> W 0x07=09 boost config, POR default (2 MHz, 2.8 A ILIM,
short detect on)
W 0x01=03 standby, LED1+LED2 enable, TX pin enable off

                           (POR is 0x80)

W 0x08=00 no torch ramp, flash timeout 10 ms

Per pulse (repeats every ~133 ms):

  W 0x01=03                standby
  W 0x08=0F                no torch ramp, flash timeout 400 ms
  W 0x03=99                bit7 = LED2 flash current override (LED2 = LED1),
                           code 0x19 -> 25 x 11.725 + 10.9 = ~304 mA per
                           LED (~608 mA total)
  W 0x01=0F                flash mode (M1,M0=11), LED1+LED2  <- LED on
  ... ~65 ms ...
  W 0x08=00                timeout set to 10 ms while the flash is running
  W 0x01=03                standby                           <- LED off
  R 0x0A=01  R 0x0B=00     Flags1 bit0 = flash time-out flag (0x00 after
                           the first pulse, 0x01 after every later pulse)

This unlock had 6 pulses. The last one was turned off after ~3 ms, once the face was recognised. The driver never wrote the torch registers (0x05/0x06) or the LED2 flash register (0x04), and never used IR mode, STROBE or TX. The only values written to 0x01 were 0x03 and 0x0F.

The LM3643 transactions with timestamps are attached. The raw ETL/XML trace is available on request.

--
Rillian Grant

10:47:24.493347  LM3643 W 0x0A | R 0x00
10:47:24.493427  -- controller 0x3CF250DE2738 D-state 0x1
10:47:24.504454  LM3643 W 0x0B | R 0x00
10:47:24.504748  LM3643 W 0x01 | R 0x03
10:47:24.505018  LM3643 W 0x0C | R 0x02
10:47:24.505315  LM3643 W 0x07 | R 0x09
10:47:24.505564  LM3643 W 0x0709
10:47:24.505741  LM3643 W 0x01 | R 0x03
10:47:24.506021  LM3643 W 0x0103
10:47:24.506229  LM3643 W 0x01 | R 0x03
10:47:24.506479  LM3643 W 0x01 | R 0x03
10:47:24.506736  LM3643 W 0x0103
10:47:24.507080  LM3643 W 0x08 | R 0x00
10:47:24.507317  LM3643 W 0x0800
10:47:24.507537  LM3643 W 0x01 | R 0x03
10:47:24.507777  LM3643 W 0x0103
10:47:24.507935  LM3643 W 0x01 | R 0x03
10:47:24.508181  LM3643 W 0x0103
10:47:24.552953  HM1092(IR) W 0x010000
10:47:24.632548  HM1092(IR) W 0x010001
10:47:24.669203  -- controller 0x3CF250DDE738 D-state 0x1
10:47:24.675057  LM3643 W 0x01 | R 0x03
10:47:24.675520  LM3643 W 0x0103
10:47:24.675806  LM3643 W 0x08 | R 0x00
10:47:24.676278  LM3643 W 0x080F
10:47:24.676575  LM3643 W 0x03 | R 0x99
10:47:24.676857  LM3643 W 0x0399
10:47:24.677059  LM3643 W 0x01 | R 0x03
10:47:24.677316  LM3643 W 0x010F
10:47:24.681780  IMX471(RGB) W 0x010000
10:47:24.741365  LM3643 W 0x08 | R 0x0F
10:47:24.741647  LM3643 W 0x0800
10:47:24.741872  LM3643 W 0x01 | R 0x0F
10:47:24.742178  LM3643 W 0x0103
10:47:24.742372  LM3643 W 0x0A | R 0x00
10:47:24.742621  LM3643 W 0x0B | R 0x00
10:47:24.742969  IMX471(RGB) W 0x010001
10:47:24.807808  LM3643 W 0x01 | R 0x03
10:47:24.808069  LM3643 W 0x0103
10:47:24.808246  LM3643 W 0x08 | R 0x00
10:47:24.808503  LM3643 W 0x080F
10:47:24.808776  LM3643 W 0x03 | R 0x99
10:47:24.809023  LM3643 W 0x0399
10:47:24.809178  LM3643 W 0x01 | R 0x03
10:47:24.809456  LM3643 W 0x010F
10:47:24.874410  LM3643 W 0x08 | R 0x0F
10:47:24.874691  LM3643 W 0x0800
10:47:24.874913  LM3643 W 0x01 | R 0x0F
10:47:24.875165  LM3643 W 0x0103
10:47:24.875371  LM3643 W 0x0A | R 0x01
10:47:24.875619  LM3643 W 0x0B | R 0x00
10:47:24.940847  LM3643 W 0x01 | R 0x03
10:47:24.941139  LM3643 W 0x0103
10:47:24.941306  LM3643 W 0x08 | R 0x00
10:47:24.941552  LM3643 W 0x080F
10:47:24.941768  LM3643 W 0x03 | R 0x99
10:47:24.942104  LM3643 W 0x0399
10:47:24.942271  LM3643 W 0x01 | R 0x03
10:47:24.942513  LM3643 W 0x010F
10:47:25.007386  LM3643 W 0x08 | R 0x0F
10:47:25.007683  LM3643 W 0x0800
10:47:25.007896  LM3643 W 0x01 | R 0x0F
10:47:25.008160  LM3643 W 0x0103
10:47:25.008322  LM3643 W 0x0A | R 0x01
10:47:25.008577  LM3643 W 0x0B | R 0x00
10:47:25.073907  LM3643 W 0x01 | R 0x03
10:47:25.074207  LM3643 W 0x0103
10:47:25.074392  LM3643 W 0x08 | R 0x00
10:47:25.074649  LM3643 W 0x080F
10:47:25.074867  LM3643 W 0x03 | R 0x99
10:47:25.075123  LM3643 W 0x0399
10:47:25.075366  LM3643 W 0x01 | R 0x03
10:47:25.075621  LM3643 W 0x010F
10:47:25.140383  LM3643 W 0x08 | R 0x0F
10:47:25.140639  LM3643 W 0x0800
10:47:25.140858  LM3643 W 0x01 | R 0x0F
10:47:25.141103  LM3643 W 0x0103
10:47:25.141266  LM3643 W 0x0A | R 0x01
10:47:25.141507  LM3643 W 0x0B | R 0x00
10:47:25.206938  LM3643 W 0x01 | R 0x03
10:47:25.207270  LM3643 W 0x0103
10:47:25.207443  LM3643 W 0x08 | R 0x00
10:47:25.207689  LM3643 W 0x080F
10:47:25.207897  LM3643 W 0x03 | R 0x99
10:47:25.208150  LM3643 W 0x0399
10:47:25.208318  LM3643 W 0x01 | R 0x03
10:47:25.208581  LM3643 W 0x010F
10:47:25.273481  LM3643 W 0x08 | R 0x0F
10:47:25.273782  LM3643 W 0x0800
10:47:25.274032  LM3643 W 0x01 | R 0x0F
10:47:25.274303  LM3643 W 0x0103
10:47:25.274485  LM3643 W 0x0A | R 0x01
10:47:25.274721  LM3643 W 0x0B | R 0x00
10:47:25.339949  LM3643 W 0x01 | R 0x03
10:47:25.340239  LM3643 W 0x0103
10:47:25.340418  LM3643 W 0x08 | R 0x00
10:47:25.340684  LM3643 W 0x080F
10:47:25.340932  LM3643 W 0x03 | R 0x99
10:47:25.341210  LM3643 W 0x0399
10:47:25.341406  LM3643 W 0x01 | R 0x03
10:47:25.341660  LM3643 W 0x010F
10:47:25.344654  LM3643 W 0x08 | R 0x0F
10:47:25.344956  LM3643 W 0x0800
10:47:25.345171  LM3643 W 0x01 | R 0x0F
10:47:25.345419  LM3643 W 0x0103
10:47:25.345575  LM3643 W 0x0A | R 0x01
10:47:25.345808  LM3643 W 0x0B | R 0x00
10:47:25.473344  HM1092(IR) W 0x010000
10:47:25.474241  LM3643 W 0x08 | R 0x00
10:47:25.474501  LM3643 W 0x0800
10:47:25.474715  LM3643 W 0x01 | R 0x03
10:47:25.474956  LM3643 W 0x0103
10:47:25.475106  LM3643 W 0x01 | R 0x03
10:47:25.475403  LM3643 W 0x0103
10:47:25.486367  LM3643 W 0x0A | R 0x01
10:47:25.486763  LM3643 W 0x0B | R 0x00
10:47:25.623971  IMX471(RGB) W 0x010000
10:47:27.620034  -- controller 0x3CF250DE2738 D-state 0x4
10:47:28.631808  -- controller 0x3CF250DDE738 D-state 0x4