leds: flash: LM3643 dual LED flash driver

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index bbe9358c9caa..1c0de38ebcdf 100644
@@ -9,6 +9,7 @@
 #include <linux/bitfield.h>
 #include <linux/bits.h>
 #include <linux/cleanup.h>
+#include <linux/dmi.h>
 #include <linux/i2c.h>
 #include <linux/led-class-flash.h>
 #include <linux/leds.h>

@@ -690,6 +691,92 @@ 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_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_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_info(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;

@@ -699,6 +786,12 @@ 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);

index 1c0de38ebcdf..b9d167e25375 100644
@@ -691,16 +691,21 @@ 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),

@@ -711,19 +716,46 @@ 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
 };
 

@@ -734,7 +766,15 @@ static const struct dmi_system_id lm3643_dmi_leds[] = {
 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
 			DMI_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_MATCH(DMI_SYS_VENDOR, "LENOVO"),
+			DMI_MATCH(DMI_PRODUCT_VERSION, "ThinkPad X9-15 Gen 1"),
+		},
+		.driver_data = (void *)lm3643_x9_15_nodes,
 	},
 	{ }
 };