[PATCH v2 0/2] Add support for LX1308

[PATCH v2 0/2] Add support for LX1308

[Brian Chiang]

The LX1308 is a high-efficiency, non-isolated power module. The module
operates from a 40V to 60V DC primary bus and a 12V regulated output
voltage. It can deliver up to 860W continuous and 1300W in transient.
The built-in digital controller can store and restore module
configurations. The fault status, input voltage, output voltage, output
current, and temperature are monitored via the PMBus interface.

Add support for this driver.

Signed-off-by: Brian Chiang <chiang.brian@inventec.com>
---
Changes in v2:
- Remove the unused compatibles of mechanical variants
- Drop the existing pmbus binding in v1, and move lx1308 to trivial binding
- Reorganize the id tables to be placed to each other
- Reorder lx1308 with alphabetical ordering in Kconfig and Makefile
- Fix undefined behavior left-shifting of a negative integer
- Link to v1: https://lore.kernel.org/r/20260422-add-support-lx1308-v1-0-9b8322f45aae@inventec.com

---
Brian Chiang (2):
      dt-bindings: trivial: Add LX1308 support
      hwmon: (pmbus/lx1308) Add support for LX1308

 .../devicetree/bindings/trivial-devices.yaml       |   2 +
 .../devicetree/bindings/vendor-prefixes.yaml       |   2 +
 Documentation/hwmon/index.rst                      |   1 +
 Documentation/hwmon/lx1308.rst                     |  90 +++++++++
 drivers/hwmon/pmbus/Kconfig                        |  10 +
 drivers/hwmon/pmbus/Makefile                       |   1 +
 drivers/hwmon/pmbus/lx1308.c                       | 204 +++++++++++++++++++++
 7 files changed, 310 insertions(+)
---
base-commit: 591cd656a1bf5ea94a222af5ef2ee76df029c1d2
change-id: 20260415-add-support-lx1308-165a4206ab69

Best regards,
-- 
Brian Chiang <chiang.brian@inventec.com>

[PATCH v2 1/2] dt-bindings: trivial: Add LX1308 support

[Brian Chiang]

Add device tree bindings for the Luxshare LX1308, a high-efficiency
12V 860W DC/DC power module with PMBus interface.

Signed-off-by: Brian Chiang <chiang.brian@inventec.com>
---
 Documentation/devicetree/bindings/trivial-devices.yaml | 2 ++
 Documentation/devicetree/bindings/vendor-prefixes.yaml | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/Documentation/devicetree/bindings/trivial-devices.yaml b/Documentation/devicetree/bindings/trivial-devices.yaml
index a482aeadcd44..037baf4cd67d 100644
--- a/Documentation/devicetree/bindings/trivial-devices.yaml
+++ b/Documentation/devicetree/bindings/trivial-devices.yaml
@@ -181,6 +181,8 @@ properties:
           - jedec,spd5118
             # Linear Technology LTC2488
           - lineartechnology,ltc2488
+            # Regulated 12V, 860W, Digital DC/DC Power Module
+          - luxshare,lx1308
             # 5 Bit Programmable, Pulse-Width Modulator
           - maxim,ds1050
             # 10 kOhm digital potentiometer with I2C interface
diff --git a/Documentation/devicetree/bindings/vendor-prefixes.yaml b/Documentation/devicetree/bindings/vendor-prefixes.yaml
index ee7fd3cfe203..67fb1592daaa 100644
--- a/Documentation/devicetree/bindings/vendor-prefixes.yaml
+++ b/Documentation/devicetree/bindings/vendor-prefixes.yaml
@@ -967,6 +967,8 @@ patternProperties:
     description: Shenzhen Luckfox Technology Co., Ltd.
   "^lunzn,.*":
     description: Shenzhen Lunzn Technology Co., Ltd.
+  "^luxshare,.*":
+    description: Luxshare-ICT Co., Ltd.
   "^luxul,.*":
     description: Lagrand | AV
   "^lwn,.*":

-- 
2.43.0

[PATCH v2 2/2] hwmon: (pmbus/lx1308) Add support for LX1308

[Brian Chiang]

Add support for the Luxshare LX1308, a high-efficiency 12V 860W
DC/DC power module. The module operates from 40-60V input voltage.

Signed-off-by: Brian Chiang <chiang.brian@inventec.com>
---
 Documentation/hwmon/index.rst  |   1 +
 Documentation/hwmon/lx1308.rst |  90 ++++++++++++++++++
 drivers/hwmon/pmbus/Kconfig    |  10 ++
 drivers/hwmon/pmbus/Makefile   |   1 +
 drivers/hwmon/pmbus/lx1308.c   | 204 +++++++++++++++++++++++++++++++++++++++++
 5 files changed, 306 insertions(+)

diff --git a/Documentation/hwmon/index.rst b/Documentation/hwmon/index.rst
index b2ca8513cfcd..c86c21554c37 100644
--- a/Documentation/hwmon/index.rst
+++ b/Documentation/hwmon/index.rst
@@ -145,6 +145,7 @@ Hardware Monitoring Kernel Drivers
    ltc4261
    ltc4282
    ltc4286
+   lx1308
    macsmc-hwmon
    max127
    max15301
diff --git a/Documentation/hwmon/lx1308.rst b/Documentation/hwmon/lx1308.rst
new file mode 100644
index 000000000000..c1b72e1647c5
--- /dev/null
+++ b/Documentation/hwmon/lx1308.rst
@@ -0,0 +1,90 @@
+.. SPDX-License-Identifier: GPL-2.0-or-later
+
+Kernel driver lx1308
+====================
+
+Supported chips:
+
+  * Luxshare LX1308
+
+    Prefixes: 'lx1308'
+
+    Addresses scanned: -
+
+    Datasheet: Datasheet is not publicly available.
+
+Author: Brian Chiang <chiang.brian@inventec.com>
+
+
+Description
+-----------
+
+The LX1308 is a high-efficiency, non-isolated, regulated 12V, 860W,
+digital DC/DC power module. The module operates from a 40V to 60V DC
+primary bus and provides a 12V regulated output voltage. It can deliver
+up to 860W continuous and 1300W in transient.
+
+The module has slow OCP and fast OCP. If the module output current is higher
+than slow OCP set point and the lasting time is also longer than the delay,
+the module will shut down and retry 3 time, if the fault still exists then
+module enter latch mode.
+
+If the module output current is higher than fast OCP set point then it shut
+down and enter latch mode.
+
+The driver is a client driver to the core PMBus driver.
+Please see Documentation/hwmon/pmbus.rst for details on PMBus client drivers.
+
+
+Usage Notes
+-----------
+
+This driver does not auto-detect devices. You will have to instantiate the
+devices explicitly. Please see Documentation/i2c/instantiating-devices.rst for
+details.
+
+
+Sysfs entries
+-------------
+
+======================= ======================================================
+curr1_alarm             Input current alarm
+curr1_input             Input current (IIN)
+curr1_label             "iin"
+curr2_crit              Output over current fault threshold (slow OCP, 60ms delay)
+curr2_crit_alarm        Output over current fault alarm
+curr2_input             Output current (IOUT)
+curr2_label             "iout1"
+curr2_max               Output over current warning threshold (slow OCP, 60ms delay)
+curr2_max_alarm         Output over current warning alarm
+in1_crit                Input over voltage fault threshold
+in1_crit_alarm          Input over voltage fault alarm
+in1_input               Input voltage (VIN)
+in1_label               "vin"
+in1_lcrit               Input under voltage fault threshold
+in1_lcrit_alarm         Input under voltage fault alarm
+in1_max                 Input over voltage warning threshold
+in1_max_alarm           Input over voltage warning alarm
+in1_min                 Input under voltage warning threshold
+in1_min_alarm           Input under voltage warning alarm
+in2_crit                Output over voltage fault threshold
+in2_crit_alarm          Output over voltage fault alarm
+in2_input               Output voltage (VOUT)
+in2_label               "vout1"
+in2_lcrit               Output under voltage fault threshold
+in2_lcrit_alarm         Output under voltage fault alarm
+in2_max                 Output over voltage warning threshold
+in2_max_alarm           Output over voltage warning alarm
+in2_min                 Output under voltage warning threshold
+in2_min_alarm           Output under voltage warning alarm
+power1_alarm            Input power alarm
+power1_input            Input power (PIN)
+power1_label            "pin"
+power2_input            Output power (POUT)
+power2_label            "pout1"
+temp1_crit              Over temperature fault threshold
+temp1_crit_alarm        Over temperature fault alarm
+temp1_input             Module hot spot temperature
+temp1_max               Over temperature warning threshold
+temp1_max_alarm         Over temperature warning alarm
+======================= ======================================================
diff --git a/drivers/hwmon/pmbus/Kconfig b/drivers/hwmon/pmbus/Kconfig
index fc1273abe357..1b003a828537 100644
--- a/drivers/hwmon/pmbus/Kconfig
+++ b/drivers/hwmon/pmbus/Kconfig
@@ -302,6 +302,16 @@ config SENSORS_LTC4286
 	  If you say yes here you get hardware monitoring support for Analog
 	  Devices LTC4286.
 
+config SENSORS_LX1308
+	tristate "Luxshare LX1308 DC/DC Power Module"
+	help
+	  If you say yes here you get hardware monitoring support for
+	  Luxshare LX1308, a high-efficiency 12V 860W DC/DC power module
+	  with PMBus interface.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called lx1308.
+
 config SENSORS_MAX15301
 	tristate "Maxim MAX15301"
 	help
diff --git a/drivers/hwmon/pmbus/Makefile b/drivers/hwmon/pmbus/Makefile
index d6c86924f887..95fc539a77e9 100644
--- a/drivers/hwmon/pmbus/Makefile
+++ b/drivers/hwmon/pmbus/Makefile
@@ -29,6 +29,7 @@ obj-$(CONFIG_SENSORS_LT7182S)	+= lt7182s.o
 obj-$(CONFIG_SENSORS_LTC2978)	+= ltc2978.o
 obj-$(CONFIG_SENSORS_LTC3815)	+= ltc3815.o
 obj-$(CONFIG_SENSORS_LTC4286)	+= ltc4286.o
+obj-$(CONFIG_SENSORS_LX1308)	+= lx1308.o
 obj-$(CONFIG_SENSORS_MAX15301)	+= max15301.o
 obj-$(CONFIG_SENSORS_MAX16064)	+= max16064.o
 obj-$(CONFIG_SENSORS_MAX16601)	+= max16601.o
diff --git a/drivers/hwmon/pmbus/lx1308.c b/drivers/hwmon/pmbus/lx1308.c
new file mode 100644
index 000000000000..0c453393796b
--- /dev/null
+++ b/drivers/hwmon/pmbus/lx1308.c
@@ -0,0 +1,204 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include "pmbus.h"
+
+#define LX1308_MFR_IOUT_OCP3_FAULT	0xBE
+#define LX1308_MFR_IOUT_OCP3_WARN	0xBF
+
+/*
+ * Decode a Linear11-encoded word to an integer value.
+ * Linear11 format: bits[15:11] = signed 5-bit exponent,
+ * bits[10:0] = signed 11-bit mantissa. Result = mant * 2^exp.
+ */
+static inline int linear11_to_int(u16 word)
+{
+	s16 exp = ((s16)word) >> 11;
+	s16 mant = ((s16)((word & 0x7ff) << 5)) >> 5;
+
+	return (exp >= 0) ? (int)((u32)mant << exp) : (mant >> -exp);
+}
+
+static int lx1308_read_word_data(struct i2c_client *client, int page,
+				 int phase, int reg)
+{
+	int ret;
+
+	if (page > 0)
+		return -ENXIO;
+
+	switch (reg) {
+	/*
+	 * The LX1308 OCP3 registers (slow OCP, 60ms delay) use a
+	 * manufacturer-specific U8.0 format. Read the byte value N and present
+	 * it as a Linear11 word with exponent 0.
+	 */
+	case PMBUS_IOUT_OC_FAULT_LIMIT:
+		ret = i2c_smbus_read_byte_data(client, LX1308_MFR_IOUT_OCP3_FAULT);
+		if (ret < 0)
+			break;
+		ret &= 0x7FF;
+		break;
+
+	case PMBUS_IOUT_OC_WARN_LIMIT:
+		ret = i2c_smbus_read_byte_data(client, LX1308_MFR_IOUT_OCP3_WARN);
+		if (ret < 0)
+			break;
+		ret &= 0x7FF;
+		break;
+
+	/*
+	 * The following registers are not implemented by the LX1308. Return
+	 * -ENXIO to suppress the corresponding sysfs attributes.
+	 */
+	case PMBUS_IIN_OC_WARN_LIMIT:
+	case PMBUS_IIN_OC_FAULT_LIMIT:
+	case PMBUS_IOUT_UC_FAULT_LIMIT:
+	case PMBUS_PIN_OP_WARN_LIMIT:
+	case PMBUS_POUT_OP_WARN_LIMIT:
+	case PMBUS_UT_WARN_LIMIT:
+	case PMBUS_UT_FAULT_LIMIT:
+	case PMBUS_MFR_IIN_MAX:
+	case PMBUS_MFR_IOUT_MAX:
+	case PMBUS_MFR_VIN_MIN:
+	case PMBUS_MFR_VIN_MAX:
+	case PMBUS_MFR_VOUT_MIN:
+	case PMBUS_MFR_VOUT_MAX:
+	case PMBUS_MFR_PIN_MAX:
+	case PMBUS_MFR_POUT_MAX:
+	case PMBUS_MFR_MAX_TEMP_1:
+		ret = -ENXIO;
+		break;
+
+	default:
+		ret = -ENODATA;
+		break;
+	}
+
+	return ret;
+}
+
+static int lx1308_write_word_data(struct i2c_client *client, int page,
+				  int reg, u16 word)
+{
+	int ret;
+
+	if (page > 0)
+		return -ENXIO;
+
+	switch (reg) {
+	case PMBUS_IOUT_OC_FAULT_LIMIT:
+		/*
+		 * Decode Linear11 word from pmbus_core back to a plain integer
+		 * and write as the U8.0 byte the device expects.
+		 */
+		ret = i2c_smbus_write_byte_data(client, LX1308_MFR_IOUT_OCP3_FAULT,
+						clamp_val(linear11_to_int(word), 0, 255));
+		break;
+
+	case PMBUS_IOUT_OC_WARN_LIMIT:
+		ret = i2c_smbus_write_byte_data(client, LX1308_MFR_IOUT_OCP3_WARN,
+						clamp_val(linear11_to_int(word), 0, 255));
+		break;
+
+	default:
+		ret = -ENODATA;
+		break;
+	}
+
+	return ret;
+}
+
+static struct pmbus_driver_info lx1308_info = {
+	.pages = 1,
+	.format[PSC_VOLTAGE_IN] = linear,
+	.format[PSC_VOLTAGE_OUT] = linear,
+	.format[PSC_CURRENT_IN] = linear,
+	.format[PSC_CURRENT_OUT] = linear,
+	.format[PSC_POWER] = linear,
+	.format[PSC_TEMPERATURE] = linear,
+
+	.func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_VOUT
+		| PMBUS_HAVE_IIN | PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
+		| PMBUS_HAVE_PIN | PMBUS_HAVE_POUT
+		| PMBUS_HAVE_TEMP | PMBUS_HAVE_STATUS_TEMP
+		| PMBUS_HAVE_STATUS_INPUT,
+
+	.read_word_data  = lx1308_read_word_data,
+	.write_word_data = lx1308_write_word_data,
+};
+
+static const struct of_device_id lx1308_of_match[] = {
+	{ .compatible = "luxshare,lx1308" },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(of, lx1308_of_match);
+
+static const struct i2c_device_id lx1308_id[] = {
+	{ "lx1308" },
+	{ }
+};
+
+MODULE_DEVICE_TABLE(i2c, lx1308_id);
+
+static int lx1308_probe(struct i2c_client *client)
+{
+	u8 buf[I2C_SMBUS_BLOCK_MAX + 1];
+	const struct i2c_device_id *mid;
+	int ret;
+
+	ret = i2c_smbus_read_block_data(client, PMBUS_MFR_ID, buf);
+	if (ret < 0)
+		return dev_err_probe(&client->dev, ret,
+				     "Failed to read manufacturer id\n");
+	buf[ret] = '\0';
+
+	if (ret != 12 || strncmp(buf, "LUXSHARE", 8))
+		return dev_err_probe(&client->dev, -ENODEV,
+				     "Unsupported Manufacturer ID '%s'\n", buf);
+
+	ret = i2c_smbus_read_block_data(client, PMBUS_MFR_MODEL, buf);
+	if (ret < 0)
+		return dev_err_probe(&client->dev, ret,
+				     "Failed to read Manufacturer Model\n");
+	buf[ret] = '\0';
+
+	for (mid = lx1308_id; mid->name[0]; mid++) {
+		if (!strncasecmp(mid->name, buf, strlen(mid->name)))
+			break;
+	}
+	if (!mid->name[0])
+		return dev_err_probe(&client->dev, -ENODEV,
+				     "Unsupported Manufacturer Model '%s'\n", buf);
+
+	ret = i2c_smbus_read_block_data(client, PMBUS_MFR_REVISION, buf);
+	if (ret < 0)
+		return dev_err_probe(&client->dev, ret,
+				     "Failed to read Manufacturer Revision\n");
+	buf[ret] = '\0';
+
+	if (ret != 12 || buf[0] != 'V')
+		return dev_err_probe(&client->dev, -ENODEV,
+				     "Unsupported Manufacturer Revision '%s'\n", buf);
+	return pmbus_do_probe(client, &lx1308_info);
+}
+
+static struct i2c_driver lx1308_driver = {
+	.driver = {
+		.name = "lx1308",
+		.of_match_table = lx1308_of_match,
+	},
+	.probe = lx1308_probe,
+	.id_table = lx1308_id,
+};
+
+module_i2c_driver(lx1308_driver);
+
+MODULE_AUTHOR("Brian Chiang <chiang.brian@inventec.com>");
+MODULE_DESCRIPTION("PMBus driver for Luxshare LX1308");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("PMBUS");

-- 
2.43.0

Re: [PATCH v2 1/2] dt-bindings: trivial: Add LX1308 support

[Krzysztof Kozlowski]

On Tue, Apr 28, 2026 at 12:19:28PM +0000, Brian Chiang wrote:
> Add device tree bindings for the Luxshare LX1308, a high-efficiency
> 12V 860W DC/DC power module with PMBus interface.
> 
> Signed-off-by: Brian Chiang <chiang.brian@inventec.com>
> ---
>  Documentation/devicetree/bindings/trivial-devices.yaml | 2 ++
>  Documentation/devicetree/bindings/vendor-prefixes.yaml | 2 ++
>  2 files changed, 4 insertions(+)

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

Best regards,
Krzysztof

Re: [PATCH v2 1/2] dt-bindings: trivial: Add LX1308 support

[Guenter Roeck]

On Tue, Apr 28, 2026 at 12:19:28PM +0000, Brian Chiang wrote:
> Add device tree bindings for the Luxshare LX1308, a high-efficiency
> 12V 860W DC/DC power module with PMBus interface.
> 
> Signed-off-by: Brian Chiang <chiang.brian@inventec.com>
> Acked-by: Krzysztof Kozlowski <krzysztof.kozlowski@oss.qualcomm.com>

Applied.

Thanks,
Guenter

Re: [PATCH v2 2/2] hwmon: (pmbus/lx1308) Add support for LX1308

[Guenter Roeck]

On Tue, Apr 28, 2026 at 12:19:29PM +0000, Brian Chiang wrote:
> Add support for the Luxshare LX1308, a high-efficiency 12V 860W
> DC/DC power module. The module operates from 40-60V input voltage.
> 
> Signed-off-by: Brian Chiang <chiang.brian@inventec.com>

Applied.

Thanks,
Guenter