[PATCH 0/2] Add LT8491 driver

[PATCH 0/2] Add LT8491 driver

[John Erasmus Mari Geronimo]

This patch series adds a driver and device tree bindings for the LT8491
battery charge controller.

The LT8491 is a buck-boost switching regulator battery charger that
implements a constant-current constant-voltage (CCCV) charging profile
used for most battery types, including sealed lead-acid (SLA), flooded,
gel and lithium-ion.

John Erasmus Mari Geronimo (2):
  dt-bindings: power: supply: add adi,lt8491.yaml
  power: supply: add LT8491 battery charger driver

 .../bindings/power/supply/adi,lt8491.yaml     |  89 ++++
 MAINTAINERS                                   |   7 +
 drivers/power/supply/Kconfig                  |   9 +
 drivers/power/supply/Makefile                 |   1 +
 drivers/power/supply/lt8491_charger.c         | 410 ++++++++++++++++++
 5 files changed, 516 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/power/supply/adi,lt8491.yaml
 create mode 100644 drivers/power/supply/lt8491_charger.c


base-commit: a3a8799165ff83bb764fd800c6559c3cba0ddac3
-- 
2.34.1

[PATCH 1/2] dt-bindings: power: supply: add adi,lt8491.yaml

[John Erasmus Mari Geronimo]

Add documentation for devicetree bindings for LT8491

Signed-off-by: John Erasmus Mari Geronimo <johnerasmusmari.geronimo@analog.com>
---
 .../bindings/power/supply/adi,lt8491.yaml     | 89 +++++++++++++++++++
 MAINTAINERS                                   |  6 ++
 2 files changed, 95 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/power/supply/adi,lt8491.yaml

diff --git a/Documentation/devicetree/bindings/power/supply/adi,lt8491.yaml b/Documentation/devicetree/bindings/power/supply/adi,lt8491.yaml
new file mode 100644
index 000000000..1451fa1d5
--- /dev/null
+++ b/Documentation/devicetree/bindings/power/supply/adi,lt8491.yaml
@@ -0,0 +1,89 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/power/supply/adi,lt8491.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Linear Technology (Analog Devices) LT8491 Battery Charger
+
+maintainers:
+  - John Erasmus Mari Geronimo <johnerasmusmari.geronimo@analog.com>
+
+description: |
+  The LT8491 is a buck-boost switching regulator battery charger that implements
+  a constant-current constant-voltage (CCCV) charging profile used for most
+  battery types, including sealed lead-acid (SLA), flooded, gel and lithium-ion.
+
+  Specifications about the charger can be found at:
+    https://www.analog.com/en/products/lt8491.html
+
+properties:
+  compatible:
+    enum:
+      - adi,lt8491
+
+  reg:
+    maxItems: 1
+
+  adi,rsense1-micro-ohms:
+    description: Resistance value of RSENSE1 in micro ohms.
+
+  adi,rimon-out-ohms:
+    description: Resistance value of RIMON_OUT in ohms.
+
+  adi,rsense2-micro-ohms:
+    description: Resistance value of RSENSE2 in micro ohms.
+
+  adi,rdaco-ohms:
+    description: Resistance value of RDACO1 + RDACO2 in ohms.
+
+  adi,rfbout1-ohms:
+    description: Resistance value of RFBOUT1 in ohms.
+
+  adi,rfbout2-ohms:
+    description: Resistance value of RFBOUT2 in ohms.
+
+  adi,rdaci-ohms:
+    description: Resistance value of RDACI1 + RDACI2 in ohms.
+
+  adi,rfbin2-ohms:
+    description: Resistance value of RFBIN2 in ohms.
+
+  adi,rfbin1-ohms:
+    description: Resistance value of RFBIN1 in ohms.
+
+required:
+  - compatible
+  - reg
+  - adi,rsense1-micro-ohms
+  - adi,rimon-out-ohms
+  - adi,rsense2-micro-ohms
+  - adi,rdaco-ohms
+  - adi,rfbout1-ohms
+  - adi,rfbout2-ohms
+  - adi,rdaci-ohms
+  - adi,rfbin2-ohms
+  - adi,rfbin1-ohms
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        battery-charger@10 {
+            compatible = "adi,lt8491";
+            reg = <0x10>;
+            adi,rsense1-micro-ohms = <5000>;
+            adi,rimon-out-ohms = <124000>;
+            adi,rsense2-micro-ohms = <3000>;
+            adi,rdaco-ohms = <64900>;
+            adi,rfbout1-ohms = <113000>;
+            adi,rfbout2-ohms = <10000>;
+            adi,rdaci-ohms = <7000>;
+            adi,rfbin2-ohms = <3480>;
+            adi,rfbin1-ohms = <102000>;
+        };
+    };
diff --git a/MAINTAINERS b/MAINTAINERS
index 6e04c83eb..96f510358 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13559,6 +13559,12 @@ L:	linux-scsi@vger.kernel.org
 S:	Maintained
 F:	drivers/scsi/sym53c8xx_2/
 
+LT8491 BATTERY CHARGER DRIVER
+M:	John Erasmus Mari Geronimo <johnerasmusmari.geronimo@analog.com>
+L:	linux-pm@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/power/supply/adi,lt8491.yaml
+
 LTC1660 DAC DRIVER
 M:	Marcus Folkesson <marcus.folkesson@gmail.com>
 L:	linux-iio@vger.kernel.org
-- 
2.34.1

Re: [PATCH 1/2] dt-bindings: power: supply: add adi,lt8491.yaml

[Krzysztof Kozlowski]

On 10/01/2025 09:02, John Erasmus Mari Geronimo wrote:
> +$id: http://devicetree.org/schemas/power/supply/adi,lt8491.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Linear Technology (Analog Devices) LT8491 Battery Charger
> +
> +maintainers:
> +  - John Erasmus Mari Geronimo <johnerasmusmari.geronimo@analog.com>
> +
> +description: |
> +  The LT8491 is a buck-boost switching regulator battery charger that implements
> +  a constant-current constant-voltage (CCCV) charging profile used for most
> +  battery types, including sealed lead-acid (SLA), flooded, gel and lithium-ion.
> +
> +  Specifications about the charger can be found at:
> +    https://www.analog.com/en/products/lt8491.html
> +

Mostly looks good, but I don't see $ref to power-supply, which brings
you the battery property.

Best regards,
Krzysztof

[PATCH 2/2] power: supply: add LT8491 battery charger driver

[John Erasmus Mari Geronimo]

Adds initial support for the LT8491 High Voltage Buck-Boost Battery
Charge Controller with I2C

The driver provides functionality to monitor key parameters including:
Voltage, Current, Power, Temperature, Status

Signed-off-by: John Erasmus Mari Geronimo <johnerasmusmari.geronimo@analog.com>
---
 MAINTAINERS                           |   1 +
 drivers/power/supply/Kconfig          |   9 +
 drivers/power/supply/Makefile         |   1 +
 drivers/power/supply/lt8491_charger.c | 410 ++++++++++++++++++++++++++
 4 files changed, 421 insertions(+)
 create mode 100644 drivers/power/supply/lt8491_charger.c

diff --git a/MAINTAINERS b/MAINTAINERS
index 96f510358..0d98734de 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -13564,6 +13564,7 @@ M:	John Erasmus Mari Geronimo <johnerasmusmari.geronimo@analog.com>
 L:	linux-pm@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/power/supply/adi,lt8491.yaml
+F:	drivers/power/supply/lt8491_charger.c
 
 LTC1660 DAC DRIVER
 M:	Marcus Folkesson <marcus.folkesson@gmail.com>
diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
index 7b18358f1..2a85ae1f7 100644
--- a/drivers/power/supply/Kconfig
+++ b/drivers/power/supply/Kconfig
@@ -545,6 +545,15 @@ config CHARGER_LT3651
 	  Say Y to include support for the Analog Devices (Linear Technology)
 	  LT3651 battery charger which reports its status via GPIO lines.
 
+config CHARGER_LT8491
+	tristate "Analog Devices LT8491 charger"
+	depends on I2C
+	help
+	  Say Y to include support for the Analog Devices (Linear Technology)
+	  LT8491 battery charge controller connected to I2C. The LT8491 is a
+	  high voltage buck-boost switching regulator battery charger
+	  controller.
+
 config CHARGER_LTC4162L
 	tristate "LTC4162-L charger"
 	depends on I2C
diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
index b55cc48a4..68699430b 100644
--- a/drivers/power/supply/Makefile
+++ b/drivers/power/supply/Makefile
@@ -75,6 +75,7 @@ obj-$(CONFIG_CHARGER_LP8788)	+= lp8788-charger.o
 obj-$(CONFIG_CHARGER_GPIO)	+= gpio-charger.o
 obj-$(CONFIG_CHARGER_MANAGER)	+= charger-manager.o
 obj-$(CONFIG_CHARGER_LT3651)	+= lt3651-charger.o
+obj-$(CONFIG_CHARGER_LT8491)	+= lt8491_charger.o
 obj-$(CONFIG_CHARGER_LTC4162L)	+= ltc4162-l-charger.o
 obj-$(CONFIG_CHARGER_MAX14577)	+= max14577_charger.o
 obj-$(CONFIG_CHARGER_DETECTOR_MAX14656)	+= max14656_charger_detector.o
diff --git a/drivers/power/supply/lt8491_charger.c b/drivers/power/supply/lt8491_charger.c
new file mode 100644
index 000000000..dcef6691d
--- /dev/null
+++ b/drivers/power/supply/lt8491_charger.c
@@ -0,0 +1,410 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Analog Devices LT8491 Battery Charger
+ *
+ * Copyright 2024 Analog Devices Inc.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/power_supply.h>
+
+#define LT8491_TELE_TBAT_REG 0x0
+#define LT8491_TELE_POUT_REG 0x2
+#define LT8491_TELE_PIN_REG  0x4
+#define LT8491_TELE_EFF_REG  0x6
+#define LT8491_TELE_IOUT_REG 0x8
+#define LT8491_TELE_IIN_REG  0xA
+#define LT8491_TELE_VBAT_REG 0xC
+#define LT8491_TELE_VIN_REG  0xE
+#define LT8491_TELE_VINR_REG 0x10
+#define LT8491_STAT_CHARGER_REG 0x12
+#define LT8491_STAT_CHRG_FAULTS_REG 0x19
+#define LT8491_CTRL_UPDATE_TELEM_REG 0x26
+
+#define LT8491_CFG_RSENSE1_REG 0x28
+#define LT8491_CFG_RIMON_OUT_REG 0x2A
+#define LT8491_CFG_RSENSE2_REG 0x2C
+#define LT8491_CFG_RDACO_REG 0x2E
+#define LT8491_CFG_RFBOUT1_REG 0x30
+#define LT8491_CFG_RFBOUT2_REG 0x32
+#define LT8491_CFG_RDACI_REG 0x34
+#define LT8491_CFG_RFBIN2_REG 0x36
+#define LT8491_CFG_RFBIN1_REG 0x38
+#define LT8491_CFG_TBAT_MIN_REG 0x40
+#define LT8491_CFG_TBAT_MAX_REG 0x41
+#define LT8491_MFR_DATA1_LSB_REG 0x5C
+
+#define LT8491_TELEM_ACTIVE_MASK BIT(6)
+#define LT8491_CHARGING_MASK BIT(2)
+#define LT8491_BAT_DISCON_FLT_MASK BIT(3)
+
+#define LT8491_UPDATE_TELEM_CMD 0xAA
+
+#define LT8491_MFR_DATA_LEN 0x3
+
+struct lt8491_info {
+	struct i2c_client *client;
+	struct power_supply *psp;
+	char serial_number[16];
+	/* protect against device accesses */
+	struct mutex lock;
+};
+
+static int lt8491_read_serial_number(struct lt8491_info *info)
+{
+	int i, ret;
+	u32 serial_number[LT8491_MFR_DATA_LEN];
+
+	for (i = 0; i < LT8491_MFR_DATA_LEN; i++) {
+		serial_number[i] = i2c_smbus_read_word_data(info->client,
+					LT8491_MFR_DATA1_LSB_REG + i * 2);
+		if (serial_number[i] < 0)
+			return serial_number[i];
+	}
+
+	ret = sprintf(info->serial_number, "%04x%04x%04x", serial_number[0],
+		      serial_number[1], serial_number[2]);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int lt8491_get_property(struct power_supply *psy,
+				enum power_supply_property psp,
+				union power_supply_propval *val)
+{
+	struct lt8491_info *info = power_supply_get_drvdata(psy);
+	s16 ret;
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_STATUS:
+		ret = i2c_smbus_read_byte_data(info->client,
+					       LT8491_STAT_CHARGER_REG);
+		if (ret < 0)
+			return ret;
+
+		val->intval = FIELD_GET(LT8491_CHARGING_MASK, ret) ?
+					POWER_SUPPLY_STATUS_CHARGING :
+					POWER_SUPPLY_STATUS_NOT_CHARGING;
+
+		return 0;
+	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+		scoped_guard(mutex, &info->lock) {
+			ret = i2c_smbus_read_byte_data(info->client,
+						LT8491_STAT_CHARGER_REG);
+			if (ret < 0)
+				return ret;
+
+			if (!FIELD_GET(LT8491_TELEM_ACTIVE_MASK, ret)) {
+				ret = i2c_smbus_write_byte_data(info->client,
+						LT8491_CTRL_UPDATE_TELEM_REG,
+						LT8491_UPDATE_TELEM_CMD);
+				if (ret)
+					return ret;
+			}
+
+			ret = i2c_smbus_read_word_data(info->client,
+						LT8491_TELE_VBAT_REG);
+			if (ret < 0)
+				return ret;
+		}
+
+		val->intval = ret * 10000;
+
+		return 0;
+	case POWER_SUPPLY_PROP_CURRENT_NOW:
+		scoped_guard(mutex, &info->lock) {
+			ret = i2c_smbus_read_byte_data(info->client,
+						       LT8491_STAT_CHARGER_REG);
+			if (ret < 0)
+				return ret;
+
+			if (!FIELD_GET(LT8491_TELEM_ACTIVE_MASK, ret)) {
+				ret = i2c_smbus_write_byte_data(info->client,
+						LT8491_CTRL_UPDATE_TELEM_REG,
+						LT8491_UPDATE_TELEM_CMD);
+				if (ret)
+					return ret;
+			}
+
+			ret = i2c_smbus_read_word_data(info->client,
+						       LT8491_TELE_IOUT_REG);
+			if (ret < 0)
+				return ret;
+		}
+
+		val->intval = ret;
+
+		return 0;
+	case POWER_SUPPLY_PROP_POWER_NOW:
+		scoped_guard(mutex, &info->lock) {
+			ret = i2c_smbus_read_byte_data(info->client,
+						       LT8491_STAT_CHARGER_REG);
+			if (ret < 0)
+				return ret;
+
+			if (!FIELD_GET(LT8491_TELEM_ACTIVE_MASK, ret)) {
+				ret = i2c_smbus_write_byte_data(info->client,
+						LT8491_CTRL_UPDATE_TELEM_REG,
+						LT8491_UPDATE_TELEM_CMD);
+				if (ret)
+					return ret;
+			}
+
+			ret = i2c_smbus_read_word_data(info->client,
+						       LT8491_TELE_POUT_REG);
+			if (ret < 0)
+				return ret;
+		}
+
+		val->intval = ret * 10000;
+
+		return 0;
+	case POWER_SUPPLY_PROP_TEMP:
+		scoped_guard(mutex, &info->lock) {
+			ret = i2c_smbus_read_byte_data(info->client,
+						       LT8491_STAT_CHARGER_REG);
+			if (ret < 0)
+				return ret;
+
+			if (!FIELD_GET(LT8491_TELEM_ACTIVE_MASK, ret)) {
+				ret = i2c_smbus_write_byte_data(info->client,
+						LT8491_CTRL_UPDATE_TELEM_REG,
+						LT8491_UPDATE_TELEM_CMD);
+				if (ret)
+					return ret;
+			}
+
+			ret = i2c_smbus_read_word_data(info->client,
+						       LT8491_TELE_TBAT_REG);
+			if (ret < 0)
+				return ret;
+		}
+
+		val->intval = sign_extend32(ret, 15);
+
+		return 0;
+	case POWER_SUPPLY_PROP_TEMP_ALERT_MIN:
+		ret = i2c_smbus_read_byte_data(info->client,
+					       LT8491_CFG_TBAT_MIN_REG);
+		if (ret < 0)
+			return ret;
+
+		val->intval = sign_extend32(ret, 7) * 10;
+
+		return 0;
+	case POWER_SUPPLY_PROP_TEMP_ALERT_MAX:
+		ret = i2c_smbus_read_byte_data(info->client,
+					       LT8491_CFG_TBAT_MAX_REG);
+		if (ret < 0)
+			return ret;
+
+		val->intval = sign_extend32(ret, 7) * 10;
+
+		return 0;
+	case POWER_SUPPLY_PROP_MODEL_NAME:
+		val->strval = "lt8491";
+
+		return 0;
+	case POWER_SUPPLY_PROP_MANUFACTURER:
+		val->strval = "Analog Devices";
+
+		return 0;
+	case POWER_SUPPLY_PROP_SERIAL_NUMBER:
+		val->strval = info->serial_number;
+
+		return 0;
+	default:
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+static int lt8491_set_property(struct power_supply *psy,
+				enum power_supply_property psp,
+				const union power_supply_propval *val)
+{
+	struct lt8491_info *info = power_supply_get_drvdata(psy);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_TEMP_ALERT_MIN:
+		return i2c_smbus_write_byte_data(info->client,
+						 LT8491_CFG_TBAT_MIN_REG,
+						 val->intval / 10);
+	case POWER_SUPPLY_PROP_TEMP_ALERT_MAX:
+		return i2c_smbus_write_byte_data(info->client,
+						 LT8491_CFG_TBAT_MAX_REG,
+						 val->intval / 10);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int lt8491_property_is_writeable(struct power_supply *psy,
+					enum power_supply_property psp)
+{
+	switch (psp) {
+	case POWER_SUPPLY_PROP_TEMP_ALERT_MIN:
+	case POWER_SUPPLY_PROP_TEMP_ALERT_MAX:
+		return 1;
+	default:
+		return 0;
+	}
+}
+
+static enum power_supply_property lt8491_properties[] = {
+	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_VOLTAGE_NOW,
+	POWER_SUPPLY_PROP_CURRENT_NOW,
+	POWER_SUPPLY_PROP_POWER_NOW,
+	POWER_SUPPLY_PROP_TEMP,
+	POWER_SUPPLY_PROP_TEMP_ALERT_MIN,
+	POWER_SUPPLY_PROP_TEMP_ALERT_MAX,
+	POWER_SUPPLY_PROP_MODEL_NAME,
+	POWER_SUPPLY_PROP_MANUFACTURER,
+	POWER_SUPPLY_PROP_SERIAL_NUMBER,
+};
+
+static const struct power_supply_desc lt8491_desc = {
+	.name		= "lt8491",
+	.type		= POWER_SUPPLY_TYPE_BATTERY,
+	.properties	= lt8491_properties,
+	.num_properties	= ARRAY_SIZE(lt8491_properties),
+	.get_property	= lt8491_get_property,
+	.set_property	= lt8491_set_property,
+	.property_is_writeable = lt8491_property_is_writeable,
+};
+
+static int lt8491_configure_resistor(struct lt8491_info *info,
+				     const char *propname, int divider,
+				     unsigned int reg)
+{
+	struct device *dev = &info->client->dev;
+	int ret;
+	u32 val;
+
+	ret = device_property_read_u32(dev, propname, &val);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "Missing %s property.\n",
+				     propname);
+
+	return i2c_smbus_write_word_data(info->client, reg, val / divider);
+}
+
+static int lt8491_configure_telemetry(struct lt8491_info *info)
+{
+	int ret;
+
+	ret = lt8491_configure_resistor(info, "adi,rsense1-micro-ohms", 10,
+					LT8491_CFG_RSENSE1_REG);
+	if (ret)
+		return ret;
+
+	ret = lt8491_configure_resistor(info, "adi,rimon-out-ohms", 10,
+					LT8491_CFG_RIMON_OUT_REG);
+	if (ret)
+		return ret;
+
+	ret = lt8491_configure_resistor(info, "adi,rsense2-micro-ohms", 10,
+					LT8491_CFG_RSENSE2_REG);
+	if (ret)
+		return ret;
+
+	ret = lt8491_configure_resistor(info, "adi,rdaco-ohms", 10,
+					LT8491_CFG_RDACO_REG);
+	if (ret)
+		return ret;
+
+	ret = lt8491_configure_resistor(info, "adi,rfbout1-ohms", 100,
+					LT8491_CFG_RFBOUT1_REG);
+	if (ret)
+		return ret;
+
+	ret = lt8491_configure_resistor(info, "adi,rfbout2-ohms", 10,
+					LT8491_CFG_RFBOUT2_REG);
+	if (ret)
+		return ret;
+
+	ret = lt8491_configure_resistor(info, "adi,rdaci-ohms", 10,
+					LT8491_CFG_RDACI_REG);
+	if (ret)
+		return ret;
+
+	ret = lt8491_configure_resistor(info, "adi,rfbin2-ohms", 10,
+					LT8491_CFG_RFBIN2_REG);
+	if (ret)
+		return ret;
+
+	return lt8491_configure_resistor(info, "adi,rfbin1-ohms", 100,
+					 LT8491_CFG_RFBIN1_REG);
+}
+
+static int lt8491_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct lt8491_info *info;
+	struct power_supply_config psy_cfg = {};
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
+				     I2C_FUNC_SMBUS_READ_WORD_DATA))
+		return -EOPNOTSUPP;
+
+	info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	info->client = client;
+	psy_cfg.drv_data = info;
+
+	devm_mutex_init(dev, &info->lock);
+
+	ret = lt8491_read_serial_number(info);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Can't read serial. Hardware error.\n");
+
+	ret = lt8491_configure_telemetry(info);
+	if (ret)
+		return ret;
+
+	info->psp = power_supply_register(dev, &lt8491_desc, &psy_cfg);
+	if (IS_ERR(info->psp))
+		return dev_err_probe(dev, PTR_ERR(info->psp),
+				     "Failed to register power supply.\n");
+
+	return 0;
+}
+
+static const struct i2c_device_id lt8491_id[] = {
+	{ "lt8491", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, lt8491_id);
+
+static const struct of_device_id lt8491_of_match[] = {
+	{ .compatible = "adi,lt8491" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, lt8491_of_match);
+
+static struct i2c_driver lt8491_driver = {
+	.driver = {
+		.name = "lt8491",
+		.of_match_table = lt8491_of_match,
+	},
+	.probe = lt8491_probe,
+	.id_table = lt8491_id,
+};
+module_i2c_driver(lt8491_driver);
+
+MODULE_AUTHOR("John Erasmus Mari Geronimo <johnerasmusmari.geronimo@analog.com");
+MODULE_DESCRIPTION("LT8491 battery charger");
+MODULE_LICENSE("GPL");
-- 
2.34.1

Re: [PATCH 2/2] power: supply: add LT8491 battery charger driver

[kernel test robot]

Hi John,

kernel test robot noticed the following build warnings:

[auto build test WARNING on a3a8799165ff83bb764fd800c6559c3cba0ddac3]

url:    https://github.com/intel-lab-lkp/linux/commits/John-Erasmus-Mari-Geronimo/dt-bindings-power-supply-add-adi-lt8491-yaml/20250110-160441
base:   a3a8799165ff83bb764fd800c6559c3cba0ddac3
patch link:    https://lore.kernel.org/r/20250110080235.54808-3-johnerasmusmari.geronimo%40analog.com
patch subject: [PATCH 2/2] power: supply: add LT8491 battery charger driver
config: sparc64-randconfig-r071-20250114 (https://download.01.org/0day-ci/archive/20250115/202501150030.cWwtcIoo-lkp@intel.com/config)
compiler: sparc64-linux-gcc (GCC) 14.2.0

If you fix the issue in a separate patch/commit (i.e. not just a new version of
the same patch/commit), kindly add following tags
| Reported-by: kernel test robot <lkp@intel.com>
| Closes: https://lore.kernel.org/oe-kbuild-all/202501150030.cWwtcIoo-lkp@intel.com/

smatch warnings:
drivers/power/supply/lt8491_charger.c:66 lt8491_read_serial_number() warn: unsigned 'serial_number[i]' is never less than zero.

vim +66 drivers/power/supply/lt8491_charger.c

    57	
    58	static int lt8491_read_serial_number(struct lt8491_info *info)
    59	{
    60		int i, ret;
    61		u32 serial_number[LT8491_MFR_DATA_LEN];
    62	
    63		for (i = 0; i < LT8491_MFR_DATA_LEN; i++) {
    64			serial_number[i] = i2c_smbus_read_word_data(info->client,
    65						LT8491_MFR_DATA1_LSB_REG + i * 2);
  > 66			if (serial_number[i] < 0)
    67				return serial_number[i];
    68		}
    69	
    70		ret = sprintf(info->serial_number, "%04x%04x%04x", serial_number[0],
    71			      serial_number[1], serial_number[2]);
    72		if (ret < 0)
    73			return ret;
    74	
    75		return 0;
    76	}
    77	

-- 
0-DAY CI Kernel Test Service
https://github.com/intel/lkp-tests/wiki

[PATCH v2 0/2] Add LT8491 driver

[John Erasmus Mari Geronimo]

This patch series adds a driver and DeviceTree binding for the LT8491
battery charge controller.

The LT8491 is a buck-boost switching regulator battery charger that
implements a constant-current constant-voltage (CCCV) charging profile.

Changes since v1:
 - Add a reference to power-supply.yaml so the binding inherits the
   standard battery property.
 - Fix serial-number error handling by using a signed temporary array.
 - Check the return value of devm_mutex_init().


John Erasmus Mari Geronimo (2):
  dt-bindings: power: supply: add adi,lt8491.yaml
  power: supply: add LT8491 battery charger driver

 .../bindings/power/supply/adi,lt8491.yaml     |  92 ++++
 MAINTAINERS                                   |   7 +
 drivers/power/supply/Kconfig                  |   9 +
 drivers/power/supply/Makefile                 |   1 +
 drivers/power/supply/lt8491_charger.c         | 412 ++++++++++++++++++
 5 files changed, 521 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/power/supply/adi,lt8491.yaml
 create mode 100644 drivers/power/supply/lt8491_charger.c


base-commit: a888754e51e915731c8974c4d6d62709facb35d3
-- 
2.34.1

[PATCH v2 1/2] dt-bindings: power: supply: add adi,lt8491.yaml

[John Erasmus Mari Geronimo]

Add documentation for devicetree bindings for LT8491

Signed-off-by: John Erasmus Mari Geronimo <johnerasmusmari.geronimo@analog.com>
---
 .../bindings/power/supply/adi,lt8491.yaml     | 92 +++++++++++++++++++
 MAINTAINERS                                   |  6 ++
 2 files changed, 98 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/power/supply/adi,lt8491.yaml

diff --git a/Documentation/devicetree/bindings/power/supply/adi,lt8491.yaml b/Documentation/devicetree/bindings/power/supply/adi,lt8491.yaml
new file mode 100644
index 0000000000000..bb364b48fee58
--- /dev/null
+++ b/Documentation/devicetree/bindings/power/supply/adi,lt8491.yaml
@@ -0,0 +1,92 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/power/supply/adi,lt8491.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Linear Technology (Analog Devices) LT8491 Battery Charger
+
+maintainers:
+  - John Erasmus Mari Geronimo <johnerasmusmari.geronimo@analog.com>
+
+description: |
+  The LT8491 is a buck-boost switching regulator battery charger that implements
+  a constant-current constant-voltage (CCCV) charging profile used for most
+  battery types, including sealed lead-acid (SLA), flooded, gel and lithium-ion.
+
+  Specifications about the charger can be found at:
+    https://www.analog.com/en/products/lt8491.html
+
+allOf:
+  - $ref: power-supply.yaml#
+
+properties:
+  compatible:
+    enum:
+      - adi,lt8491
+
+  reg:
+    maxItems: 1
+
+  adi,rsense1-micro-ohms:
+    description: Resistance value of RSENSE1 in micro ohms.
+
+  adi,rimon-out-ohms:
+    description: Resistance value of RIMON_OUT in ohms.
+
+  adi,rsense2-micro-ohms:
+    description: Resistance value of RSENSE2 in micro ohms.
+
+  adi,rdaco-ohms:
+    description: Resistance value of RDACO1 + RDACO2 in ohms.
+
+  adi,rfbout1-ohms:
+    description: Resistance value of RFBOUT1 in ohms.
+
+  adi,rfbout2-ohms:
+    description: Resistance value of RFBOUT2 in ohms.
+
+  adi,rdaci-ohms:
+    description: Resistance value of RDACI1 + RDACI2 in ohms.
+
+  adi,rfbin2-ohms:
+    description: Resistance value of RFBIN2 in ohms.
+
+  adi,rfbin1-ohms:
+    description: Resistance value of RFBIN1 in ohms.
+
+required:
+  - compatible
+  - reg
+  - adi,rsense1-micro-ohms
+  - adi,rimon-out-ohms
+  - adi,rsense2-micro-ohms
+  - adi,rdaco-ohms
+  - adi,rfbout1-ohms
+  - adi,rfbout2-ohms
+  - adi,rdaci-ohms
+  - adi,rfbin2-ohms
+  - adi,rfbin1-ohms
+
+additionalProperties: false
+
+examples:
+  - |
+    i2c {
+        #address-cells = <1>;
+        #size-cells = <0>;
+
+        battery-charger@10 {
+            compatible = "adi,lt8491";
+            reg = <0x10>;
+            adi,rsense1-micro-ohms = <5000>;
+            adi,rimon-out-ohms = <124000>;
+            adi,rsense2-micro-ohms = <3000>;
+            adi,rdaco-ohms = <64900>;
+            adi,rfbout1-ohms = <113000>;
+            adi,rfbout2-ohms = <10000>;
+            adi,rdaci-ohms = <7000>;
+            adi,rfbin2-ohms = <3480>;
+            adi,rfbin1-ohms = <102000>;
+        };
+    };
diff --git a/MAINTAINERS b/MAINTAINERS
index 2fb1c75afd163..d79187312f789 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15170,6 +15170,12 @@ F:	Documentation/devicetree/bindings/hwmon/pmbus/adi,lt3074.yaml
 F:	Documentation/hwmon/lt3074.rst
 F:	drivers/hwmon/pmbus/lt3074.c
 
+LT8491 BATTERY CHARGER DRIVER
+M:	John Erasmus Mari Geronimo <johnerasmusmari.geronimo@analog.com>
+L:	linux-pm@vger.kernel.org
+S:	Maintained
+F:	Documentation/devicetree/bindings/power/supply/adi,lt8491.yaml
+
 LTC1660 DAC DRIVER
 M:	Marcus Folkesson <marcus.folkesson@gmail.com>
 L:	linux-iio@vger.kernel.org
-- 
2.34.1

Re: [PATCH v2 1/2] dt-bindings: power: supply: add adi,lt8491.yaml

[Conor Dooley]

[-- Attachment #1: Type: text/plain, Size: 4261 bytes --]

On Thu, Sep 03, 2026 at 06:46:36PM +0800, John Erasmus Mari Geronimo wrote:
> Add documentation for devicetree bindings for LT8491
> 
> Signed-off-by: John Erasmus Mari Geronimo <johnerasmusmari.geronimo@analog.com>
> ---
>  .../bindings/power/supply/adi,lt8491.yaml     | 92 +++++++++++++++++++
>  MAINTAINERS                                   |  6 ++
>  2 files changed, 98 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/power/supply/adi,lt8491.yaml
> 
> diff --git a/Documentation/devicetree/bindings/power/supply/adi,lt8491.yaml b/Documentation/devicetree/bindings/power/supply/adi,lt8491.yaml
> new file mode 100644
> index 0000000000000..bb364b48fee58
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/power/supply/adi,lt8491.yaml
> @@ -0,0 +1,92 @@
> +# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
> +%YAML 1.2
> +---
> +$id: http://devicetree.org/schemas/power/supply/adi,lt8491.yaml#
> +$schema: http://devicetree.org/meta-schemas/core.yaml#
> +
> +title: Linear Technology (Analog Devices) LT8491 Battery Charger
> +
> +maintainers:
> +  - John Erasmus Mari Geronimo <johnerasmusmari.geronimo@analog.com>
> +
> +description: |
> +  The LT8491 is a buck-boost switching regulator battery charger that implements
> +  a constant-current constant-voltage (CCCV) charging profile used for most
> +  battery types, including sealed lead-acid (SLA), flooded, gel and lithium-ion.
> +
> +  Specifications about the charger can be found at:
> +    https://www.analog.com/en/products/lt8491.html
> +
> +allOf:
> +  - $ref: power-supply.yaml#
> +
> +properties:
> +  compatible:
> +    enum:
> +      - adi,lt8491
> +
> +  reg:
> +    maxItems: 1
> +
> +  adi,rsense1-micro-ohms:
> +    description: Resistance value of RSENSE1 in micro ohms.
> +
> +  adi,rimon-out-ohms:
> +    description: Resistance value of RIMON_OUT in ohms.
> +
> +  adi,rsense2-micro-ohms:
> +    description: Resistance value of RSENSE2 in micro ohms.
> +
> +  adi,rdaco-ohms:
> +    description: Resistance value of RDACO1 + RDACO2 in ohms.
> +
> +  adi,rfbout1-ohms:
> +    description: Resistance value of RFBOUT1 in ohms.
> +
> +  adi,rfbout2-ohms:
> +    description: Resistance value of RFBOUT2 in ohms.
> +
> +  adi,rdaci-ohms:
> +    description: Resistance value of RDACI1 + RDACI2 in ohms.
> +
> +  adi,rfbin2-ohms:
> +    description: Resistance value of RFBIN2 in ohms.
> +
> +  adi,rfbin1-ohms:
> +    description: Resistance value of RFBIN1 in ohms.
> +
> +required:
> +  - compatible
> +  - reg
> +  - adi,rsense1-micro-ohms
> +  - adi,rimon-out-ohms
> +  - adi,rsense2-micro-ohms
> +  - adi,rdaco-ohms
> +  - adi,rfbout1-ohms
> +  - adi,rfbout2-ohms
> +  - adi,rdaci-ohms
> +  - adi,rfbin2-ohms
> +  - adi,rfbin1-ohms
> +
> +additionalProperties: false

Valid point here from Sashiko.
pw-bot: changes-requested

Thanks,
Conor.

> +
> +examples:
> +  - |
> +    i2c {
> +        #address-cells = <1>;
> +        #size-cells = <0>;
> +
> +        battery-charger@10 {
> +            compatible = "adi,lt8491";
> +            reg = <0x10>;
> +            adi,rsense1-micro-ohms = <5000>;
> +            adi,rimon-out-ohms = <124000>;
> +            adi,rsense2-micro-ohms = <3000>;
> +            adi,rdaco-ohms = <64900>;
> +            adi,rfbout1-ohms = <113000>;
> +            adi,rfbout2-ohms = <10000>;
> +            adi,rdaci-ohms = <7000>;
> +            adi,rfbin2-ohms = <3480>;
> +            adi,rfbin1-ohms = <102000>;
> +        };
> +    };
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 2fb1c75afd163..d79187312f789 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -15170,6 +15170,12 @@ F:	Documentation/devicetree/bindings/hwmon/pmbus/adi,lt3074.yaml
>  F:	Documentation/hwmon/lt3074.rst
>  F:	drivers/hwmon/pmbus/lt3074.c
>  
> +LT8491 BATTERY CHARGER DRIVER
> +M:	John Erasmus Mari Geronimo <johnerasmusmari.geronimo@analog.com>
> +L:	linux-pm@vger.kernel.org
> +S:	Maintained
> +F:	Documentation/devicetree/bindings/power/supply/adi,lt8491.yaml
> +
>  LTC1660 DAC DRIVER
>  M:	Marcus Folkesson <marcus.folkesson@gmail.com>
>  L:	linux-iio@vger.kernel.org
> -- 
> 2.34.1
> 

[-- Attachment #2: signature.asc --]
[-- Type: application/pgp-signature, Size: 228 bytes --]

[PATCH v2 2/2] power: supply: add LT8491 battery charger driver

[John Erasmus Mari Geronimo]

Adds initial support for the LT8491 High Voltage Buck-Boost Battery
Charge Controller with I2C

The driver provides functionality to monitor key parameters including:
Voltage, Current, Power, Temperature, Status

Signed-off-by: John Erasmus Mari Geronimo <johnerasmusmari.geronimo@analog.com>
---
 MAINTAINERS                           |   1 +
 drivers/power/supply/Kconfig          |   9 +
 drivers/power/supply/Makefile         |   1 +
 drivers/power/supply/lt8491_charger.c | 412 ++++++++++++++++++++++++++
 4 files changed, 423 insertions(+)
 create mode 100644 drivers/power/supply/lt8491_charger.c

diff --git a/MAINTAINERS b/MAINTAINERS
index d79187312f789..317ca2e8ca9bd 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15175,6 +15175,7 @@ M:	John Erasmus Mari Geronimo <johnerasmusmari.geronimo@analog.com>
 L:	linux-pm@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/power/supply/adi,lt8491.yaml
+F:	drivers/power/supply/lt8491_charger.c
 
 LTC1660 DAC DRIVER
 M:	Marcus Folkesson <marcus.folkesson@gmail.com>
diff --git a/drivers/power/supply/Kconfig b/drivers/power/supply/Kconfig
index f0ede1cecb6a8..146ea3743eb2d 100644
--- a/drivers/power/supply/Kconfig
+++ b/drivers/power/supply/Kconfig
@@ -598,6 +598,15 @@ config CHARGER_LT3651
 	  Say Y to include support for the Analog Devices (Linear Technology)
 	  LT3651 battery charger which reports its status via GPIO lines.
 
+config CHARGER_LT8491
+	tristate "Analog Devices LT8491 charger"
+	depends on I2C
+	help
+	  Say Y to include support for the Analog Devices (Linear Technology)
+	  LT8491 battery charge controller connected to I2C. The LT8491 is a
+	  high voltage buck-boost switching regulator battery charger
+	  controller.
+
 config CHARGER_LTC4162L
 	tristate "LTC4162-L charger"
 	depends on I2C
diff --git a/drivers/power/supply/Makefile b/drivers/power/supply/Makefile
index 31fe4a145929a..d3d2721333204 100644
--- a/drivers/power/supply/Makefile
+++ b/drivers/power/supply/Makefile
@@ -81,6 +81,7 @@ obj-$(CONFIG_CHARGER_LP8788)	+= lp8788-charger.o
 obj-$(CONFIG_CHARGER_GPIO)	+= gpio-charger.o
 obj-$(CONFIG_CHARGER_MANAGER)	+= charger-manager.o
 obj-$(CONFIG_CHARGER_LT3651)	+= lt3651-charger.o
+obj-$(CONFIG_CHARGER_LT8491)	+= lt8491_charger.o
 obj-$(CONFIG_CHARGER_LTC4162L)	+= ltc4162-l-charger.o
 obj-$(CONFIG_CHARGER_MAX14577)	+= max14577_charger.o
 obj-$(CONFIG_CHARGER_DETECTOR_MAX14656)	+= max14656_charger_detector.o
diff --git a/drivers/power/supply/lt8491_charger.c b/drivers/power/supply/lt8491_charger.c
new file mode 100644
index 0000000000000..225d5dd4dd721
--- /dev/null
+++ b/drivers/power/supply/lt8491_charger.c
@@ -0,0 +1,412 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Analog Devices LT8491 Battery Charger
+ *
+ * Copyright 2024 Analog Devices Inc.
+ */
+
+#include <linux/bitfield.h>
+#include <linux/device.h>
+#include <linux/errno.h>
+#include <linux/i2c.h>
+#include <linux/mod_devicetable.h>
+#include <linux/module.h>
+#include <linux/power_supply.h>
+
+#define LT8491_TELE_TBAT_REG 0x0
+#define LT8491_TELE_POUT_REG 0x2
+#define LT8491_TELE_PIN_REG  0x4
+#define LT8491_TELE_EFF_REG  0x6
+#define LT8491_TELE_IOUT_REG 0x8
+#define LT8491_TELE_IIN_REG  0xA
+#define LT8491_TELE_VBAT_REG 0xC
+#define LT8491_TELE_VIN_REG  0xE
+#define LT8491_TELE_VINR_REG 0x10
+#define LT8491_STAT_CHARGER_REG 0x12
+#define LT8491_STAT_CHRG_FAULTS_REG 0x19
+#define LT8491_CTRL_UPDATE_TELEM_REG 0x26
+
+#define LT8491_CFG_RSENSE1_REG 0x28
+#define LT8491_CFG_RIMON_OUT_REG 0x2A
+#define LT8491_CFG_RSENSE2_REG 0x2C
+#define LT8491_CFG_RDACO_REG 0x2E
+#define LT8491_CFG_RFBOUT1_REG 0x30
+#define LT8491_CFG_RFBOUT2_REG 0x32
+#define LT8491_CFG_RDACI_REG 0x34
+#define LT8491_CFG_RFBIN2_REG 0x36
+#define LT8491_CFG_RFBIN1_REG 0x38
+#define LT8491_CFG_TBAT_MIN_REG 0x40
+#define LT8491_CFG_TBAT_MAX_REG 0x41
+#define LT8491_MFR_DATA1_LSB_REG 0x5C
+
+#define LT8491_TELEM_ACTIVE_MASK BIT(6)
+#define LT8491_CHARGING_MASK BIT(2)
+#define LT8491_BAT_DISCON_FLT_MASK BIT(3)
+
+#define LT8491_UPDATE_TELEM_CMD 0xAA
+
+#define LT8491_MFR_DATA_LEN 0x3
+
+struct lt8491_info {
+	struct i2c_client *client;
+	struct power_supply *psp;
+	char serial_number[16];
+	/* protect against device accesses */
+	struct mutex lock;
+};
+
+static int lt8491_read_serial_number(struct lt8491_info *info)
+{
+	int i, ret;
+	int serial_number[LT8491_MFR_DATA_LEN];
+
+	for (i = 0; i < LT8491_MFR_DATA_LEN; i++) {
+		serial_number[i] = i2c_smbus_read_word_data(info->client,
+					LT8491_MFR_DATA1_LSB_REG + i * 2);
+		if (serial_number[i] < 0)
+			return serial_number[i];
+	}
+
+	ret = sprintf(info->serial_number, "%04x%04x%04x", serial_number[0],
+		      serial_number[1], serial_number[2]);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
+static int lt8491_get_property(struct power_supply *psy,
+				enum power_supply_property psp,
+				union power_supply_propval *val)
+{
+	struct lt8491_info *info = power_supply_get_drvdata(psy);
+	s16 ret;
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_STATUS:
+		ret = i2c_smbus_read_byte_data(info->client,
+					       LT8491_STAT_CHARGER_REG);
+		if (ret < 0)
+			return ret;
+
+		val->intval = FIELD_GET(LT8491_CHARGING_MASK, ret) ?
+					POWER_SUPPLY_STATUS_CHARGING :
+					POWER_SUPPLY_STATUS_NOT_CHARGING;
+
+		return 0;
+	case POWER_SUPPLY_PROP_VOLTAGE_NOW:
+		scoped_guard(mutex, &info->lock) {
+			ret = i2c_smbus_read_byte_data(info->client,
+						LT8491_STAT_CHARGER_REG);
+			if (ret < 0)
+				return ret;
+
+			if (!FIELD_GET(LT8491_TELEM_ACTIVE_MASK, ret)) {
+				ret = i2c_smbus_write_byte_data(info->client,
+						LT8491_CTRL_UPDATE_TELEM_REG,
+						LT8491_UPDATE_TELEM_CMD);
+				if (ret)
+					return ret;
+			}
+
+			ret = i2c_smbus_read_word_data(info->client,
+						LT8491_TELE_VBAT_REG);
+			if (ret < 0)
+				return ret;
+		}
+
+		val->intval = ret * 10000;
+
+		return 0;
+	case POWER_SUPPLY_PROP_CURRENT_NOW:
+		scoped_guard(mutex, &info->lock) {
+			ret = i2c_smbus_read_byte_data(info->client,
+						       LT8491_STAT_CHARGER_REG);
+			if (ret < 0)
+				return ret;
+
+			if (!FIELD_GET(LT8491_TELEM_ACTIVE_MASK, ret)) {
+				ret = i2c_smbus_write_byte_data(info->client,
+						LT8491_CTRL_UPDATE_TELEM_REG,
+						LT8491_UPDATE_TELEM_CMD);
+				if (ret)
+					return ret;
+			}
+
+			ret = i2c_smbus_read_word_data(info->client,
+						       LT8491_TELE_IOUT_REG);
+			if (ret < 0)
+				return ret;
+		}
+
+		val->intval = ret;
+
+		return 0;
+	case POWER_SUPPLY_PROP_POWER_NOW:
+		scoped_guard(mutex, &info->lock) {
+			ret = i2c_smbus_read_byte_data(info->client,
+						       LT8491_STAT_CHARGER_REG);
+			if (ret < 0)
+				return ret;
+
+			if (!FIELD_GET(LT8491_TELEM_ACTIVE_MASK, ret)) {
+				ret = i2c_smbus_write_byte_data(info->client,
+						LT8491_CTRL_UPDATE_TELEM_REG,
+						LT8491_UPDATE_TELEM_CMD);
+				if (ret)
+					return ret;
+			}
+
+			ret = i2c_smbus_read_word_data(info->client,
+						       LT8491_TELE_POUT_REG);
+			if (ret < 0)
+				return ret;
+		}
+
+		val->intval = ret * 10000;
+
+		return 0;
+	case POWER_SUPPLY_PROP_TEMP:
+		scoped_guard(mutex, &info->lock) {
+			ret = i2c_smbus_read_byte_data(info->client,
+						       LT8491_STAT_CHARGER_REG);
+			if (ret < 0)
+				return ret;
+
+			if (!FIELD_GET(LT8491_TELEM_ACTIVE_MASK, ret)) {
+				ret = i2c_smbus_write_byte_data(info->client,
+						LT8491_CTRL_UPDATE_TELEM_REG,
+						LT8491_UPDATE_TELEM_CMD);
+				if (ret)
+					return ret;
+			}
+
+			ret = i2c_smbus_read_word_data(info->client,
+						       LT8491_TELE_TBAT_REG);
+			if (ret < 0)
+				return ret;
+		}
+
+		val->intval = sign_extend32(ret, 15);
+
+		return 0;
+	case POWER_SUPPLY_PROP_TEMP_ALERT_MIN:
+		ret = i2c_smbus_read_byte_data(info->client,
+					       LT8491_CFG_TBAT_MIN_REG);
+		if (ret < 0)
+			return ret;
+
+		val->intval = sign_extend32(ret, 7) * 10;
+
+		return 0;
+	case POWER_SUPPLY_PROP_TEMP_ALERT_MAX:
+		ret = i2c_smbus_read_byte_data(info->client,
+					       LT8491_CFG_TBAT_MAX_REG);
+		if (ret < 0)
+			return ret;
+
+		val->intval = sign_extend32(ret, 7) * 10;
+
+		return 0;
+	case POWER_SUPPLY_PROP_MODEL_NAME:
+		val->strval = "lt8491";
+
+		return 0;
+	case POWER_SUPPLY_PROP_MANUFACTURER:
+		val->strval = "Analog Devices";
+
+		return 0;
+	case POWER_SUPPLY_PROP_SERIAL_NUMBER:
+		val->strval = info->serial_number;
+
+		return 0;
+	default:
+		return -EINVAL;
+	}
+
+	return ret;
+}
+
+static int lt8491_set_property(struct power_supply *psy,
+				enum power_supply_property psp,
+				const union power_supply_propval *val)
+{
+	struct lt8491_info *info = power_supply_get_drvdata(psy);
+
+	switch (psp) {
+	case POWER_SUPPLY_PROP_TEMP_ALERT_MIN:
+		return i2c_smbus_write_byte_data(info->client,
+						 LT8491_CFG_TBAT_MIN_REG,
+						 val->intval / 10);
+	case POWER_SUPPLY_PROP_TEMP_ALERT_MAX:
+		return i2c_smbus_write_byte_data(info->client,
+						 LT8491_CFG_TBAT_MAX_REG,
+						 val->intval / 10);
+	default:
+		return -EINVAL;
+	}
+}
+
+static int lt8491_property_is_writeable(struct power_supply *psy,
+					enum power_supply_property psp)
+{
+	switch (psp) {
+	case POWER_SUPPLY_PROP_TEMP_ALERT_MIN:
+	case POWER_SUPPLY_PROP_TEMP_ALERT_MAX:
+		return 1;
+	default:
+		return 0;
+	}
+}
+
+static enum power_supply_property lt8491_properties[] = {
+	POWER_SUPPLY_PROP_STATUS,
+	POWER_SUPPLY_PROP_VOLTAGE_NOW,
+	POWER_SUPPLY_PROP_CURRENT_NOW,
+	POWER_SUPPLY_PROP_POWER_NOW,
+	POWER_SUPPLY_PROP_TEMP,
+	POWER_SUPPLY_PROP_TEMP_ALERT_MIN,
+	POWER_SUPPLY_PROP_TEMP_ALERT_MAX,
+	POWER_SUPPLY_PROP_MODEL_NAME,
+	POWER_SUPPLY_PROP_MANUFACTURER,
+	POWER_SUPPLY_PROP_SERIAL_NUMBER,
+};
+
+static const struct power_supply_desc lt8491_desc = {
+	.name		= "lt8491",
+	.type		= POWER_SUPPLY_TYPE_BATTERY,
+	.properties	= lt8491_properties,
+	.num_properties	= ARRAY_SIZE(lt8491_properties),
+	.get_property	= lt8491_get_property,
+	.set_property	= lt8491_set_property,
+	.property_is_writeable = lt8491_property_is_writeable,
+};
+
+static int lt8491_configure_resistor(struct lt8491_info *info,
+				     const char *propname, int divider,
+				     unsigned int reg)
+{
+	struct device *dev = &info->client->dev;
+	int ret;
+	u32 val;
+
+	ret = device_property_read_u32(dev, propname, &val);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "Missing %s property.\n",
+				     propname);
+
+	return i2c_smbus_write_word_data(info->client, reg, val / divider);
+}
+
+static int lt8491_configure_telemetry(struct lt8491_info *info)
+{
+	int ret;
+
+	ret = lt8491_configure_resistor(info, "adi,rsense1-micro-ohms", 10,
+					LT8491_CFG_RSENSE1_REG);
+	if (ret)
+		return ret;
+
+	ret = lt8491_configure_resistor(info, "adi,rimon-out-ohms", 10,
+					LT8491_CFG_RIMON_OUT_REG);
+	if (ret)
+		return ret;
+
+	ret = lt8491_configure_resistor(info, "adi,rsense2-micro-ohms", 10,
+					LT8491_CFG_RSENSE2_REG);
+	if (ret)
+		return ret;
+
+	ret = lt8491_configure_resistor(info, "adi,rdaco-ohms", 10,
+					LT8491_CFG_RDACO_REG);
+	if (ret)
+		return ret;
+
+	ret = lt8491_configure_resistor(info, "adi,rfbout1-ohms", 100,
+					LT8491_CFG_RFBOUT1_REG);
+	if (ret)
+		return ret;
+
+	ret = lt8491_configure_resistor(info, "adi,rfbout2-ohms", 10,
+					LT8491_CFG_RFBOUT2_REG);
+	if (ret)
+		return ret;
+
+	ret = lt8491_configure_resistor(info, "adi,rdaci-ohms", 10,
+					LT8491_CFG_RDACI_REG);
+	if (ret)
+		return ret;
+
+	ret = lt8491_configure_resistor(info, "adi,rfbin2-ohms", 10,
+					LT8491_CFG_RFBIN2_REG);
+	if (ret)
+		return ret;
+
+	return lt8491_configure_resistor(info, "adi,rfbin1-ohms", 100,
+					 LT8491_CFG_RFBIN1_REG);
+}
+
+static int lt8491_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	struct lt8491_info *info;
+	struct power_supply_config psy_cfg = {};
+	int ret;
+
+	if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
+				     I2C_FUNC_SMBUS_READ_WORD_DATA))
+		return -EOPNOTSUPP;
+
+	info = devm_kzalloc(dev, sizeof(*info), GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	info->client = client;
+	psy_cfg.drv_data = info;
+
+	ret = devm_mutex_init(dev, &info->lock);
+	if (ret)
+		return ret;
+
+	ret = lt8491_read_serial_number(info);
+	if (ret)
+		return dev_err_probe(dev, ret,
+				     "Can't read serial. Hardware error.\n");
+
+	ret = lt8491_configure_telemetry(info);
+	if (ret)
+		return ret;
+
+	info->psp = power_supply_register(dev, &lt8491_desc, &psy_cfg);
+	if (IS_ERR(info->psp))
+		return dev_err_probe(dev, PTR_ERR(info->psp),
+				     "Failed to register power supply.\n");
+
+	return 0;
+}
+
+static const struct i2c_device_id lt8491_id[] = {
+	{ "lt8491", 0 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, lt8491_id);
+
+static const struct of_device_id lt8491_of_match[] = {
+	{ .compatible = "adi,lt8491" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, lt8491_of_match);
+
+static struct i2c_driver lt8491_driver = {
+	.driver = {
+		.name = "lt8491",
+		.of_match_table = lt8491_of_match,
+	},
+	.probe = lt8491_probe,
+	.id_table = lt8491_id,
+};
+module_i2c_driver(lt8491_driver);
+
+MODULE_AUTHOR("John Erasmus Mari Geronimo <johnerasmusmari.geronimo@analog.com");
+MODULE_DESCRIPTION("LT8491 battery charger");
+MODULE_LICENSE("GPL");
-- 
2.34.1