hwmon: Add driver for TI INA233 Current and Power Monitor

Driver for Texas Instruments INA233 Current and Power Monitor
With I2C-, SMBus-, and PMBus-Compatible Interface

Signed-off-by: Leo Yang <leo.yang.sy0@gmail.com>
Link: https://lore.kernel.org/r/20250116085939.1235598-3-leo.yang.sy0@gmail.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Documentation/hwmon/ina233.rst

@@ -0,0 +1,75 @@
+.. SPDX-License-Identifier: GPL-2.0
+
+Kernel driver ina233
+====================
+
+Supported chips:
+
+  * TI INA233
+
+    Prefix: 'ina233'
+
+  * Datasheet
+
+    Publicly available at the TI website : https://www.ti.com/lit/ds/symlink/ina233.pdf
+
+Author: Leo Yang <leo.yang.sy0@gmail.com>
+
+Usage Notes
+-----------
+
+The shunt resistor value can be configured by a device tree property;
+see Documentation/devicetree/bindings/hwmon/ti,ina2xx.yaml for details.
+
+
+Description
+-----------
+
+This driver supports hardware monitoring for TI INA233.
+
+The driver is a client driver to the core PMBus driver. Please see
+Documentation/hwmon/pmbus.rst for details on PMBus client drivers.
+
+The driver provides the following attributes for input voltage:
+
+**in1_input**
+
+**in1_label**
+
+**in1_max**
+
+**in1_max_alarm**
+
+**in1_min**
+
+**in1_min_alarm**
+
+The driver provides the following attributes for shunt voltage:
+
+**in2_input**
+
+**in2_label**
+
+The driver provides the following attributes for output voltage:
+
+**in3_input**
+
+**in3_label**
+
+**in3_alarm**
+
+The driver provides the following attributes for output current:
+
+**curr1_input**
+
+**curr1_label**
+
+**curr1_max**
+
+**curr1_max_alarm**
+
+The driver provides the following attributes for input power:
+
+**power1_input**
+
+**power1_label**

Documentation/hwmon/index.rst

@@ -91,6 +91,7 @@ Hardware Monitoring Kernel Drivers
    ibmpowernv
    ina209
    ina2xx
+   ina233
    ina238
    ina3221
    inspur-ipsps1

MAINTAINERS

@@ -11331,6 +11331,13 @@ L:	linux-fbdev@vger.kernel.org
 S:	Orphan
 F:	drivers/video/fbdev/imsttfb.c
 
+INA233 HARDWARE MONITOR DRIVERS
+M:	Leo Yang <leo.yang.sy0@gmail.com>
+L:	linux-hwmon@vger.kernel.org
+S:	Maintained
+F:	Documentation/hwmon/ina233.rst
+F:	drivers/hwmon/pmbus/ina233.c
+
 INDEX OF FURTHER KERNEL DOCUMENTATION
 M:	Carlos Bilbao <carlos.bilbao@kernel.org>
 S:	Maintained

drivers/hwmon/pmbus/Kconfig

@@ -133,6 +133,15 @@ config SENSORS_DPS920AB
 	  This driver can also be built as a module. If so, the module will
 	  be called dps920ab.
 
+config SENSORS_INA233
+	tristate "Texas Instruments INA233 and compatibles"
+	help
+	  If you say yes here you get hardware monitoring support for Texas
+	  Instruments INA233.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called ina233.
+
 config SENSORS_INSPUR_IPSPS
 	tristate "INSPUR Power System Power Supply"
 	help

drivers/hwmon/pmbus/Makefile

@@ -15,6 +15,7 @@ obj-$(CONFIG_SENSORS_DELTA_AHE50DC_FAN) += delta-ahe50dc-fan.o
 obj-$(CONFIG_SENSORS_FSP_3Y)	+= fsp-3y.o
 obj-$(CONFIG_SENSORS_IBM_CFFPS)	+= ibm-cffps.o
 obj-$(CONFIG_SENSORS_DPS920AB)	+= dps920ab.o
+obj-$(CONFIG_SENSORS_INA233)	+= ina233.o
 obj-$(CONFIG_SENSORS_INSPUR_IPSPS) += inspur-ipsps.o
 obj-$(CONFIG_SENSORS_IR35221)	+= ir35221.o
 obj-$(CONFIG_SENSORS_IR36021)	+= ir36021.o

drivers/hwmon/pmbus/ina233.c

@@ -0,0 +1,191 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Hardware monitoring driver for ina233
+ *
+ * Copyright (c) 2025 Leo Yang
+ */
+
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include "pmbus.h"
+
+#define MFR_READ_VSHUNT 0xd1
+#define MFR_CALIBRATION 0xd4
+
+#define INA233_MAX_CURRENT_DEFAULT	32768000 /* uA */
+#define INA233_RSHUNT_DEFAULT		2000 /* uOhm */
+
+#define MAX_M_VAL 32767
+
+static void calculate_coef(int *m, int *R, u32 current_lsb, int power_coef)
+{
+	u64 scaled_m;
+	int scale_factor = 0;
+	int scale_coef = 1;
+
+	/*
+	 * 1000000 from Current_LSB A->uA .
+	 * scale_coef is for scaling up to minimize rounding errors,
+	 * If there is no decimal information, no need to scale.
+	 */
+	if (1000000 % current_lsb) {
+		/* Scaling to keep integer precision */
+		scale_factor = -3;
+		scale_coef = 1000;
+	}
+
+	/*
+	 * Unit Conversion (Current_LSB A->uA) and use scaling(scale_factor)
+	 * to keep integer precision.
+	 * Formulae referenced from spec.
+	 */
+	scaled_m = div64_u64(1000000 * scale_coef, (u64)current_lsb * power_coef);
+
+	/* Maximize while keeping it bounded.*/
+	while (scaled_m > MAX_M_VAL) {
+		scaled_m = div_u64(scaled_m, 10);
+		scale_factor++;
+	}
+	/* Scale up only if fractional part exists. */
+	while (scaled_m * 10 < MAX_M_VAL && scale_coef != 1) {
+		scaled_m *= 10;
+		scale_factor--;
+	}
+
+	*m = scaled_m;
+	*R = scale_factor;
+}
+
+static int ina233_read_word_data(struct i2c_client *client, int page,
+				 int phase, int reg)
+{
+	int ret;
+
+	switch (reg) {
+	case PMBUS_VIRT_READ_VMON:
+		ret = pmbus_read_word_data(client, 0, 0xff, MFR_READ_VSHUNT);
+
+		/* Adjust returned value to match VIN coefficients */
+		/* VIN: 1.25 mV VSHUNT: 2.5 uV LSB */
+		ret = DIV_ROUND_CLOSEST(ret * 25, 12500);
+		break;
+	default:
+		ret = -ENODATA;
+		break;
+	}
+	return ret;
+}
+
+static int ina233_probe(struct i2c_client *client)
+{
+	struct device *dev = &client->dev;
+	int ret, m, R;
+	u32 rshunt;
+	u32 max_current;
+	u32 current_lsb;
+	u16 calibration;
+	struct pmbus_driver_info *info;
+
+	info = devm_kzalloc(dev, sizeof(struct pmbus_driver_info),
+			    GFP_KERNEL);
+	if (!info)
+		return -ENOMEM;
+
+	info->pages = 1;
+	info->format[PSC_VOLTAGE_IN] = direct;
+	info->format[PSC_VOLTAGE_OUT] = direct;
+	info->format[PSC_CURRENT_OUT] = direct;
+	info->format[PSC_POWER] = direct;
+	info->func[0] = PMBUS_HAVE_VIN | PMBUS_HAVE_VOUT | PMBUS_HAVE_STATUS_INPUT
+		| PMBUS_HAVE_IOUT | PMBUS_HAVE_STATUS_IOUT
+		| PMBUS_HAVE_POUT
+		| PMBUS_HAVE_VMON | PMBUS_HAVE_STATUS_VMON;
+	info->m[PSC_VOLTAGE_IN] = 8;
+	info->R[PSC_VOLTAGE_IN] = 2;
+	info->m[PSC_VOLTAGE_OUT] = 8;
+	info->R[PSC_VOLTAGE_OUT] = 2;
+	info->read_word_data = ina233_read_word_data;
+
+	/* If INA233 skips current/power, shunt-resistor and current-lsb aren't needed.	*/
+	/* read rshunt value (uOhm) */
+	ret = device_property_read_u32(dev, "shunt-resistor", &rshunt);
+	if (ret) {
+		if (ret != -EINVAL)
+			return dev_err_probe(dev, ret, "Shunt resistor property read fail.\n");
+		rshunt = INA233_RSHUNT_DEFAULT;
+	}
+	if (!rshunt)
+		return dev_err_probe(dev, -EINVAL,
+				     "Shunt resistor cannot be zero.\n");
+
+	/* read Maximum expected current value (uA) */
+	ret = device_property_read_u32(dev, "ti,maximum-expected-current-microamp", &max_current);
+	if (ret) {
+		if (ret != -EINVAL)
+			return dev_err_probe(dev, ret,
+					     "Maximum expected current property read fail.\n");
+		max_current = INA233_MAX_CURRENT_DEFAULT;
+	}
+	if (max_current < 32768)
+		return dev_err_probe(dev, -EINVAL,
+				     "Maximum expected current cannot less then 32768.\n");
+
+	/* Calculate Current_LSB according to the spec formula */
+	current_lsb = max_current / 32768;
+
+	/* calculate current coefficient */
+	calculate_coef(&m, &R, current_lsb, 1);
+	info->m[PSC_CURRENT_OUT] = m;
+	info->R[PSC_CURRENT_OUT] = R;
+
+	/* calculate power coefficient */
+	calculate_coef(&m, &R, current_lsb, 25);
+	info->m[PSC_POWER] = m;
+	info->R[PSC_POWER] = R;
+
+	/* write MFR_CALIBRATION register, Apply formula from spec with unit scaling. */
+	calibration = div64_u64(5120000000ULL, (u64)rshunt * current_lsb);
+	if (calibration > 0x7FFF)
+		return dev_err_probe(dev, -EINVAL,
+				     "Product of Current_LSB %u and shunt resistor %u too small, MFR_CALIBRATION reg exceeds 0x7FFF.\n",
+				     current_lsb, rshunt);
+	ret = i2c_smbus_write_word_data(client, MFR_CALIBRATION, calibration);
+	if (ret < 0)
+		return dev_err_probe(dev, ret, "Unable to write calibration.\n");
+
+	dev_dbg(dev, "power monitor %s (Rshunt = %u uOhm, Current_LSB = %u uA/bit)\n",
+		client->name, rshunt, current_lsb);
+
+	return pmbus_do_probe(client, info);
+}
+
+static const struct i2c_device_id ina233_id[] = {
+	{"ina233", 0},
+	{}
+};
+MODULE_DEVICE_TABLE(i2c, ina233_id);
+
+static const struct of_device_id __maybe_unused ina233_of_match[] = {
+	{ .compatible = "ti,ina233" },
+	{}
+};
+MODULE_DEVICE_TABLE(of, ina233_of_match);
+
+static struct i2c_driver ina233_driver = {
+	.driver = {
+		   .name = "ina233",
+		   .of_match_table = of_match_ptr(ina233_of_match),
+	},
+	.probe = ina233_probe,
+	.id_table = ina233_id,
+};
+
+module_i2c_driver(ina233_driver);
+
+MODULE_AUTHOR("Leo Yang <leo.yang.sy0@gmail.com>");
+MODULE_DESCRIPTION("PMBus driver for INA233 and compatible chips");
+MODULE_LICENSE("GPL");
+MODULE_IMPORT_NS("PMBUS");