hwmon: Add support for INA3221 Triple Current/Voltage Monitors

Add support for the the INA3221 26v capable, Triple channel,
Bi-Directional, Zero-Drift, Low-/High-Side, Current/Voltage Monitor
with I2C interface.

Signed-off-by: Andrew F. Davis <afd@ti.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

4 files changed, 493 insertions, 0 deletions

diff --git a/Documentation/hwmon/ina3221 b/Documentation/hwmon/ina3221
new file mode 100644
index 000000000000..0ff74854cb2e
--- /dev/null
+++ b/Documentation/hwmon/ina3221
@@ -0,0 +1,35 @@
+Kernel driver ina3221
+=====================
+
+Supported chips:
+  * Texas Instruments INA3221
+    Prefix: 'ina3221'
+    Addresses: I2C 0x40 - 0x43
+    Datasheet: Publicly available at the Texas Instruments website
+               http://www.ti.com/
+
+Author: Andrew F. Davis <afd@ti.com>
+
+Description
+-----------
+
+The Texas Instruments INA3221 monitors voltage, current, and power on the high
+side of up to three D.C. power supplies. The INA3221 monitors both shunt drop
+and supply voltage, with programmable conversion times and averaging, current
+and power are calculated host-side from these.
+
+Sysfs entries
+-------------
+
+in[123]_input           Bus voltage(mV) channels
+curr[123]_input         Current(mA) measurement channels
+shunt[123]_resistor     Shunt resistance(uOhm) channels
+curr[123]_crit          Critical alert current(mA) setting, activates the
+                          corresponding alarm when the respective current
+                          is above this value
+curr[123]_crit_alarm    Critical alert current limit exceeded
+curr[123]_max           Warning alert current(mA) setting, activates the
+                          corresponding alarm when the respective current
+                          average is above this value.
+curr[123]_max_alarm     Warning alert current limit exceeded
+in[456]_input           Shunt voltage(uV) for channels 1, 2, and 3 respectively
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index be63b140a976..b2aa13bd89dc 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -1525,6 +1525,17 @@ config SENSORS_INA2XX
 	  This driver can also be built as a module.  If so, the module
 	  will be called ina2xx.
 
+config SENSORS_INA3221
+	tristate "Texas Instruments INA3221 Triple Power Monitor"
+	depends on I2C
+	select REGMAP_I2C
+	help
+	  If you say yes here you get support for  the TI INA3221 Triple Power
+	  Monitor.
+
+	  This driver can also be built as a module.  If so, the module
+	  will be called ina3221.
+
 config SENSORS_TC74
 	tristate "Microchip TC74"
 	depends on I2C
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 406b18b995b3..446a4e74c7cf 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -77,6 +77,7 @@ obj-$(CONFIG_SENSORS_IBMPOWERNV)+= ibmpowernv.o
 obj-$(CONFIG_SENSORS_IIO_HWMON) += iio_hwmon.o
 obj-$(CONFIG_SENSORS_INA209)	+= ina209.o
 obj-$(CONFIG_SENSORS_INA2XX)	+= ina2xx.o
+obj-$(CONFIG_SENSORS_INA3221)	+= ina3221.o
 obj-$(CONFIG_SENSORS_IT87)	+= it87.o
 obj-$(CONFIG_SENSORS_JC42)	+= jc42.o
 obj-$(CONFIG_SENSORS_JZ4740)	+= jz4740-hwmon.o
diff --git a/drivers/hwmon/ina3221.c b/drivers/hwmon/ina3221.c
new file mode 100644
index 000000000000..d055b6a2266b
--- /dev/null
+++ b/drivers/hwmon/ina3221.c
@@ -0,0 +1,446 @@
+/*
+ * INA3221 Triple Current/Voltage Monitor
+ *
+ * Copyright (C) 2016 Texas Instruments Incorporated - http://www.ti.com/
+ *	Andrew F. Davis <afd@ti.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * General Public License for more details.
+ */
+
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of.h>
+#include <linux/regmap.h>
+
+#define INA3221_DRIVER_NAME		"ina3221"
+
+#define INA3221_CONFIG			0x00
+#define INA3221_SHUNT1			0x01
+#define INA3221_BUS1			0x02
+#define INA3221_SHUNT2			0x03
+#define INA3221_BUS2			0x04
+#define INA3221_SHUNT3			0x05
+#define INA3221_BUS3			0x06
+#define INA3221_CRIT1			0x07
+#define INA3221_WARN1			0x08
+#define INA3221_CRIT2			0x09
+#define INA3221_WARN2			0x0a
+#define INA3221_CRIT3			0x0b
+#define INA3221_WARN3			0x0c
+#define INA3221_MASK_ENABLE		0x0f
+
+#define INA3221_CONFIG_MODE_SHUNT	BIT(1)
+#define INA3221_CONFIG_MODE_BUS		BIT(2)
+#define INA3221_CONFIG_MODE_CONTINUOUS	BIT(3)
+
+#define INA3221_RSHUNT_DEFAULT		10000
+
+enum ina3221_fields {
+	/* Configuration */
+	F_RST,
+
+	/* Alert Flags */
+	F_WF3, F_WF2, F_WF1,
+	F_CF3, F_CF2, F_CF1,
+
+	/* sentinel */
+	F_MAX_FIELDS
+};
+
+static const struct reg_field ina3221_reg_fields[] = {
+	[F_RST] = REG_FIELD(INA3221_CONFIG, 15, 15),
+
+	[F_WF3] = REG_FIELD(INA3221_MASK_ENABLE, 3, 3),
+	[F_WF2] = REG_FIELD(INA3221_MASK_ENABLE, 4, 4),
+	[F_WF1] = REG_FIELD(INA3221_MASK_ENABLE, 5, 5),
+	[F_CF3] = REG_FIELD(INA3221_MASK_ENABLE, 7, 7),
+	[F_CF2] = REG_FIELD(INA3221_MASK_ENABLE, 8, 8),
+	[F_CF1] = REG_FIELD(INA3221_MASK_ENABLE, 9, 9),
+};
+
+enum ina3221_channels {
+	INA3221_CHANNEL1,
+	INA3221_CHANNEL2,
+	INA3221_CHANNEL3,
+	INA3221_NUM_CHANNELS
+};
+
+static const unsigned int register_channel[] = {
+	[INA3221_SHUNT1] = INA3221_CHANNEL1,
+	[INA3221_SHUNT2] = INA3221_CHANNEL2,
+	[INA3221_SHUNT3] = INA3221_CHANNEL3,
+	[INA3221_CRIT1] = INA3221_CHANNEL1,
+	[INA3221_CRIT2] = INA3221_CHANNEL2,
+	[INA3221_CRIT3] = INA3221_CHANNEL3,
+	[INA3221_WARN1] = INA3221_CHANNEL1,
+	[INA3221_WARN2] = INA3221_CHANNEL2,
+	[INA3221_WARN3] = INA3221_CHANNEL3,
+};
+
+/**
+ * struct ina3221_data - device specific information
+ * @regmap: Register map of the device
+ * @fields: Register fields of the device
+ * @shunt_resistors: Array of resistor values per channel
+ */
+struct ina3221_data {
+	struct regmap *regmap;
+	struct regmap_field *fields[F_MAX_FIELDS];
+	unsigned int shunt_resistors[INA3221_NUM_CHANNELS];
+};
+
+static int ina3221_read_value(struct ina3221_data *ina, unsigned int reg,
+			      int *val)
+{
+	unsigned int regval;
+	int ret;
+
+	ret = regmap_read(ina->regmap, reg, &regval);
+	if (ret)
+		return ret;
+
+	*val = sign_extend32(regval >> 3, 12);
+
+	return 0;
+}
+
+static ssize_t ina3221_show_bus_voltage(struct device *dev,
+					struct device_attribute *attr,
+					char *buf)
+{
+	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
+	struct ina3221_data *ina = dev_get_drvdata(dev);
+	unsigned int reg = sd_attr->index;
+	int val, voltage_mv, ret;
+
+	ret = ina3221_read_value(ina, reg, &val);
+	if (ret)
+		return ret;
+
+	voltage_mv = val * 8;
+
+	return snprintf(buf, PAGE_SIZE, "%d\n", voltage_mv);
+}
+
+static ssize_t ina3221_show_shunt_voltage(struct device *dev,
+					  struct device_attribute *attr,
+					  char *buf)
+{
+	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
+	struct ina3221_data *ina = dev_get_drvdata(dev);
+	unsigned int reg = sd_attr->index;
+	int val, voltage_uv, ret;
+
+	ret = ina3221_read_value(ina, reg, &val);
+	if (ret)
+		return ret;
+	voltage_uv = val * 40;
+
+	return snprintf(buf, PAGE_SIZE, "%d\n", voltage_uv);
+}
+
+static ssize_t ina3221_show_current(struct device *dev,
+				    struct device_attribute *attr, char *buf)
+{
+	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
+	struct ina3221_data *ina = dev_get_drvdata(dev);
+	unsigned int reg = sd_attr->index;
+	unsigned int channel = register_channel[reg];
+	unsigned int resistance_uo = ina->shunt_resistors[channel];
+	int val, current_ma, voltage_nv, ret;
+
+	ret = ina3221_read_value(ina, reg, &val);
+	if (ret)
+		return ret;
+	voltage_nv = val * 40000;
+
+	current_ma = DIV_ROUND_CLOSEST(voltage_nv, resistance_uo);
+
+	return snprintf(buf, PAGE_SIZE, "%d\n", current_ma);
+}
+
+static ssize_t ina3221_set_current(struct device *dev,
+				   struct device_attribute *attr,
+				   const char *buf, size_t count)
+{
+	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
+	struct ina3221_data *ina = dev_get_drvdata(dev);
+	unsigned int reg = sd_attr->index;
+	unsigned int channel = register_channel[reg];
+	unsigned int resistance_uo = ina->shunt_resistors[channel];
+	int val, current_ma, voltage_uv, ret;
+
+	ret = kstrtoint(buf, 0, &current_ma);
+	if (ret)
+		return ret;
+
+	/* clamp current */
+	current_ma = clamp_val(current_ma,
+			       INT_MIN / resistance_uo,
+			       INT_MAX / resistance_uo);
+
+	voltage_uv = DIV_ROUND_CLOSEST(current_ma * resistance_uo, 1000);
+
+	/* clamp voltage */
+	voltage_uv = clamp_val(voltage_uv, -163800, 163800);
+
+	/* 1 / 40uV(scale) << 3(register shift) = 5 */
+	val = DIV_ROUND_CLOSEST(voltage_uv, 5) & 0xfff8;
+
+	ret = regmap_write(ina->regmap, reg, val);
+	if (ret)
+		return ret;
+
+	return count;
+}
+
+static ssize_t ina3221_show_shunt(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
+	struct ina3221_data *ina = dev_get_drvdata(dev);
+	unsigned int channel = sd_attr->index;
+	unsigned int resistance_uo;
+
+	resistance_uo = ina->shunt_resistors[channel];
+
+	return snprintf(buf, PAGE_SIZE, "%d\n", resistance_uo);
+}
+
+static ssize_t ina3221_set_shunt(struct device *dev,
+				 struct device_attribute *attr,
+				 const char *buf, size_t count)
+{
+	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
+	struct ina3221_data *ina = dev_get_drvdata(dev);
+	unsigned int channel = sd_attr->index;
+	unsigned int val;
+	int ret;
+
+	ret = kstrtouint(buf, 0, &val);
+	if (ret)
+		return ret;
+
+	if (val == 0)
+		return -EINVAL;
+
+	ina->shunt_resistors[channel] = val;
+
+	return count;
+}
+
+static ssize_t ina3221_show_alert(struct device *dev,
+				  struct device_attribute *attr, char *buf)
+{
+	struct sensor_device_attribute *sd_attr = to_sensor_dev_attr(attr);
+	struct ina3221_data *ina = dev_get_drvdata(dev);
+	unsigned int field = sd_attr->index;
+	unsigned int regval;
+	int ret;
+
+	ret = regmap_field_read(ina->fields[field], &regval);
+	if (ret)
+		return ret;
+
+	return snprintf(buf, PAGE_SIZE, "%d\n", regval);
+}
+
+/* bus voltage */
+static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO,
+		ina3221_show_bus_voltage, NULL, INA3221_BUS1);
+static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO,
+		ina3221_show_bus_voltage, NULL, INA3221_BUS2);
+static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO,
+		ina3221_show_bus_voltage, NULL, INA3221_BUS3);
+
+/* calculated current */
+static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO,
+		ina3221_show_current, NULL, INA3221_SHUNT1);
+static SENSOR_DEVICE_ATTR(curr2_input, S_IRUGO,
+		ina3221_show_current, NULL, INA3221_SHUNT2);
+static SENSOR_DEVICE_ATTR(curr3_input, S_IRUGO,
+		ina3221_show_current, NULL, INA3221_SHUNT3);
+
+/* shunt resistance */
+static SENSOR_DEVICE_ATTR(shunt1_resistor, S_IRUGO | S_IWUSR,
+		ina3221_show_shunt, ina3221_set_shunt, INA3221_CHANNEL1);
+static SENSOR_DEVICE_ATTR(shunt2_resistor, S_IRUGO | S_IWUSR,
+		ina3221_show_shunt, ina3221_set_shunt, INA3221_CHANNEL2);
+static SENSOR_DEVICE_ATTR(shunt3_resistor, S_IRUGO | S_IWUSR,
+		ina3221_show_shunt, ina3221_set_shunt, INA3221_CHANNEL3);
+
+/* critical current */
+static SENSOR_DEVICE_ATTR(curr1_crit, S_IRUGO | S_IWUSR,
+		ina3221_show_current, ina3221_set_current, INA3221_CRIT1);
+static SENSOR_DEVICE_ATTR(curr2_crit, S_IRUGO | S_IWUSR,
+		ina3221_show_current, ina3221_set_current, INA3221_CRIT2);
+static SENSOR_DEVICE_ATTR(curr3_crit, S_IRUGO | S_IWUSR,
+		ina3221_show_current, ina3221_set_current, INA3221_CRIT3);
+
+/* critical current alert */
+static SENSOR_DEVICE_ATTR(curr1_crit_alarm, S_IRUGO,
+		ina3221_show_alert, NULL, F_CF1);
+static SENSOR_DEVICE_ATTR(curr2_crit_alarm, S_IRUGO,
+		ina3221_show_alert, NULL, F_CF2);
+static SENSOR_DEVICE_ATTR(curr3_crit_alarm, S_IRUGO,
+		ina3221_show_alert, NULL, F_CF3);
+
+/* warning current */
+static SENSOR_DEVICE_ATTR(curr1_max, S_IRUGO | S_IWUSR,
+		ina3221_show_current, ina3221_set_current, INA3221_WARN1);
+static SENSOR_DEVICE_ATTR(curr2_max, S_IRUGO | S_IWUSR,
+		ina3221_show_current, ina3221_set_current, INA3221_WARN2);
+static SENSOR_DEVICE_ATTR(curr3_max, S_IRUGO | S_IWUSR,
+		ina3221_show_current, ina3221_set_current, INA3221_WARN3);
+
+/* warning current alert */
+static SENSOR_DEVICE_ATTR(curr1_max_alarm, S_IRUGO,
+		ina3221_show_alert, NULL, F_WF1);
+static SENSOR_DEVICE_ATTR(curr2_max_alarm, S_IRUGO,
+		ina3221_show_alert, NULL, F_WF2);
+static SENSOR_DEVICE_ATTR(curr3_max_alarm, S_IRUGO,
+		ina3221_show_alert, NULL, F_WF3);
+
+/* shunt voltage */
+static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO,
+		ina3221_show_shunt_voltage, NULL, INA3221_SHUNT1);
+static SENSOR_DEVICE_ATTR(in5_input, S_IRUGO,
+		ina3221_show_shunt_voltage, NULL, INA3221_SHUNT2);
+static SENSOR_DEVICE_ATTR(in6_input, S_IRUGO,
+		ina3221_show_shunt_voltage, NULL, INA3221_SHUNT3);
+
+static struct attribute *ina3221_attrs[] = {
+	/* channel 1 */
+	&sensor_dev_attr_in1_input.dev_attr.attr,
+	&sensor_dev_attr_curr1_input.dev_attr.attr,
+	&sensor_dev_attr_shunt1_resistor.dev_attr.attr,
+	&sensor_dev_attr_curr1_crit.dev_attr.attr,
+	&sensor_dev_attr_curr1_crit_alarm.dev_attr.attr,
+	&sensor_dev_attr_curr1_max.dev_attr.attr,
+	&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
+	&sensor_dev_attr_in4_input.dev_attr.attr,
+
+	/* channel 2 */
+	&sensor_dev_attr_in2_input.dev_attr.attr,
+	&sensor_dev_attr_curr2_input.dev_attr.attr,
+	&sensor_dev_attr_shunt2_resistor.dev_attr.attr,
+	&sensor_dev_attr_curr2_crit.dev_attr.attr,
+	&sensor_dev_attr_curr2_crit_alarm.dev_attr.attr,
+	&sensor_dev_attr_curr2_max.dev_attr.attr,
+	&sensor_dev_attr_curr2_max_alarm.dev_attr.attr,
+	&sensor_dev_attr_in5_input.dev_attr.attr,
+
+	/* channel 3 */
+	&sensor_dev_attr_in3_input.dev_attr.attr,
+	&sensor_dev_attr_curr3_input.dev_attr.attr,
+	&sensor_dev_attr_shunt3_resistor.dev_attr.attr,
+	&sensor_dev_attr_curr3_crit.dev_attr.attr,
+	&sensor_dev_attr_curr3_crit_alarm.dev_attr.attr,
+	&sensor_dev_attr_curr3_max.dev_attr.attr,
+	&sensor_dev_attr_curr3_max_alarm.dev_attr.attr,
+	&sensor_dev_attr_in6_input.dev_attr.attr,
+
+	NULL,
+};
+ATTRIBUTE_GROUPS(ina3221);
+
+static const struct regmap_range ina3221_yes_ranges[] = {
+	regmap_reg_range(INA3221_SHUNT1, INA3221_BUS3),
+	regmap_reg_range(INA3221_MASK_ENABLE, INA3221_MASK_ENABLE),
+};
+
+static const struct regmap_access_table ina3221_volatile_table = {
+	.yes_ranges = ina3221_yes_ranges,
+	.n_yes_ranges = ARRAY_SIZE(ina3221_yes_ranges),
+};
+
+static const struct regmap_config ina3221_regmap_config = {
+	.reg_bits = 8,
+	.val_bits = 16,
+
+	.cache_type = REGCACHE_RBTREE,
+	.volatile_table = &ina3221_volatile_table,
+};
+
+static int ina3221_probe(struct i2c_client *client,
+			 const struct i2c_device_id *id)
+{
+	struct device *dev = &client->dev;
+	struct ina3221_data *ina;
+	struct device *hwmon_dev;
+	int i, ret;
+
+	ina = devm_kzalloc(dev, sizeof(*ina), GFP_KERNEL);
+	if (!ina)
+		return -ENOMEM;
+
+	ina->regmap = devm_regmap_init_i2c(client, &ina3221_regmap_config);
+	if (IS_ERR(ina->regmap)) {
+		dev_err(dev, "Unable to allocate register map\n");
+		return PTR_ERR(ina->regmap);
+	}
+
+	for (i = 0; i < F_MAX_FIELDS; i++) {
+		ina->fields[i] = devm_regmap_field_alloc(dev,
+							 ina->regmap,
+							 ina3221_reg_fields[i]);
+		if (IS_ERR(ina->fields[i])) {
+			dev_err(dev, "Unable to allocate regmap fields\n");
+			return PTR_ERR(ina->fields[i]);
+		}
+	}
+
+	for (i = 0; i < INA3221_NUM_CHANNELS; i++)
+		ina->shunt_resistors[i] = INA3221_RSHUNT_DEFAULT;
+
+	ret = regmap_field_write(ina->fields[F_RST], true);
+	if (ret) {
+		dev_err(dev, "Unable to reset device\n");
+		return ret;
+	}
+
+	hwmon_dev = devm_hwmon_device_register_with_groups(dev,
+							   client->name,
+							   ina, ina3221_groups);
+	if (IS_ERR(hwmon_dev)) {
+		dev_err(dev, "Unable to register hwmon device\n");
+		return PTR_ERR(hwmon_dev);
+	}
+
+	return 0;
+}
+
+static const struct of_device_id ina3221_of_match_table[] = {
+	{ .compatible = "ti,ina3221", },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(of, ina3221_of_match_table);
+
+static const struct i2c_device_id ina3221_ids[] = {
+	{ "ina3221", 0 },
+	{ /* sentinel */ }
+};
+MODULE_DEVICE_TABLE(i2c, ina3221_ids);
+
+static struct i2c_driver ina3221_i2c_driver = {
+	.probe = ina3221_probe,
+	.driver = {
+		.name = INA3221_DRIVER_NAME,
+		.of_match_table = ina3221_of_match_table,
+	},
+	.id_table = ina3221_ids,
+};
+module_i2c_driver(ina3221_i2c_driver);
+
+MODULE_AUTHOR("Andrew F. Davis <afd@ti.com>");
+MODULE_DESCRIPTION("Texas Instruments INA3221 HWMon Driver");
+MODULE_LICENSE("GPL v2");