[PATCH] hwmon/ltc2990: Support all modes of operation

[PATCH] hwmon/ltc2990: Support all modes of operation

[Mike Looijmans]

The LTC2990 driver so far only supported "current" monitoring. This expands
the driver to support all 8 modes of operation as defined in the mode bits
in the datasheet, thus the device can now be used to monitor up to 4
voltages, 2 currents, or 2 temperature sensors, and some combinations
thereof.

The device mode is configured by using the "mode" value as device name,
e.g. specifying compatible="lltc,ltc2990-6" in the devicetree will set it
to dual-current monitoring mode (6). For backward compatibility, the
default is mode 6.

Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
---
 drivers/hwmon/Kconfig   |   8 +--
 drivers/hwmon/ltc2990.c | 172 ++++++++++++++++++++++++++++++++++++++++--------
 2 files changed, 148 insertions(+), 32 deletions(-)

diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index 5c2d13a..242e22f 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -686,15 +686,13 @@ config SENSORS_LTC2945
 	  be called ltc2945.
 
 config SENSORS_LTC2990
-	tristate "Linear Technology LTC2990 (current monitoring mode only)"
+	tristate "Linear Technology LTC2990"
 	depends on I2C
 	help
 	  If you say yes here you get support for Linear Technology LTC2990
 	  I2C System Monitor. The LTC2990 supports a combination of voltage,
-	  current and temperature monitoring, but in addition to the Vcc supply
-	  voltage and chip temperature, this driver currently only supports
-	  reading two currents by measuring two differential voltages across
-	  series resistors.
+	  current and temperature monitoring, in addition to the Vcc supply
+	  voltage and chip temperature.
 
 	  This driver can also be built as a module. If so, the module will
 	  be called ltc2990.
diff --git a/drivers/hwmon/ltc2990.c b/drivers/hwmon/ltc2990.c
index 8f8fe05..9c621a1 100644
--- a/drivers/hwmon/ltc2990.c
+++ b/drivers/hwmon/ltc2990.c
@@ -6,9 +6,10 @@
  *
  * License: GPLv2
  *
- * This driver assumes the chip is wired as a dual current monitor, and
- * reports the voltage drop across two series resistors. It also reports
- * the chip's internal temperature and Vcc power supply voltage.
+ * To configure the driver, pass its desired "mode" (lower 3 bits of control
+ * register) as its device name. Depending on this mode, the chip will report
+ * temperature, current and/or voltage measuments. It always reports the chip's
+ * internal temperature and Vcc power supply voltage.
  */
 
 #include <linux/err.h>
@@ -27,12 +28,18 @@
 #define LTC2990_V3_MSB	0x0A
 #define LTC2990_V4_MSB	0x0C
 #define LTC2990_VCC_MSB	0x0E
+#define LTC2990_REGISTER_MASK	0x0F
 
 #define LTC2990_CONTROL_KELVIN		BIT(7)
 #define LTC2990_CONTROL_SINGLE		BIT(6)
 #define LTC2990_CONTROL_MEASURE_ALL	(0x3 << 3)
-#define LTC2990_CONTROL_MODE_CURRENT	0x06
-#define LTC2990_CONTROL_MODE_VOLTAGE	0x07
+#define LTC2990_CONTROL_MODE_DEFAULT	0x06
+
+#define LTC2990_CONVERSION_CURRENT	0x00
+#define LTC2990_CONVERSION_TEMPERATURE	0x40
+#define LTC2990_CONVERSION_VOLTAGE	0x80
+#define LTC2990_CONVERSION_VOLTAGE25	0xC0
+#define LTC2990_CONVERSION_MASK 	0xC0
 
 /* convert raw register value to sign-extended integer in 16-bit range */
 static int ltc2990_voltage_to_int(int raw)
@@ -44,26 +51,30 @@ static int ltc2990_voltage_to_int(int raw)
 }
 
 /* Return the converted value from the given register in uV or mC */
-static int ltc2990_get_value(struct i2c_client *i2c, u8 reg, int *result)
+static int ltc2990_get_value(struct i2c_client *i2c, u8 conv_reg, int *result)
 {
 	int val;
 
-	val = i2c_smbus_read_word_swapped(i2c, reg);
+	val = i2c_smbus_read_word_swapped(i2c, conv_reg & LTC2990_REGISTER_MASK);
 	if (unlikely(val < 0))
 		return val;
 
-	switch (reg) {
-	case LTC2990_TINT_MSB:
-		/* internal temp, 0.0625 degrees/LSB, 13-bit  */
+	switch (conv_reg & LTC2990_CONVERSION_MASK) {
+	case LTC2990_CONVERSION_CURRENT:
+		 /* Current as differential Vx-Vy, 19.42uV/LSB. */
+		*result = ltc2990_voltage_to_int(val) * 1942 / (4 * 100);
+		break;
+	case LTC2990_CONVERSION_TEMPERATURE:
+		/* Temperature, 0.0625 degrees/LSB, 13-bit  */
 		val = (val & 0x1FFF) << 3;
 		*result = (val * 1000) >> 7;
 		break;
-	case LTC2990_V1_MSB:
-	case LTC2990_V3_MSB:
-		 /* Vx-Vy, 19.42uV/LSB. Depends on mode. */
-		*result = ltc2990_voltage_to_int(val) * 1942 / (4 * 100);
+	case LTC2990_CONVERSION_VOLTAGE:
+		/* Voltage, 305.18μV/LSB */
+		*result = (ltc2990_voltage_to_int(val) * 30518 /
+			   (4 * 100 * 1000));
 		break;
-	case LTC2990_VCC_MSB:
+	case LTC2990_CONVERSION_VOLTAGE25:
 		/* Vcc, 305.18μV/LSB, 2.5V offset */
 		*result = (ltc2990_voltage_to_int(val) * 30518 /
 			   (4 * 100 * 1000)) + 2500;
@@ -89,38 +100,129 @@ static ssize_t ltc2990_show_value(struct device *dev,
 	return snprintf(buf, PAGE_SIZE, "%d\n", value);
 }
 
+/* Internal temperature and Vcc voltage are always present */
 static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ltc2990_show_value, NULL,
-			  LTC2990_TINT_MSB);
+			  LTC2990_CONVERSION_TEMPERATURE | LTC2990_TINT_MSB);
+static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ltc2990_show_value, NULL,
+			  LTC2990_CONVERSION_VOLTAGE25 | LTC2990_VCC_MSB);
+/* Current measurement requires 2 inputs per channel */
 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc2990_show_value, NULL,
-			  LTC2990_V1_MSB);
+			  LTC2990_CONVERSION_CURRENT | LTC2990_V1_MSB);
 static SENSOR_DEVICE_ATTR(curr2_input, S_IRUGO, ltc2990_show_value, NULL,
-			  LTC2990_V3_MSB);
-static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ltc2990_show_value, NULL,
-			  LTC2990_VCC_MSB);
+			  LTC2990_CONVERSION_CURRENT | LTC2990_V3_MSB);
+/* Voltage measurement requires 1 input per channel */
+static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc2990_show_value, NULL,
+			  LTC2990_CONVERSION_VOLTAGE | LTC2990_V1_MSB);
+static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc2990_show_value, NULL,
+			  LTC2990_CONVERSION_VOLTAGE | LTC2990_V2_MSB);
+static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ltc2990_show_value, NULL,
+			  LTC2990_CONVERSION_VOLTAGE | LTC2990_V3_MSB);
+static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ltc2990_show_value, NULL,
+			  LTC2990_CONVERSION_VOLTAGE | LTC2990_V4_MSB);
+/* Temperature measurement requires 2 inputs per channel */
+static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, ltc2990_show_value, NULL,
+			  LTC2990_CONVERSION_TEMPERATURE | LTC2990_V1_MSB);
+static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, ltc2990_show_value, NULL,
+			  LTC2990_CONVERSION_TEMPERATURE | LTC2990_V3_MSB);
 
-static struct attribute *ltc2990_attrs[] = {
+
+/* Common attributes regardless of mode */
+static struct attribute *ltc2990_common_attrs[] = {
 	&sensor_dev_attr_temp1_input.dev_attr.attr,
+	&sensor_dev_attr_in0_input.dev_attr.attr,
+	NULL,
+};
+static const struct attribute_group ltc2990_common_group = {
+	.attrs = ltc2990_common_attrs,
+};
+
+/* Attribute to mode mapping, as per the CONTROL register bits [2:0] */
+
+/* 000 = V1 V2 TR2 */
+static struct attribute *ltc2990_000_attrs[] = {
+	&sensor_dev_attr_in1_input.dev_attr.attr,
+	&sensor_dev_attr_in2_input.dev_attr.attr,
+	&sensor_dev_attr_temp3_input.dev_attr.attr,
+	NULL,
+};
+/* 001 = V1-V2 TR2 */
+static struct attribute *ltc2990_001_attrs[] = {
+	&sensor_dev_attr_curr1_input.dev_attr.attr,
+	&sensor_dev_attr_temp3_input.dev_attr.attr,
+	NULL,
+};
+/* 010 = V1-V2 V3 V4 */
+static struct attribute *ltc2990_010_attrs[] = {
 	&sensor_dev_attr_curr1_input.dev_attr.attr,
+	&sensor_dev_attr_in3_input.dev_attr.attr,
+	&sensor_dev_attr_in4_input.dev_attr.attr,
+	NULL,
+};
+/* 011 = TR1 V3 V4 */
+static struct attribute *ltc2990_011_attrs[] = {
+	&sensor_dev_attr_temp2_input.dev_attr.attr,
+	&sensor_dev_attr_in3_input.dev_attr.attr,
+	&sensor_dev_attr_in4_input.dev_attr.attr,
+	NULL,
+};
+/* 100 = TR1 V3-V4 */
+static struct attribute *ltc2990_100_attrs[] = {
+	&sensor_dev_attr_temp2_input.dev_attr.attr,
 	&sensor_dev_attr_curr2_input.dev_attr.attr,
-	&sensor_dev_attr_in0_input.dev_attr.attr,
 	NULL,
 };
-ATTRIBUTE_GROUPS(ltc2990);
+/* 101 = TR1 TR2 */
+static struct attribute *ltc2990_101_attrs[] = {
+	&sensor_dev_attr_temp2_input.dev_attr.attr,
+	&sensor_dev_attr_temp3_input.dev_attr.attr,
+	NULL,
+};
+/* 110 = V1-V2 V3-V4 */
+static struct attribute *ltc2990_110_attrs[] = {
+	&sensor_dev_attr_curr1_input.dev_attr.attr,
+	&sensor_dev_attr_curr2_input.dev_attr.attr,
+	NULL,
+};
+/* 111 = V1 V2 V3 V4 */
+static struct attribute *ltc2990_111_attrs[] = {
+	&sensor_dev_attr_in1_input.dev_attr.attr,
+	&sensor_dev_attr_in2_input.dev_attr.attr,
+	&sensor_dev_attr_in3_input.dev_attr.attr,
+	&sensor_dev_attr_in4_input.dev_attr.attr,
+	NULL,
+};
+/* Decoder array for mode index */
+static struct attribute **ltc2990_attr_list[] = {
+	ltc2990_000_attrs,
+	ltc2990_001_attrs,
+	ltc2990_010_attrs,
+	ltc2990_011_attrs,
+	ltc2990_100_attrs,
+	ltc2990_101_attrs,
+	ltc2990_110_attrs,
+	ltc2990_111_attrs,
+};
+
+struct ltc2990_driver_data {
+	struct attribute_group ltc2990_extra_group;
+	const struct attribute_group *ltc2990_groups[3];
+};
 
 static int ltc2990_i2c_probe(struct i2c_client *i2c,
 			     const struct i2c_device_id *id)
 {
 	int ret;
 	struct device *hwmon_dev;
+	struct ltc2990_driver_data *data;
 
 	if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
 				     I2C_FUNC_SMBUS_WORD_DATA))
 		return -ENODEV;
 
-	/* Setup continuous mode, current monitor */
+	/* Setup continuous monitoring mode */
 	ret = i2c_smbus_write_byte_data(i2c, LTC2990_CONTROL,
 					LTC2990_CONTROL_MEASURE_ALL |
-					LTC2990_CONTROL_MODE_CURRENT);
+					id->driver_data);
 	if (ret < 0) {
 		dev_err(&i2c->dev, "Error: Failed to set control mode.\n");
 		return ret;
@@ -132,16 +234,32 @@ static int ltc2990_i2c_probe(struct i2c_client *i2c,
 		return ret;
 	}
 
+	/* Define attributes based on chip mode */
+	data = devm_kzalloc(&i2c->dev, sizeof(*data), GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+	data->ltc2990_extra_group.attrs = ltc2990_attr_list[id->driver_data];
+	data->ltc2990_groups[0] = &ltc2990_common_group;
+	data->ltc2990_groups[1] = &data->ltc2990_extra_group;
+
 	hwmon_dev = devm_hwmon_device_register_with_groups(&i2c->dev,
 							   i2c->name,
 							   i2c,
-							   ltc2990_groups);
+							   data->ltc2990_groups);
 
 	return PTR_ERR_OR_ZERO(hwmon_dev);
 }
 
 static const struct i2c_device_id ltc2990_i2c_id[] = {
-	{ "ltc2990", 0 },
+	{ "ltc2990",   LTC2990_CONTROL_MODE_DEFAULT},
+	{ "ltc29900", 0},
+	{ "ltc29901", 1},
+	{ "ltc29902", 2},
+	{ "ltc29903", 3},
+	{ "ltc29904", 4},
+	{ "ltc29905", 5},
+	{ "ltc29906", 6},
+	{ "ltc29907", 7},
 	{}
 };
 MODULE_DEVICE_TABLE(i2c, ltc2990_i2c_id);
-- 
1.9.1

Re: [PATCH] hwmon/ltc2990: Support all modes of operation

[Guenter Roeck]

On Wed, Jun 28, 2017 at 04:17:50PM +0200, Mike Looijmans wrote:
> The LTC2990 driver so far only supported "current" monitoring. This expands
> the driver to support all 8 modes of operation as defined in the mode bits
> in the datasheet, thus the device can now be used to monitor up to 4
> voltages, 2 currents, or 2 temperature sensors, and some combinations
> thereof.
> 
> The device mode is configured by using the "mode" value as device name,
> e.g. specifying compatible="lltc,ltc2990-6" in the devicetree will set it
> to dual-current monitoring mode (6). For backward compatibility, the
> default is mode 6.
> 
That is wrong, sorry. There should be devicetree properties to
select the different modes.

Guenter

> Signed-off-by: Mike Looijmans <mike.looijmans@topic.nl>
> ---
>  drivers/hwmon/Kconfig   |   8 +--
>  drivers/hwmon/ltc2990.c | 172 ++++++++++++++++++++++++++++++++++++++++--------
>  2 files changed, 148 insertions(+), 32 deletions(-)
> 
> diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
> index 5c2d13a..242e22f 100644
> --- a/drivers/hwmon/Kconfig
> +++ b/drivers/hwmon/Kconfig
> @@ -686,15 +686,13 @@ config SENSORS_LTC2945
>  	  be called ltc2945.
>  
>  config SENSORS_LTC2990
> -	tristate "Linear Technology LTC2990 (current monitoring mode only)"
> +	tristate "Linear Technology LTC2990"
>  	depends on I2C
>  	help
>  	  If you say yes here you get support for Linear Technology LTC2990
>  	  I2C System Monitor. The LTC2990 supports a combination of voltage,
> -	  current and temperature monitoring, but in addition to the Vcc supply
> -	  voltage and chip temperature, this driver currently only supports
> -	  reading two currents by measuring two differential voltages across
> -	  series resistors.
> +	  current and temperature monitoring, in addition to the Vcc supply
> +	  voltage and chip temperature.
>  
>  	  This driver can also be built as a module. If so, the module will
>  	  be called ltc2990.
> diff --git a/drivers/hwmon/ltc2990.c b/drivers/hwmon/ltc2990.c
> index 8f8fe05..9c621a1 100644
> --- a/drivers/hwmon/ltc2990.c
> +++ b/drivers/hwmon/ltc2990.c
> @@ -6,9 +6,10 @@
>   *
>   * License: GPLv2
>   *
> - * This driver assumes the chip is wired as a dual current monitor, and
> - * reports the voltage drop across two series resistors. It also reports
> - * the chip's internal temperature and Vcc power supply voltage.
> + * To configure the driver, pass its desired "mode" (lower 3 bits of control
> + * register) as its device name. Depending on this mode, the chip will report
> + * temperature, current and/or voltage measuments. It always reports the chip's
> + * internal temperature and Vcc power supply voltage.
>   */
>  
>  #include <linux/err.h>
> @@ -27,12 +28,18 @@
>  #define LTC2990_V3_MSB	0x0A
>  #define LTC2990_V4_MSB	0x0C
>  #define LTC2990_VCC_MSB	0x0E
> +#define LTC2990_REGISTER_MASK	0x0F
>  
>  #define LTC2990_CONTROL_KELVIN		BIT(7)
>  #define LTC2990_CONTROL_SINGLE		BIT(6)
>  #define LTC2990_CONTROL_MEASURE_ALL	(0x3 << 3)
> -#define LTC2990_CONTROL_MODE_CURRENT	0x06
> -#define LTC2990_CONTROL_MODE_VOLTAGE	0x07
> +#define LTC2990_CONTROL_MODE_DEFAULT	0x06
> +
> +#define LTC2990_CONVERSION_CURRENT	0x00
> +#define LTC2990_CONVERSION_TEMPERATURE	0x40
> +#define LTC2990_CONVERSION_VOLTAGE	0x80
> +#define LTC2990_CONVERSION_VOLTAGE25	0xC0
> +#define LTC2990_CONVERSION_MASK 	0xC0
>  
>  /* convert raw register value to sign-extended integer in 16-bit range */
>  static int ltc2990_voltage_to_int(int raw)
> @@ -44,26 +51,30 @@ static int ltc2990_voltage_to_int(int raw)
>  }
>  
>  /* Return the converted value from the given register in uV or mC */
> -static int ltc2990_get_value(struct i2c_client *i2c, u8 reg, int *result)
> +static int ltc2990_get_value(struct i2c_client *i2c, u8 conv_reg, int *result)
>  {
>  	int val;
>  
> -	val = i2c_smbus_read_word_swapped(i2c, reg);
> +	val = i2c_smbus_read_word_swapped(i2c, conv_reg & LTC2990_REGISTER_MASK);
>  	if (unlikely(val < 0))
>  		return val;
>  
> -	switch (reg) {
> -	case LTC2990_TINT_MSB:
> -		/* internal temp, 0.0625 degrees/LSB, 13-bit  */
> +	switch (conv_reg & LTC2990_CONVERSION_MASK) {
> +	case LTC2990_CONVERSION_CURRENT:
> +		 /* Current as differential Vx-Vy, 19.42uV/LSB. */
> +		*result = ltc2990_voltage_to_int(val) * 1942 / (4 * 100);
> +		break;
> +	case LTC2990_CONVERSION_TEMPERATURE:
> +		/* Temperature, 0.0625 degrees/LSB, 13-bit  */
>  		val = (val & 0x1FFF) << 3;
>  		*result = (val * 1000) >> 7;
>  		break;
> -	case LTC2990_V1_MSB:
> -	case LTC2990_V3_MSB:
> -		 /* Vx-Vy, 19.42uV/LSB. Depends on mode. */
> -		*result = ltc2990_voltage_to_int(val) * 1942 / (4 * 100);
> +	case LTC2990_CONVERSION_VOLTAGE:
> +		/* Voltage, 305.18μV/LSB */
> +		*result = (ltc2990_voltage_to_int(val) * 30518 /
> +			   (4 * 100 * 1000));
>  		break;
> -	case LTC2990_VCC_MSB:
> +	case LTC2990_CONVERSION_VOLTAGE25:
>  		/* Vcc, 305.18μV/LSB, 2.5V offset */
>  		*result = (ltc2990_voltage_to_int(val) * 30518 /
>  			   (4 * 100 * 1000)) + 2500;
> @@ -89,38 +100,129 @@ static ssize_t ltc2990_show_value(struct device *dev,
>  	return snprintf(buf, PAGE_SIZE, "%d\n", value);
>  }
>  
> +/* Internal temperature and Vcc voltage are always present */
>  static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ltc2990_show_value, NULL,
> -			  LTC2990_TINT_MSB);
> +			  LTC2990_CONVERSION_TEMPERATURE | LTC2990_TINT_MSB);
> +static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ltc2990_show_value, NULL,
> +			  LTC2990_CONVERSION_VOLTAGE25 | LTC2990_VCC_MSB);
> +/* Current measurement requires 2 inputs per channel */
>  static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc2990_show_value, NULL,
> -			  LTC2990_V1_MSB);
> +			  LTC2990_CONVERSION_CURRENT | LTC2990_V1_MSB);
>  static SENSOR_DEVICE_ATTR(curr2_input, S_IRUGO, ltc2990_show_value, NULL,
> -			  LTC2990_V3_MSB);
> -static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ltc2990_show_value, NULL,
> -			  LTC2990_VCC_MSB);
> +			  LTC2990_CONVERSION_CURRENT | LTC2990_V3_MSB);
> +/* Voltage measurement requires 1 input per channel */
> +static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc2990_show_value, NULL,
> +			  LTC2990_CONVERSION_VOLTAGE | LTC2990_V1_MSB);
> +static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc2990_show_value, NULL,
> +			  LTC2990_CONVERSION_VOLTAGE | LTC2990_V2_MSB);
> +static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ltc2990_show_value, NULL,
> +			  LTC2990_CONVERSION_VOLTAGE | LTC2990_V3_MSB);
> +static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ltc2990_show_value, NULL,
> +			  LTC2990_CONVERSION_VOLTAGE | LTC2990_V4_MSB);
> +/* Temperature measurement requires 2 inputs per channel */
> +static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, ltc2990_show_value, NULL,
> +			  LTC2990_CONVERSION_TEMPERATURE | LTC2990_V1_MSB);
> +static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, ltc2990_show_value, NULL,
> +			  LTC2990_CONVERSION_TEMPERATURE | LTC2990_V3_MSB);
>  
> -static struct attribute *ltc2990_attrs[] = {
> +
> +/* Common attributes regardless of mode */
> +static struct attribute *ltc2990_common_attrs[] = {
>  	&sensor_dev_attr_temp1_input.dev_attr.attr,
> +	&sensor_dev_attr_in0_input.dev_attr.attr,
> +	NULL,
> +};
> +static const struct attribute_group ltc2990_common_group = {
> +	.attrs = ltc2990_common_attrs,
> +};
> +
> +/* Attribute to mode mapping, as per the CONTROL register bits [2:0] */
> +
> +/* 000 = V1 V2 TR2 */
> +static struct attribute *ltc2990_000_attrs[] = {
> +	&sensor_dev_attr_in1_input.dev_attr.attr,
> +	&sensor_dev_attr_in2_input.dev_attr.attr,
> +	&sensor_dev_attr_temp3_input.dev_attr.attr,
> +	NULL,
> +};
> +/* 001 = V1-V2 TR2 */
> +static struct attribute *ltc2990_001_attrs[] = {
> +	&sensor_dev_attr_curr1_input.dev_attr.attr,
> +	&sensor_dev_attr_temp3_input.dev_attr.attr,
> +	NULL,
> +};
> +/* 010 = V1-V2 V3 V4 */
> +static struct attribute *ltc2990_010_attrs[] = {
>  	&sensor_dev_attr_curr1_input.dev_attr.attr,
> +	&sensor_dev_attr_in3_input.dev_attr.attr,
> +	&sensor_dev_attr_in4_input.dev_attr.attr,
> +	NULL,
> +};
> +/* 011 = TR1 V3 V4 */
> +static struct attribute *ltc2990_011_attrs[] = {
> +	&sensor_dev_attr_temp2_input.dev_attr.attr,
> +	&sensor_dev_attr_in3_input.dev_attr.attr,
> +	&sensor_dev_attr_in4_input.dev_attr.attr,
> +	NULL,
> +};
> +/* 100 = TR1 V3-V4 */
> +static struct attribute *ltc2990_100_attrs[] = {
> +	&sensor_dev_attr_temp2_input.dev_attr.attr,
>  	&sensor_dev_attr_curr2_input.dev_attr.attr,
> -	&sensor_dev_attr_in0_input.dev_attr.attr,
>  	NULL,
>  };
> -ATTRIBUTE_GROUPS(ltc2990);
> +/* 101 = TR1 TR2 */
> +static struct attribute *ltc2990_101_attrs[] = {
> +	&sensor_dev_attr_temp2_input.dev_attr.attr,
> +	&sensor_dev_attr_temp3_input.dev_attr.attr,
> +	NULL,
> +};
> +/* 110 = V1-V2 V3-V4 */
> +static struct attribute *ltc2990_110_attrs[] = {
> +	&sensor_dev_attr_curr1_input.dev_attr.attr,
> +	&sensor_dev_attr_curr2_input.dev_attr.attr,
> +	NULL,
> +};
> +/* 111 = V1 V2 V3 V4 */
> +static struct attribute *ltc2990_111_attrs[] = {
> +	&sensor_dev_attr_in1_input.dev_attr.attr,
> +	&sensor_dev_attr_in2_input.dev_attr.attr,
> +	&sensor_dev_attr_in3_input.dev_attr.attr,
> +	&sensor_dev_attr_in4_input.dev_attr.attr,
> +	NULL,
> +};
> +/* Decoder array for mode index */
> +static struct attribute **ltc2990_attr_list[] = {
> +	ltc2990_000_attrs,
> +	ltc2990_001_attrs,
> +	ltc2990_010_attrs,
> +	ltc2990_011_attrs,
> +	ltc2990_100_attrs,
> +	ltc2990_101_attrs,
> +	ltc2990_110_attrs,
> +	ltc2990_111_attrs,
> +};
> +
> +struct ltc2990_driver_data {
> +	struct attribute_group ltc2990_extra_group;
> +	const struct attribute_group *ltc2990_groups[3];
> +};
>  
>  static int ltc2990_i2c_probe(struct i2c_client *i2c,
>  			     const struct i2c_device_id *id)
>  {
>  	int ret;
>  	struct device *hwmon_dev;
> +	struct ltc2990_driver_data *data;
>  
>  	if (!i2c_check_functionality(i2c->adapter, I2C_FUNC_SMBUS_BYTE_DATA |
>  				     I2C_FUNC_SMBUS_WORD_DATA))
>  		return -ENODEV;
>  
> -	/* Setup continuous mode, current monitor */
> +	/* Setup continuous monitoring mode */
>  	ret = i2c_smbus_write_byte_data(i2c, LTC2990_CONTROL,
>  					LTC2990_CONTROL_MEASURE_ALL |
> -					LTC2990_CONTROL_MODE_CURRENT);
> +					id->driver_data);
>  	if (ret < 0) {
>  		dev_err(&i2c->dev, "Error: Failed to set control mode.\n");
>  		return ret;
> @@ -132,16 +234,32 @@ static int ltc2990_i2c_probe(struct i2c_client *i2c,
>  		return ret;
>  	}
>  
> +	/* Define attributes based on chip mode */
> +	data = devm_kzalloc(&i2c->dev, sizeof(*data), GFP_KERNEL);
> +	if (!data)
> +		return -ENOMEM;
> +	data->ltc2990_extra_group.attrs = ltc2990_attr_list[id->driver_data];
> +	data->ltc2990_groups[0] = &ltc2990_common_group;
> +	data->ltc2990_groups[1] = &data->ltc2990_extra_group;
> +
>  	hwmon_dev = devm_hwmon_device_register_with_groups(&i2c->dev,
>  							   i2c->name,
>  							   i2c,
> -							   ltc2990_groups);
> +							   data->ltc2990_groups);
>  
>  	return PTR_ERR_OR_ZERO(hwmon_dev);
>  }
>  
>  static const struct i2c_device_id ltc2990_i2c_id[] = {
> -	{ "ltc2990", 0 },
> +	{ "ltc2990",   LTC2990_CONTROL_MODE_DEFAULT},
> +	{ "ltc29900", 0},
> +	{ "ltc29901", 1},
> +	{ "ltc29902", 2},
> +	{ "ltc29903", 3},
> +	{ "ltc29904", 4},
> +	{ "ltc29905", 5},
> +	{ "ltc29906", 6},
> +	{ "ltc29907", 7},
>  	{}
>  };
>  MODULE_DEVICE_TABLE(i2c, ltc2990_i2c_id);
> -- 
> 1.9.1
>