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Date: Wed, 28 Jun 2017 07:58:01 -0700
From: Guenter Roeck <linux@...ck-us.net>
To: Mike Looijmans <mike.looijmans@...ic.nl>
Cc: lm-sensors@...sensors.org, linux-kernel@...r.kernel.org,
jdelvare@...e.com
Subject: Re: [PATCH] hwmon/ltc2990: Support all modes of operation
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@...ic.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] = <c2990_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
>
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