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SubjectRe: [PATCH v3 3/3] hwmon: ltc2990: support all measurement modes


On Mon, 3 Jul 2017, Guenter Roeck wrote:

> On 07/02/2017 11:29 PM, Mike Looijmans wrote:
>> Applied, and tested on my board, so you have my
>>
>> Tested-By: mike.looijmans@topic.nl
>>
>> Probably the maintainers will like to see a patch header mail with a "v3"
>> summary for what you've changed ("git send-email --cover-letter" or
>> something similar to that)
>>
>
> ... and without it, the patch series tends to end up at the end of my review
> list since I'll have to spend time tracking down the changes myself or, per
> my choice, start all over and hope I catch all the problems found earlier.
>
> In other words, if people would like their patch series handled with
> priority, making life easy for maintainers is a good start.

Apologies, it seems the change summary got lost when sending the patches.
Here it is:

Changes since v2:
* If a devicetree node does not exist, do not initialise the chip. In
this case it is assumed that the initialisation has been done by
another source.
* Allow configuration of both of the "mode" fields in the control
register.
* Rename the devicetree property lltc->mode to lltc->meas-mode.
* Specifying the mode in the devicetree node is now mandatory.
* Small documentation updates.
* Revert some unnecessary change of types.

> Guenter
>
>> On 03-07-17 06:29, Tom Levens wrote:
>> > Updated version of the ltc2990 driver which supports all measurement
>> > modes (current, voltage, temperature) available in the chip.
>> >
>> > If devicetree is used, the mode must be specified with the property
>> > "lltc,meas-mode". The format and possible values of the property are
>
> AFAIK, DT maintainers are not much into abbreviations.

As far as I recall, this change was the suggestion of Rob as "mode" was
too vague.

>> > described in the binding.
>> >
>> > If devicetree is not used, the mode of the chip will not be configured.
>> > Unless the chip is configured by another source, only the internal
>> > temperature and supply voltage will be measured.
>> >
>> > Signed-off-by: Tom Levens <tom.levens@cern.ch>
>> > ---
>> > Documentation/hwmon/ltc2990 | 24 ++++--
>> > drivers/hwmon/Kconfig | 7 +-
>> > drivers/hwmon/ltc2990.c | 196
>> > +++++++++++++++++++++++++++++++++++++-------
>> > 3 files changed, 185 insertions(+), 42 deletions(-)
>> >
>> > diff --git a/Documentation/hwmon/ltc2990 b/Documentation/hwmon/ltc2990
>> > index c25211e..3ed68f6 100644
>> > --- a/Documentation/hwmon/ltc2990
>> > +++ b/Documentation/hwmon/ltc2990
>> > @@ -8,6 +8,7 @@ Supported chips:
>> > Datasheet: http://www.linear.com/product/ltc2990
>> > Author: Mike Looijmans <mike.looijmans@topic.nl>
>> > + Tom Levens <tom.levens@cern.ch>
>> > Description
>> > @@ -16,10 +17,8 @@ Description
>> > LTC2990 is a Quad I2C Voltage, Current and Temperature Monitor.
>> > The chip's inputs can measure 4 voltages, or two inputs together (1+2
>> > and 3+4)
>> > can be combined to measure a differential voltage, which is typically
>> > used to
>> > -measure current through a series resistor, or a temperature.
>> > -
>> > -This driver currently uses the 2x differential mode only. In order to
>> > support
>> > -other modes, the driver will need to be expanded.
>> > +measure current through a series resistor, or a temperature with an
>> > external
>> > +diode.
>> > Usage Notes
>> > @@ -32,12 +31,19 @@ devices explicitly.
>> > Sysfs attributes
>> > ----------------
>> > +in0_input Voltage at Vcc pin in millivolt (range 2.5V to 5V)
>> > +temp1_input Internal chip temperature in millidegrees Celcius
>> > +
>> > +A subset of the following attributes are visible, depending on the
>> > measurement
>> > +mode of the chip.
>> > +
>> > +in[1-4]_input Voltage at V[1-4] pin in millivolt
>> > +temp2_input External temperature sensor TR1 in millidegrees Celcius
>> > +temp3_input External temperature sensor TR2 in millidegrees Celcius
>> > +curr1_input Current in mA across V1-V2 assuming a 1mOhm sense
>> > resistor
>> > +curr2_input Current in mA across V3-V4 assuming a 1mOhm sense
>> > resistor
>> > +
>> > The "curr*_input" measurements actually report the voltage drop across
>> > the
>> > input pins in microvolts. This is equivalent to the current through a
>> > 1mOhm
>> > sense resistor. Divide the reported value by the actual sense resistor
>> > value
>> > in mOhm to get the actual value.
>> > -
>> > -in0_input Voltage at Vcc pin in millivolt (range 2.5V to 5V)
>> > -temp1_input Internal chip temperature in millidegrees Celcius
>> > -curr1_input Current in mA across v1-v2 assuming a 1mOhm sense
>> > resistor.
>> > -curr2_input Current in mA across v3-v4 assuming a 1mOhm sense
>> > resistor.
>> > diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
>> > index 5ef2814..578e5a9 100644
>> > --- a/drivers/hwmon/Kconfig
>> > +++ b/drivers/hwmon/Kconfig
>> > @@ -709,15 +709,12 @@ 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.
>> > 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 e320d21..32f3a8d 100644
>> > --- a/drivers/hwmon/ltc2990.c
>> > +++ b/drivers/hwmon/ltc2990.c
>> > @@ -5,10 +5,6 @@
>> > * Author: Mike Looijmans <mike.looijmans@topic.nl>
>> > *
>> > * 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.
>> > */
>> > #include <linux/bitops.h>
>> > @@ -18,6 +14,7 @@
>> > #include <linux/i2c.h>
>> > #include <linux/kernel.h>
>> > #include <linux/module.h>
>> > +#include <linux/of.h>
>> > #define LTC2990_STATUS 0x00
>> > #define LTC2990_CONTROL 0x01
>> > @@ -29,35 +26,109 @@
>> > #define LTC2990_V4_MSB 0x0C
>> > #define LTC2990_VCC_MSB 0x0E
>> > -#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_IN0 BIT(0)
>> > +#define LTC2990_IN1 BIT(1)
>> > +#define LTC2990_IN2 BIT(2)
>> > +#define LTC2990_IN3 BIT(3)
>> > +#define LTC2990_IN4 BIT(4)
>> > +#define LTC2990_CURR1 BIT(5)
>> > +#define LTC2990_CURR2 BIT(6)
>> > +#define LTC2990_TEMP1 BIT(7)
>> > +#define LTC2990_TEMP2 BIT(8)
>> > +#define LTC2990_TEMP3 BIT(9)
>> > +#define LTC2990_NONE 0
>> > +#define LTC2990_ALL GENMASK(9, 0)
>> > +
>> > +#define LTC2990_MODE0_SHIFT 0
>> > +#define LTC2990_MODE0_MASK GENMASK(2, 0)
>> > +#define LTC2990_MODE1_SHIFT 3
>> > +#define LTC2990_MODE1_MASK GENMASK(1, 0)
>> > +
>> > +/* Enabled measurements for mode bits 2..0 */
>> > +static const int ltc2990_attrs_ena_0[] = {
>> > + LTC2990_IN1 | LTC2990_IN2 | LTC2990_TEMP3,
>> > + LTC2990_CURR1 | LTC2990_TEMP3,
>> > + LTC2990_CURR1 | LTC2990_IN3 | LTC2990_IN4,
>> > + LTC2990_TEMP2 | LTC2990_IN3 | LTC2990_IN4,
>> > + LTC2990_TEMP2 | LTC2990_CURR2,
>> > + LTC2990_TEMP2 | LTC2990_TEMP3,
>> > + LTC2990_CURR1 | LTC2990_CURR2,
>> > + LTC2990_IN1 | LTC2990_IN2 | LTC2990_IN3 | LTC2990_IN4
>> > +};
>> > +
>> > +/* Enabled measurements for mode bits 4..3 */
>> > +static const int ltc2990_attrs_ena_1[] = {
>> > + LTC2990_NONE,
>> > + LTC2990_TEMP2 | LTC2990_IN1 | LTC2990_CURR1,
>> > + LTC2990_TEMP3 | LTC2990_IN3 | LTC2990_CURR2,
>> > + LTC2990_ALL
>> > +};
>> > +
>> > +struct ltc2990_data {
>> > + struct i2c_client *i2c;
>> > + u32 mode[2];
>> > +};
>> > /* 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, int index, int
>> > *result)
>> > {
>> > int val;
>> > + u8 reg;
>> > +
>> > + switch (index) {
>> > + case LTC2990_IN0:
>> > + reg = LTC2990_VCC_MSB;
>> > + break;
>> > + case LTC2990_IN1:
>> > + case LTC2990_CURR1:
>> > + case LTC2990_TEMP2:
>> > + reg = LTC2990_V1_MSB;
>> > + break;
>> > + case LTC2990_IN2:
>> > + reg = LTC2990_V2_MSB;
>> > + break;
>> > + case LTC2990_IN3:
>> > + case LTC2990_CURR2:
>> > + case LTC2990_TEMP3:
>> > + reg = LTC2990_V3_MSB;
>> > + break;
>> > + case LTC2990_IN4:
>> > + reg = LTC2990_V4_MSB;
>> > + break;
>> > + case LTC2990_TEMP1:
>> > + reg = LTC2990_TINT_MSB;
>> > + break;
>> > + default:
>> > + return -EINVAL;
>> > + }
>> > val = i2c_smbus_read_word_swapped(i2c, reg);
>> > if (unlikely(val < 0))
>> > return val;
>> > - switch (reg) {
>> > - case LTC2990_TINT_MSB:
>> > - /* internal temp, 0.0625 degrees/LSB, 13-bit */
>> > + switch (index) {
>> > + case LTC2990_TEMP1:
>> > + case LTC2990_TEMP2:
>> > + case LTC2990_TEMP3:
>> > + /* temp, 0.0625 degrees/LSB */
>> > *result = sign_extend32(val, 12) * 1000 / 16;
>> > break;
>> > - case LTC2990_V1_MSB:
>> > - case LTC2990_V3_MSB:
>> > - /* Vx-Vy, 19.42uV/LSB. Depends on mode. */
>> > + case LTC2990_CURR1:
>> > + case LTC2990_CURR2:
>> > + /* Vx-Vy, 19.42uV/LSB */
>> > *result = sign_extend32(val, 14) * 1942 / 100;
>> > break;
>> > - case LTC2990_VCC_MSB:
>> > - /* Vcc, 305.18μV/LSB, 2.5V offset */
>> > + case LTC2990_IN0:
>> > + /* Vcc, 305.18uV/LSB, 2.5V offset */
>> > *result = sign_extend32(val, 14) * 30518 / (100 * 1000) +
>> > 2500;
>> > break;
>> > + case LTC2990_IN1:
>> > + case LTC2990_IN2:
>> > + case LTC2990_IN3:
>> > + case LTC2990_IN4:
>> > + /* Vx, 305.18uV/LSB */
>> > + *result = sign_extend32(val, 14) * 30518 / (100 * 1000);
>> > + break;
>> > default:
>> > return -EINVAL; /* won't happen, keep compiler happy */
>> > }
>> > @@ -69,48 +140,117 @@ static ssize_t ltc2990_show_value(struct device
>> > *dev,
>> > struct device_attribute *da, char *buf)
>> > {
>> > struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
>> > + struct ltc2990_data *data = dev_get_drvdata(dev);
>> > int value;
>> > int ret;
>> > - ret = ltc2990_get_value(dev_get_drvdata(dev), attr->index, &value);
>> > + ret = ltc2990_get_value(data->i2c, attr->index, &value);
>> > if (unlikely(ret < 0))
>> > return ret;
>> > return snprintf(buf, PAGE_SIZE, "%d\n", value);
>> > }
>> > +static umode_t ltc2990_attrs_visible(struct kobject *kobj,
>> > + struct attribute *a, int n)
>> > +{
>> > + struct device *dev = container_of(kobj, struct device, kobj);
>> > + struct ltc2990_data *data = dev_get_drvdata(dev);
>> > + struct device_attribute *da =
>> > + container_of(a, struct device_attribute, attr);
>> > + struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
>> > +
>> > + int attrs_mask = LTC2990_IN0 | LTC2990_TEMP1 |
>> > + ltc2990_attrs_ena_0[data->mode[0]] &
>> > + ltc2990_attrs_ena_1[data->mode[1]];
>> > +
>> > + if (attr->index & attrs_mask)
>> > + return a->mode;
>> > +
>> > + return 0;
>> > +}
>> > +
>> > static SENSOR_DEVICE_ATTR(temp1_input, S_IRUGO, ltc2990_show_value,
>> > NULL,
>> > - LTC2990_TINT_MSB);
>> > + LTC2990_TEMP1);
>> > +static SENSOR_DEVICE_ATTR(temp2_input, S_IRUGO, ltc2990_show_value,
>> > NULL,
>> > + LTC2990_TEMP2);
>> > +static SENSOR_DEVICE_ATTR(temp3_input, S_IRUGO, ltc2990_show_value,
>> > NULL,
>> > + LTC2990_TEMP3);
>> > static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc2990_show_value,
>> > NULL,
>> > - LTC2990_V1_MSB);
>> > + LTC2990_CURR1);
>> > static SENSOR_DEVICE_ATTR(curr2_input, S_IRUGO, ltc2990_show_value,
>> > NULL,
>> > - LTC2990_V3_MSB);
>> > + LTC2990_CURR2);
>> > static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ltc2990_show_value,
>> > NULL,
>> > - LTC2990_VCC_MSB);
>> > + LTC2990_IN0);
>> > +static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc2990_show_value, NULL,
>> > + LTC2990_IN1);
>> > +static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc2990_show_value, NULL,
>> > + LTC2990_IN2);
>> > +static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ltc2990_show_value, NULL,
>> > + LTC2990_IN3);
>> > +static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ltc2990_show_value, NULL,
>> > + LTC2990_IN4);
>> > static struct attribute *ltc2990_attrs[] = {
>> > & sensor_dev_attr_temp1_input.dev_attr.attr,
>> > + &sensor_dev_attr_temp2_input.dev_attr.attr,
>> > + &sensor_dev_attr_temp3_input.dev_attr.attr,
>> > & sensor_dev_attr_curr1_input.dev_attr.attr,
>> > & sensor_dev_attr_curr2_input.dev_attr.attr,
>> > & sensor_dev_attr_in0_input.dev_attr.attr,
>> > + &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,
>> > };
>> > -ATTRIBUTE_GROUPS(ltc2990);
>> > +
>> > +static const struct attribute_group ltc2990_group = {
>> > + .attrs = ltc2990_attrs,
>> > + .is_visible = ltc2990_attrs_visible,
>> > +};
>> > +__ATTRIBUTE_GROUPS(ltc2990);
>> > static int ltc2990_i2c_probe(struct i2c_client *i2c,
>> > const struct i2c_device_id *id)
>> > {
>> > int ret;
>> > struct device *hwmon_dev;
>> > + struct ltc2990_data *data;
>> > + struct device_node *of_node = i2c->dev.of_node;
>> > if (!i2c_check_functionality(i2c->adapter,
>> > I2C_FUNC_SMBUS_BYTE_DATA |
>> > I2C_FUNC_SMBUS_WORD_DATA))
>> > return -ENODEV;
>> > - /* Setup continuous mode, current monitor */
>> > + data = devm_kzalloc(&i2c->dev, sizeof(struct ltc2990_data),
>> > GFP_KERNEL);
>> > + if (unlikely(!data))
>> > + return -ENOMEM;
>> > +
>> > + data->i2c = i2c;
>> > +
>> > + if (of_node) {
>> > + ret = of_property_read_u32_array(of_node, "lltc,meas-mode",
>> > + data->mode, 2);
>> > + if (ret < 0)
>> > + return ret;
>> > +
>> > + if (data->mode[0] & ~LTC2990_MODE0_MASK ||
>> > + data->mode[1] & ~LTC2990_MODE1_MASK)
>> > + return -EINVAL;
>> > + } else {
>> > + ret = i2c_smbus_read_byte_data(i2c, LTC2990_CONTROL);
>> > + if (ret < 0)
>> > + return ret;
>> > +
>> > + data->mode[0] = ret >> LTC2990_MODE0_SHIFT &
>> > LTC2990_MODE0_MASK;
>> > + data->mode[1] = ret >> LTC2990_MODE1_SHIFT &
>> > LTC2990_MODE1_MASK;
>> > + }
>> > +
>> > + /* Setup continuous mode */
>> > ret = i2c_smbus_write_byte_data(i2c, LTC2990_CONTROL,
>> > - LTC2990_CONTROL_MEASURE_ALL |
>> > - LTC2990_CONTROL_MODE_CURRENT);
>> > + data->mode[0] << LTC2990_MODE0_SHIFT |
>> > + data->mode[1] << LTC2990_MODE1_SHIFT);
>> > if (ret < 0) {
>> > dev_err(&i2c->dev, "Error: Failed to set control mode.\n");
>> > return ret;
>> > @@ -124,7 +264,7 @@ static int ltc2990_i2c_probe(struct i2c_client *i2c,
>> > hwmon_dev = devm_hwmon_device_register_with_groups(&i2c->dev,
>> > i2c->name,
>> > - i2c,
>> > + data,
>> > ltc2990_groups);
>> > return PTR_ERR_OR_ZERO(hwmon_dev);
>> >
>>
>>
>>
>> Kind regards,
>>
>> Mike Looijmans
>> System Expert
>>
>> TOPIC Products
>> Materiaalweg 4, NL-5681 RJ Best
>> Postbus 440, NL-5680 AK Best
>> Telefoon: +31 (0) 499 33 69 79
>> E-mail: mike.looijmans@topicproducts.com
>> Website: www.topicproducts.com
>>
>> Please consider the environment before printing this e-mail
>>
>>
>>
>>
>
>
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