Messages in this thread | | | Subject | Re: [PATCH] hwmon: ltc2990: support all measurement modes | From | Guenter Roeck <> | Date | Wed, 16 Nov 2016 06:45:17 -0800 |
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On 11/16/2016 05:53 AM, Tom Levens wrote: > Updated ltc2990 driver to support all possible measurement modes that > the chip provides. Mode can be set through a device tree attribute or by > writing to the "mode" sysfs attribute. > > Signed-off-by: Tom Levens <tom.levens@cern.ch> > --- > .../devicetree/bindings/hwmon/ltc2990.txt | 15 + > Documentation/hwmon/ltc2990 | 25 ++- > drivers/hwmon/Kconfig | 7 +- > drivers/hwmon/ltc2990.c | 268 +++++++++++++++++--- > 4 files changed, 266 insertions(+), 49 deletions(-) > create mode 100644 Documentation/devicetree/bindings/hwmon/ltc2990.txt > > diff --git a/Documentation/devicetree/bindings/hwmon/ltc2990.txt b/Documentation/devicetree/bindings/hwmon/ltc2990.txt > new file mode 100644 > index 0000000..0a17e8d > --- /dev/null > +++ b/Documentation/devicetree/bindings/hwmon/ltc2990.txt > @@ -0,0 +1,15 @@ > +ltc2990 > + > +Required properties: > +- compatible: must be "lltc,ltc2990" > +- reg: I2C slave address > + > +Optional properties: > +- mode: measurement mode (0-7), see Documentation/hwmon/ltc2990 for details > + This needs to be documented here.
> +Example: > +ltc2990@4c { > + compatible = "lltc,ltc2990"; > + mode = <7>; > + reg = <0x4c>; > +};
Please submit as separate patch and copy devicetree maintainers for Ack. You'll probably want to specify valid modes and their impact.
> diff --git a/Documentation/hwmon/ltc2990 b/Documentation/hwmon/ltc2990 > index c25211e..a97df88 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 +31,20 @@ 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 > +mode Set the measurement mode (range 0 to 7) > + The mode is determined by the hardware configuration. It does not make sense to have it user configurable.
> +A subset of the following attributes are visible, depending on the programmed > +measurement mode. > + > +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 45cef3d..f7096ca 100644 > --- a/drivers/hwmon/Kconfig > +++ b/drivers/hwmon/Kconfig > @@ -699,15 +699,12 @@ 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 8f8fe05..b6f910d 100644 > --- a/drivers/hwmon/ltc2990.c > +++ b/drivers/hwmon/ltc2990.c > @@ -4,11 +4,10 @@ > * Copyright (C) 2014 Topic Embedded Products > * Author: Mike Looijmans <mike.looijmans@topic.nl> > * > - * License: GPLv2 > + * Copyright (C) 2016 European Organization for Nuclear Research (CERN) > + * Author: Tom Levens <tom.levens@cern.ch> > * Please specify your changes. Something like "Support for all chip modes by ..." would be more appropriate.
> - * 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. > + * License: GPLv2 > */ > > #include <linux/err.h> > @@ -17,6 +16,7 @@ > #include <linux/i2c.h> > #include <linux/kernel.h> > #include <linux/module.h> > +#include <linux/of.h> > > #define LTC2990_STATUS 0x00 > #define LTC2990_CONTROL 0x01 > @@ -31,8 +31,36 @@ > #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_CONTROL_MODE_MAX 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) > + > +static const int ltc2990_attrs_ena[] = { > + 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 > +}; > + > +struct ltc2990_data { > + struct i2c_client *i2c; > + struct mutex update_lock; > + u32 mode; > +}; > > /* convert raw register value to sign-extended integer in 16-bit range */ > static int ltc2990_voltage_to_int(int raw) > @@ -44,30 +72,68 @@ 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, 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, 13-bit */ > val = (val & 0x1FFF) << 3; > *result = (val * 1000) >> 7;
Turns out this is actually wrong. Bit 12 is a sign bit per datasheet. Separate problem, though, and should be fixed with a separate patch. The first line should probably use sign_extend().
> 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 = ltc2990_voltage_to_int(val) * 1942 / (4 * 100);
Hmmm .. voltage_to_int() always adds two bits which are then just taken off subsequently. Another unrelated change - ltc2990_voltage_to_int() should just use sign_extend() and not bother shifting the result to the left. Or maybe just use sign_extend() and drop ltc2990_voltage_to_int() entirely.
Another separate patch, though.
> break; > - case LTC2990_VCC_MSB: > - /* Vcc, 305.18μV/LSB, 2.5V offset */ > + case LTC2990_IN0: > + /* Vcc, 305.18uV/LSB, 2.5V offset */ > *result = (ltc2990_voltage_to_int(val) * 30518 / > (4 * 100 * 1000)) + 2500; > break; > + case LTC2990_IN1: > + case LTC2990_IN2: > + case LTC2990_IN3: > + case LTC2990_IN4: > + /* Vx: 305.18uV/LSB */ > + *result = (ltc2990_voltage_to_int(val) * 30518 / > + (4 * 100 * 1000)); > + break; > default: > return -EINVAL; /* won't happen, keep compiler happy */ > } > @@ -75,66 +141,198 @@ static int ltc2990_get_value(struct i2c_client *i2c, u8 reg, int *result) > return 0; > } > > + No double empty lines please.
> +static int ltc2990_write_control_trigger(struct ltc2990_data *data) > +{
more like ltc2990_init_chip().
> + int ret; > + > + /* Setup continuous mode */ > + ret = i2c_smbus_write_byte_data(data->i2c, LTC2990_CONTROL, > + LTC2990_CONTROL_MEASURE_ALL | > + data->mode); > + if (unlikely(ret < 0)) { > + dev_err(&data->i2c->dev, > + "Error: Failed to set control mode.\n"); > + return ret; > + } > + /* Trigger once to start continuous conversion */ > + ret = i2c_smbus_write_byte_data(data->i2c, LTC2990_TRIGGER, 0x01); > + if (unlikely(ret < 0)) { > + dev_err(&data->i2c->dev, > + "Error: Failed to start acquisition.\n");
This looks like a bad multi-line alignment. Please align continuation lines with '('.
> + return ret; > + } > + > + return 0; > +} > + > 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 ssize_t ltc2990_get_mode(struct device *dev, > + struct device_attribute *da, char *buf) > +{ > + struct ltc2990_data *data = dev_get_drvdata(dev); > + > + return snprintf(buf, PAGE_SIZE, "%d\n", data->mode); > +} > + > +static const struct attribute_group ltc2990_group; > + > +static ssize_t ltc2990_set_mode(struct device *dev, > + struct device_attribute *da, > + const char *buf, size_t count) > +{ > + struct ltc2990_data *data = dev_get_drvdata(dev); > + int ret; > + unsigned long mode; > + > + ret = kstrtoul(buf, 10, &mode); > + if (unlikely(ret)) > + return ret; > + > + if (mode > LTC2990_CONTROL_MODE_MAX) > + return -EINVAL; > + > + mutex_lock(&data->update_lock); > + > + data->mode = mode; > + > + ret = ltc2990_write_control_trigger(data); > + if (unlikely(ret < 0)) > + goto abort; > + > + ret = sysfs_update_group(&dev->kobj, <c2990_group); > + if (unlikely(ret < 0)) > + goto abort; > + > + ret = count; > + > +abort: > + mutex_unlock(&data->update_lock); > + return ret; > +}
As mentioned above, mode is a hardware configuration and should not be changeable (or accessible, for that matter) using a sysfs attribute.
> + > +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); > + > + if (ltc2990_attrs_ena[data->mode] & attr->index) > + return a->mode; > + else > + 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 SENSOR_DEVICE_ATTR(mode, S_IRUGO | S_IWUSR, ltc2990_get_mode, > + ltc2990_set_mode, 0); > > 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_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, > +}; > + > +static const struct attribute_group ltc2990_group = { > + .attrs = ltc2990_attrs, > + .is_visible = ltc2990_attrs_visible, > +}; > + > +static struct attribute *ltc2990_static_attrs[] = { > + &sensor_dev_attr_temp1_input.dev_attr.attr, > &sensor_dev_attr_in0_input.dev_attr.attr, > + &sensor_dev_attr_mode.dev_attr.attr, > + NULL, > +}; > + > +static const struct attribute_group ltc2990_static_group = { > + .attrs = ltc2990_static_attrs > +}; > + > +static const struct attribute_group *ltc2990_groups[] = { > + <c2990_group, > + <c2990_static_group, > NULL, > }; > -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 */ > - ret = i2c_smbus_write_byte_data(i2c, LTC2990_CONTROL, > - LTC2990_CONTROL_MEASURE_ALL | > - LTC2990_CONTROL_MODE_CURRENT); > - if (ret < 0) { > - dev_err(&i2c->dev, "Error: Failed to set control mode.\n"); > - return ret; > + data = devm_kzalloc(&i2c->dev, sizeof(struct ltc2990_data), GFP_KERNEL); > + if (unlikely(!data)) > + return -ENOMEM; > + data->i2c = i2c; > + > + if (!of_node || of_property_read_u32(of_node, "mode", &data->mode)) > + data->mode = LTC2990_CONTROL_MODE_DEFAULT; > + > + if (data->mode > LTC2990_CONTROL_MODE_MAX) { > + dev_warn(&data->i2c->dev, > + "Warning: Mode %d out of range, defaulting to %d.\n", > + data->mode, LTC2990_CONTROL_MODE_DEFAULT); > + data->mode = LTC2990_CONTROL_MODE_DEFAULT;
This should fail loading the driver with -EINVAL.
> } > - /* Trigger once to start continuous conversion */ > - ret = i2c_smbus_write_byte_data(i2c, LTC2990_TRIGGER, 1); > - if (ret < 0) { > - dev_err(&i2c->dev, "Error: Failed to start acquisition.\n"); > + > + ret = ltc2990_write_control_trigger(data); > + if (unlikely(ret < 0)) > return ret; > - } > + > + mutex_init(&data->update_lock); > > hwmon_dev = devm_hwmon_device_register_with_groups(&i2c->dev, > i2c->name, > - i2c, > + data, > ltc2990_groups); > > return PTR_ERR_OR_ZERO(hwmon_dev); >
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