Re: [PATCH] hwmon: ltc2990: support all measurement modes
From: Guenter Roeck
Date: Wed Nov 16 2016 - 09:45:34 EST
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@xxxxxxx>
---
.../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@xxxxxxxx>
+ Tom Levens <tom.levens@xxxxxxx>
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@xxxxxxxx>
*
- * License: GPLv2
+ * Copyright (C) 2016 European Organization for Nuclear Research (CERN)
+ * Author: Tom Levens <tom.levens@xxxxxxx>
*
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);