[lm-sensors] [RFC] hwmon: add INA209 driver

Ira Snyder iws at ovro.caltech.edu
Thu Oct 16 22:13:09 CEST 2008


Add Linux support for the Texas Intstruments / Burr Brown INA209
voltage / current / power monitor I2C interface.

Signed-off-by: Ira W. Snyder <iws at ovro.caltech.edu>
---

This driver is definitely not ready for inclusion, however, I hope there
aren't too many mistakes.

The biggest problem is the calibration register, whose value is used to
calculate the power and current values, as well as their maximum range.
Without programming the appropriate value, the registers are meaningless.
I currently added a sysfs node so the value could be set easily.
However, I hardcoded the meanings of the power and current registers
using a calibration value of 4096, which is appropriate for my board.

I'm looking for suggestions here :)

Other than that, I think everything should be in pretty good shape.


 Documentation/hwmon/ina209 |   83 ++++++
 drivers/hwmon/Kconfig      |   11 +
 drivers/hwmon/Makefile     |    1 +
 drivers/hwmon/ina209.c     |  598 ++++++++++++++++++++++++++++++++++++++++++++
 4 files changed, 693 insertions(+), 0 deletions(-)
 create mode 100644 Documentation/hwmon/ina209
 create mode 100644 drivers/hwmon/ina209.c

diff --git a/Documentation/hwmon/ina209 b/Documentation/hwmon/ina209
new file mode 100644
index 0000000..97936e4
--- /dev/null
+++ b/Documentation/hwmon/ina209
@@ -0,0 +1,83 @@
+Kernel driver ina209
+=====================
+
+Supported chips:
+  * Burr-Brown / Texas Instruments INA209
+    Prefix: 'ina209'
+    Addresses scanned: 0x40-0x4f
+    Datasheet:
+        http://www.ti.com/lit/gpn/ina209
+
+Author: Paul Hays <haysp at magma.net>
+Author: Ira W. Snyder <iws at ovro.caltech.edu>
+
+
+Description
+-----------
+
+The Burr-Brown INA209 monitors voltage and current on the high side
+of a D.C. power supply. It can perform measurements and calculations
+in the background to supply readings at any time. It includes a
+programmable calibration multiplier to scale the displayed current
+and power values.
+
+
+Sysfs entries
+-------------
+
+The INA209 chip is highly configurable both via hardwiring and via
+the I2C bus. See the datasheet for details.
+
+This tries to expose most monitoring features of the hardware via
+sysfs. It does not support every feature of this chip.
+
+
+calibration		calibration register, see remarks below
+
+in0_input		shunt voltage (mV)
+in0_input_highest	shunt voltage historical maximum reading (mV)
+in0_input_lowest	shunt voltage historical minimum reading (mV)
+in0_max			shunt voltage max alarm limit (mV)
+in0_min			shunt voltage min alarm limit (mV)
+in0_crit_max		shunt voltage crit max alarm limit (mV)
+in0_crit_min		shunt voltage crit min alarm limit (mV)
+in0_max_alarm		shunt voltage max alarm limit exceeded
+in0_min_alarm		shunt voltage min alarm limit exceeded
+in0_crit_max_alarm	shunt voltage crit max alarm limit exceeded
+in0_crit_min_alarm	shunt voltage crit min alarm limit exceeded
+
+in1_input		bus voltage (mV)
+in1_input_highest	bus voltage historical maximum reading (mV)
+in1_input_lowest	bus voltage historical minimum reading (mV)
+in1_max			bus voltage max alarm limit (mV)
+in1_min			bus voltage min alarm limit (mV)
+in1_crit_max		bus voltage crit max alarm limit (mV)
+in1_crit_min		bus voltage crit min alarm limit (mV)
+in1_max_alarm		bus voltage max alarm limit exceeded
+in1_min_alarm		bus voltage min alarm limit exceeded
+in1_crit_max_alarm	bus voltage crit max alarm limit exceeded
+in1_crit_min_alarm	bus voltage crit min alarm limit exceeded
+
+power1_input		power measurement (uW)
+power1_input_highest	power historical maximum reading (uW)
+power1_max		power max alarm limit (uW)
+power1_crit		power crit alarm limit (uW)
+power1_alarm		power max alarm limit exceeded
+power1_crit_alarm	power crit alarm limit exceeded
+
+curr1_input		current measurement (mA)
+
+
+General Remarks
+---------------
+
+You will need to write the correct value to the calibration register
+for this chip to function properly. TI provides a Windows-only tool
+that will calculate the values for you. The datasheet has the specifics
+on the calculation. You can follow along with pen and paper to get the
+correct value for your calibration register.
+
+Application information in the datasheet shows 10 Ohm resistors
+in series with the sensing inputs to filter noise and for
+transient protection. Experience shows that they also degrade
+accuracy.
diff --git a/drivers/hwmon/Kconfig b/drivers/hwmon/Kconfig
index d402e8d..47cd73c 100644
--- a/drivers/hwmon/Kconfig
+++ b/drivers/hwmon/Kconfig
@@ -836,6 +836,17 @@ config SENSORS_APPLESMC
 	  Say Y here if you have an applicable laptop and want to experience
 	  the awesome power of applesmc.
 
+config SENSORS_INA209
+	tristate "TI / Burr Brown INA209"
+	depends on I2C && EXPERIMENTAL
+	default n
+	help
+	  If you say yes here you get support for the TI / Burr Brown INA209
+	  voltage / current / power monitor I2C interface.
+
+	  This driver can also be built as a module. If so, the module will
+	  be called ina209.
+
 config HWMON_DEBUG_CHIP
 	bool "Hardware Monitoring Chip debugging messages"
 	default n
diff --git a/drivers/hwmon/Makefile b/drivers/hwmon/Makefile
index 950134a..c148c06 100644
--- a/drivers/hwmon/Makefile
+++ b/drivers/hwmon/Makefile
@@ -45,6 +45,7 @@ obj-$(CONFIG_SENSORS_HDAPS)	+= hdaps.o
 obj-$(CONFIG_SENSORS_I5K_AMB)	+= i5k_amb.o
 obj-$(CONFIG_SENSORS_IBMAEM)	+= ibmaem.o
 obj-$(CONFIG_SENSORS_IBMPEX)	+= ibmpex.o
+obj-$(CONFIG_SENSORS_INA209)	+= ina209.o
 obj-$(CONFIG_SENSORS_IT87)	+= it87.o
 obj-$(CONFIG_SENSORS_K8TEMP)	+= k8temp.o
 obj-$(CONFIG_SENSORS_LM63)	+= lm63.o
diff --git a/drivers/hwmon/ina209.c b/drivers/hwmon/ina209.c
new file mode 100644
index 0000000..978e7af
--- /dev/null
+++ b/drivers/hwmon/ina209.c
@@ -0,0 +1,598 @@
+/*
+ * Driver for the Texas Instruments / Burr Brown INA209
+ * Bidirectional Current/Power Monitor
+ *
+ * Copyright (C) 2008 Paul Hays <haysp at magma.ca>
+ * Copyright (C) 2008 Ira W. Snyder <iws at ovro.caltech.edu>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; version 2 of the License.
+ *
+ * Datasheet:
+ * http://www.ti.com/lit/gpn/ina209
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/bug.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+
+/* Addresses to probe. The chip can be hardwired to use any of these
+ * addresses using pins A0 and A1. (E.g. connecting both to the SDA pin
+ * selects address 0x4a).
+ */
+static unsigned short normal_i2c[] = {
+	0x40, 0x41, 0x42, 0x43, 0x44, 0x45, 0x46, 0x47,
+	0x48, 0x49, 0x4a, 0x4b, 0x4c, 0x4d, 0x4e, 0x4f,
+	I2C_CLIENT_END};
+
+/* Insmod parameters */
+I2C_CLIENT_INSMOD_1(ina209);
+
+/* Here are names of the chip's registers (a.k.a. commands) */
+enum ina209_cmd {
+	INA209_CONFIGURATION		= 0x00,
+	INA209_STATUS			= 0x01,
+	INA209_STATUS_MASK		= 0x02,
+	INA209_SHUNT_V			= 0x03,
+	INA209_BUS_V			= 0x04,
+	INA209_POWER			= 0x05,
+	INA209_BUS_CURRENT		= 0x06,
+	INA209_SHUNT_V_POS_PEAK		= 0x07,
+	INA209_SHUNT_V_NEG_PEAK		= 0x08,
+	INA209_BUS_V_MAX_PEAK		= 0x09,
+	INA209_BUS_V_MIN_PEAK		= 0x0a,
+	INA209_POWER_PEAK		= 0x0b,
+	INA209_SHUNT_V_POS_WARN		= 0x0c,
+	INA209_SHUNT_V_NEG_WARN		= 0x0d,
+	INA209_POWER_WARN		= 0x0e,
+	INA209_BUS_OVER_V_WARN		= 0x0f,
+	INA209_BUS_UNDER_V_WARN		= 0x10,
+	INA209_POWER_OVER_LIMIT		= 0x11,
+	INA209_BUS_OVER_V_OVER_LIMIT	= 0x12,
+	INA209_BUS_UNDER_V_OVER_LIMIT	= 0x13,
+	INA209_CRITICAL_DAC_POS		= 0x14,
+	INA209_CRITICAL_DAC_NEG		= 0x15,
+	INA209_CALIBRATION		= 0x16,
+};
+
+struct ina209_data {
+	struct device *hwmon_dev;
+
+	struct mutex update_lock;
+	bool valid;
+	unsigned long last_updated; /* in jiffies */
+
+	/* All chip registers */
+	u16 regs[0x17];
+};
+
+/* All registers are word-sized (16 bit)
+ *
+ * INA209 uses a high-byte first convention, which is exactly opposite
+ * to the SMBus standard
+ */
+static s32 ina209_read_reg(struct i2c_client *client, u8 reg)
+{
+	s32 val = i2c_smbus_read_word_data(client, reg);
+
+	if (val < 0)
+		return val;
+
+	return swab16(val);
+}
+
+static s32 ina209_write_reg(struct i2c_client *client, u8 reg, u16 val)
+{
+	return i2c_smbus_write_word_data(client, reg, swab16(val));
+}
+
+/* Update the chip once every second */
+static struct ina209_data *ina209_update_device(struct device *dev)
+{
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ina209_data *data = i2c_get_clientdata(client);
+	int i;
+
+	mutex_lock(&data->update_lock);
+
+	if (time_after(jiffies, data->last_updated + HZ) || !data->valid) {
+
+		dev_dbg(&client->dev, "Starting ina209 update\n");
+
+		for (i = 0; i < ARRAY_SIZE(data->regs); i++)
+			data->regs[i] = ina209_read_reg(client, i);
+
+		data->last_updated = jiffies;
+		data->valid = 1;
+	}
+
+	mutex_unlock(&data->update_lock);
+
+	return data;
+}
+
+/* Read a value from a device register and convert it to the
+ * appropriate sysfs units */
+static int ina209_from_reg(struct device *dev, u8 reg)
+{
+	struct ina209_data *data = ina209_update_device(dev);
+	const s32 val = data->regs[reg];
+
+	if (unlikely(val < 0)) {
+		dev_dbg(dev, "Unable to read register 0x%.2x\n", reg);
+		return 0;
+	}
+
+	switch (reg) {
+	case INA209_SHUNT_V:
+	case INA209_SHUNT_V_POS_PEAK:
+	case INA209_SHUNT_V_NEG_PEAK:
+	case INA209_SHUNT_V_POS_WARN:
+	case INA209_SHUNT_V_NEG_WARN:
+		/* 10 uV per division */
+		return (s16)val / 100;
+
+	case INA209_BUS_V:
+	case INA209_BUS_V_MAX_PEAK:
+	case INA209_BUS_V_MIN_PEAK:
+	case INA209_BUS_OVER_V_WARN:
+	case INA209_BUS_UNDER_V_WARN:
+	case INA209_BUS_OVER_V_OVER_LIMIT:
+	case INA209_BUS_UNDER_V_OVER_LIMIT:
+		/* 4 mV per division, last 3 bits unused */
+		return ((u16)val >> 3) * 4;
+
+	case INA209_CRITICAL_DAC_POS:
+		/* 1 mV per division, in the higest 8 bits */
+		return (u16)val >> 8;
+
+	case INA209_CRITICAL_DAC_NEG:
+		/* 1 mV per division, in the higest 8 bits */
+		return -1 * ((u16)val >> 8);
+
+	case INA209_POWER:
+	case INA209_POWER_PEAK:
+	case INA209_POWER_WARN:
+	case INA209_POWER_OVER_LIMIT:
+		/* FIXME: This is derived from the configuration register! */
+		/* 20000 uW per division -- PowerLSB */
+		return (u16)val * 20000;
+
+	case INA209_BUS_CURRENT:
+		/* FIXME: This is derived from the configuration register! */
+		/* 1000 uA == 1 mA per division -- CurrentLSB */
+		return (s16)val * 1;
+	}
+
+	/* You tried to read a register that isn't supported yet! */
+	WARN_ON_ONCE(1);
+	return 0;
+}
+
+/* Take a value and convert it to register format, clamping the value
+ * to the appropriate range. Write it to the register */
+static void ina209_to_reg(struct device *dev, u8 reg, int val)
+{
+	struct ina209_data *data = ina209_update_device(dev);
+	struct i2c_client *client = to_i2c_client(dev);
+	u16 regval = 0;
+
+	/* We lock around this switch because we're essentially doing
+	 * a read-modify-write of values in data->regs[] */
+	mutex_lock(&data->update_lock);
+
+	switch (reg) {
+	case INA209_SHUNT_V_POS_WARN:
+	case INA209_SHUNT_V_NEG_WARN:
+		/* Limit to +- 320 mV, 10 uV per division */
+		regval = SENSORS_LIMIT(val, -320, 320) * 100;
+		break;
+
+	case INA209_BUS_OVER_V_WARN:
+	case INA209_BUS_UNDER_V_WARN:
+	case INA209_BUS_OVER_V_OVER_LIMIT:
+	case INA209_BUS_UNDER_V_OVER_LIMIT:
+		/* Limit to 0-32000 mV, 4 mV per division */
+		regval = SENSORS_LIMIT(val, 0, 32000) / 4;
+
+		/* The last three bits aren't part of the value, but we'll
+		 * preserve them in their original state */
+		regval = (regval << 3) | (data->regs[reg] & 0x7);
+		break;
+
+	case INA209_CRITICAL_DAC_NEG:
+		/* Limit to -255-0 mV, 1 mV per division
+		 * Convert the value to a positive value for the register */
+		regval = abs(SENSORS_LIMIT(val, -255, 0));
+
+		/* The value lives in the top 8 bits only, be careful
+		 * and keep the original value of the other bits */
+		regval = (regval << 8) | (data->regs[reg] & 0xff);
+		break;
+
+	case INA209_CRITICAL_DAC_POS:
+		/* Limit to 0-255 mV, 1 mV per division */
+		regval = SENSORS_LIMIT(val, 0, 255);
+
+		/* The value lives in the top 8 bits only, be careful
+		 * and keep the original value of the other bits */
+		regval = (regval << 8) | (data->regs[reg] & 0xff);
+		break;
+
+	case INA209_POWER_WARN:
+	case INA209_POWER_OVER_LIMIT:
+		/* FIXME: This is derived from the configuration register! */
+		/* Limit to 0-1 kW, 20000 uW per division -- PowerLSB */
+		regval = SENSORS_LIMIT(val, 0, 1024000000) / 20000;
+		break;
+
+	case INA209_SHUNT_V:
+	case INA209_BUS_V:
+	case INA209_POWER:
+	case INA209_BUS_CURRENT:
+	case INA209_SHUNT_V_POS_PEAK:
+	case INA209_SHUNT_V_NEG_PEAK:
+	case INA209_BUS_V_MAX_PEAK:
+	case INA209_BUS_V_MIN_PEAK:
+	case INA209_POWER_PEAK:
+	default:
+		/* These registers are read only! */
+		WARN_ON_ONCE(1);
+		break;
+	}
+
+	/* Write the value to the register */
+	data->regs[reg] = regval;
+	ina209_write_reg(client, reg, regval);
+	mutex_unlock(&data->update_lock);
+}
+
+static ssize_t ina209_set_value(struct device *dev,
+				struct device_attribute *da,
+				const char *buf,
+				size_t count)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+	long val = simple_strtol(buf, NULL, 10);
+
+	ina209_to_reg(dev, attr->index, val);
+	return count;
+}
+
+static ssize_t ina209_show_value(struct device *dev,
+				 struct device_attribute *da,
+				 char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+	int val = ina209_from_reg(dev, attr->index);
+
+	return snprintf(buf, PAGE_SIZE, "%d\n", val);
+}
+
+static ssize_t ina209_show_alarm(struct device *dev,
+				 struct device_attribute *da,
+				 char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+	struct ina209_data *data = ina209_update_device(dev);
+	const s32 status = data->regs[INA209_STATUS];
+	const unsigned int mask = attr->index;
+
+	/* All alarms are in the INA209_STATUS register. To avoid a long
+	 * switch statement here, we pass the mask in the attr->index field */
+
+	if (unlikely(status < 0)) {
+		memset(buf, 0, PAGE_SIZE); /* user should not see old data */
+		return 0;
+	}
+
+	return snprintf(buf, PAGE_SIZE, "%u\n", status & mask ? 1 : 0);
+}
+
+/* This function is used to save values of raw registers
+ *
+ * You had better know exactly what you are doing if you use it, otherwise
+ * you may end up doing some strange things. Read the datasheet.
+ *
+ * This function accepts values in any format parseable by simple_strtol()
+ */
+static ssize_t ina209_set_raw(struct device *dev,
+			    struct device_attribute *da,
+			    const char *buf,
+			    size_t count)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+	struct i2c_client *client = to_i2c_client(dev);
+	struct ina209_data *data = ina209_update_device(dev);
+	const long val = simple_strtol(buf, NULL, 0);
+
+	mutex_lock(&data->update_lock);
+	data->regs[attr->index] = val;
+	ina209_write_reg(client, attr->index, val);
+	mutex_unlock(&data->update_lock);
+
+	return count;
+}
+
+/* Show the value of a raw register without doing any conversion */
+static ssize_t ina209_show_raw(struct device *dev,
+			   struct device_attribute *da,
+			   char *buf)
+{
+	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+	struct ina209_data *data = ina209_update_device(dev);
+	const s32 val = data->regs[attr->index];
+
+	if (val < 0) {
+		dev_dbg(dev, "failed to read register 0x%2.2x\n", attr->index);
+		memset(buf, 0, PAGE_SIZE); /* user should not see old data */
+		return 0;
+	}
+
+	return snprintf(buf, PAGE_SIZE, "%hd\n", (u16)val);
+}
+
+/* These macros are used below in constructing device attribute objects
+ * for use with sysfs_create_group() to make a sysfs device file
+ * for each register.
+ */
+
+#define INA209_RO(name, ina209_cmd_idx) \
+	static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
+	ina209_show_value, NULL, ina209_cmd_idx)
+
+#define INA209_RW(name, ina209_cmd_idx) \
+	static SENSOR_DEVICE_ATTR(name, S_IRUGO | S_IWUSR, \
+	ina209_show_value, ina209_set_value, ina209_cmd_idx)
+
+#define INA209_RAW(name, ina209_cmd_idx) \
+	static SENSOR_DEVICE_ATTR(name, S_IRUGO | S_IWUSR, \
+	ina209_show_raw, ina209_set_raw, ina209_cmd_idx)
+
+#define INA209_ALARM(name, ina209_cmd_idx) \
+	static SENSOR_DEVICE_ATTR(name, S_IRUGO, \
+	ina209_show_alarm, NULL, ina209_cmd_idx)
+
+/* Construct a sensor_device_attribute structure for each register */
+INA209_RAW(calibration,			INA209_CALIBRATION);
+
+/* Shunt voltage reading, history, limits, alarms */
+INA209_RO(in0_input,			INA209_SHUNT_V);
+INA209_RO(in0_input_highest,		INA209_SHUNT_V_POS_PEAK);
+INA209_RO(in0_input_lowest,		INA209_SHUNT_V_NEG_PEAK);
+INA209_RW(in0_max,			INA209_SHUNT_V_POS_WARN);
+INA209_RW(in0_min,			INA209_SHUNT_V_NEG_WARN);
+INA209_RW(in0_crit_max,			INA209_CRITICAL_DAC_POS);
+INA209_RW(in0_crit_min,			INA209_CRITICAL_DAC_NEG);
+INA209_ALARM(in0_min_alarm,		(1 << 11));
+INA209_ALARM(in0_max_alarm,		(1 << 12));
+INA209_ALARM(in0_crit_min_alarm,	(1 << 6));
+INA209_ALARM(in0_crit_max_alarm,	(1 << 7));
+
+/* Bus voltage reading, history, limits, alarms */
+INA209_RO(in1_input,			INA209_BUS_V);
+INA209_RO(in1_input_highest,		INA209_BUS_V_MAX_PEAK);
+INA209_RO(in1_input_lowest,		INA209_BUS_V_MIN_PEAK);
+INA209_RW(in1_max,			INA209_BUS_OVER_V_WARN);
+INA209_RW(in1_min,			INA209_BUS_UNDER_V_WARN);
+INA209_RW(in1_crit_max,			INA209_BUS_OVER_V_OVER_LIMIT);
+INA209_RW(in1_crit_min,			INA209_BUS_UNDER_V_OVER_LIMIT);
+INA209_ALARM(in1_min_alarm,		(1 << 14));
+INA209_ALARM(in1_max_alarm,		(1 << 15));
+INA209_ALARM(in1_crit_min_alarm,	(1 << 9));
+INA209_ALARM(in1_crit_max_alarm,	(1 << 10));
+
+/* Power reading, history, limits, alarms */
+INA209_RO(power1_input,			INA209_POWER);
+INA209_RO(power1_input_highest,		INA209_POWER_PEAK);
+INA209_RW(power1_max,			INA209_POWER_WARN);
+INA209_RW(power1_crit,			INA209_POWER_OVER_LIMIT);
+INA209_ALARM(power1_alarm,		(1 << 13));
+INA209_ALARM(power1_crit_alarm,		(1 << 8));
+
+/* Current reading */
+INA209_RO(curr1_input,			INA209_BUS_CURRENT);
+
+/* Finally, construct an array of pointers to members of the above objects,
+ * as required for sysfs_create_group()
+ */
+static struct attribute *ina209_attributes[] = {
+	&sensor_dev_attr_calibration.dev_attr.attr,
+
+	&sensor_dev_attr_in0_input.dev_attr.attr,
+	&sensor_dev_attr_in0_input_highest.dev_attr.attr,
+	&sensor_dev_attr_in0_input_lowest.dev_attr.attr,
+	&sensor_dev_attr_in0_max.dev_attr.attr,
+	&sensor_dev_attr_in0_min.dev_attr.attr,
+	&sensor_dev_attr_in0_crit_max.dev_attr.attr,
+	&sensor_dev_attr_in0_crit_min.dev_attr.attr,
+	&sensor_dev_attr_in0_max_alarm.dev_attr.attr,
+	&sensor_dev_attr_in0_min_alarm.dev_attr.attr,
+	&sensor_dev_attr_in0_crit_max_alarm.dev_attr.attr,
+	&sensor_dev_attr_in0_crit_min_alarm.dev_attr.attr,
+
+	&sensor_dev_attr_in1_input.dev_attr.attr,
+	&sensor_dev_attr_in1_input_highest.dev_attr.attr,
+	&sensor_dev_attr_in1_input_lowest.dev_attr.attr,
+	&sensor_dev_attr_in1_max.dev_attr.attr,
+	&sensor_dev_attr_in1_min.dev_attr.attr,
+	&sensor_dev_attr_in1_crit_max.dev_attr.attr,
+	&sensor_dev_attr_in1_crit_min.dev_attr.attr,
+	&sensor_dev_attr_in1_max_alarm.dev_attr.attr,
+	&sensor_dev_attr_in1_min_alarm.dev_attr.attr,
+	&sensor_dev_attr_in1_crit_max_alarm.dev_attr.attr,
+	&sensor_dev_attr_in1_crit_min_alarm.dev_attr.attr,
+
+	&sensor_dev_attr_power1_input.dev_attr.attr,
+	&sensor_dev_attr_power1_input_highest.dev_attr.attr,
+	&sensor_dev_attr_power1_max.dev_attr.attr,
+	&sensor_dev_attr_power1_crit.dev_attr.attr,
+	&sensor_dev_attr_power1_alarm.dev_attr.attr,
+	&sensor_dev_attr_power1_crit_alarm.dev_attr.attr,
+
+	&sensor_dev_attr_curr1_input.dev_attr.attr,
+
+	NULL,
+};
+
+static struct attribute_group ina209_group = {
+	.attrs = ina209_attributes,
+};
+
+static int ina209_probe(struct i2c_client *client,
+			const struct i2c_device_id *id)
+{
+	struct ina209_data *data;
+	int ret;
+
+	data = kzalloc(sizeof(*data), GFP_KERNEL);
+
+	if (!data) {
+		ret = -ENOMEM;
+		goto out_kzalloc;
+	}
+
+	i2c_set_clientdata(client, data);
+	mutex_init(&data->update_lock);
+
+	/* Initialize the INA209 chip */
+
+	/* This writes the reset value to the chip. This chip's gain is
+	 * completely fake, it just chops the significant bits off of values.
+	 * Therefore, we don't lose any resolution by doing this */
+	ina209_write_reg(client, INA209_CONFIGURATION, 0x399F);
+
+	/* NOTE: This assumes that the chip is in the default 32V / 320mV state
+	 * NOTE: and that you are using a 0.01 ohm shunt resistor
+	 *
+	 * NOTE: the calculations in the data sheet then give 20000 uW per power
+	 * NOTE: bit and 1000 uA per current bit
+	 *
+	 * FIXME: what is the appropriate thing to do here? This value must
+	 * FIXME: be set to match the circuit */
+	ina209_write_reg(client, INA209_CALIBRATION, 4096);
+
+	/* Register sysfs hooks */
+	ret = sysfs_create_group(&client->dev.kobj, &ina209_group);
+
+	if (ret)
+		goto out_sysfs_create_group;
+
+	data->hwmon_dev = hwmon_device_register(&client->dev);
+
+	if (IS_ERR(data->hwmon_dev)) {
+		ret = PTR_ERR(data->hwmon_dev);
+		goto out_hwmon_device_register;
+	}
+
+	return 0;
+
+out_hwmon_device_register:
+	sysfs_remove_group(&client->dev.kobj, &ina209_group);
+out_sysfs_create_group:
+	kfree(data);
+out_kzalloc:
+	return ret;
+}
+
+static int ina209_remove(struct i2c_client *client)
+{
+	struct ina209_data *data = i2c_get_clientdata(client);
+
+	hwmon_device_unregister(data->hwmon_dev);
+	sysfs_remove_group(&client->dev.kobj, &ina209_group);
+
+	kfree(data);
+
+	return 0;
+}
+
+static int ina209_detect(struct i2c_client *client,
+			 int kind,
+			 struct i2c_board_info *info)
+{
+	struct i2c_adapter *adapter = client->adapter;
+
+	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
+		return -ENODEV;
+
+	if (kind < 0) {		/* probed detection - check the chip type */
+		s32 v;		/* 16 bits from the chip, or -1 for error */
+
+		/* Chip registers 0x00-0x16 are documented. The vendor's
+		 * program INA209EVM.exe hints that register 0x17 is "unused"
+		 * and that 0x18-0x1b provide internal status data.
+		 * i2cdump shows that 0x17 returns 0 and that the chip
+		 * ignores register address bits 0x20 and higher (e.g.
+		 * registers 0x00, 0x20, 0x40 etc through 0xe0 give
+		 * identical values).
+		 */
+
+		/* read "unused" register, expect 0 */
+		if (ina209_read_reg(client, 0x17) != 0)
+			return -ENODEV;
+
+		/* expect 0 bits in configuration */
+		v = ina209_read_reg(client, INA209_CONFIGURATION);
+		if (v < 0 || (v & 0xc000) != 0)
+			return -ENODEV;
+
+		/* chip must ignore address bit 0x20 */
+		if (ina209_read_reg(client, 0x20 | INA209_CONFIGURATION) != v)
+			return -ENODEV;
+
+		/* unused bits in status register, expect 0 */
+		v = ina209_read_reg(client, INA209_STATUS);
+		if (v < 0 || (v & 0x0007) != 0)
+			return -ENODEV;
+	}
+
+	strlcpy(info->type, "ina209", I2C_NAME_SIZE);
+	pr_info("ina209: %s on i2c-%u address 0x%02x\n",
+			kind < 0 ? "probed" : "forced",
+			adapter->nr, client->addr);
+
+	return 0;
+}
+
+static const struct i2c_device_id ina209_id[] = {
+	{ "ina209", ina209 },
+	{ }
+};
+MODULE_DEVICE_TABLE(i2c, ina209_id);
+
+/* This is the driver that will be inserted */
+static struct i2c_driver ina209_driver = {
+	.class		= I2C_CLASS_HWMON,
+	.driver = {
+		.name	= "ina209",
+	},
+	.probe		= ina209_probe,
+	.remove		= ina209_remove,
+	.id_table	= ina209_id,
+	.detect		= ina209_detect,
+	.address_data	= &addr_data,
+};
+
+static int __init ina209_init(void)
+{
+	return i2c_add_driver(&ina209_driver);
+}
+
+static void __exit ina209_exit(void)
+{
+	i2c_del_driver(&ina209_driver);
+}
+
+MODULE_AUTHOR("Ira W. Snyder <iws at ovro.caltech.edu>");
+MODULE_DESCRIPTION("INA209 driver");
+MODULE_LICENSE("GPL");
+
+module_init(ina209_init);
+module_exit(ina209_exit);
-- 
1.5.4.3





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