hwmon: INA219 and INA226 support

Add support for the Texas Instruments INA219 and INA226 power monitors.

Signed-off-by: Lothar Felten <l-felten@ti.com>
[guenter.roeck@ericsson.com: formatting cleanup; check for smbus word data;
 select PGA=8 for INA219]
Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>

1 files changed, 368 insertions, 0 deletions

diff --git a/drivers/hwmon/ina2xx.c b/drivers/hwmon/ina2xx.c
new file mode 100644
index 000000000000..7f3f4a385729
--- /dev/null
+++ b/drivers/hwmon/ina2xx.c
@@ -0,0 +1,368 @@
+/*
+ * Driver for Texas Instruments INA219, INA226 power monitor chips
+ *
+ * INA219:
+ * Zero Drift Bi-Directional Current/Power Monitor with I2C Interface
+ * Datasheet: http://www.ti.com/product/ina219
+ *
+ * INA226:
+ * Bi-Directional Current/Power Monitor with I2C Interface
+ * Datasheet: http://www.ti.com/product/ina226
+ *
+ * Copyright (C) 2012 Lothar Felten <l-felten@ti.com>
+ * Thanks to Jan Volkering
+ *
+ * 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.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/err.h>
+#include <linux/slab.h>
+#include <linux/i2c.h>
+#include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
+
+#include <linux/platform_data/ina2xx.h>
+
+/* common register definitions */
+#define INA2XX_CONFIG                   0x00
+#define INA2XX_SHUNT_VOLTAGE            0x01 /* readonly */
+#define INA2XX_BUS_VOLTAGE              0x02 /* readonly */
+#define INA2XX_POWER                    0x03 /* readonly */
+#define INA2XX_CURRENT                  0x04 /* readonly */
+#define INA2XX_CALIBRATION              0x05
+
+/* INA226 register definitions */
+#define INA226_MASK_ENABLE              0x06
+#define INA226_ALERT_LIMIT              0x07
+#define INA226_DIE_ID                   0xFF
+
+
+/* register count */
+#define INA219_REGISTERS                6
+#define INA226_REGISTERS                8
+
+#define INA2XX_MAX_REGISTERS            8
+
+/* settings - depend on use case */
+#define INA219_CONFIG_DEFAULT           0x399F  /* PGA=8 */
+#define INA226_CONFIG_DEFAULT           0x4527  /* averages=16 */
+
+/* worst case is 68.10 ms (~14.6Hz, ina219) */
+#define INA2XX_CONVERSION_RATE          15
+
+enum ina2xx_ids { ina219, ina226 };
+
+struct ina2xx_data {
+        struct device *hwmon_dev;
+
+        struct mutex update_lock;
+        bool valid;
+        unsigned long last_updated;
+
+        int kind;
+        int registers;
+        u16 regs[INA2XX_MAX_REGISTERS];
+};
+
+int ina2xx_read_word(struct i2c_client *client, int reg)
+{
+        int val = i2c_smbus_read_word_data(client, reg);
+        if (unlikely(val < 0)) {
+                dev_dbg(&client->dev,
+                        "Failed to read register: %d\n", reg);
+                return val;
+        }
+        return be16_to_cpu(val);
+}
+
+void ina2xx_write_word(struct i2c_client *client, int reg, int data)
+{
+        i2c_smbus_write_word_data(client, reg, cpu_to_be16(data));
+}
+
+static struct ina2xx_data *ina2xx_update_device(struct device *dev)
+{
+        struct i2c_client *client = to_i2c_client(dev);
+        struct ina2xx_data *data = i2c_get_clientdata(client);
+        struct ina2xx_data *ret = data;
+
+        mutex_lock(&data->update_lock);
+
+        if (time_after(jiffies, data->last_updated +
+                       HZ / INA2XX_CONVERSION_RATE) || !data->valid) {
+
+                int i;
+
+                dev_dbg(&client->dev, "Starting ina2xx update\n");
+
+                /* Read all registers */
+                for (i = 0; i < data->registers; i++) {
+                        int rv = ina2xx_read_word(client, i);
+                        if (rv < 0) {
+                                ret = ERR_PTR(rv);
+                                goto abort;
+                        }
+                        data->regs[i] = rv;
+                }
+                data->last_updated = jiffies;
+                data->valid = 1;
+        }
+abort:
+        mutex_unlock(&data->update_lock);
+        return ret;
+}
+
+static int ina219_get_value(struct ina2xx_data *data, u8 reg)
+{
+        /*
+         * calculate exact value for the given register
+         * we assume default power-on reset settings:
+         * bus voltage range 32V
+         * gain = /8
+         * adc 1 & 2 -> conversion time 532uS
+         * mode is continuous shunt and bus
+         * calibration value is INA219_CALIBRATION_VALUE
+         */
+        int val = data->regs[reg];
+
+        switch (reg) {
+        case INA2XX_SHUNT_VOLTAGE:
+                /* LSB=10uV. Convert to mV. */
+                val = DIV_ROUND_CLOSEST(val, 100);
+                break;
+        case INA2XX_BUS_VOLTAGE:
+                /* LSB=4mV. Register is not right aligned, convert to mV. */
+                val = (val >> 3) * 4;
+                break;
+        case INA2XX_POWER:
+                /* LSB=20mW. Convert to uW */
+                val = val * 20 * 1000;
+                break;
+        case INA2XX_CURRENT:
+                /* LSB=1mA (selected). Is in mA */
+                break;
+        default:
+                /* programmer goofed */
+                WARN_ON_ONCE(1);
+                val = 0;
+                break;
+        }
+
+        return val;
+}
+
+static int ina226_get_value(struct ina2xx_data *data, u8 reg)
+{
+        /*
+         * calculate exact value for the given register
+         * we assume default power-on reset settings:
+         * bus voltage range 32V
+         * gain = /8
+         * adc 1 & 2 -> conversion time 532uS
+         * mode is continuous shunt and bus
+         * calibration value is INA226_CALIBRATION_VALUE
+         */
+        int val = data->regs[reg];
+
+        switch (reg) {
+        case INA2XX_SHUNT_VOLTAGE:
+                /* LSB=2.5uV. Convert to mV. */
+                val = DIV_ROUND_CLOSEST(val, 400);
+                break;
+        case INA2XX_BUS_VOLTAGE:
+                /* LSB=1.25mV. Convert to mV. */
+                val = val + DIV_ROUND_CLOSEST(val, 4);
+                break;
+        case INA2XX_POWER:
+                /* LSB=25mW. Convert to uW */
+                val = val * 25 * 1000;
+                break;
+        case INA2XX_CURRENT:
+                /* LSB=1mA (selected). Is in mA */
+                break;
+        default:
+                /* programmer goofed */
+                WARN_ON_ONCE(1);
+                val = 0;
+                break;
+        }
+
+        return val;
+}
+
+static ssize_t ina2xx_show_value(struct device *dev,
+                                 struct device_attribute *da, char *buf)
+{
+        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
+        struct ina2xx_data *data = ina2xx_update_device(dev);
+        int value = 0;
+
+        if (IS_ERR(data))
+                return PTR_ERR(data);
+
+        switch (data->kind) {
+        case ina219:
+                value = ina219_get_value(data, attr->index);
+                break;
+        case ina226:
+                value = ina226_get_value(data, attr->index);
+                break;
+        default:
+                WARN_ON_ONCE(1);
+                break;
+        }
+        return snprintf(buf, PAGE_SIZE, "%d\n", value);
+}
+
+/* shunt voltage */
+static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, \
+        ina2xx_show_value, NULL, INA2XX_SHUNT_VOLTAGE);
+
+/* bus voltage */
+static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, \
+        ina2xx_show_value, NULL, INA2XX_BUS_VOLTAGE);
+
+/* calculated current */
+static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, \
+        ina2xx_show_value, NULL, INA2XX_CURRENT);
+
+/* calculated power */
+static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, \
+        ina2xx_show_value, NULL, INA2XX_POWER);
+
+/* pointers to created device attributes */
+static struct attribute *ina2xx_attributes[] = {
+        &sensor_dev_attr_in0_input.dev_attr.attr,
+        &sensor_dev_attr_in1_input.dev_attr.attr,
+        &sensor_dev_attr_curr1_input.dev_attr.attr,
+        &sensor_dev_attr_power1_input.dev_attr.attr,
+        NULL,
+};
+
+static const struct attribute_group ina2xx_group = {
+        .attrs = ina2xx_attributes,
+};
+
+static int ina2xx_probe(struct i2c_client *client,
+                        const struct i2c_device_id *id)
+{
+        struct i2c_adapter *adapter = client->adapter;
+        struct ina2xx_data *data;
+        struct ina2xx_platform_data *pdata;
+        int ret = 0;
+        long shunt = 10000; /* default shunt value 10mOhms */
+
+        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
+                return -ENODEV;
+
+        data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL);
+        if (!data)
+                return -ENOMEM;
+
+        if (client->dev.platform_data) {
+                pdata =
+                  (struct ina2xx_platform_data *)client->dev.platform_data;
+                shunt = pdata->shunt_uohms;
+        }
+
+        if (shunt <= 0)
+                return -ENODEV;
+
+        /* set the device type */
+        data->kind = id->driver_data;
+
+        switch (data->kind) {
+        case ina219:
+                /* device configuration */
+                ina2xx_write_word(client, INA2XX_CONFIG, INA219_CONFIG_DEFAULT);
+
+                /* set current LSB to 1mA, shunt is in uOhms */
+                /* (equation 13 in datasheet) */
+                ina2xx_write_word(client, INA2XX_CALIBRATION, 40960000 / shunt);
+                dev_info(&client->dev,
+                         "power monitor INA219 (Rshunt = %li uOhm)\n", shunt);
+                data->registers = INA219_REGISTERS;
+                break;
+        case ina226:
+                /* device configuration */
+                ina2xx_write_word(client, INA2XX_CONFIG, INA226_CONFIG_DEFAULT);
+
+                /* set current LSB to 1mA, shunt is in uOhms */
+                /* (equation 1 in datasheet)*/
+                ina2xx_write_word(client, INA2XX_CALIBRATION, 5120000 / shunt);
+                dev_info(&client->dev,
+                         "power monitor INA226 (Rshunt = %li uOhm)\n", shunt);
+                data->registers = INA226_REGISTERS;
+                break;
+        default:
+                /* unknown device id */
+                return -ENODEV;
+        }
+
+        i2c_set_clientdata(client, data);
+        mutex_init(&data->update_lock);
+
+        ret = sysfs_create_group(&client->dev.kobj, &ina2xx_group);
+        if (ret)
+                return ret;
+
+        data->hwmon_dev = hwmon_device_register(&client->dev);
+        if (IS_ERR(data->hwmon_dev)) {
+                ret = PTR_ERR(data->hwmon_dev);
+                goto out_err_hwmon;
+        }
+
+        return 0;
+
+out_err_hwmon:
+        sysfs_remove_group(&client->dev.kobj, &ina2xx_group);
+        return ret;
+}
+
+static int ina2xx_remove(struct i2c_client *client)
+{
+        struct ina2xx_data *data = i2c_get_clientdata(client);
+
+        hwmon_device_unregister(data->hwmon_dev);
+        sysfs_remove_group(&client->dev.kobj, &ina2xx_group);
+
+        return 0;
+}
+
+static const struct i2c_device_id ina2xx_id[] = {
+        { "ina219", ina219 },
+        { "ina226", ina226 },
+        { }
+};
+MODULE_DEVICE_TABLE(i2c, ina2xx_id);
+
+static struct i2c_driver ina2xx_driver = {
+        .driver = {
+                .name   = "ina2xx",
+        },
+        .probe          = ina2xx_probe,
+        .remove         = ina2xx_remove,
+        .id_table       = ina2xx_id,
+};
+
+static int __init ina2xx_init(void)
+{
+        return i2c_add_driver(&ina2xx_driver);
+}
+
+static void __exit ina2xx_exit(void)
+{
+        i2c_del_driver(&ina2xx_driver);
+}
+
+MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
+MODULE_DESCRIPTION("ina2xx driver");
+MODULE_LICENSE("GPL");
+
+module_init(ina2xx_init);
+module_exit(ina2xx_exit);