#include <linux/hwmon-sysfs.h>
#include <linux/jiffies.h>
#include <linux/of.h>
+#include <linux/delay.h>
#include <linux/platform_data/ina2xx.h>
#define INA226_ALERT_LIMIT 0x07
#define INA226_DIE_ID 0xFF
-
/* register count */
#define INA219_REGISTERS 6
#define INA226_REGISTERS 8
/* worst case is 68.10 ms (~14.6Hz, ina219) */
#define INA2XX_CONVERSION_RATE 15
+#define INA2XX_MAX_DELAY 69 /* worst case delay in ms */
+
+#define INA2XX_RSHUNT_DEFAULT 10000
+
+/* bit mask for reading the averaging setting in the configuration register */
+#define INA226_AVG_RD_MASK 0x0E00
+
+#define INA226_READ_AVG(reg) (((reg) & INA226_AVG_RD_MASK) >> 9)
+#define INA226_SHIFT_AVG(val) ((val) << 9)
+
+/* common attrs, ina226 attrs and NULL */
+#define INA2XX_MAX_ATTRIBUTE_GROUPS 3
+
+/*
+ * Both bus voltage and shunt voltage conversion times for ina226 are set
+ * to 0b0100 on POR, which translates to 2200 microseconds in total.
+ */
+#define INA226_TOTAL_CONV_TIME_DEFAULT 2200
enum ina2xx_ids { ina219, ina226 };
struct i2c_client *client;
const struct ina2xx_config *config;
+ long rshunt;
+ u16 curr_config;
+
struct mutex update_lock;
bool valid;
unsigned long last_updated;
+ int update_interval; /* in jiffies */
int kind;
+ const struct attribute_group *groups[INA2XX_MAX_ATTRIBUTE_GROUPS];
u16 regs[INA2XX_MAX_REGISTERS];
};
},
};
-static struct ina2xx_data *ina2xx_update_device(struct device *dev)
+/*
+ * Available averaging rates for ina226. The indices correspond with
+ * the bit values expected by the chip (according to the ina226 datasheet,
+ * table 3 AVG bit settings, found at
+ * http://www.ti.com/lit/ds/symlink/ina226.pdf.
+ */
+static const int ina226_avg_tab[] = { 1, 4, 16, 64, 128, 256, 512, 1024 };
+
+static int ina226_avg_bits(int avg)
+{
+ int i;
+
+ /* Get the closest average from the tab. */
+ for (i = 0; i < ARRAY_SIZE(ina226_avg_tab) - 1; i++) {
+ if (avg <= (ina226_avg_tab[i] + ina226_avg_tab[i + 1]) / 2)
+ break;
+ }
+
+ return i; /* Return 0b0111 for values greater than 1024. */
+}
+
+static int ina226_reg_to_interval(u16 config)
+{
+ int avg = ina226_avg_tab[INA226_READ_AVG(config)];
+
+ /*
+ * Multiply the total conversion time by the number of averages.
+ * Return the result in milliseconds.
+ */
+ return DIV_ROUND_CLOSEST(avg * INA226_TOTAL_CONV_TIME_DEFAULT, 1000);
+}
+
+static u16 ina226_interval_to_reg(int interval, u16 config)
+{
+ int avg, avg_bits;
+
+ avg = DIV_ROUND_CLOSEST(interval * 1000,
+ INA226_TOTAL_CONV_TIME_DEFAULT);
+ avg_bits = ina226_avg_bits(avg);
+
+ return (config & ~INA226_AVG_RD_MASK) | INA226_SHIFT_AVG(avg_bits);
+}
+
+static void ina226_set_update_interval(struct ina2xx_data *data)
+{
+ int ms;
+
+ ms = ina226_reg_to_interval(data->curr_config);
+ data->update_interval = msecs_to_jiffies(ms);
+}
+
+static int ina2xx_calibrate(struct ina2xx_data *data)
+{
+ return i2c_smbus_write_word_swapped(data->client, INA2XX_CALIBRATION,
+ data->config->calibration_factor / data->rshunt);
+}
+
+/*
+ * Initialize the configuration and calibration registers.
+ */
+static int ina2xx_init(struct ina2xx_data *data)
{
- struct ina2xx_data *data = dev_get_drvdata(dev);
struct i2c_client *client = data->client;
- struct ina2xx_data *ret = data;
+ int ret;
- mutex_lock(&data->update_lock);
+ /* device configuration */
+ ret = i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,
+ data->curr_config);
+ if (ret < 0)
+ return ret;
- if (time_after(jiffies, data->last_updated +
- HZ / INA2XX_CONVERSION_RATE) || !data->valid) {
+ /*
+ * Set current LSB to 1mA, shunt is in uOhms
+ * (equation 13 in datasheet).
+ */
+ return ina2xx_calibrate(data);
+}
- int i;
+static int ina2xx_do_update(struct device *dev)
+{
+ struct ina2xx_data *data = dev_get_drvdata(dev);
+ struct i2c_client *client = data->client;
+ int i, rv, retry;
- dev_dbg(&client->dev, "Starting ina2xx update\n");
+ dev_dbg(&client->dev, "Starting ina2xx update\n");
+ for (retry = 5; retry; retry--) {
/* Read all registers */
for (i = 0; i < data->config->registers; i++) {
- int rv = i2c_smbus_read_word_swapped(client, i);
- if (rv < 0) {
- ret = ERR_PTR(rv);
- goto abort;
- }
+ rv = i2c_smbus_read_word_swapped(client, i);
+ if (rv < 0)
+ return rv;
data->regs[i] = rv;
}
+
+ /*
+ * If the current value in the calibration register is 0, the
+ * power and current registers will also remain at 0. In case
+ * the chip has been reset let's check the calibration
+ * register and reinitialize if needed.
+ */
+ if (data->regs[INA2XX_CALIBRATION] == 0) {
+ dev_warn(dev, "chip not calibrated, reinitializing\n");
+
+ rv = ina2xx_init(data);
+ if (rv < 0)
+ return rv;
+
+ /*
+ * Let's make sure the power and current registers
+ * have been updated before trying again.
+ */
+ msleep(INA2XX_MAX_DELAY);
+ continue;
+ }
+
data->last_updated = jiffies;
data->valid = 1;
+
+ return 0;
}
-abort:
+
+ /*
+ * If we're here then although all write operations succeeded, the
+ * chip still returns 0 in the calibration register. Nothing more we
+ * can do here.
+ */
+ dev_err(dev, "unable to reinitialize the chip\n");
+ return -ENODEV;
+}
+
+static struct ina2xx_data *ina2xx_update_device(struct device *dev)
+{
+ struct ina2xx_data *data = dev_get_drvdata(dev);
+ struct ina2xx_data *ret = data;
+ unsigned long after;
+ int rv;
+
+ mutex_lock(&data->update_lock);
+
+ after = data->last_updated + data->update_interval;
+ if (time_after(jiffies, after) || !data->valid) {
+ rv = ina2xx_do_update(dev);
+ if (rv < 0)
+ ret = ERR_PTR(rv);
+ }
+
mutex_unlock(&data->update_lock);
return ret;
}
/* signed register, LSB=1mA (selected), in mA */
val = (s16)data->regs[reg];
break;
+ case INA2XX_CALIBRATION:
+ val = data->config->calibration_factor / data->regs[reg];
+ break;
default:
/* programmer goofed */
WARN_ON_ONCE(1);
ina2xx_get_value(data, attr->index));
}
+static ssize_t ina2xx_set_shunt(struct device *dev,
+ struct device_attribute *da,
+ const char *buf, size_t count)
+{
+ struct ina2xx_data *data = ina2xx_update_device(dev);
+ unsigned long val;
+ int status;
+
+ if (IS_ERR(data))
+ return PTR_ERR(data);
+
+ status = kstrtoul(buf, 10, &val);
+ if (status < 0)
+ return status;
+
+ if (val == 0 ||
+ /* Values greater than the calibration factor make no sense. */
+ val > data->config->calibration_factor)
+ return -EINVAL;
+
+ mutex_lock(&data->update_lock);
+ data->rshunt = val;
+ status = ina2xx_calibrate(data);
+ mutex_unlock(&data->update_lock);
+ if (status < 0)
+ return status;
+
+ return count;
+}
+
+static ssize_t ina226_set_interval(struct device *dev,
+ struct device_attribute *da,
+ const char *buf, size_t count)
+{
+ struct ina2xx_data *data = dev_get_drvdata(dev);
+ unsigned long val;
+ int status;
+
+ if (IS_ERR(data))
+ return PTR_ERR(data);
+
+ status = kstrtoul(buf, 10, &val);
+ if (status < 0)
+ return status;
+
+ if (val > INT_MAX || val == 0)
+ return -EINVAL;
+
+ mutex_lock(&data->update_lock);
+ data->curr_config = ina226_interval_to_reg(val,
+ data->regs[INA2XX_CONFIG]);
+ status = i2c_smbus_write_word_swapped(data->client,
+ INA2XX_CONFIG,
+ data->curr_config);
+
+ ina226_set_update_interval(data);
+ /* Make sure the next access re-reads all registers. */
+ data->valid = 0;
+ mutex_unlock(&data->update_lock);
+ if (status < 0)
+ return status;
+
+ return count;
+}
+
+static ssize_t ina226_show_interval(struct device *dev,
+ struct device_attribute *da, char *buf)
+{
+ struct ina2xx_data *data = ina2xx_update_device(dev);
+
+ if (IS_ERR(data))
+ return PTR_ERR(data);
+
+ /*
+ * We don't use data->update_interval here as we want to display
+ * the actual interval used by the chip and jiffies_to_msecs()
+ * doesn't seem to be accurate enough.
+ */
+ return snprintf(buf, PAGE_SIZE, "%d\n",
+ ina226_reg_to_interval(data->regs[INA2XX_CONFIG]));
+}
+
/* shunt voltage */
static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina2xx_show_value, NULL,
INA2XX_SHUNT_VOLTAGE);
static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL,
INA2XX_POWER);
+/* shunt resistance */
+static SENSOR_DEVICE_ATTR(shunt_resistor, S_IRUGO | S_IWUSR,
+ ina2xx_show_value, ina2xx_set_shunt,
+ INA2XX_CALIBRATION);
+
+/* update interval (ina226 only) */
+static SENSOR_DEVICE_ATTR(update_interval, S_IRUGO | S_IWUSR,
+ ina226_show_interval, ina226_set_interval, 0);
+
/* pointers to created device attributes */
static struct attribute *ina2xx_attrs[] = {
&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,
+ &sensor_dev_attr_shunt_resistor.dev_attr.attr,
NULL,
};
-ATTRIBUTE_GROUPS(ina2xx);
+
+static const struct attribute_group ina2xx_group = {
+ .attrs = ina2xx_attrs,
+};
+
+static struct attribute *ina226_attrs[] = {
+ &sensor_dev_attr_update_interval.dev_attr.attr,
+ NULL,
+};
+
+static const struct attribute_group ina226_group = {
+ .attrs = ina226_attrs,
+};
static int ina2xx_probe(struct i2c_client *client,
const struct i2c_device_id *id)
struct device *dev = &client->dev;
struct ina2xx_data *data;
struct device *hwmon_dev;
- long shunt = 10000; /* default shunt value 10mOhms */
u32 val;
- int ret;
+ int ret, group = 0;
if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
return -ENODEV;
if (dev_get_platdata(dev)) {
pdata = dev_get_platdata(dev);
- shunt = pdata->shunt_uohms;
+ data->rshunt = pdata->shunt_uohms;
} else if (!of_property_read_u32(dev->of_node,
"shunt-resistor", &val)) {
- shunt = val;
+ data->rshunt = val;
+ } else {
+ data->rshunt = INA2XX_RSHUNT_DEFAULT;
}
- if (shunt <= 0)
- return -ENODEV;
-
/* set the device type */
data->kind = id->driver_data;
data->config = &ina2xx_config[data->kind];
-
- /* device configuration */
- ret = i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,
- data->config->config_default);
- if (ret < 0) {
- dev_err(dev,
- "error writing to the config register: %d", ret);
- return -ENODEV;
- }
+ data->curr_config = data->config->config_default;
+ data->client = client;
/*
- * Set current LSB to 1mA, shunt is in uOhms
- * (equation 13 in datasheet).
+ * Ina226 has a variable update_interval. For ina219 we
+ * use a constant value.
*/
- ret = i2c_smbus_write_word_swapped(client, INA2XX_CALIBRATION,
- data->config->calibration_factor / shunt);
+ if (data->kind == ina226)
+ ina226_set_update_interval(data);
+ else
+ data->update_interval = HZ / INA2XX_CONVERSION_RATE;
+
+ if (data->rshunt <= 0 ||
+ data->rshunt > data->config->calibration_factor)
+ return -ENODEV;
+
+ ret = ina2xx_init(data);
if (ret < 0) {
- dev_err(dev,
- "error writing to the calibration register: %d", ret);
+ dev_err(dev, "error configuring the device: %d\n", ret);
return -ENODEV;
}
- data->client = client;
mutex_init(&data->update_lock);
+ data->groups[group++] = &ina2xx_group;
+ if (data->kind == ina226)
+ data->groups[group++] = &ina226_group;
+
hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
- data, ina2xx_groups);
+ data, data->groups);
if (IS_ERR(hwmon_dev))
return PTR_ERR(hwmon_dev);
dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n",
- id->name, shunt);
+ id->name, data->rshunt);
return 0;
}
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