/*
* Driver for Linear Technology LTC4222 Dual Hot Swap controller
*
* Copyright (c) 2014 Guenter Roeck
*
* 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; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/slab.h>
#include <linux/bitops.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/jiffies.h>
#include <linux/regmap.h>
/* chip registers */
#define LTC4222_CONTROL1 0xd0
#define LTC4222_ALERT1 0xd1
#define LTC4222_STATUS1 0xd2
#define LTC4222_FAULT1 0xd3
#define LTC4222_CONTROL2 0xd4
#define LTC4222_ALERT2 0xd5
#define LTC4222_STATUS2 0xd6
#define LTC4222_FAULT2 0xd7
#define LTC4222_SOURCE1 0xd8
#define LTC4222_SOURCE2 0xda
#define LTC4222_ADIN1 0xdc
#define LTC4222_ADIN2 0xde
#define LTC4222_SENSE1 0xe0
#define LTC4222_SENSE2 0xe2
#define LTC4222_ADC_CONTROL 0xe4
/*
* Fault register bits
*/
#define FAULT_OV BIT(0)
#define FAULT_UV BIT(1)
#define FAULT_OC BIT(2)
#define FAULT_POWER_BAD BIT(3)
#define FAULT_FET_BAD BIT(5)
/* Return the voltage from the given register in mV or mA */
static int ltc4222_get_value(struct device *dev, u8 reg)
{
struct regmap *regmap = dev_get_drvdata(dev);
unsigned int val;
u8 buf[2];
int ret;
ret = regmap_bulk_read(regmap, reg, buf, 2);
if (ret < 0)
return ret;
val = ((buf[0] << 8) + buf[1]) >> 6;
switch (reg) {
case LTC4222_ADIN1:
case LTC4222_ADIN2:
/* 1.25 mV resolution. Convert to mV. */
val = DIV_ROUND_CLOSEST(val * 5, 4);
break;
case LTC4222_SOURCE1:
case LTC4222_SOURCE2:
/* 31.25 mV resolution. Convert to mV. */
val = DIV_ROUND_CLOSEST(val * 125, 4);
break;
case LTC4222_SENSE1:
case LTC4222_SENSE2:
/*
* 62.5 uV resolution. Convert to current as measured with
* an 1 mOhm sense resistor, in mA. If a different sense
* resistor is installed, calculate the actual current by
* dividing the reported current by the sense resistor value
* in mOhm.
*/
val = DIV_ROUND_CLOSEST(val * 125, 2);
break;
default:
return -EINVAL;
}
return val;
}
static ssize_t ltc4222_show_value(struct device *dev,
struct device_attribute *da, char *buf)
{
struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
int value;
value = ltc4222_get_value(dev, attr->index);
if (value < 0)
return value;
return snprintf(buf, PAGE_SIZE, "%d\n", value);
}
static ssize_t ltc4222_show_bool(struct device *dev,
struct device_attribute *da, char *buf)
{
struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da);
struct regmap *regmap = dev_get_drvdata(dev);
unsigned int fault;
int ret;
ret = regmap_read(regmap, attr->nr, &fault);
if (ret < 0)
return ret;
fault &= attr->index;
if (fault) /* Clear reported faults in chip register */
regmap_update_bits(regmap, attr->nr, attr->index, 0);
return snprintf(buf, PAGE_SIZE, "%d\n", !!fault);
}
/* Voltages */
static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4222_show_value, NULL,
LTC4222_SOURCE1);
static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4222_show_value, NULL,
LTC4222_ADIN1);
static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ltc4222_show_value, NULL,
LTC4222_SOURCE2);
static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ltc4222_show_value, NULL,
LTC4222_ADIN2);
/*
* Voltage alarms
* UV/OV faults are associated with the input voltage, and power bad and fet
* faults are associated with the output voltage.
*/
static SENSOR_DEVICE_ATTR_2(in1_min_alarm, S_IRUGO, ltc4222_show_bool, NULL,
LTC4222_FAULT1, FAULT_UV);
static SENSOR_DEVICE_ATTR_2(in1_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
LTC4222_FAULT1, FAULT_OV);
static SENSOR_DEVICE_ATTR_2(in2_alarm, S_IRUGO, ltc4222_show_bool, NULL,
LTC4222_FAULT1, FAULT_POWER_BAD | FAULT_FET_BAD);
static SENSOR_DEVICE_ATTR_2(in3_min_alarm, S_IRUGO, ltc4222_show_bool, NULL,
LTC4222_FAULT2, FAULT_UV);
static SENSOR_DEVICE_ATTR_2(in3_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
LTC4222_FAULT2, FAULT_OV);
static SENSOR_DEVICE_ATTR_2(in4_alarm, S_IRUGO, ltc4222_show_bool, NULL,
LTC4222_FAULT2, FAULT_POWER_BAD | FAULT_FET_BAD);
/* Current (via sense resistor) */
static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4222_show_value, NULL,
LTC4222_SENSE1);
static SENSOR_DEVICE_ATTR(curr2_input, S_IRUGO, ltc4222_show_value, NULL,
LTC4222_SENSE2);
/* Overcurrent alarm */
static SENSOR_DEVICE_ATTR_2(curr1_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
LTC4222_FAULT1, FAULT_OC);
static SENSOR_DEVICE_ATTR_2(curr2_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
LTC4222_FAULT2, FAULT_OC);
static struct attribute *ltc4222_attrs[] = {
&sensor_dev_attr_in1_input.dev_attr.attr,
&sensor_dev_attr_in1_min_alarm.dev_attr.attr,
&sensor_dev_attr_in1_max_alarm.dev_attr.attr,
&sensor_dev_attr_in2_input.dev_attr.attr,
&sensor_dev_attr_in2_alarm.dev_attr.attr,
&sensor_dev_attr_in3_input.dev_attr.attr,
&sensor_dev_attr_in3_min_alarm.dev_attr.attr,
&sensor_dev_attr_in3_max_alarm.dev_attr.attr,
&sensor_dev_attr_in4_input.dev_attr.attr,
&sensor_dev_attr_in4_alarm.dev_attr.attr,
&sensor_dev_attr_curr1_input.dev_attr.attr,
&sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
&sensor_dev_attr_curr2_input.dev_attr.attr,
&sensor_dev_attr_curr2_max_alarm.dev_attr.attr,
NULL,
};
ATTRIBUTE_GROUPS(ltc4222);
static const struct regmap_config ltc4222_regmap_config = {
.reg_bits = 8,
.val_bits = 8,
.max_register = LTC4222_ADC_CONTROL,
};
static int ltc4222_probe(struct i2c_client *client,
const struct i2c_device_id *id)
{
struct device *dev = &client->dev;
struct device *hwmon_dev;
struct regmap *regmap;
regmap = devm_regmap_init_i2c(client, <c4222_regmap_config);
if (IS_ERR(regmap)) {
dev_err(dev, "failed to allocate register map\n");
return PTR_ERR(regmap);
}
/* Clear faults */
regmap_write(regmap, LTC4222_FAULT1, 0x00);
regmap_write(regmap, LTC4222_FAULT2, 0x00);
hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
regmap,
ltc4222_groups);
return PTR_ERR_OR_ZERO(hwmon_dev);
}
static const struct i2c_device_id ltc4222_id[] = {
{"ltc4222", 0},
{ }
};
MODULE_DEVICE_TABLE(i2c, ltc4222_id);
static struct i2c_driver ltc4222_driver = {
.driver = {
.name = "ltc4222",
},
.probe = ltc4222_probe,
.id_table = ltc4222_id,
};
module_i2c_driver(ltc4222_driver);
MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
MODULE_DESCRIPTION("LTC4222 driver");
MODULE_LICENSE("GPL");