diff options
Diffstat (limited to 'drivers/hwmon/ltc4260.c')
| -rw-r--r-- | drivers/hwmon/ltc4260.c | 200 |
1 files changed, 200 insertions, 0 deletions
diff --git a/drivers/hwmon/ltc4260.c b/drivers/hwmon/ltc4260.c new file mode 100644 index 000000000..afb09574b --- /dev/null +++ b/drivers/hwmon/ltc4260.c @@ -0,0 +1,200 @@ +/* + * Driver for Linear Technology LTC4260 I2C Positive Voltage 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/i2c.h> +#include <linux/hwmon.h> +#include <linux/hwmon-sysfs.h> +#include <linux/jiffies.h> +#include <linux/regmap.h> + +/* chip registers */ +#define LTC4260_CONTROL 0x00 +#define LTC4260_ALERT 0x01 +#define LTC4260_STATUS 0x02 +#define LTC4260_FAULT 0x03 +#define LTC4260_SENSE 0x04 +#define LTC4260_SOURCE 0x05 +#define LTC4260_ADIN 0x06 + +/* + * Fault register bits + */ +#define FAULT_OV (1 << 0) +#define FAULT_UV (1 << 1) +#define FAULT_OC (1 << 2) +#define FAULT_POWER_BAD (1 << 3) +#define FAULT_FET_SHORT (1 << 5) + +/* Return the voltage from the given register in mV or mA */ +static int ltc4260_get_value(struct device *dev, u8 reg) +{ + struct regmap *regmap = dev_get_drvdata(dev); + unsigned int val; + int ret; + + ret = regmap_read(regmap, reg, &val); + if (ret < 0) + return ret; + + switch (reg) { + case LTC4260_ADIN: + /* 10 mV resolution. Convert to mV. */ + val = val * 10; + break; + case LTC4260_SOURCE: + /* 400 mV resolution. Convert to mV. */ + val = val * 400; + break; + case LTC4260_SENSE: + /* + * 300 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 = val * 300; + break; + default: + return -EINVAL; + } + + return val; +} + +static ssize_t ltc4260_show_value(struct device *dev, + struct device_attribute *da, char *buf) +{ + struct sensor_device_attribute *attr = to_sensor_dev_attr(da); + int value; + + value = ltc4260_get_value(dev, attr->index); + if (value < 0) + return value; + return snprintf(buf, PAGE_SIZE, "%d\n", value); +} + +static ssize_t ltc4260_show_bool(struct device *dev, + struct device_attribute *da, char *buf) +{ + struct sensor_device_attribute *attr = to_sensor_dev_attr(da); + struct regmap *regmap = dev_get_drvdata(dev); + unsigned int fault; + int ret; + + ret = regmap_read(regmap, LTC4260_FAULT, &fault); + if (ret < 0) + return ret; + + fault &= attr->index; + if (fault) /* Clear reported faults in chip register */ + regmap_update_bits(regmap, LTC4260_FAULT, attr->index, 0); + + return snprintf(buf, PAGE_SIZE, "%d\n", !!fault); +} + +/* Voltages */ +static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4260_show_value, NULL, + LTC4260_SOURCE); +static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4260_show_value, NULL, + LTC4260_ADIN); + +/* + * Voltage alarms + * UV/OV faults are associated with the input voltage, and the POWER BAD and + * FET SHORT faults are associated with the output voltage. + */ +static SENSOR_DEVICE_ATTR(in1_min_alarm, S_IRUGO, ltc4260_show_bool, NULL, + FAULT_UV); +static SENSOR_DEVICE_ATTR(in1_max_alarm, S_IRUGO, ltc4260_show_bool, NULL, + FAULT_OV); +static SENSOR_DEVICE_ATTR(in2_alarm, S_IRUGO, ltc4260_show_bool, NULL, + FAULT_POWER_BAD | FAULT_FET_SHORT); + +/* Current (via sense resistor) */ +static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4260_show_value, NULL, + LTC4260_SENSE); + +/* Overcurrent alarm */ +static SENSOR_DEVICE_ATTR(curr1_max_alarm, S_IRUGO, ltc4260_show_bool, NULL, + FAULT_OC); + +static struct attribute *ltc4260_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_curr1_input.dev_attr.attr, + &sensor_dev_attr_curr1_max_alarm.dev_attr.attr, + + NULL, +}; +ATTRIBUTE_GROUPS(ltc4260); + +static const struct regmap_config ltc4260_regmap_config = { + .reg_bits = 8, + .val_bits = 8, + .max_register = LTC4260_ADIN, +}; + +static int ltc4260_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, <c4260_regmap_config); + if (IS_ERR(regmap)) { + dev_err(dev, "failed to allocate register map\n"); + return PTR_ERR(regmap); + } + + /* Clear faults */ + regmap_write(regmap, LTC4260_FAULT, 0x00); + + hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, + regmap, + ltc4260_groups); + return PTR_ERR_OR_ZERO(hwmon_dev); +} + +static const struct i2c_device_id ltc4260_id[] = { + {"ltc4260", 0}, + { } +}; + +MODULE_DEVICE_TABLE(i2c, ltc4260_id); + +static struct i2c_driver ltc4260_driver = { + .driver = { + .name = "ltc4260", + }, + .probe = ltc4260_probe, + .id_table = ltc4260_id, +}; + +module_i2c_driver(ltc4260_driver); + +MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>"); +MODULE_DESCRIPTION("LTC4260 driver"); +MODULE_LICENSE("GPL"); |