diff options
Diffstat (limited to 'drivers/hwmon/ltc4222.c')
| -rw-r--r-- | drivers/hwmon/ltc4222.c | 237 |
1 files changed, 237 insertions, 0 deletions
diff --git a/drivers/hwmon/ltc4222.c b/drivers/hwmon/ltc4222.c new file mode 100644 index 000000000000..07c25653659f --- /dev/null +++ b/drivers/hwmon/ltc4222.c @@ -0,0 +1,237 @@ +/* + * 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 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"); |