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184 lines
4.6 KiB
184 lines
4.6 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
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/* |
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* Driver for Linear Technology LTC4260 I2C Positive Voltage Hot Swap Controller |
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* |
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* Copyright (c) 2014 Guenter Roeck |
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*/ |
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#include <linux/kernel.h> |
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#include <linux/module.h> |
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#include <linux/err.h> |
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#include <linux/slab.h> |
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#include <linux/i2c.h> |
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#include <linux/hwmon.h> |
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#include <linux/hwmon-sysfs.h> |
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#include <linux/jiffies.h> |
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#include <linux/regmap.h> |
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/* chip registers */ |
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#define LTC4260_CONTROL 0x00 |
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#define LTC4260_ALERT 0x01 |
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#define LTC4260_STATUS 0x02 |
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#define LTC4260_FAULT 0x03 |
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#define LTC4260_SENSE 0x04 |
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#define LTC4260_SOURCE 0x05 |
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#define LTC4260_ADIN 0x06 |
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/* |
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* Fault register bits |
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*/ |
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#define FAULT_OV (1 << 0) |
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#define FAULT_UV (1 << 1) |
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#define FAULT_OC (1 << 2) |
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#define FAULT_POWER_BAD (1 << 3) |
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#define FAULT_FET_SHORT (1 << 5) |
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/* Return the voltage from the given register in mV or mA */ |
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static int ltc4260_get_value(struct device *dev, u8 reg) |
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{ |
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struct regmap *regmap = dev_get_drvdata(dev); |
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unsigned int val; |
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int ret; |
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ret = regmap_read(regmap, reg, &val); |
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if (ret < 0) |
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return ret; |
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switch (reg) { |
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case LTC4260_ADIN: |
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/* 10 mV resolution. Convert to mV. */ |
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val = val * 10; |
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break; |
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case LTC4260_SOURCE: |
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/* 400 mV resolution. Convert to mV. */ |
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val = val * 400; |
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break; |
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case LTC4260_SENSE: |
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/* |
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* 300 uV resolution. Convert to current as measured with |
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* an 1 mOhm sense resistor, in mA. If a different sense |
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* resistor is installed, calculate the actual current by |
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* dividing the reported current by the sense resistor value |
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* in mOhm. |
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*/ |
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val = val * 300; |
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break; |
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default: |
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return -EINVAL; |
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} |
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return val; |
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} |
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static ssize_t ltc4260_value_show(struct device *dev, |
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struct device_attribute *da, char *buf) |
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{ |
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struct sensor_device_attribute *attr = to_sensor_dev_attr(da); |
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int value; |
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value = ltc4260_get_value(dev, attr->index); |
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if (value < 0) |
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return value; |
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return snprintf(buf, PAGE_SIZE, "%d\n", value); |
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} |
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static ssize_t ltc4260_bool_show(struct device *dev, |
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struct device_attribute *da, char *buf) |
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{ |
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struct sensor_device_attribute *attr = to_sensor_dev_attr(da); |
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struct regmap *regmap = dev_get_drvdata(dev); |
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unsigned int fault; |
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int ret; |
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ret = regmap_read(regmap, LTC4260_FAULT, &fault); |
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if (ret < 0) |
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return ret; |
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fault &= attr->index; |
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if (fault) /* Clear reported faults in chip register */ |
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regmap_update_bits(regmap, LTC4260_FAULT, attr->index, 0); |
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return snprintf(buf, PAGE_SIZE, "%d\n", !!fault); |
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} |
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/* Voltages */ |
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static SENSOR_DEVICE_ATTR_RO(in1_input, ltc4260_value, LTC4260_SOURCE); |
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static SENSOR_DEVICE_ATTR_RO(in2_input, ltc4260_value, LTC4260_ADIN); |
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/* |
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* Voltage alarms |
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* UV/OV faults are associated with the input voltage, and the POWER BAD and |
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* FET SHORT faults are associated with the output voltage. |
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*/ |
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static SENSOR_DEVICE_ATTR_RO(in1_min_alarm, ltc4260_bool, FAULT_UV); |
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static SENSOR_DEVICE_ATTR_RO(in1_max_alarm, ltc4260_bool, FAULT_OV); |
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static SENSOR_DEVICE_ATTR_RO(in2_alarm, ltc4260_bool, |
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FAULT_POWER_BAD | FAULT_FET_SHORT); |
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/* Current (via sense resistor) */ |
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static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc4260_value, LTC4260_SENSE); |
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/* Overcurrent alarm */ |
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static SENSOR_DEVICE_ATTR_RO(curr1_max_alarm, ltc4260_bool, FAULT_OC); |
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static struct attribute *ltc4260_attrs[] = { |
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&sensor_dev_attr_in1_input.dev_attr.attr, |
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&sensor_dev_attr_in1_min_alarm.dev_attr.attr, |
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&sensor_dev_attr_in1_max_alarm.dev_attr.attr, |
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&sensor_dev_attr_in2_input.dev_attr.attr, |
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&sensor_dev_attr_in2_alarm.dev_attr.attr, |
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&sensor_dev_attr_curr1_input.dev_attr.attr, |
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&sensor_dev_attr_curr1_max_alarm.dev_attr.attr, |
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NULL, |
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}; |
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ATTRIBUTE_GROUPS(ltc4260); |
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static const struct regmap_config ltc4260_regmap_config = { |
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.reg_bits = 8, |
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.val_bits = 8, |
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.max_register = LTC4260_ADIN, |
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}; |
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static int ltc4260_probe(struct i2c_client *client) |
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{ |
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struct device *dev = &client->dev; |
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struct device *hwmon_dev; |
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struct regmap *regmap; |
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regmap = devm_regmap_init_i2c(client, <c4260_regmap_config); |
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if (IS_ERR(regmap)) { |
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dev_err(dev, "failed to allocate register map\n"); |
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return PTR_ERR(regmap); |
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} |
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/* Clear faults */ |
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regmap_write(regmap, LTC4260_FAULT, 0x00); |
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hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, |
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regmap, |
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ltc4260_groups); |
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return PTR_ERR_OR_ZERO(hwmon_dev); |
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} |
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static const struct i2c_device_id ltc4260_id[] = { |
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{"ltc4260", 0}, |
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{ } |
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}; |
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MODULE_DEVICE_TABLE(i2c, ltc4260_id); |
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static struct i2c_driver ltc4260_driver = { |
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.driver = { |
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.name = "ltc4260", |
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}, |
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.probe_new = ltc4260_probe, |
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.id_table = ltc4260_id, |
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}; |
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module_i2c_driver(ltc4260_driver); |
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MODULE_AUTHOR("Guenter Roeck <[email protected]>"); |
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MODULE_DESCRIPTION("LTC4260 driver"); |
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MODULE_LICENSE("GPL");
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