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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Driver for Linear Technology LTC4260 I2C Positive Voltage Hot Swap Controller4 *5 * Copyright (c) 2014 Guenter Roeck6 */7 8#include <linux/kernel.h>9#include <linux/module.h>10#include <linux/err.h>11#include <linux/slab.h>12#include <linux/i2c.h>13#include <linux/hwmon.h>14#include <linux/hwmon-sysfs.h>15#include <linux/jiffies.h>16#include <linux/regmap.h>17 18/* chip registers */19#define LTC4260_CONTROL 0x0020#define LTC4260_ALERT 0x0121#define LTC4260_STATUS 0x0222#define LTC4260_FAULT 0x0323#define LTC4260_SENSE 0x0424#define LTC4260_SOURCE 0x0525#define LTC4260_ADIN 0x0626 27/*28 * Fault register bits29 */30#define FAULT_OV (1 << 0)31#define FAULT_UV (1 << 1)32#define FAULT_OC (1 << 2)33#define FAULT_POWER_BAD (1 << 3)34#define FAULT_FET_SHORT (1 << 5)35 36/* Return the voltage from the given register in mV or mA */37static int ltc4260_get_value(struct device *dev, u8 reg)38{39 struct regmap *regmap = dev_get_drvdata(dev);40 unsigned int val;41 int ret;42 43 ret = regmap_read(regmap, reg, &val);44 if (ret < 0)45 return ret;46 47 switch (reg) {48 case LTC4260_ADIN:49 /* 10 mV resolution. Convert to mV. */50 val = val * 10;51 break;52 case LTC4260_SOURCE:53 /* 400 mV resolution. Convert to mV. */54 val = val * 400;55 break;56 case LTC4260_SENSE:57 /*58 * 300 uV resolution. Convert to current as measured with59 * an 1 mOhm sense resistor, in mA. If a different sense60 * resistor is installed, calculate the actual current by61 * dividing the reported current by the sense resistor value62 * in mOhm.63 */64 val = val * 300;65 break;66 default:67 return -EINVAL;68 }69 70 return val;71}72 73static ssize_t ltc4260_value_show(struct device *dev,74 struct device_attribute *da, char *buf)75{76 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);77 int value;78 79 value = ltc4260_get_value(dev, attr->index);80 if (value < 0)81 return value;82 return sysfs_emit(buf, "%d\n", value);83}84 85static ssize_t ltc4260_bool_show(struct device *dev,86 struct device_attribute *da, char *buf)87{88 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);89 struct regmap *regmap = dev_get_drvdata(dev);90 unsigned int fault;91 int ret;92 93 ret = regmap_read(regmap, LTC4260_FAULT, &fault);94 if (ret < 0)95 return ret;96 97 fault &= attr->index;98 if (fault) /* Clear reported faults in chip register */99 regmap_update_bits(regmap, LTC4260_FAULT, attr->index, 0);100 101 return sysfs_emit(buf, "%d\n", !!fault);102}103 104/* Voltages */105static SENSOR_DEVICE_ATTR_RO(in1_input, ltc4260_value, LTC4260_SOURCE);106static SENSOR_DEVICE_ATTR_RO(in2_input, ltc4260_value, LTC4260_ADIN);107 108/*109 * Voltage alarms110 * UV/OV faults are associated with the input voltage, and the POWER BAD and111 * FET SHORT faults are associated with the output voltage.112 */113static SENSOR_DEVICE_ATTR_RO(in1_min_alarm, ltc4260_bool, FAULT_UV);114static SENSOR_DEVICE_ATTR_RO(in1_max_alarm, ltc4260_bool, FAULT_OV);115static SENSOR_DEVICE_ATTR_RO(in2_alarm, ltc4260_bool,116 FAULT_POWER_BAD | FAULT_FET_SHORT);117 118/* Current (via sense resistor) */119static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc4260_value, LTC4260_SENSE);120 121/* Overcurrent alarm */122static SENSOR_DEVICE_ATTR_RO(curr1_max_alarm, ltc4260_bool, FAULT_OC);123 124static struct attribute *ltc4260_attrs[] = {125 &sensor_dev_attr_in1_input.dev_attr.attr,126 &sensor_dev_attr_in1_min_alarm.dev_attr.attr,127 &sensor_dev_attr_in1_max_alarm.dev_attr.attr,128 &sensor_dev_attr_in2_input.dev_attr.attr,129 &sensor_dev_attr_in2_alarm.dev_attr.attr,130 131 &sensor_dev_attr_curr1_input.dev_attr.attr,132 &sensor_dev_attr_curr1_max_alarm.dev_attr.attr,133 134 NULL,135};136ATTRIBUTE_GROUPS(ltc4260);137 138static const struct regmap_config ltc4260_regmap_config = {139 .reg_bits = 8,140 .val_bits = 8,141 .max_register = LTC4260_ADIN,142};143 144static int ltc4260_probe(struct i2c_client *client)145{146 struct device *dev = &client->dev;147 struct device *hwmon_dev;148 struct regmap *regmap;149 150 regmap = devm_regmap_init_i2c(client, <c4260_regmap_config);151 if (IS_ERR(regmap)) {152 dev_err(dev, "failed to allocate register map\n");153 return PTR_ERR(regmap);154 }155 156 /* Clear faults */157 regmap_write(regmap, LTC4260_FAULT, 0x00);158 159 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,160 regmap,161 ltc4260_groups);162 return PTR_ERR_OR_ZERO(hwmon_dev);163}164 165static const struct i2c_device_id ltc4260_id[] = {166 {"ltc4260"},167 { }168};169 170MODULE_DEVICE_TABLE(i2c, ltc4260_id);171 172static struct i2c_driver ltc4260_driver = {173 .driver = {174 .name = "ltc4260",175 },176 .probe = ltc4260_probe,177 .id_table = ltc4260_id,178};179 180module_i2c_driver(ltc4260_driver);181 182MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");183MODULE_DESCRIPTION("LTC4260 driver");184MODULE_LICENSE("GPL");185