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1// SPDX-License-Identifier: GPL-2.0-or-later2/*3 * Driver for Linear Technology LTC4222 Dual 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/bitops.h>13#include <linux/i2c.h>14#include <linux/hwmon.h>15#include <linux/hwmon-sysfs.h>16#include <linux/jiffies.h>17#include <linux/regmap.h>18 19/* chip registers */20 21#define LTC4222_CONTROL1 0xd022#define LTC4222_ALERT1 0xd123#define LTC4222_STATUS1 0xd224#define LTC4222_FAULT1 0xd325#define LTC4222_CONTROL2 0xd426#define LTC4222_ALERT2 0xd527#define LTC4222_STATUS2 0xd628#define LTC4222_FAULT2 0xd729#define LTC4222_SOURCE1 0xd830#define LTC4222_SOURCE2 0xda31#define LTC4222_ADIN1 0xdc32#define LTC4222_ADIN2 0xde33#define LTC4222_SENSE1 0xe034#define LTC4222_SENSE2 0xe235#define LTC4222_ADC_CONTROL 0xe436 37/*38 * Fault register bits39 */40#define FAULT_OV BIT(0)41#define FAULT_UV BIT(1)42#define FAULT_OC BIT(2)43#define FAULT_POWER_BAD BIT(3)44#define FAULT_FET_BAD BIT(5)45 46/* Return the voltage from the given register in mV or mA */47static int ltc4222_get_value(struct device *dev, u8 reg)48{49 struct regmap *regmap = dev_get_drvdata(dev);50 unsigned int val;51 u8 buf[2];52 int ret;53 54 ret = regmap_bulk_read(regmap, reg, buf, 2);55 if (ret < 0)56 return ret;57 58 val = ((buf[0] << 8) + buf[1]) >> 6;59 60 switch (reg) {61 case LTC4222_ADIN1:62 case LTC4222_ADIN2:63 /* 1.25 mV resolution. Convert to mV. */64 val = DIV_ROUND_CLOSEST(val * 5, 4);65 break;66 case LTC4222_SOURCE1:67 case LTC4222_SOURCE2:68 /* 31.25 mV resolution. Convert to mV. */69 val = DIV_ROUND_CLOSEST(val * 125, 4);70 break;71 case LTC4222_SENSE1:72 case LTC4222_SENSE2:73 /*74 * 62.5 uV resolution. Convert to current as measured with75 * an 1 mOhm sense resistor, in mA. If a different sense76 * resistor is installed, calculate the actual current by77 * dividing the reported current by the sense resistor value78 * in mOhm.79 */80 val = DIV_ROUND_CLOSEST(val * 125, 2);81 break;82 default:83 return -EINVAL;84 }85 return val;86}87 88static ssize_t ltc4222_value_show(struct device *dev,89 struct device_attribute *da, char *buf)90{91 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);92 int value;93 94 value = ltc4222_get_value(dev, attr->index);95 if (value < 0)96 return value;97 return sysfs_emit(buf, "%d\n", value);98}99 100static ssize_t ltc4222_bool_show(struct device *dev,101 struct device_attribute *da, char *buf)102{103 struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da);104 struct regmap *regmap = dev_get_drvdata(dev);105 unsigned int fault;106 int ret;107 108 ret = regmap_read(regmap, attr->nr, &fault);109 if (ret < 0)110 return ret;111 fault &= attr->index;112 if (fault) /* Clear reported faults in chip register */113 regmap_update_bits(regmap, attr->nr, attr->index, 0);114 115 return sysfs_emit(buf, "%d\n", !!fault);116}117 118/* Voltages */119static SENSOR_DEVICE_ATTR_RO(in1_input, ltc4222_value, LTC4222_SOURCE1);120static SENSOR_DEVICE_ATTR_RO(in2_input, ltc4222_value, LTC4222_ADIN1);121static SENSOR_DEVICE_ATTR_RO(in3_input, ltc4222_value, LTC4222_SOURCE2);122static SENSOR_DEVICE_ATTR_RO(in4_input, ltc4222_value, LTC4222_ADIN2);123 124/*125 * Voltage alarms126 * UV/OV faults are associated with the input voltage, and power bad and fet127 * faults are associated with the output voltage.128 */129static SENSOR_DEVICE_ATTR_2_RO(in1_min_alarm, ltc4222_bool, LTC4222_FAULT1,130 FAULT_UV);131static SENSOR_DEVICE_ATTR_2_RO(in1_max_alarm, ltc4222_bool, LTC4222_FAULT1,132 FAULT_OV);133static SENSOR_DEVICE_ATTR_2_RO(in2_alarm, ltc4222_bool, LTC4222_FAULT1,134 FAULT_POWER_BAD | FAULT_FET_BAD);135 136static SENSOR_DEVICE_ATTR_2_RO(in3_min_alarm, ltc4222_bool, LTC4222_FAULT2,137 FAULT_UV);138static SENSOR_DEVICE_ATTR_2_RO(in3_max_alarm, ltc4222_bool, LTC4222_FAULT2,139 FAULT_OV);140static SENSOR_DEVICE_ATTR_2_RO(in4_alarm, ltc4222_bool, LTC4222_FAULT2,141 FAULT_POWER_BAD | FAULT_FET_BAD);142 143/* Current (via sense resistor) */144static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc4222_value, LTC4222_SENSE1);145static SENSOR_DEVICE_ATTR_RO(curr2_input, ltc4222_value, LTC4222_SENSE2);146 147/* Overcurrent alarm */148static SENSOR_DEVICE_ATTR_2_RO(curr1_max_alarm, ltc4222_bool, LTC4222_FAULT1,149 FAULT_OC);150static SENSOR_DEVICE_ATTR_2_RO(curr2_max_alarm, ltc4222_bool, LTC4222_FAULT2,151 FAULT_OC);152 153static struct attribute *ltc4222_attrs[] = {154 &sensor_dev_attr_in1_input.dev_attr.attr,155 &sensor_dev_attr_in1_min_alarm.dev_attr.attr,156 &sensor_dev_attr_in1_max_alarm.dev_attr.attr,157 &sensor_dev_attr_in2_input.dev_attr.attr,158 &sensor_dev_attr_in2_alarm.dev_attr.attr,159 &sensor_dev_attr_in3_input.dev_attr.attr,160 &sensor_dev_attr_in3_min_alarm.dev_attr.attr,161 &sensor_dev_attr_in3_max_alarm.dev_attr.attr,162 &sensor_dev_attr_in4_input.dev_attr.attr,163 &sensor_dev_attr_in4_alarm.dev_attr.attr,164 165 &sensor_dev_attr_curr1_input.dev_attr.attr,166 &sensor_dev_attr_curr1_max_alarm.dev_attr.attr,167 &sensor_dev_attr_curr2_input.dev_attr.attr,168 &sensor_dev_attr_curr2_max_alarm.dev_attr.attr,169 170 NULL,171};172ATTRIBUTE_GROUPS(ltc4222);173 174static const struct regmap_config ltc4222_regmap_config = {175 .reg_bits = 8,176 .val_bits = 8,177 .max_register = LTC4222_ADC_CONTROL,178};179 180static int ltc4222_probe(struct i2c_client *client)181{182 struct device *dev = &client->dev;183 struct device *hwmon_dev;184 struct regmap *regmap;185 186 regmap = devm_regmap_init_i2c(client, <c4222_regmap_config);187 if (IS_ERR(regmap)) {188 dev_err(dev, "failed to allocate register map\n");189 return PTR_ERR(regmap);190 }191 192 /* Clear faults */193 regmap_write(regmap, LTC4222_FAULT1, 0x00);194 regmap_write(regmap, LTC4222_FAULT2, 0x00);195 196 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,197 regmap,198 ltc4222_groups);199 return PTR_ERR_OR_ZERO(hwmon_dev);200}201 202static const struct i2c_device_id ltc4222_id[] = {203 {"ltc4222"},204 { }205};206 207MODULE_DEVICE_TABLE(i2c, ltc4222_id);208 209static struct i2c_driver ltc4222_driver = {210 .driver = {211 .name = "ltc4222",212 },213 .probe = ltc4222_probe,214 .id_table = ltc4222_id,215};216 217module_i2c_driver(ltc4222_driver);218 219MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");220MODULE_DESCRIPTION("LTC4222 driver");221MODULE_LICENSE("GPL");222