LXR linux/drivers/hwmon/ltc4222.c

   1/*
   2 * Driver for Linear Technology LTC4222 Dual Hot Swap controller
   3 *
   4 * Copyright (c) 2014 Guenter Roeck
   5 *
   6 * This program is free software; you can redistribute it and/or modify
   7 * it under the terms of the GNU General Public License as published by
   8 * the Free Software Foundation; either version 2 of the License, or
   9 * (at your option) any later version.
  10 *
  11 * This program is distributed in the hope that it will be useful,
  12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 * GNU General Public License for more details.
  15 */
  16
  17#include <linux/kernel.h>
  18#include <linux/module.h>
  19#include <linux/err.h>
  20#include <linux/slab.h>
  21#include <linux/bitops.h>
  22#include <linux/i2c.h>
  23#include <linux/hwmon.h>
  24#include <linux/hwmon-sysfs.h>
  25#include <linux/jiffies.h>
  26#include <linux/regmap.h>
  27
  28/* chip registers */
  29
  30#define LTC4222_CONTROL1        0xd0
  31#define LTC4222_ALERT1          0xd1
  32#define LTC4222_STATUS1         0xd2
  33#define LTC4222_FAULT1          0xd3
  34#define LTC4222_CONTROL2        0xd4
  35#define LTC4222_ALERT2          0xd5
  36#define LTC4222_STATUS2         0xd6
  37#define LTC4222_FAULT2          0xd7
  38#define LTC4222_SOURCE1         0xd8
  39#define LTC4222_SOURCE2         0xda
  40#define LTC4222_ADIN1           0xdc
  41#define LTC4222_ADIN2           0xde
  42#define LTC4222_SENSE1          0xe0
  43#define LTC4222_SENSE2          0xe2
  44#define LTC4222_ADC_CONTROL     0xe4
  45
  46/*
  47 * Fault register bits
  48 */
  49#define FAULT_OV        BIT(0)
  50#define FAULT_UV        BIT(1)
  51#define FAULT_OC        BIT(2)
  52#define FAULT_POWER_BAD BIT(3)
  53#define FAULT_FET_BAD   BIT(5)
  54
  55/* Return the voltage from the given register in mV or mA */
  56static int ltc4222_get_value(struct device *dev, u8 reg)
  57{
  58        struct regmap *regmap = dev_get_drvdata(dev);
  59        unsigned int val;
  60        u8 buf[2];
  61        int ret;
  62
  63        ret = regmap_bulk_read(regmap, reg, buf, 2);
  64        if (ret < 0)
  65                return ret;
  66
  67        val = ((buf[0] << 8) + buf[1]) >> 6;
  68
  69        switch (reg) {
  70        case LTC4222_ADIN1:
  71        case LTC4222_ADIN2:
  72                /* 1.25 mV resolution. Convert to mV. */
  73                val = DIV_ROUND_CLOSEST(val * 5, 4);
  74                break;
  75        case LTC4222_SOURCE1:
  76        case LTC4222_SOURCE2:
  77                /* 31.25 mV resolution. Convert to mV. */
  78                val = DIV_ROUND_CLOSEST(val * 125, 4);
  79                break;
  80        case LTC4222_SENSE1:
  81        case LTC4222_SENSE2:
  82                /*
  83                 * 62.5 uV resolution. Convert to current as measured with
  84                 * an 1 mOhm sense resistor, in mA. If a different sense
  85                 * resistor is installed, calculate the actual current by
  86                 * dividing the reported current by the sense resistor value
  87                 * in mOhm.
  88                 */
  89                val = DIV_ROUND_CLOSEST(val * 125, 2);
  90                break;
  91        default:
  92                return -EINVAL;
  93        }
  94        return val;
  95}
  96
  97static ssize_t ltc4222_show_value(struct device *dev,
  98                                  struct device_attribute *da, char *buf)
  99{
 100        struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
 101        int value;
 102
 103        value = ltc4222_get_value(dev, attr->index);
 104        if (value < 0)
 105                return value;
 106        return snprintf(buf, PAGE_SIZE, "%d\n", value);
 107}
 108
 109static ssize_t ltc4222_show_bool(struct device *dev,
 110                                 struct device_attribute *da, char *buf)
 111{
 112        struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(da);
 113        struct regmap *regmap = dev_get_drvdata(dev);
 114        unsigned int fault;
 115        int ret;
 116
 117        ret = regmap_read(regmap, attr->nr, &fault);
 118        if (ret < 0)
 119                return ret;
 120        fault &= attr->index;
 121        if (fault)              /* Clear reported faults in chip register */
 122                regmap_update_bits(regmap, attr->nr, attr->index, 0);
 123
 124        return snprintf(buf, PAGE_SIZE, "%d\n", !!fault);
 125}
 126
 127/* Voltages */
 128static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4222_show_value, NULL,
 129                          LTC4222_SOURCE1);
 130static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4222_show_value, NULL,
 131                          LTC4222_ADIN1);
 132static SENSOR_DEVICE_ATTR(in3_input, S_IRUGO, ltc4222_show_value, NULL,
 133                          LTC4222_SOURCE2);
 134static SENSOR_DEVICE_ATTR(in4_input, S_IRUGO, ltc4222_show_value, NULL,
 135                          LTC4222_ADIN2);
 136
 137/*
 138 * Voltage alarms
 139 * UV/OV faults are associated with the input voltage, and power bad and fet
 140 * faults are associated with the output voltage.
 141 */
 142static SENSOR_DEVICE_ATTR_2(in1_min_alarm, S_IRUGO, ltc4222_show_bool, NULL,
 143                            LTC4222_FAULT1, FAULT_UV);
 144static SENSOR_DEVICE_ATTR_2(in1_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
 145                            LTC4222_FAULT1, FAULT_OV);
 146static SENSOR_DEVICE_ATTR_2(in2_alarm, S_IRUGO, ltc4222_show_bool, NULL,
 147                            LTC4222_FAULT1, FAULT_POWER_BAD | FAULT_FET_BAD);
 148
 149static SENSOR_DEVICE_ATTR_2(in3_min_alarm, S_IRUGO, ltc4222_show_bool, NULL,
 150                            LTC4222_FAULT2, FAULT_UV);
 151static SENSOR_DEVICE_ATTR_2(in3_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
 152                            LTC4222_FAULT2, FAULT_OV);
 153static SENSOR_DEVICE_ATTR_2(in4_alarm, S_IRUGO, ltc4222_show_bool, NULL,
 154                            LTC4222_FAULT2, FAULT_POWER_BAD | FAULT_FET_BAD);
 155
 156/* Current (via sense resistor) */
 157static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4222_show_value, NULL,
 158                          LTC4222_SENSE1);
 159static SENSOR_DEVICE_ATTR(curr2_input, S_IRUGO, ltc4222_show_value, NULL,
 160                          LTC4222_SENSE2);
 161
 162/* Overcurrent alarm */
 163static SENSOR_DEVICE_ATTR_2(curr1_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
 164                            LTC4222_FAULT1, FAULT_OC);
 165static SENSOR_DEVICE_ATTR_2(curr2_max_alarm, S_IRUGO, ltc4222_show_bool, NULL,
 166                            LTC4222_FAULT2, FAULT_OC);
 167
 168static struct attribute *ltc4222_attrs[] = {
 169        &sensor_dev_attr_in1_input.dev_attr.attr,
 170        &sensor_dev_attr_in1_min_alarm.dev_attr.attr,
 171        &sensor_dev_attr_in1_max_alarm.dev_attr.attr,
 172        &sensor_dev_attr_in2_input.dev_attr.attr,
 173        &sensor_dev_attr_in2_alarm.dev_attr.attr,
 174        &sensor_dev_attr_in3_input.dev_attr.attr,
 175        &sensor_dev_attr_in3_min_alarm.dev_attr.attr,
 176        &sensor_dev_attr_in3_max_alarm.dev_attr.attr,
 177        &sensor_dev_attr_in4_input.dev_attr.attr,
 178        &sensor_dev_attr_in4_alarm.dev_attr.attr,
 179
 180        &sensor_dev_attr_curr1_input.dev_attr.attr,
 181        &sensor_dev_attr_curr1_max_alarm.dev_attr.attr,
 182        &sensor_dev_attr_curr2_input.dev_attr.attr,
 183        &sensor_dev_attr_curr2_max_alarm.dev_attr.attr,
 184
 185        NULL,
 186};
 187ATTRIBUTE_GROUPS(ltc4222);
 188
 189static const struct regmap_config ltc4222_regmap_config = {
 190        .reg_bits = 8,
 191        .val_bits = 8,
 192        .max_register = LTC4222_ADC_CONTROL,
 193};
 194
 195static int ltc4222_probe(struct i2c_client *client,
 196                         const struct i2c_device_id *id)
 197{
 198        struct device *dev = &client->dev;
 199        struct device *hwmon_dev;
 200        struct regmap *regmap;
 201
 202        regmap = devm_regmap_init_i2c(client, &ltc4222_regmap_config);
 203        if (IS_ERR(regmap)) {
 204                dev_err(dev, "failed to allocate register map\n");
 205                return PTR_ERR(regmap);
 206        }
 207
 208        /* Clear faults */
 209        regmap_write(regmap, LTC4222_FAULT1, 0x00);
 210        regmap_write(regmap, LTC4222_FAULT2, 0x00);
 211
 212        hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 213                                                           regmap,
 214                                                           ltc4222_groups);
 215        return PTR_ERR_OR_ZERO(hwmon_dev);
 216}
 217
 218static const struct i2c_device_id ltc4222_id[] = {
 219        {"ltc4222", 0},
 220        { }
 221};
 222
 223MODULE_DEVICE_TABLE(i2c, ltc4222_id);
 224
 225static struct i2c_driver ltc4222_driver = {
 226        .driver = {
 227                   .name = "ltc4222",
 228                   },
 229        .probe = ltc4222_probe,
 230        .id_table = ltc4222_id,
 231};
 232
 233module_i2c_driver(ltc4222_driver);
 234
 235MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
 236MODULE_DESCRIPTION("LTC4222 driver");
 237MODULE_LICENSE("GPL");
 238