drivers/hwmon/ltc4222.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * Driver for Linear Technology LTC4222 Dual Hot Swap controller
   4  *
   5  * Copyright (c) 2014 Guenter Roeck
   6  */
   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        0xd0
  22 #define LTC4222_ALERT1          0xd1
  23 #define LTC4222_STATUS1         0xd2
  24 #define LTC4222_FAULT1          0xd3
  25 #define LTC4222_CONTROL2        0xd4
  26 #define LTC4222_ALERT2          0xd5
  27 #define LTC4222_STATUS2         0xd6
  28 #define LTC4222_FAULT2          0xd7
  29 #define LTC4222_SOURCE1         0xd8
  30 #define LTC4222_SOURCE2         0xda
  31 #define LTC4222_ADIN1           0xdc
  32 #define LTC4222_ADIN2           0xde
  33 #define LTC4222_SENSE1          0xe0
  34 #define LTC4222_SENSE2          0xe2
  35 #define LTC4222_ADC_CONTROL     0xe4
  36
  37 /*
  38  * Fault register bits
  39  */
  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 */
  47 static 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 with
  75                  * an 1 mOhm sense resistor, in mA. If a different sense
  76                  * resistor is installed, calculate the actual current by
  77                  * dividing the reported current by the sense resistor value
  78                  * in mOhm.
  79                  */
  80                 val = DIV_ROUND_CLOSEST(val * 125, 2);
  81                 break;
  82         default:
  83                 return -EINVAL;
  84         }
  85         return val;
  86 }
  87
  88 static 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 snprintf(buf, PAGE_SIZE, "%d\n", value);
  98 }
  99
 100 static 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 snprintf(buf, PAGE_SIZE, "%d\n", !!fault);
 116 }
 117
 118 /* Voltages */
 119 static SENSOR_DEVICE_ATTR_RO(in1_input, ltc4222_value, LTC4222_SOURCE1);
 120 static SENSOR_DEVICE_ATTR_RO(in2_input, ltc4222_value, LTC4222_ADIN1);
 121 static SENSOR_DEVICE_ATTR_RO(in3_input, ltc4222_value, LTC4222_SOURCE2);
 122 static SENSOR_DEVICE_ATTR_RO(in4_input, ltc4222_value, LTC4222_ADIN2);
 123
 124 /*
 125  * Voltage alarms
 126  * UV/OV faults are associated with the input voltage, and power bad and fet
 127  * faults are associated with the output voltage.
 128  */
 129 static SENSOR_DEVICE_ATTR_2_RO(in1_min_alarm, ltc4222_bool, LTC4222_FAULT1,
 130                                FAULT_UV);
 131 static SENSOR_DEVICE_ATTR_2_RO(in1_max_alarm, ltc4222_bool, LTC4222_FAULT1,
 132                                FAULT_OV);
 133 static SENSOR_DEVICE_ATTR_2_RO(in2_alarm, ltc4222_bool, LTC4222_FAULT1,
 134                                FAULT_POWER_BAD | FAULT_FET_BAD);
 135
 136 static SENSOR_DEVICE_ATTR_2_RO(in3_min_alarm, ltc4222_bool, LTC4222_FAULT2,
 137                                FAULT_UV);
 138 static SENSOR_DEVICE_ATTR_2_RO(in3_max_alarm, ltc4222_bool, LTC4222_FAULT2,
 139                                FAULT_OV);
 140 static SENSOR_DEVICE_ATTR_2_RO(in4_alarm, ltc4222_bool, LTC4222_FAULT2,
 141                                FAULT_POWER_BAD | FAULT_FET_BAD);
 142
 143 /* Current (via sense resistor) */
 144 static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc4222_value, LTC4222_SENSE1);
 145 static SENSOR_DEVICE_ATTR_RO(curr2_input, ltc4222_value, LTC4222_SENSE2);
 146
 147 /* Overcurrent alarm */
 148 static SENSOR_DEVICE_ATTR_2_RO(curr1_max_alarm, ltc4222_bool, LTC4222_FAULT1,
 149                                FAULT_OC);
 150 static SENSOR_DEVICE_ATTR_2_RO(curr2_max_alarm, ltc4222_bool, LTC4222_FAULT2,
 151                                FAULT_OC);
 152
 153 static 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 };
 172 ATTRIBUTE_GROUPS(ltc4222);
 173
 174 static const struct regmap_config ltc4222_regmap_config = {
 175         .reg_bits = 8,
 176         .val_bits = 8,
 177         .max_register = LTC4222_ADC_CONTROL,
 178 };
 179
 180 static int ltc4222_probe(struct i2c_client *client,
 181                          const struct i2c_device_id *id)
 182 {
 183         struct device *dev = &client->dev;
 184         struct device *hwmon_dev;
 185         struct regmap *regmap;
 186
 187         regmap = devm_regmap_init_i2c(client, &ltc4222_regmap_config);
 188         if (IS_ERR(regmap)) {
 189                 dev_err(dev, "failed to allocate register map\n");
 190                 return PTR_ERR(regmap);
 191         }
 192
 193         /* Clear faults */
 194         regmap_write(regmap, LTC4222_FAULT1, 0x00);
 195         regmap_write(regmap, LTC4222_FAULT2, 0x00);
 196
 197         hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
 198                                                            regmap,
 199                                                            ltc4222_groups);
 200         return PTR_ERR_OR_ZERO(hwmon_dev);
 201 }
 202
 203 static const struct i2c_device_id ltc4222_id[] = {
 204         {"ltc4222", 0},
 205         { }
 206 };
 207
 208 MODULE_DEVICE_TABLE(i2c, ltc4222_id);
 209
 210 static struct i2c_driver ltc4222_driver = {
 211         .driver = {
 212                    .name = "ltc4222",
 213                    },
 214         .probe = ltc4222_probe,
 215         .id_table = ltc4222_id,
 216 };
 217
 218 module_i2c_driver(ltc4222_driver);
 219
 220 MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
 221 MODULE_DESCRIPTION("LTC4222 driver");
 222 MODULE_LICENSE("GPL");