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 */
ltc4222_get_value(struct device * dev,u8 reg)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
ltc4222_value_show(struct device * dev,struct device_attribute * da,char * buf)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 sysfs_emit(buf, "%d\n", value);
98 }
99
ltc4222_bool_show(struct device * dev,struct device_attribute * da,char * buf)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 sysfs_emit(buf, "%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
ltc4222_probe(struct i2c_client * client)180 static 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
202 static const struct i2c_device_id ltc4222_id[] = {
203 {"ltc4222", 0},
204 { }
205 };
206
207 MODULE_DEVICE_TABLE(i2c, ltc4222_id);
208
209 static struct i2c_driver ltc4222_driver = {
210 .driver = {
211 .name = "ltc4222",
212 },
213 .probe = ltc4222_probe,
214 .id_table = ltc4222_id,
215 };
216
217 module_i2c_driver(ltc4222_driver);
218
219 MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>");
220 MODULE_DESCRIPTION("LTC4222 driver");
221 MODULE_LICENSE("GPL");
222