1 | // SPDX-License-Identifier: GPL-2.0-or-later |
2 | /* |
3 | * Driver for Linear Technology LTC4260 I2C Positive Voltage 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/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 0x00 |
20 | #define LTC4260_ALERT 0x01 |
21 | #define LTC4260_STATUS 0x02 |
22 | #define LTC4260_FAULT 0x03 |
23 | #define LTC4260_SENSE 0x04 |
24 | #define LTC4260_SOURCE 0x05 |
25 | #define LTC4260_ADIN 0x06 |
26 | |
27 | /* |
28 | * Fault register bits |
29 | */ |
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 */ |
37 | static 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(map: regmap, reg, val: &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 with |
59 | * an 1 mOhm sense resistor, in mA. If a different sense |
60 | * resistor is installed, calculate the actual current by |
61 | * dividing the reported current by the sense resistor value |
62 | * in mOhm. |
63 | */ |
64 | val = val * 300; |
65 | break; |
66 | default: |
67 | return -EINVAL; |
68 | } |
69 | |
70 | return val; |
71 | } |
72 | |
73 | static 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, reg: attr->index); |
80 | if (value < 0) |
81 | return value; |
82 | return sysfs_emit(buf, fmt: "%d\n" , value); |
83 | } |
84 | |
85 | static 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(map: regmap, LTC4260_FAULT, val: &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(map: regmap, LTC4260_FAULT, mask: attr->index, val: 0); |
100 | |
101 | return sysfs_emit(buf, fmt: "%d\n" , !!fault); |
102 | } |
103 | |
104 | /* Voltages */ |
105 | static SENSOR_DEVICE_ATTR_RO(in1_input, ltc4260_value, LTC4260_SOURCE); |
106 | static SENSOR_DEVICE_ATTR_RO(in2_input, ltc4260_value, LTC4260_ADIN); |
107 | |
108 | /* |
109 | * Voltage alarms |
110 | * UV/OV faults are associated with the input voltage, and the POWER BAD and |
111 | * FET SHORT faults are associated with the output voltage. |
112 | */ |
113 | static SENSOR_DEVICE_ATTR_RO(in1_min_alarm, ltc4260_bool, FAULT_UV); |
114 | static SENSOR_DEVICE_ATTR_RO(in1_max_alarm, ltc4260_bool, FAULT_OV); |
115 | static SENSOR_DEVICE_ATTR_RO(in2_alarm, ltc4260_bool, |
116 | FAULT_POWER_BAD | FAULT_FET_SHORT); |
117 | |
118 | /* Current (via sense resistor) */ |
119 | static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc4260_value, LTC4260_SENSE); |
120 | |
121 | /* Overcurrent alarm */ |
122 | static SENSOR_DEVICE_ATTR_RO(curr1_max_alarm, ltc4260_bool, FAULT_OC); |
123 | |
124 | static 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 | }; |
136 | ATTRIBUTE_GROUPS(ltc4260); |
137 | |
138 | static const struct regmap_config ltc4260_regmap_config = { |
139 | .reg_bits = 8, |
140 | .val_bits = 8, |
141 | .max_register = LTC4260_ADIN, |
142 | }; |
143 | |
144 | static 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(ptr: regmap)) { |
152 | dev_err(dev, "failed to allocate register map\n" ); |
153 | return PTR_ERR(ptr: regmap); |
154 | } |
155 | |
156 | /* Clear faults */ |
157 | regmap_write(map: regmap, LTC4260_FAULT, val: 0x00); |
158 | |
159 | hwmon_dev = devm_hwmon_device_register_with_groups(dev, name: client->name, |
160 | drvdata: regmap, |
161 | groups: ltc4260_groups); |
162 | return PTR_ERR_OR_ZERO(ptr: hwmon_dev); |
163 | } |
164 | |
165 | static const struct i2c_device_id ltc4260_id[] = { |
166 | {"ltc4260" , 0}, |
167 | { } |
168 | }; |
169 | |
170 | MODULE_DEVICE_TABLE(i2c, ltc4260_id); |
171 | |
172 | static struct i2c_driver ltc4260_driver = { |
173 | .driver = { |
174 | .name = "ltc4260" , |
175 | }, |
176 | .probe = ltc4260_probe, |
177 | .id_table = ltc4260_id, |
178 | }; |
179 | |
180 | module_i2c_driver(ltc4260_driver); |
181 | |
182 | MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>" ); |
183 | MODULE_DESCRIPTION("LTC4260 driver" ); |
184 | MODULE_LICENSE("GPL" ); |
185 | |