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74ba9207 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
e5f5c99a GR |
2 | /* |
3 | * Driver for Linear Technology LTC4261 I2C Negative Voltage Hot Swap Controller | |
4 | * | |
5 | * Copyright (C) 2010 Ericsson AB. | |
6 | * | |
7 | * Derived from: | |
8 | * | |
9 | * Driver for Linear Technology LTC4245 I2C Multiple Supply Hot Swap Controller | |
10 | * Copyright (C) 2008 Ira W. Snyder <iws@ovro.caltech.edu> | |
11 | * | |
12 | * Datasheet: http://cds.linear.com/docs/Datasheet/42612fb.pdf | |
e5f5c99a GR |
13 | */ |
14 | ||
15 | #include <linux/kernel.h> | |
16 | #include <linux/module.h> | |
17 | #include <linux/init.h> | |
18 | #include <linux/err.h> | |
19 | #include <linux/slab.h> | |
20 | #include <linux/i2c.h> | |
21 | #include <linux/hwmon.h> | |
22 | #include <linux/hwmon-sysfs.h> | |
dcd8f392 | 23 | #include <linux/jiffies.h> |
e5f5c99a GR |
24 | |
25 | /* chip registers */ | |
26 | #define LTC4261_STATUS 0x00 /* readonly */ | |
27 | #define LTC4261_FAULT 0x01 | |
28 | #define LTC4261_ALERT 0x02 | |
29 | #define LTC4261_CONTROL 0x03 | |
30 | #define LTC4261_SENSE_H 0x04 | |
31 | #define LTC4261_SENSE_L 0x05 | |
32 | #define LTC4261_ADIN2_H 0x06 | |
33 | #define LTC4261_ADIN2_L 0x07 | |
34 | #define LTC4261_ADIN_H 0x08 | |
35 | #define LTC4261_ADIN_L 0x09 | |
36 | ||
37 | /* | |
38 | * Fault register bits | |
39 | */ | |
40 | #define FAULT_OV (1<<0) | |
41 | #define FAULT_UV (1<<1) | |
42 | #define FAULT_OC (1<<2) | |
43 | ||
44 | struct ltc4261_data { | |
38f150fe | 45 | struct i2c_client *client; |
e5f5c99a GR |
46 | |
47 | struct mutex update_lock; | |
48 | bool valid; | |
49 | unsigned long last_updated; /* in jiffies */ | |
50 | ||
51 | /* Registers */ | |
52 | u8 regs[10]; | |
53 | }; | |
54 | ||
55 | static struct ltc4261_data *ltc4261_update_device(struct device *dev) | |
56 | { | |
38f150fe GR |
57 | struct ltc4261_data *data = dev_get_drvdata(dev); |
58 | struct i2c_client *client = data->client; | |
e5f5c99a GR |
59 | struct ltc4261_data *ret = data; |
60 | ||
61 | mutex_lock(&data->update_lock); | |
62 | ||
63 | if (time_after(jiffies, data->last_updated + HZ / 4) || !data->valid) { | |
64 | int i; | |
65 | ||
66 | /* Read registers -- 0x00 to 0x09 */ | |
67 | for (i = 0; i < ARRAY_SIZE(data->regs); i++) { | |
68 | int val; | |
69 | ||
70 | val = i2c_smbus_read_byte_data(client, i); | |
71 | if (unlikely(val < 0)) { | |
72 | dev_dbg(dev, | |
69f8b741 | 73 | "Failed to read ADC value: error %d\n", |
e5f5c99a GR |
74 | val); |
75 | ret = ERR_PTR(val); | |
aac9fe9b | 76 | data->valid = 0; |
e5f5c99a GR |
77 | goto abort; |
78 | } | |
79 | data->regs[i] = val; | |
80 | } | |
81 | data->last_updated = jiffies; | |
82 | data->valid = 1; | |
83 | } | |
84 | abort: | |
85 | mutex_unlock(&data->update_lock); | |
86 | return ret; | |
87 | } | |
88 | ||
89 | /* Return the voltage from the given register in mV or mA */ | |
90 | static int ltc4261_get_value(struct ltc4261_data *data, u8 reg) | |
91 | { | |
92 | u32 val; | |
93 | ||
94 | val = (data->regs[reg] << 2) + (data->regs[reg + 1] >> 6); | |
95 | ||
96 | switch (reg) { | |
97 | case LTC4261_ADIN_H: | |
98 | case LTC4261_ADIN2_H: | |
99 | /* 2.5mV resolution. Convert to mV. */ | |
100 | val = val * 25 / 10; | |
101 | break; | |
102 | case LTC4261_SENSE_H: | |
103 | /* | |
104 | * 62.5uV resolution. Convert to current as measured with | |
105 | * an 1 mOhm sense resistor, in mA. If a different sense | |
106 | * resistor is installed, calculate the actual current by | |
107 | * dividing the reported current by the sense resistor value | |
108 | * in mOhm. | |
109 | */ | |
110 | val = val * 625 / 10; | |
111 | break; | |
112 | default: | |
113 | /* If we get here, the developer messed up */ | |
114 | WARN_ON_ONCE(1); | |
115 | val = 0; | |
116 | break; | |
117 | } | |
118 | ||
119 | return val; | |
120 | } | |
121 | ||
decb23dc | 122 | static ssize_t ltc4261_value_show(struct device *dev, |
e5f5c99a GR |
123 | struct device_attribute *da, char *buf) |
124 | { | |
125 | struct sensor_device_attribute *attr = to_sensor_dev_attr(da); | |
126 | struct ltc4261_data *data = ltc4261_update_device(dev); | |
127 | int value; | |
128 | ||
129 | if (IS_ERR(data)) | |
130 | return PTR_ERR(data); | |
131 | ||
132 | value = ltc4261_get_value(data, attr->index); | |
133 | return snprintf(buf, PAGE_SIZE, "%d\n", value); | |
134 | } | |
135 | ||
decb23dc | 136 | static ssize_t ltc4261_bool_show(struct device *dev, |
e5f5c99a GR |
137 | struct device_attribute *da, char *buf) |
138 | { | |
139 | struct sensor_device_attribute *attr = to_sensor_dev_attr(da); | |
e5f5c99a GR |
140 | struct ltc4261_data *data = ltc4261_update_device(dev); |
141 | u8 fault; | |
142 | ||
143 | if (IS_ERR(data)) | |
144 | return PTR_ERR(data); | |
145 | ||
146 | fault = data->regs[LTC4261_FAULT] & attr->index; | |
147 | if (fault) /* Clear reported faults in chip register */ | |
38f150fe | 148 | i2c_smbus_write_byte_data(data->client, LTC4261_FAULT, ~fault); |
e5f5c99a GR |
149 | |
150 | return snprintf(buf, PAGE_SIZE, "%d\n", fault ? 1 : 0); | |
151 | } | |
152 | ||
e5f5c99a GR |
153 | /* |
154 | * Input voltages. | |
155 | */ | |
decb23dc GR |
156 | static SENSOR_DEVICE_ATTR_RO(in1_input, ltc4261_value, LTC4261_ADIN_H); |
157 | static SENSOR_DEVICE_ATTR_RO(in2_input, ltc4261_value, LTC4261_ADIN2_H); | |
e5f5c99a GR |
158 | |
159 | /* | |
160 | * Voltage alarms. The chip has only one set of voltage alarm status bits, | |
161 | * triggered by input voltage alarms. In many designs, those alarms are | |
162 | * associated with the ADIN2 sensor, due to the proximity of the ADIN2 pin | |
163 | * to the OV pin. ADIN2 is, however, not available on all chip variants. | |
164 | * To ensure that the alarm condition is reported to the user, report it | |
165 | * with both voltage sensors. | |
166 | */ | |
decb23dc GR |
167 | static SENSOR_DEVICE_ATTR_RO(in1_min_alarm, ltc4261_bool, FAULT_UV); |
168 | static SENSOR_DEVICE_ATTR_RO(in1_max_alarm, ltc4261_bool, FAULT_OV); | |
169 | static SENSOR_DEVICE_ATTR_RO(in2_min_alarm, ltc4261_bool, FAULT_UV); | |
170 | static SENSOR_DEVICE_ATTR_RO(in2_max_alarm, ltc4261_bool, FAULT_OV); | |
e5f5c99a GR |
171 | |
172 | /* Currents (via sense resistor) */ | |
decb23dc | 173 | static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc4261_value, LTC4261_SENSE_H); |
e5f5c99a GR |
174 | |
175 | /* Overcurrent alarm */ | |
decb23dc | 176 | static SENSOR_DEVICE_ATTR_RO(curr1_max_alarm, ltc4261_bool, FAULT_OC); |
e5f5c99a | 177 | |
38f150fe | 178 | static struct attribute *ltc4261_attrs[] = { |
e5f5c99a GR |
179 | &sensor_dev_attr_in1_input.dev_attr.attr, |
180 | &sensor_dev_attr_in1_min_alarm.dev_attr.attr, | |
181 | &sensor_dev_attr_in1_max_alarm.dev_attr.attr, | |
182 | &sensor_dev_attr_in2_input.dev_attr.attr, | |
183 | &sensor_dev_attr_in2_min_alarm.dev_attr.attr, | |
184 | &sensor_dev_attr_in2_max_alarm.dev_attr.attr, | |
185 | ||
186 | &sensor_dev_attr_curr1_input.dev_attr.attr, | |
187 | &sensor_dev_attr_curr1_max_alarm.dev_attr.attr, | |
188 | ||
189 | NULL, | |
190 | }; | |
38f150fe | 191 | ATTRIBUTE_GROUPS(ltc4261); |
e5f5c99a GR |
192 | |
193 | static int ltc4261_probe(struct i2c_client *client, | |
194 | const struct i2c_device_id *id) | |
195 | { | |
196 | struct i2c_adapter *adapter = client->adapter; | |
38f150fe | 197 | struct device *dev = &client->dev; |
e5f5c99a | 198 | struct ltc4261_data *data; |
38f150fe | 199 | struct device *hwmon_dev; |
e5f5c99a GR |
200 | |
201 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) | |
202 | return -ENODEV; | |
203 | ||
204 | if (i2c_smbus_read_byte_data(client, LTC4261_STATUS) < 0) { | |
38f150fe | 205 | dev_err(dev, "Failed to read status register\n"); |
e5f5c99a GR |
206 | return -ENODEV; |
207 | } | |
208 | ||
38f150fe | 209 | data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); |
36839287 GR |
210 | if (!data) |
211 | return -ENOMEM; | |
e5f5c99a | 212 | |
38f150fe | 213 | data->client = client; |
e5f5c99a GR |
214 | mutex_init(&data->update_lock); |
215 | ||
216 | /* Clear faults */ | |
217 | i2c_smbus_write_byte_data(client, LTC4261_FAULT, 0x00); | |
218 | ||
38f150fe GR |
219 | hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, |
220 | data, | |
221 | ltc4261_groups); | |
2a253c47 | 222 | return PTR_ERR_OR_ZERO(hwmon_dev); |
e5f5c99a GR |
223 | } |
224 | ||
225 | static const struct i2c_device_id ltc4261_id[] = { | |
226 | {"ltc4261", 0}, | |
227 | {} | |
228 | }; | |
229 | ||
230 | MODULE_DEVICE_TABLE(i2c, ltc4261_id); | |
231 | ||
232 | /* This is the driver that will be inserted */ | |
233 | static struct i2c_driver ltc4261_driver = { | |
234 | .driver = { | |
235 | .name = "ltc4261", | |
236 | }, | |
237 | .probe = ltc4261_probe, | |
e5f5c99a GR |
238 | .id_table = ltc4261_id, |
239 | }; | |
240 | ||
f0967eea | 241 | module_i2c_driver(ltc4261_driver); |
e5f5c99a | 242 | |
bb9a80e5 | 243 | MODULE_AUTHOR("Guenter Roeck <linux@roeck-us.net>"); |
e5f5c99a GR |
244 | MODULE_DESCRIPTION("LTC4261 driver"); |
245 | MODULE_LICENSE("GPL"); |