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74ba9207 | 1 | // SPDX-License-Identifier: GPL-2.0-or-later |
de779015 | 2 | /* |
3 | * Driver for Linear Technology LTC4151 High Voltage I2C Current | |
4 | * and Voltage Monitor | |
5 | * | |
6 | * Copyright (C) 2011 AppearTV AS | |
7 | * | |
8 | * Derived from: | |
9 | * | |
10 | * Driver for Linear Technology LTC4261 I2C Negative Voltage Hot | |
11 | * Swap Controller | |
12 | * Copyright (C) 2010 Ericsson AB. | |
13 | * | |
14 | * Datasheet: http://www.linear.com/docs/Datasheet/4151fc.pdf | |
de779015 | 15 | */ |
16 | ||
17 | #include <linux/kernel.h> | |
18 | #include <linux/module.h> | |
30fe976f | 19 | #include <linux/of.h> |
de779015 | 20 | #include <linux/init.h> |
21 | #include <linux/err.h> | |
22 | #include <linux/slab.h> | |
23 | #include <linux/i2c.h> | |
24 | #include <linux/hwmon.h> | |
25 | #include <linux/hwmon-sysfs.h> | |
dcd8f392 | 26 | #include <linux/jiffies.h> |
de779015 | 27 | |
28 | /* chip registers */ | |
29 | #define LTC4151_SENSE_H 0x00 | |
30 | #define LTC4151_SENSE_L 0x01 | |
31 | #define LTC4151_VIN_H 0x02 | |
32 | #define LTC4151_VIN_L 0x03 | |
33 | #define LTC4151_ADIN_H 0x04 | |
34 | #define LTC4151_ADIN_L 0x05 | |
35 | ||
36 | struct ltc4151_data { | |
31e38791 | 37 | struct i2c_client *client; |
de779015 | 38 | |
39 | struct mutex update_lock; | |
40 | bool valid; | |
41 | unsigned long last_updated; /* in jiffies */ | |
30fe976f | 42 | unsigned int shunt; /* in micro ohms */ |
de779015 | 43 | |
44 | /* Registers */ | |
45 | u8 regs[6]; | |
46 | }; | |
47 | ||
48 | static struct ltc4151_data *ltc4151_update_device(struct device *dev) | |
49 | { | |
31e38791 AL |
50 | struct ltc4151_data *data = dev_get_drvdata(dev); |
51 | struct i2c_client *client = data->client; | |
de779015 | 52 | struct ltc4151_data *ret = data; |
53 | ||
54 | mutex_lock(&data->update_lock); | |
55 | ||
56 | /* | |
57 | * The chip's A/D updates 6 times per second | |
58 | * (Conversion Rate 6 - 9 Hz) | |
59 | */ | |
60 | if (time_after(jiffies, data->last_updated + HZ / 6) || !data->valid) { | |
61 | int i; | |
62 | ||
63 | dev_dbg(&client->dev, "Starting ltc4151 update\n"); | |
64 | ||
65 | /* Read all registers */ | |
66 | for (i = 0; i < ARRAY_SIZE(data->regs); i++) { | |
67 | int val; | |
68 | ||
69 | val = i2c_smbus_read_byte_data(client, i); | |
70 | if (unlikely(val < 0)) { | |
71 | dev_dbg(dev, | |
72 | "Failed to read ADC value: error %d\n", | |
73 | val); | |
74 | ret = ERR_PTR(val); | |
75 | goto abort; | |
76 | } | |
77 | data->regs[i] = val; | |
78 | } | |
79 | data->last_updated = jiffies; | |
80 | data->valid = 1; | |
81 | } | |
82 | abort: | |
83 | mutex_unlock(&data->update_lock); | |
84 | return ret; | |
85 | } | |
86 | ||
87 | /* Return the voltage from the given register in mV */ | |
88 | static int ltc4151_get_value(struct ltc4151_data *data, u8 reg) | |
89 | { | |
90 | u32 val; | |
91 | ||
92 | val = (data->regs[reg] << 4) + (data->regs[reg + 1] >> 4); | |
93 | ||
94 | switch (reg) { | |
95 | case LTC4151_ADIN_H: | |
96 | /* 500uV resolution. Convert to mV. */ | |
97 | val = val * 500 / 1000; | |
98 | break; | |
99 | case LTC4151_SENSE_H: | |
100 | /* | |
101 | * 20uV resolution. Convert to current as measured with | |
30fe976f | 102 | * a given sense resistor, in mA. |
de779015 | 103 | */ |
30fe976f | 104 | val = val * 20 * 1000 / data->shunt; |
de779015 | 105 | break; |
106 | case LTC4151_VIN_H: | |
107 | /* 25 mV per increment */ | |
108 | val = val * 25; | |
109 | break; | |
110 | default: | |
111 | /* If we get here, the developer messed up */ | |
112 | WARN_ON_ONCE(1); | |
113 | val = 0; | |
114 | break; | |
115 | } | |
116 | ||
117 | return val; | |
118 | } | |
119 | ||
409e8bce | 120 | static ssize_t ltc4151_value_show(struct device *dev, |
de779015 | 121 | struct device_attribute *da, char *buf) |
122 | { | |
123 | struct sensor_device_attribute *attr = to_sensor_dev_attr(da); | |
124 | struct ltc4151_data *data = ltc4151_update_device(dev); | |
125 | int value; | |
126 | ||
127 | if (IS_ERR(data)) | |
128 | return PTR_ERR(data); | |
129 | ||
130 | value = ltc4151_get_value(data, attr->index); | |
131 | return snprintf(buf, PAGE_SIZE, "%d\n", value); | |
132 | } | |
133 | ||
134 | /* | |
135 | * Input voltages. | |
136 | */ | |
409e8bce GR |
137 | static SENSOR_DEVICE_ATTR_RO(in1_input, ltc4151_value, LTC4151_VIN_H); |
138 | static SENSOR_DEVICE_ATTR_RO(in2_input, ltc4151_value, LTC4151_ADIN_H); | |
de779015 | 139 | |
140 | /* Currents (via sense resistor) */ | |
409e8bce | 141 | static SENSOR_DEVICE_ATTR_RO(curr1_input, ltc4151_value, LTC4151_SENSE_H); |
de779015 | 142 | |
1b05d22f GR |
143 | /* |
144 | * Finally, construct an array of pointers to members of the above objects, | |
de779015 | 145 | * as required for sysfs_create_group() |
146 | */ | |
31e38791 | 147 | static struct attribute *ltc4151_attrs[] = { |
de779015 | 148 | &sensor_dev_attr_in1_input.dev_attr.attr, |
149 | &sensor_dev_attr_in2_input.dev_attr.attr, | |
150 | ||
151 | &sensor_dev_attr_curr1_input.dev_attr.attr, | |
152 | ||
153 | NULL, | |
154 | }; | |
31e38791 | 155 | ATTRIBUTE_GROUPS(ltc4151); |
de779015 | 156 | |
157 | static int ltc4151_probe(struct i2c_client *client, | |
158 | const struct i2c_device_id *id) | |
159 | { | |
160 | struct i2c_adapter *adapter = client->adapter; | |
31e38791 | 161 | struct device *dev = &client->dev; |
de779015 | 162 | struct ltc4151_data *data; |
31e38791 | 163 | struct device *hwmon_dev; |
30fe976f | 164 | u32 shunt; |
de779015 | 165 | |
166 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) | |
167 | return -ENODEV; | |
168 | ||
31e38791 | 169 | data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); |
78968642 GR |
170 | if (!data) |
171 | return -ENOMEM; | |
de779015 | 172 | |
30fe976f DG |
173 | if (of_property_read_u32(client->dev.of_node, |
174 | "shunt-resistor-micro-ohms", &shunt)) | |
175 | shunt = 1000; /* 1 mOhm if not set via DT */ | |
176 | ||
177 | if (shunt == 0) | |
178 | return -EINVAL; | |
179 | ||
180 | data->shunt = shunt; | |
181 | ||
31e38791 | 182 | data->client = client; |
de779015 | 183 | mutex_init(&data->update_lock); |
184 | ||
31e38791 AL |
185 | hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, |
186 | data, | |
187 | ltc4151_groups); | |
188 | return PTR_ERR_OR_ZERO(hwmon_dev); | |
de779015 | 189 | } |
190 | ||
191 | static const struct i2c_device_id ltc4151_id[] = { | |
192 | { "ltc4151", 0 }, | |
193 | { } | |
194 | }; | |
195 | MODULE_DEVICE_TABLE(i2c, ltc4151_id); | |
196 | ||
a90cdd13 | 197 | static const struct of_device_id __maybe_unused ltc4151_match[] = { |
30fe976f DG |
198 | { .compatible = "lltc,ltc4151" }, |
199 | {}, | |
200 | }; | |
bb85ceb1 | 201 | MODULE_DEVICE_TABLE(of, ltc4151_match); |
30fe976f | 202 | |
de779015 | 203 | /* This is the driver that will be inserted */ |
204 | static struct i2c_driver ltc4151_driver = { | |
205 | .driver = { | |
206 | .name = "ltc4151", | |
30fe976f | 207 | .of_match_table = of_match_ptr(ltc4151_match), |
de779015 | 208 | }, |
209 | .probe = ltc4151_probe, | |
de779015 | 210 | .id_table = ltc4151_id, |
211 | }; | |
212 | ||
f0967eea | 213 | module_i2c_driver(ltc4151_driver); |
de779015 | 214 | |
215 | MODULE_AUTHOR("Per Dalen <per.dalen@appeartv.com>"); | |
216 | MODULE_DESCRIPTION("LTC4151 driver"); | |
217 | MODULE_LICENSE("GPL"); |