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de779015 | 1 | /* |
2 | * Driver for Linear Technology LTC4151 High Voltage I2C Current | |
3 | * and Voltage Monitor | |
4 | * | |
5 | * Copyright (C) 2011 AppearTV AS | |
6 | * | |
7 | * Derived from: | |
8 | * | |
9 | * Driver for Linear Technology LTC4261 I2C Negative Voltage Hot | |
10 | * Swap Controller | |
11 | * Copyright (C) 2010 Ericsson AB. | |
12 | * | |
13 | * Datasheet: http://www.linear.com/docs/Datasheet/4151fc.pdf | |
14 | * | |
15 | * This program is free software; you can redistribute it and/or modify | |
16 | * it under the terms of the GNU General Public License as published by | |
17 | * the Free Software Foundation; either version 2 of the License, or | |
18 | * (at your option) any later version. | |
19 | * | |
20 | * This program is distributed in the hope that it will be useful, | |
21 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
22 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
23 | * GNU General Public License for more details. | |
24 | * | |
25 | * You should have received a copy of the GNU General Public License | |
26 | * along with this program; if not, write to the Free Software | |
27 | * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. | |
28 | * | |
29 | */ | |
30 | ||
31 | #include <linux/kernel.h> | |
32 | #include <linux/module.h> | |
30fe976f | 33 | #include <linux/of.h> |
de779015 | 34 | #include <linux/init.h> |
35 | #include <linux/err.h> | |
36 | #include <linux/slab.h> | |
37 | #include <linux/i2c.h> | |
38 | #include <linux/hwmon.h> | |
39 | #include <linux/hwmon-sysfs.h> | |
dcd8f392 | 40 | #include <linux/jiffies.h> |
de779015 | 41 | |
42 | /* chip registers */ | |
43 | #define LTC4151_SENSE_H 0x00 | |
44 | #define LTC4151_SENSE_L 0x01 | |
45 | #define LTC4151_VIN_H 0x02 | |
46 | #define LTC4151_VIN_L 0x03 | |
47 | #define LTC4151_ADIN_H 0x04 | |
48 | #define LTC4151_ADIN_L 0x05 | |
49 | ||
50 | struct ltc4151_data { | |
31e38791 | 51 | struct i2c_client *client; |
de779015 | 52 | |
53 | struct mutex update_lock; | |
54 | bool valid; | |
55 | unsigned long last_updated; /* in jiffies */ | |
30fe976f | 56 | unsigned int shunt; /* in micro ohms */ |
de779015 | 57 | |
58 | /* Registers */ | |
59 | u8 regs[6]; | |
60 | }; | |
61 | ||
62 | static struct ltc4151_data *ltc4151_update_device(struct device *dev) | |
63 | { | |
31e38791 AL |
64 | struct ltc4151_data *data = dev_get_drvdata(dev); |
65 | struct i2c_client *client = data->client; | |
de779015 | 66 | struct ltc4151_data *ret = data; |
67 | ||
68 | mutex_lock(&data->update_lock); | |
69 | ||
70 | /* | |
71 | * The chip's A/D updates 6 times per second | |
72 | * (Conversion Rate 6 - 9 Hz) | |
73 | */ | |
74 | if (time_after(jiffies, data->last_updated + HZ / 6) || !data->valid) { | |
75 | int i; | |
76 | ||
77 | dev_dbg(&client->dev, "Starting ltc4151 update\n"); | |
78 | ||
79 | /* Read all registers */ | |
80 | for (i = 0; i < ARRAY_SIZE(data->regs); i++) { | |
81 | int val; | |
82 | ||
83 | val = i2c_smbus_read_byte_data(client, i); | |
84 | if (unlikely(val < 0)) { | |
85 | dev_dbg(dev, | |
86 | "Failed to read ADC value: error %d\n", | |
87 | val); | |
88 | ret = ERR_PTR(val); | |
89 | goto abort; | |
90 | } | |
91 | data->regs[i] = val; | |
92 | } | |
93 | data->last_updated = jiffies; | |
94 | data->valid = 1; | |
95 | } | |
96 | abort: | |
97 | mutex_unlock(&data->update_lock); | |
98 | return ret; | |
99 | } | |
100 | ||
101 | /* Return the voltage from the given register in mV */ | |
102 | static int ltc4151_get_value(struct ltc4151_data *data, u8 reg) | |
103 | { | |
104 | u32 val; | |
105 | ||
106 | val = (data->regs[reg] << 4) + (data->regs[reg + 1] >> 4); | |
107 | ||
108 | switch (reg) { | |
109 | case LTC4151_ADIN_H: | |
110 | /* 500uV resolution. Convert to mV. */ | |
111 | val = val * 500 / 1000; | |
112 | break; | |
113 | case LTC4151_SENSE_H: | |
114 | /* | |
115 | * 20uV resolution. Convert to current as measured with | |
30fe976f | 116 | * a given sense resistor, in mA. |
de779015 | 117 | */ |
30fe976f | 118 | val = val * 20 * 1000 / data->shunt; |
de779015 | 119 | break; |
120 | case LTC4151_VIN_H: | |
121 | /* 25 mV per increment */ | |
122 | val = val * 25; | |
123 | break; | |
124 | default: | |
125 | /* If we get here, the developer messed up */ | |
126 | WARN_ON_ONCE(1); | |
127 | val = 0; | |
128 | break; | |
129 | } | |
130 | ||
131 | return val; | |
132 | } | |
133 | ||
134 | static ssize_t ltc4151_show_value(struct device *dev, | |
135 | struct device_attribute *da, char *buf) | |
136 | { | |
137 | struct sensor_device_attribute *attr = to_sensor_dev_attr(da); | |
138 | struct ltc4151_data *data = ltc4151_update_device(dev); | |
139 | int value; | |
140 | ||
141 | if (IS_ERR(data)) | |
142 | return PTR_ERR(data); | |
143 | ||
144 | value = ltc4151_get_value(data, attr->index); | |
145 | return snprintf(buf, PAGE_SIZE, "%d\n", value); | |
146 | } | |
147 | ||
148 | /* | |
149 | * Input voltages. | |
150 | */ | |
bc0c591e GR |
151 | static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ltc4151_show_value, NULL, |
152 | LTC4151_VIN_H); | |
153 | static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, ltc4151_show_value, NULL, | |
154 | LTC4151_ADIN_H); | |
de779015 | 155 | |
156 | /* Currents (via sense resistor) */ | |
bc0c591e GR |
157 | static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ltc4151_show_value, NULL, |
158 | LTC4151_SENSE_H); | |
de779015 | 159 | |
1b05d22f GR |
160 | /* |
161 | * Finally, construct an array of pointers to members of the above objects, | |
de779015 | 162 | * as required for sysfs_create_group() |
163 | */ | |
31e38791 | 164 | static struct attribute *ltc4151_attrs[] = { |
de779015 | 165 | &sensor_dev_attr_in1_input.dev_attr.attr, |
166 | &sensor_dev_attr_in2_input.dev_attr.attr, | |
167 | ||
168 | &sensor_dev_attr_curr1_input.dev_attr.attr, | |
169 | ||
170 | NULL, | |
171 | }; | |
31e38791 | 172 | ATTRIBUTE_GROUPS(ltc4151); |
de779015 | 173 | |
174 | static int ltc4151_probe(struct i2c_client *client, | |
175 | const struct i2c_device_id *id) | |
176 | { | |
177 | struct i2c_adapter *adapter = client->adapter; | |
31e38791 | 178 | struct device *dev = &client->dev; |
de779015 | 179 | struct ltc4151_data *data; |
31e38791 | 180 | struct device *hwmon_dev; |
30fe976f | 181 | u32 shunt; |
de779015 | 182 | |
183 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) | |
184 | return -ENODEV; | |
185 | ||
31e38791 | 186 | data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); |
78968642 GR |
187 | if (!data) |
188 | return -ENOMEM; | |
de779015 | 189 | |
30fe976f DG |
190 | if (of_property_read_u32(client->dev.of_node, |
191 | "shunt-resistor-micro-ohms", &shunt)) | |
192 | shunt = 1000; /* 1 mOhm if not set via DT */ | |
193 | ||
194 | if (shunt == 0) | |
195 | return -EINVAL; | |
196 | ||
197 | data->shunt = shunt; | |
198 | ||
31e38791 | 199 | data->client = client; |
de779015 | 200 | mutex_init(&data->update_lock); |
201 | ||
31e38791 AL |
202 | hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name, |
203 | data, | |
204 | ltc4151_groups); | |
205 | return PTR_ERR_OR_ZERO(hwmon_dev); | |
de779015 | 206 | } |
207 | ||
208 | static const struct i2c_device_id ltc4151_id[] = { | |
209 | { "ltc4151", 0 }, | |
210 | { } | |
211 | }; | |
212 | MODULE_DEVICE_TABLE(i2c, ltc4151_id); | |
213 | ||
30fe976f DG |
214 | static const struct of_device_id ltc4151_match[] = { |
215 | { .compatible = "lltc,ltc4151" }, | |
216 | {}, | |
217 | }; | |
218 | ||
de779015 | 219 | /* This is the driver that will be inserted */ |
220 | static struct i2c_driver ltc4151_driver = { | |
221 | .driver = { | |
222 | .name = "ltc4151", | |
30fe976f | 223 | .of_match_table = of_match_ptr(ltc4151_match), |
de779015 | 224 | }, |
225 | .probe = ltc4151_probe, | |
de779015 | 226 | .id_table = ltc4151_id, |
227 | }; | |
228 | ||
f0967eea | 229 | module_i2c_driver(ltc4151_driver); |
de779015 | 230 | |
231 | MODULE_AUTHOR("Per Dalen <per.dalen@appeartv.com>"); | |
232 | MODULE_DESCRIPTION("LTC4151 driver"); | |
233 | MODULE_LICENSE("GPL"); |