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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> | |
33 | #include <linux/init.h> | |
34 | #include <linux/err.h> | |
35 | #include <linux/slab.h> | |
36 | #include <linux/i2c.h> | |
37 | #include <linux/hwmon.h> | |
38 | #include <linux/hwmon-sysfs.h> | |
39 | ||
40 | /* chip registers */ | |
41 | #define LTC4151_SENSE_H 0x00 | |
42 | #define LTC4151_SENSE_L 0x01 | |
43 | #define LTC4151_VIN_H 0x02 | |
44 | #define LTC4151_VIN_L 0x03 | |
45 | #define LTC4151_ADIN_H 0x04 | |
46 | #define LTC4151_ADIN_L 0x05 | |
47 | ||
48 | struct ltc4151_data { | |
49 | struct device *hwmon_dev; | |
50 | ||
51 | struct mutex update_lock; | |
52 | bool valid; | |
53 | unsigned long last_updated; /* in jiffies */ | |
54 | ||
55 | /* Registers */ | |
56 | u8 regs[6]; | |
57 | }; | |
58 | ||
59 | static struct ltc4151_data *ltc4151_update_device(struct device *dev) | |
60 | { | |
61 | struct i2c_client *client = to_i2c_client(dev); | |
62 | struct ltc4151_data *data = i2c_get_clientdata(client); | |
63 | struct ltc4151_data *ret = data; | |
64 | ||
65 | mutex_lock(&data->update_lock); | |
66 | ||
67 | /* | |
68 | * The chip's A/D updates 6 times per second | |
69 | * (Conversion Rate 6 - 9 Hz) | |
70 | */ | |
71 | if (time_after(jiffies, data->last_updated + HZ / 6) || !data->valid) { | |
72 | int i; | |
73 | ||
74 | dev_dbg(&client->dev, "Starting ltc4151 update\n"); | |
75 | ||
76 | /* Read all registers */ | |
77 | for (i = 0; i < ARRAY_SIZE(data->regs); i++) { | |
78 | int val; | |
79 | ||
80 | val = i2c_smbus_read_byte_data(client, i); | |
81 | if (unlikely(val < 0)) { | |
82 | dev_dbg(dev, | |
83 | "Failed to read ADC value: error %d\n", | |
84 | val); | |
85 | ret = ERR_PTR(val); | |
86 | goto abort; | |
87 | } | |
88 | data->regs[i] = val; | |
89 | } | |
90 | data->last_updated = jiffies; | |
91 | data->valid = 1; | |
92 | } | |
93 | abort: | |
94 | mutex_unlock(&data->update_lock); | |
95 | return ret; | |
96 | } | |
97 | ||
98 | /* Return the voltage from the given register in mV */ | |
99 | static int ltc4151_get_value(struct ltc4151_data *data, u8 reg) | |
100 | { | |
101 | u32 val; | |
102 | ||
103 | val = (data->regs[reg] << 4) + (data->regs[reg + 1] >> 4); | |
104 | ||
105 | switch (reg) { | |
106 | case LTC4151_ADIN_H: | |
107 | /* 500uV resolution. Convert to mV. */ | |
108 | val = val * 500 / 1000; | |
109 | break; | |
110 | case LTC4151_SENSE_H: | |
111 | /* | |
112 | * 20uV resolution. Convert to current as measured with | |
113 | * an 1 mOhm sense resistor, in mA. | |
114 | */ | |
115 | val = val * 20; | |
116 | break; | |
117 | case LTC4151_VIN_H: | |
118 | /* 25 mV per increment */ | |
119 | val = val * 25; | |
120 | break; | |
121 | default: | |
122 | /* If we get here, the developer messed up */ | |
123 | WARN_ON_ONCE(1); | |
124 | val = 0; | |
125 | break; | |
126 | } | |
127 | ||
128 | return val; | |
129 | } | |
130 | ||
131 | static ssize_t ltc4151_show_value(struct device *dev, | |
132 | struct device_attribute *da, char *buf) | |
133 | { | |
134 | struct sensor_device_attribute *attr = to_sensor_dev_attr(da); | |
135 | struct ltc4151_data *data = ltc4151_update_device(dev); | |
136 | int value; | |
137 | ||
138 | if (IS_ERR(data)) | |
139 | return PTR_ERR(data); | |
140 | ||
141 | value = ltc4151_get_value(data, attr->index); | |
142 | return snprintf(buf, PAGE_SIZE, "%d\n", value); | |
143 | } | |
144 | ||
145 | /* | |
146 | * Input voltages. | |
147 | */ | |
148 | static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, \ | |
149 | ltc4151_show_value, NULL, LTC4151_VIN_H); | |
150 | static SENSOR_DEVICE_ATTR(in2_input, S_IRUGO, \ | |
151 | ltc4151_show_value, NULL, LTC4151_ADIN_H); | |
152 | ||
153 | /* Currents (via sense resistor) */ | |
154 | static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, \ | |
155 | ltc4151_show_value, NULL, LTC4151_SENSE_H); | |
156 | ||
1b05d22f GR |
157 | /* |
158 | * Finally, construct an array of pointers to members of the above objects, | |
de779015 | 159 | * as required for sysfs_create_group() |
160 | */ | |
161 | static struct attribute *ltc4151_attributes[] = { | |
162 | &sensor_dev_attr_in1_input.dev_attr.attr, | |
163 | &sensor_dev_attr_in2_input.dev_attr.attr, | |
164 | ||
165 | &sensor_dev_attr_curr1_input.dev_attr.attr, | |
166 | ||
167 | NULL, | |
168 | }; | |
169 | ||
170 | static const struct attribute_group ltc4151_group = { | |
171 | .attrs = ltc4151_attributes, | |
172 | }; | |
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; | |
178 | struct ltc4151_data *data; | |
179 | int ret; | |
180 | ||
181 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) | |
182 | return -ENODEV; | |
183 | ||
184 | data = kzalloc(sizeof(*data), GFP_KERNEL); | |
185 | if (!data) { | |
186 | ret = -ENOMEM; | |
187 | goto out_kzalloc; | |
188 | } | |
189 | ||
190 | i2c_set_clientdata(client, data); | |
191 | mutex_init(&data->update_lock); | |
192 | ||
193 | /* Register sysfs hooks */ | |
194 | ret = sysfs_create_group(&client->dev.kobj, <c4151_group); | |
195 | if (ret) | |
196 | goto out_sysfs_create_group; | |
197 | ||
198 | data->hwmon_dev = hwmon_device_register(&client->dev); | |
199 | if (IS_ERR(data->hwmon_dev)) { | |
200 | ret = PTR_ERR(data->hwmon_dev); | |
201 | goto out_hwmon_device_register; | |
202 | } | |
203 | ||
204 | return 0; | |
205 | ||
206 | out_hwmon_device_register: | |
207 | sysfs_remove_group(&client->dev.kobj, <c4151_group); | |
208 | out_sysfs_create_group: | |
209 | kfree(data); | |
210 | out_kzalloc: | |
211 | return ret; | |
212 | } | |
213 | ||
214 | static int ltc4151_remove(struct i2c_client *client) | |
215 | { | |
216 | struct ltc4151_data *data = i2c_get_clientdata(client); | |
217 | ||
218 | hwmon_device_unregister(data->hwmon_dev); | |
219 | sysfs_remove_group(&client->dev.kobj, <c4151_group); | |
220 | ||
221 | kfree(data); | |
222 | ||
223 | return 0; | |
224 | } | |
225 | ||
226 | static const struct i2c_device_id ltc4151_id[] = { | |
227 | { "ltc4151", 0 }, | |
228 | { } | |
229 | }; | |
230 | MODULE_DEVICE_TABLE(i2c, ltc4151_id); | |
231 | ||
232 | /* This is the driver that will be inserted */ | |
233 | static struct i2c_driver ltc4151_driver = { | |
234 | .driver = { | |
235 | .name = "ltc4151", | |
236 | }, | |
237 | .probe = ltc4151_probe, | |
238 | .remove = ltc4151_remove, | |
239 | .id_table = ltc4151_id, | |
240 | }; | |
241 | ||
f0967eea | 242 | module_i2c_driver(ltc4151_driver); |
de779015 | 243 | |
244 | MODULE_AUTHOR("Per Dalen <per.dalen@appeartv.com>"); | |
245 | MODULE_DESCRIPTION("LTC4151 driver"); | |
246 | MODULE_LICENSE("GPL"); |