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 | |
157 | /* Finally, construct an array of pointers to members of the above objects, |
158 | * as required for sysfs_create_group() |
159 | */ |
160 | static struct attribute *ltc4151_attributes[] = { |
161 | &sensor_dev_attr_in1_input.dev_attr.attr, |
162 | &sensor_dev_attr_in2_input.dev_attr.attr, |
163 | |
164 | &sensor_dev_attr_curr1_input.dev_attr.attr, |
165 | |
166 | NULL, |
167 | }; |
168 | |
169 | static const struct attribute_group ltc4151_group = { |
170 | .attrs = ltc4151_attributes, |
171 | }; |
172 | |
173 | static int ltc4151_probe(struct i2c_client *client, |
174 | const struct i2c_device_id *id) |
175 | { |
176 | struct i2c_adapter *adapter = client->adapter; |
177 | struct ltc4151_data *data; |
178 | int ret; |
179 | |
180 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA)) |
181 | return -ENODEV; |
182 | |
183 | data = kzalloc(sizeof(*data), GFP_KERNEL); |
184 | if (!data) { |
185 | ret = -ENOMEM; |
186 | goto out_kzalloc; |
187 | } |
188 | |
189 | i2c_set_clientdata(client, data); |
190 | mutex_init(&data->update_lock); |
191 | |
192 | /* Register sysfs hooks */ |
193 | ret = sysfs_create_group(&client->dev.kobj, <c4151_group); |
194 | if (ret) |
195 | goto out_sysfs_create_group; |
196 | |
197 | data->hwmon_dev = hwmon_device_register(&client->dev); |
198 | if (IS_ERR(data->hwmon_dev)) { |
199 | ret = PTR_ERR(data->hwmon_dev); |
200 | goto out_hwmon_device_register; |
201 | } |
202 | |
203 | return 0; |
204 | |
205 | out_hwmon_device_register: |
206 | sysfs_remove_group(&client->dev.kobj, <c4151_group); |
207 | out_sysfs_create_group: |
208 | kfree(data); |
209 | out_kzalloc: |
210 | return ret; |
211 | } |
212 | |
213 | static int ltc4151_remove(struct i2c_client *client) |
214 | { |
215 | struct ltc4151_data *data = i2c_get_clientdata(client); |
216 | |
217 | hwmon_device_unregister(data->hwmon_dev); |
218 | sysfs_remove_group(&client->dev.kobj, <c4151_group); |
219 | |
220 | kfree(data); |
221 | |
222 | return 0; |
223 | } |
224 | |
225 | static const struct i2c_device_id ltc4151_id[] = { |
226 | { "ltc4151", 0 }, |
227 | { } |
228 | }; |
229 | MODULE_DEVICE_TABLE(i2c, ltc4151_id); |
230 | |
231 | /* This is the driver that will be inserted */ |
232 | static struct i2c_driver ltc4151_driver = { |
233 | .driver = { |
234 | .name = "ltc4151", |
235 | }, |
236 | .probe = ltc4151_probe, |
237 | .remove = ltc4151_remove, |
238 | .id_table = ltc4151_id, |
239 | }; |
240 | |
241 | static int __init ltc4151_init(void) |
242 | { |
243 | return i2c_add_driver(<c4151_driver); |
244 | } |
245 | |
246 | static void __exit ltc4151_exit(void) |
247 | { |
248 | i2c_del_driver(<c4151_driver); |
249 | } |
250 | |
251 | MODULE_AUTHOR("Per Dalen <per.dalen@appeartv.com>"); |
252 | MODULE_DESCRIPTION("LTC4151 driver"); |
253 | MODULE_LICENSE("GPL"); |
254 | |
255 | module_init(ltc4151_init); |
256 | module_exit(ltc4151_exit); |