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1 | /* |
2 | * Driver for Texas Instruments INA219, INA226 power monitor chips |
3 | * |
4 | * INA219: |
5 | * Zero Drift Bi-Directional Current/Power Monitor with I2C Interface |
6 | * Datasheet: http://www.ti.com/product/ina219 |
7 | * |
8 | * INA226: |
9 | * Bi-Directional Current/Power Monitor with I2C Interface |
10 | * Datasheet: http://www.ti.com/product/ina226 |
11 | * |
12 | * Copyright (C) 2012 Lothar Felten <l-felten@ti.com> |
13 | * Thanks to Jan Volkering |
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; version 2 of the License. |
18 | */ |
19 | |
20 | #include <linux/kernel.h> |
21 | #include <linux/module.h> |
22 | #include <linux/init.h> |
23 | #include <linux/err.h> |
24 | #include <linux/slab.h> |
25 | #include <linux/i2c.h> |
26 | #include <linux/hwmon.h> |
27 | #include <linux/hwmon-sysfs.h> |
28 | |
29 | #include <linux/platform_data/ina2xx.h> |
30 | |
31 | /* common register definitions */ |
32 | #define INA2XX_CONFIG 0x00 |
33 | #define INA2XX_SHUNT_VOLTAGE 0x01 /* readonly */ |
34 | #define INA2XX_BUS_VOLTAGE 0x02 /* readonly */ |
35 | #define INA2XX_POWER 0x03 /* readonly */ |
36 | #define INA2XX_CURRENT 0x04 /* readonly */ |
37 | #define INA2XX_CALIBRATION 0x05 |
38 | |
39 | /* INA226 register definitions */ |
40 | #define INA226_MASK_ENABLE 0x06 |
41 | #define INA226_ALERT_LIMIT 0x07 |
42 | #define INA226_DIE_ID 0xFF |
43 | |
44 | |
45 | /* register count */ |
46 | #define INA219_REGISTERS 6 |
47 | #define INA226_REGISTERS 8 |
48 | |
49 | #define INA2XX_MAX_REGISTERS 8 |
50 | |
51 | /* settings - depend on use case */ |
52 | #define INA219_CONFIG_DEFAULT 0x399F /* PGA=8 */ |
53 | #define INA226_CONFIG_DEFAULT 0x4527 /* averages=16 */ |
54 | |
55 | /* worst case is 68.10 ms (~14.6Hz, ina219) */ |
56 | #define INA2XX_CONVERSION_RATE 15 |
57 | |
58 | enum ina2xx_ids { ina219, ina226 }; |
59 | |
60 | struct ina2xx_data { |
61 | struct device *hwmon_dev; |
62 | |
63 | struct mutex update_lock; |
64 | bool valid; |
65 | unsigned long last_updated; |
66 | |
67 | int kind; |
68 | int registers; |
69 | u16 regs[INA2XX_MAX_REGISTERS]; |
70 | }; |
71 | |
72 | static struct ina2xx_data *ina2xx_update_device(struct device *dev) |
73 | { |
74 | struct i2c_client *client = to_i2c_client(dev); |
75 | struct ina2xx_data *data = i2c_get_clientdata(client); |
76 | struct ina2xx_data *ret = data; |
77 | |
78 | mutex_lock(&data->update_lock); |
79 | |
80 | if (time_after(jiffies, data->last_updated + |
81 | HZ / INA2XX_CONVERSION_RATE) || !data->valid) { |
82 | |
83 | int i; |
84 | |
85 | dev_dbg(&client->dev, "Starting ina2xx update\n"); |
86 | |
87 | /* Read all registers */ |
88 | for (i = 0; i < data->registers; i++) { |
89 | int rv = i2c_smbus_read_word_swapped(client, i); |
90 | if (rv < 0) { |
91 | ret = ERR_PTR(rv); |
92 | goto abort; |
93 | } |
94 | data->regs[i] = rv; |
95 | } |
96 | data->last_updated = jiffies; |
97 | data->valid = 1; |
98 | } |
99 | abort: |
100 | mutex_unlock(&data->update_lock); |
101 | return ret; |
102 | } |
103 | |
104 | static int ina219_get_value(struct ina2xx_data *data, u8 reg) |
105 | { |
106 | /* |
107 | * calculate exact value for the given register |
108 | * we assume default power-on reset settings: |
109 | * bus voltage range 32V |
110 | * gain = /8 |
111 | * adc 1 & 2 -> conversion time 532uS |
112 | * mode is continuous shunt and bus |
113 | * calibration value is INA219_CALIBRATION_VALUE |
114 | */ |
115 | int val = data->regs[reg]; |
116 | |
117 | switch (reg) { |
118 | case INA2XX_SHUNT_VOLTAGE: |
119 | /* LSB=10uV. Convert to mV. */ |
120 | val = DIV_ROUND_CLOSEST(val, 100); |
121 | break; |
122 | case INA2XX_BUS_VOLTAGE: |
123 | /* LSB=4mV. Register is not right aligned, convert to mV. */ |
124 | val = (val >> 3) * 4; |
125 | break; |
126 | case INA2XX_POWER: |
127 | /* LSB=20mW. Convert to uW */ |
128 | val = val * 20 * 1000; |
129 | break; |
130 | case INA2XX_CURRENT: |
131 | /* LSB=1mA (selected). Is in mA */ |
132 | break; |
133 | default: |
134 | /* programmer goofed */ |
135 | WARN_ON_ONCE(1); |
136 | val = 0; |
137 | break; |
138 | } |
139 | |
140 | return val; |
141 | } |
142 | |
143 | static int ina226_get_value(struct ina2xx_data *data, u8 reg) |
144 | { |
145 | /* |
146 | * calculate exact value for the given register |
147 | * we assume default power-on reset settings: |
148 | * bus voltage range 32V |
149 | * gain = /8 |
150 | * adc 1 & 2 -> conversion time 532uS |
151 | * mode is continuous shunt and bus |
152 | * calibration value is INA226_CALIBRATION_VALUE |
153 | */ |
154 | int val = data->regs[reg]; |
155 | |
156 | switch (reg) { |
157 | case INA2XX_SHUNT_VOLTAGE: |
158 | /* LSB=2.5uV. Convert to mV. */ |
159 | val = DIV_ROUND_CLOSEST(val, 400); |
160 | break; |
161 | case INA2XX_BUS_VOLTAGE: |
162 | /* LSB=1.25mV. Convert to mV. */ |
163 | val = val + DIV_ROUND_CLOSEST(val, 4); |
164 | break; |
165 | case INA2XX_POWER: |
166 | /* LSB=25mW. Convert to uW */ |
167 | val = val * 25 * 1000; |
168 | break; |
169 | case INA2XX_CURRENT: |
170 | /* LSB=1mA (selected). Is in mA */ |
171 | break; |
172 | default: |
173 | /* programmer goofed */ |
174 | WARN_ON_ONCE(1); |
175 | val = 0; |
176 | break; |
177 | } |
178 | |
179 | return val; |
180 | } |
181 | |
182 | static ssize_t ina2xx_show_value(struct device *dev, |
183 | struct device_attribute *da, char *buf) |
184 | { |
185 | struct sensor_device_attribute *attr = to_sensor_dev_attr(da); |
186 | struct ina2xx_data *data = ina2xx_update_device(dev); |
187 | int value = 0; |
188 | |
189 | if (IS_ERR(data)) |
190 | return PTR_ERR(data); |
191 | |
192 | switch (data->kind) { |
193 | case ina219: |
194 | value = ina219_get_value(data, attr->index); |
195 | break; |
196 | case ina226: |
197 | value = ina226_get_value(data, attr->index); |
198 | break; |
199 | default: |
200 | WARN_ON_ONCE(1); |
201 | break; |
202 | } |
203 | return snprintf(buf, PAGE_SIZE, "%d\n", value); |
204 | } |
205 | |
206 | /* shunt voltage */ |
207 | static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, \ |
208 | ina2xx_show_value, NULL, INA2XX_SHUNT_VOLTAGE); |
209 | |
210 | /* bus voltage */ |
211 | static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, \ |
212 | ina2xx_show_value, NULL, INA2XX_BUS_VOLTAGE); |
213 | |
214 | /* calculated current */ |
215 | static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, \ |
216 | ina2xx_show_value, NULL, INA2XX_CURRENT); |
217 | |
218 | /* calculated power */ |
219 | static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, \ |
220 | ina2xx_show_value, NULL, INA2XX_POWER); |
221 | |
222 | /* pointers to created device attributes */ |
223 | static struct attribute *ina2xx_attributes[] = { |
224 | &sensor_dev_attr_in0_input.dev_attr.attr, |
225 | &sensor_dev_attr_in1_input.dev_attr.attr, |
226 | &sensor_dev_attr_curr1_input.dev_attr.attr, |
227 | &sensor_dev_attr_power1_input.dev_attr.attr, |
228 | NULL, |
229 | }; |
230 | |
231 | static const struct attribute_group ina2xx_group = { |
232 | .attrs = ina2xx_attributes, |
233 | }; |
234 | |
235 | static int ina2xx_probe(struct i2c_client *client, |
236 | const struct i2c_device_id *id) |
237 | { |
238 | struct i2c_adapter *adapter = client->adapter; |
239 | struct ina2xx_data *data; |
240 | struct ina2xx_platform_data *pdata; |
241 | int ret = 0; |
242 | long shunt = 10000; /* default shunt value 10mOhms */ |
243 | |
244 | if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA)) |
245 | return -ENODEV; |
246 | |
247 | data = devm_kzalloc(&client->dev, sizeof(*data), GFP_KERNEL); |
248 | if (!data) |
249 | return -ENOMEM; |
250 | |
251 | if (client->dev.platform_data) { |
252 | pdata = |
253 | (struct ina2xx_platform_data *)client->dev.platform_data; |
254 | shunt = pdata->shunt_uohms; |
255 | } |
256 | |
257 | if (shunt <= 0) |
258 | return -ENODEV; |
259 | |
260 | /* set the device type */ |
261 | data->kind = id->driver_data; |
262 | |
263 | switch (data->kind) { |
264 | case ina219: |
265 | /* device configuration */ |
266 | i2c_smbus_write_word_swapped(client, INA2XX_CONFIG, |
267 | INA219_CONFIG_DEFAULT); |
268 | |
269 | /* set current LSB to 1mA, shunt is in uOhms */ |
270 | /* (equation 13 in datasheet) */ |
271 | i2c_smbus_write_word_swapped(client, INA2XX_CALIBRATION, |
272 | 40960000 / shunt); |
273 | dev_info(&client->dev, |
274 | "power monitor INA219 (Rshunt = %li uOhm)\n", shunt); |
275 | data->registers = INA219_REGISTERS; |
276 | break; |
277 | case ina226: |
278 | /* device configuration */ |
279 | i2c_smbus_write_word_swapped(client, INA2XX_CONFIG, |
280 | INA226_CONFIG_DEFAULT); |
281 | |
282 | /* set current LSB to 1mA, shunt is in uOhms */ |
283 | /* (equation 1 in datasheet)*/ |
284 | i2c_smbus_write_word_swapped(client, INA2XX_CALIBRATION, |
285 | 5120000 / shunt); |
286 | dev_info(&client->dev, |
287 | "power monitor INA226 (Rshunt = %li uOhm)\n", shunt); |
288 | data->registers = INA226_REGISTERS; |
289 | break; |
290 | default: |
291 | /* unknown device id */ |
292 | return -ENODEV; |
293 | } |
294 | |
295 | i2c_set_clientdata(client, data); |
296 | mutex_init(&data->update_lock); |
297 | |
298 | ret = sysfs_create_group(&client->dev.kobj, &ina2xx_group); |
299 | if (ret) |
300 | return ret; |
301 | |
302 | data->hwmon_dev = hwmon_device_register(&client->dev); |
303 | if (IS_ERR(data->hwmon_dev)) { |
304 | ret = PTR_ERR(data->hwmon_dev); |
305 | goto out_err_hwmon; |
306 | } |
307 | |
308 | return 0; |
309 | |
310 | out_err_hwmon: |
311 | sysfs_remove_group(&client->dev.kobj, &ina2xx_group); |
312 | return ret; |
313 | } |
314 | |
315 | static int ina2xx_remove(struct i2c_client *client) |
316 | { |
317 | struct ina2xx_data *data = i2c_get_clientdata(client); |
318 | |
319 | hwmon_device_unregister(data->hwmon_dev); |
320 | sysfs_remove_group(&client->dev.kobj, &ina2xx_group); |
321 | |
322 | return 0; |
323 | } |
324 | |
325 | static const struct i2c_device_id ina2xx_id[] = { |
326 | { "ina219", ina219 }, |
327 | { "ina226", ina226 }, |
328 | { } |
329 | }; |
330 | MODULE_DEVICE_TABLE(i2c, ina2xx_id); |
331 | |
332 | static struct i2c_driver ina2xx_driver = { |
333 | .driver = { |
334 | .name = "ina2xx", |
335 | }, |
336 | .probe = ina2xx_probe, |
337 | .remove = ina2xx_remove, |
338 | .id_table = ina2xx_id, |
339 | }; |
340 | |
341 | static int __init ina2xx_init(void) |
342 | { |
343 | return i2c_add_driver(&ina2xx_driver); |
344 | } |
345 | |
346 | static void __exit ina2xx_exit(void) |
347 | { |
348 | i2c_del_driver(&ina2xx_driver); |
349 | } |
350 | |
351 | MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>"); |
352 | MODULE_DESCRIPTION("ina2xx driver"); |
353 | MODULE_LICENSE("GPL"); |
354 | |
355 | module_init(ina2xx_init); |
356 | module_exit(ina2xx_exit); |
357 |
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