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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
58enum ina2xx_ids { ina219, ina226 };
59
60struct 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
72static 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 }
99abort:
100 mutex_unlock(&data->update_lock);
101 return ret;
102}
103
104static 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
143static 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
182static 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 */
207static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, \
208 ina2xx_show_value, NULL, INA2XX_SHUNT_VOLTAGE);
209
210/* bus voltage */
211static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, \
212 ina2xx_show_value, NULL, INA2XX_BUS_VOLTAGE);
213
214/* calculated current */
215static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, \
216 ina2xx_show_value, NULL, INA2XX_CURRENT);
217
218/* calculated power */
219static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, \
220 ina2xx_show_value, NULL, INA2XX_POWER);
221
222/* pointers to created device attributes */
223static 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
231static const struct attribute_group ina2xx_group = {
232 .attrs = ina2xx_attributes,
233};
234
235static 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
310out_err_hwmon:
311 sysfs_remove_group(&client->dev.kobj, &ina2xx_group);
312 return ret;
313}
314
315static 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
325static const struct i2c_device_id ina2xx_id[] = {
326 { "ina219", ina219 },
327 { "ina226", ina226 },
328 { }
329};
330MODULE_DEVICE_TABLE(i2c, ina2xx_id);
331
332static 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
341static int __init ina2xx_init(void)
342{
343 return i2c_add_driver(&ina2xx_driver);
344}
345
346static void __exit ina2xx_exit(void)
347{
348 i2c_del_driver(&ina2xx_driver);
349}
350
351MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
352MODULE_DESCRIPTION("ina2xx driver");
353MODULE_LICENSE("GPL");
354
355module_init(ina2xx_init);
356module_exit(ina2xx_exit);