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 * INA220:
9 * Bi-Directional Current/Power Monitor with I2C Interface
10 * Datasheet: http://www.ti.com/product/ina220
11 *
12 * INA226:
13 * Bi-Directional Current/Power Monitor with I2C Interface
14 * Datasheet: http://www.ti.com/product/ina226
15 *
16 * INA230:
17 * Bi-directional Current/Power Monitor with I2C Interface
18 * Datasheet: http://www.ti.com/product/ina230
19 *
20 * Copyright (C) 2012 Lothar Felten <l-felten@ti.com>
21 * Thanks to Jan Volkering
22 *
23 * This program is free software; you can redistribute it and/or modify
24 * it under the terms of the GNU General Public License as published by
25 * the Free Software Foundation; version 2 of the License.
26 */
27
28 #include <linux/kernel.h>
29 #include <linux/module.h>
30 #include <linux/init.h>
31 #include <linux/err.h>
32 #include <linux/slab.h>
33 #include <linux/i2c.h>
34 #include <linux/hwmon.h>
35 #include <linux/hwmon-sysfs.h>
36 #include <linux/jiffies.h>
37 #include <linux/of.h>
38
39 #include <linux/platform_data/ina2xx.h>
40
41 /* common register definitions */
42 #define INA2XX_CONFIG 0x00
43 #define INA2XX_SHUNT_VOLTAGE 0x01 /* readonly */
44 #define INA2XX_BUS_VOLTAGE 0x02 /* readonly */
45 #define INA2XX_POWER 0x03 /* readonly */
46 #define INA2XX_CURRENT 0x04 /* readonly */
47 #define INA2XX_CALIBRATION 0x05
48
49 /* INA226 register definitions */
50 #define INA226_MASK_ENABLE 0x06
51 #define INA226_ALERT_LIMIT 0x07
52 #define INA226_DIE_ID 0xFF
53
54
55 /* register count */
56 #define INA219_REGISTERS 6
57 #define INA226_REGISTERS 8
58
59 #define INA2XX_MAX_REGISTERS 8
60
61 /* settings - depend on use case */
62 #define INA219_CONFIG_DEFAULT 0x399F /* PGA=8 */
63 #define INA226_CONFIG_DEFAULT 0x4527 /* averages=16 */
64
65 /* worst case is 68.10 ms (~14.6Hz, ina219) */
66 #define INA2XX_CONVERSION_RATE 15
67
68 enum ina2xx_ids { ina219, ina226 };
69
70 struct ina2xx_config {
71 u16 config_default;
72 int calibration_factor;
73 int registers;
74 int shunt_div;
75 int bus_voltage_shift;
76 int bus_voltage_lsb; /* uV */
77 int power_lsb; /* uW */
78 };
79
80 struct ina2xx_data {
81 struct i2c_client *client;
82 const struct ina2xx_config *config;
83
84 struct mutex update_lock;
85 bool valid;
86 unsigned long last_updated;
87
88 int kind;
89 u16 regs[INA2XX_MAX_REGISTERS];
90 };
91
92 static const struct ina2xx_config ina2xx_config[] = {
93 [ina219] = {
94 .config_default = INA219_CONFIG_DEFAULT,
95 .calibration_factor = 40960000,
96 .registers = INA219_REGISTERS,
97 .shunt_div = 100,
98 .bus_voltage_shift = 3,
99 .bus_voltage_lsb = 4000,
100 .power_lsb = 20000,
101 },
102 [ina226] = {
103 .config_default = INA226_CONFIG_DEFAULT,
104 .calibration_factor = 5120000,
105 .registers = INA226_REGISTERS,
106 .shunt_div = 400,
107 .bus_voltage_shift = 0,
108 .bus_voltage_lsb = 1250,
109 .power_lsb = 25000,
110 },
111 };
112
ina2xx_update_device(struct device * dev)113 static struct ina2xx_data *ina2xx_update_device(struct device *dev)
114 {
115 struct ina2xx_data *data = dev_get_drvdata(dev);
116 struct i2c_client *client = data->client;
117 struct ina2xx_data *ret = data;
118
119 mutex_lock(&data->update_lock);
120
121 if (time_after(jiffies, data->last_updated +
122 HZ / INA2XX_CONVERSION_RATE) || !data->valid) {
123
124 int i;
125
126 dev_dbg(&client->dev, "Starting ina2xx update\n");
127
128 /* Read all registers */
129 for (i = 0; i < data->config->registers; i++) {
130 int rv = i2c_smbus_read_word_swapped(client, i);
131 if (rv < 0) {
132 ret = ERR_PTR(rv);
133 goto abort;
134 }
135 data->regs[i] = rv;
136 }
137 data->last_updated = jiffies;
138 data->valid = 1;
139 }
140 abort:
141 mutex_unlock(&data->update_lock);
142 return ret;
143 }
144
ina2xx_get_value(struct ina2xx_data * data,u8 reg)145 static int ina2xx_get_value(struct ina2xx_data *data, u8 reg)
146 {
147 int val;
148
149 switch (reg) {
150 case INA2XX_SHUNT_VOLTAGE:
151 /* signed register */
152 val = DIV_ROUND_CLOSEST((s16)data->regs[reg],
153 data->config->shunt_div);
154 break;
155 case INA2XX_BUS_VOLTAGE:
156 val = (data->regs[reg] >> data->config->bus_voltage_shift)
157 * data->config->bus_voltage_lsb;
158 val = DIV_ROUND_CLOSEST(val, 1000);
159 break;
160 case INA2XX_POWER:
161 val = data->regs[reg] * data->config->power_lsb;
162 break;
163 case INA2XX_CURRENT:
164 /* signed register, LSB=1mA (selected), in mA */
165 val = (s16)data->regs[reg];
166 break;
167 default:
168 /* programmer goofed */
169 WARN_ON_ONCE(1);
170 val = 0;
171 break;
172 }
173
174 return val;
175 }
176
ina2xx_show_value(struct device * dev,struct device_attribute * da,char * buf)177 static ssize_t ina2xx_show_value(struct device *dev,
178 struct device_attribute *da, char *buf)
179 {
180 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
181 struct ina2xx_data *data = ina2xx_update_device(dev);
182
183 if (IS_ERR(data))
184 return PTR_ERR(data);
185
186 return snprintf(buf, PAGE_SIZE, "%d\n",
187 ina2xx_get_value(data, attr->index));
188 }
189
190 /* shunt voltage */
191 static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina2xx_show_value, NULL,
192 INA2XX_SHUNT_VOLTAGE);
193
194 /* bus voltage */
195 static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina2xx_show_value, NULL,
196 INA2XX_BUS_VOLTAGE);
197
198 /* calculated current */
199 static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina2xx_show_value, NULL,
200 INA2XX_CURRENT);
201
202 /* calculated power */
203 static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL,
204 INA2XX_POWER);
205
206 /* pointers to created device attributes */
207 static struct attribute *ina2xx_attrs[] = {
208 &sensor_dev_attr_in0_input.dev_attr.attr,
209 &sensor_dev_attr_in1_input.dev_attr.attr,
210 &sensor_dev_attr_curr1_input.dev_attr.attr,
211 &sensor_dev_attr_power1_input.dev_attr.attr,
212 NULL,
213 };
214 ATTRIBUTE_GROUPS(ina2xx);
215
ina2xx_probe(struct i2c_client * client,const struct i2c_device_id * id)216 static int ina2xx_probe(struct i2c_client *client,
217 const struct i2c_device_id *id)
218 {
219 struct i2c_adapter *adapter = client->adapter;
220 struct ina2xx_platform_data *pdata;
221 struct device *dev = &client->dev;
222 struct ina2xx_data *data;
223 struct device *hwmon_dev;
224 long shunt = 10000; /* default shunt value 10mOhms */
225 u32 val;
226
227 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_WORD_DATA))
228 return -ENODEV;
229
230 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
231 if (!data)
232 return -ENOMEM;
233
234 if (dev_get_platdata(dev)) {
235 pdata = dev_get_platdata(dev);
236 shunt = pdata->shunt_uohms;
237 } else if (!of_property_read_u32(dev->of_node,
238 "shunt-resistor", &val)) {
239 shunt = val;
240 }
241
242 if (shunt <= 0)
243 return -ENODEV;
244
245 /* set the device type */
246 data->kind = id->driver_data;
247 data->config = &ina2xx_config[data->kind];
248
249 /* device configuration */
250 i2c_smbus_write_word_swapped(client, INA2XX_CONFIG,
251 data->config->config_default);
252 /* set current LSB to 1mA, shunt is in uOhms */
253 /* (equation 13 in datasheet) */
254 i2c_smbus_write_word_swapped(client, INA2XX_CALIBRATION,
255 data->config->calibration_factor / shunt);
256
257 data->client = client;
258 mutex_init(&data->update_lock);
259
260 hwmon_dev = devm_hwmon_device_register_with_groups(dev, client->name,
261 data, ina2xx_groups);
262 if (IS_ERR(hwmon_dev))
263 return PTR_ERR(hwmon_dev);
264
265 dev_info(dev, "power monitor %s (Rshunt = %li uOhm)\n",
266 id->name, shunt);
267
268 return 0;
269 }
270
271 static const struct i2c_device_id ina2xx_id[] = {
272 { "ina219", ina219 },
273 { "ina220", ina219 },
274 { "ina226", ina226 },
275 { "ina230", ina226 },
276 { }
277 };
278 MODULE_DEVICE_TABLE(i2c, ina2xx_id);
279
280 static struct i2c_driver ina2xx_driver = {
281 .driver = {
282 .name = "ina2xx",
283 },
284 .probe = ina2xx_probe,
285 .id_table = ina2xx_id,
286 };
287
288 module_i2c_driver(ina2xx_driver);
289
290 MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
291 MODULE_DESCRIPTION("ina2xx driver");
292 MODULE_LICENSE("GPL");
293