xref: /openbmc/linux/drivers/hwmon/ina2xx.c (revision d2999e1b)
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 
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 
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 
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 
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