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
68enum ina2xx_ids { ina219, ina226 };
69
70struct 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
80struct 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
92static 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
113static 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	}
140abort:
141	mutex_unlock(&data->update_lock);
142	return ret;
143}
144
145static 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
177static 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 */
191static SENSOR_DEVICE_ATTR(in0_input, S_IRUGO, ina2xx_show_value, NULL,
192			  INA2XX_SHUNT_VOLTAGE);
193
194/* bus voltage */
195static SENSOR_DEVICE_ATTR(in1_input, S_IRUGO, ina2xx_show_value, NULL,
196			  INA2XX_BUS_VOLTAGE);
197
198/* calculated current */
199static SENSOR_DEVICE_ATTR(curr1_input, S_IRUGO, ina2xx_show_value, NULL,
200			  INA2XX_CURRENT);
201
202/* calculated power */
203static SENSOR_DEVICE_ATTR(power1_input, S_IRUGO, ina2xx_show_value, NULL,
204			  INA2XX_POWER);
205
206/* pointers to created device attributes */
207static 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};
214ATTRIBUTE_GROUPS(ina2xx);
215
216static 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
271static const struct i2c_device_id ina2xx_id[] = {
272	{ "ina219", ina219 },
273	{ "ina220", ina219 },
274	{ "ina226", ina226 },
275	{ "ina230", ina226 },
276	{ }
277};
278MODULE_DEVICE_TABLE(i2c, ina2xx_id);
279
280static struct i2c_driver ina2xx_driver = {
281	.driver = {
282		.name	= "ina2xx",
283	},
284	.probe		= ina2xx_probe,
285	.id_table	= ina2xx_id,
286};
287
288module_i2c_driver(ina2xx_driver);
289
290MODULE_AUTHOR("Lothar Felten <l-felten@ti.com>");
291MODULE_DESCRIPTION("ina2xx driver");
292MODULE_LICENSE("GPL");
293