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Dirk Eibach8c22a8f2011-03-21 17:59:36 +01001/*
2 * ads1015.c - lm_sensors driver for ads1015 12-bit 4-input ADC
3 * (C) Copyright 2010
4 * Dirk Eibach, Guntermann & Drunck GmbH <eibach@gdsys.de>
5 *
6 * Based on the ads7828 driver by Steve Hardy.
7 *
8 * Datasheet available at: http://focus.ti.com/lit/ds/symlink/ads1015.pdf
9 *
10 * This program is free software; you can redistribute it and/or modify
11 * it under the terms of the GNU General Public License as published by
12 * the Free Software Foundation; either version 2 of the License, or
13 * (at your option) any later version.
14 *
15 * This program is distributed in the hope that it will be useful,
16 * but WITHOUT ANY WARRANTY; without even the implied warranty of
17 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
18 * GNU General Public License for more details.
19 *
20 * You should have received a copy of the GNU General Public License
21 * along with this program; if not, write to the Free Software
22 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
23 */
24
25#include <linux/module.h>
26#include <linux/init.h>
27#include <linux/slab.h>
28#include <linux/delay.h>
29#include <linux/i2c.h>
30#include <linux/hwmon.h>
31#include <linux/hwmon-sysfs.h>
32#include <linux/err.h>
33#include <linux/mutex.h>
34#include <linux/of.h>
35
36#include <linux/i2c/ads1015.h>
37
38/* ADS1015 registers */
39enum {
40 ADS1015_CONVERSION = 0,
41 ADS1015_CONFIG = 1,
42};
43
44/* PGA fullscale voltages in mV */
45static const unsigned int fullscale_table[8] = {
46 6144, 4096, 2048, 1024, 512, 256, 256, 256 };
47
Dirk Eibachc0046862011-03-21 17:59:37 +010048/* Data rates in samples per second */
49static const unsigned int data_rate_table[8] = {
50 128, 250, 490, 920, 1600, 2400, 3300, 3300 };
51
Dirk Eibach8c22a8f2011-03-21 17:59:36 +010052#define ADS1015_DEFAULT_CHANNELS 0xff
Dirk Eibachc0046862011-03-21 17:59:37 +010053#define ADS1015_DEFAULT_PGA 2
54#define ADS1015_DEFAULT_DATA_RATE 4
Dirk Eibach8c22a8f2011-03-21 17:59:36 +010055
56struct ads1015_data {
57 struct device *hwmon_dev;
58 struct mutex update_lock; /* mutex protect updates */
Dirk Eibachc0046862011-03-21 17:59:37 +010059 struct ads1015_channel_data channel_data[ADS1015_CHANNELS];
Dirk Eibach8c22a8f2011-03-21 17:59:36 +010060};
61
Dirk Eibach8c22a8f2011-03-21 17:59:36 +010062static int ads1015_read_value(struct i2c_client *client, unsigned int channel,
63 int *value)
64{
65 u16 config;
66 s16 conversion;
Dirk Eibach8c22a8f2011-03-21 17:59:36 +010067 struct ads1015_data *data = i2c_get_clientdata(client);
Dirk Eibachc0046862011-03-21 17:59:37 +010068 unsigned int pga = data->channel_data[channel].pga;
69 int fullscale;
70 unsigned int data_rate = data->channel_data[channel].data_rate;
71 unsigned int conversion_time_ms;
Dirk Eibach8c22a8f2011-03-21 17:59:36 +010072 int res;
73
74 mutex_lock(&data->update_lock);
75
Dirk Eibachc0046862011-03-21 17:59:37 +010076 /* get channel parameters */
Jean Delvare90f41022011-11-04 12:00:47 +010077 res = i2c_smbus_read_word_swapped(client, ADS1015_CONFIG);
Dirk Eibach8c22a8f2011-03-21 17:59:36 +010078 if (res < 0)
79 goto err_unlock;
80 config = res;
Dirk Eibach8c22a8f2011-03-21 17:59:36 +010081 fullscale = fullscale_table[pga];
Dirk Eibachc0046862011-03-21 17:59:37 +010082 conversion_time_ms = DIV_ROUND_UP(1000, data_rate_table[data_rate]);
Dirk Eibach8c22a8f2011-03-21 17:59:36 +010083
Dirk Eibachc0046862011-03-21 17:59:37 +010084 /* setup and start single conversion */
85 config &= 0x001f;
86 config |= (1 << 15) | (1 << 8);
87 config |= (channel & 0x0007) << 12;
88 config |= (pga & 0x0007) << 9;
89 config |= (data_rate & 0x0007) << 5;
Dirk Eibach8c22a8f2011-03-21 17:59:36 +010090
Jean Delvare90f41022011-11-04 12:00:47 +010091 res = i2c_smbus_write_word_swapped(client, ADS1015_CONFIG, config);
Dirk Eibach8c22a8f2011-03-21 17:59:36 +010092 if (res < 0)
93 goto err_unlock;
Dirk Eibachc0046862011-03-21 17:59:37 +010094
95 /* wait until conversion finished */
96 msleep(conversion_time_ms);
Jean Delvare90f41022011-11-04 12:00:47 +010097 res = i2c_smbus_read_word_swapped(client, ADS1015_CONFIG);
Dirk Eibachc0046862011-03-21 17:59:37 +010098 if (res < 0)
99 goto err_unlock;
100 config = res;
101 if (!(config & (1 << 15))) {
102 /* conversion not finished in time */
Dirk Eibach8c22a8f2011-03-21 17:59:36 +0100103 res = -EIO;
104 goto err_unlock;
105 }
106
Jean Delvare90f41022011-11-04 12:00:47 +0100107 res = i2c_smbus_read_word_swapped(client, ADS1015_CONVERSION);
Dirk Eibach8c22a8f2011-03-21 17:59:36 +0100108 if (res < 0)
109 goto err_unlock;
110 conversion = res;
111
112 mutex_unlock(&data->update_lock);
113
114 *value = DIV_ROUND_CLOSEST(conversion * fullscale, 0x7ff0);
115
116 return 0;
117
118err_unlock:
119 mutex_unlock(&data->update_lock);
120 return res;
121}
122
123/* sysfs callback function */
124static ssize_t show_in(struct device *dev, struct device_attribute *da,
125 char *buf)
126{
127 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
128 struct i2c_client *client = to_i2c_client(dev);
129 int in;
130 int res;
131
132 res = ads1015_read_value(client, attr->index, &in);
133
134 return (res < 0) ? res : sprintf(buf, "%d\n", in);
135}
136
Jean Delvarefdf241a2011-03-21 17:59:37 +0100137static const struct sensor_device_attribute ads1015_in[] = {
138 SENSOR_ATTR(in0_input, S_IRUGO, show_in, NULL, 0),
139 SENSOR_ATTR(in1_input, S_IRUGO, show_in, NULL, 1),
140 SENSOR_ATTR(in2_input, S_IRUGO, show_in, NULL, 2),
141 SENSOR_ATTR(in3_input, S_IRUGO, show_in, NULL, 3),
142 SENSOR_ATTR(in4_input, S_IRUGO, show_in, NULL, 4),
143 SENSOR_ATTR(in5_input, S_IRUGO, show_in, NULL, 5),
144 SENSOR_ATTR(in6_input, S_IRUGO, show_in, NULL, 6),
145 SENSOR_ATTR(in7_input, S_IRUGO, show_in, NULL, 7),
Dirk Eibach8c22a8f2011-03-21 17:59:36 +0100146};
147
148/*
149 * Driver interface
150 */
151
152static int ads1015_remove(struct i2c_client *client)
153{
154 struct ads1015_data *data = i2c_get_clientdata(client);
Jean Delvarefdf241a2011-03-21 17:59:37 +0100155 int k;
156
Dirk Eibach8c22a8f2011-03-21 17:59:36 +0100157 hwmon_device_unregister(data->hwmon_dev);
Dirk Eibachc0046862011-03-21 17:59:37 +0100158 for (k = 0; k < ADS1015_CHANNELS; ++k)
Jean Delvarefdf241a2011-03-21 17:59:37 +0100159 device_remove_file(&client->dev, &ads1015_in[k].dev_attr);
Dirk Eibach8c22a8f2011-03-21 17:59:36 +0100160 kfree(data);
161 return 0;
162}
163
Dirk Eibach8c22a8f2011-03-21 17:59:36 +0100164#ifdef CONFIG_OF
Dirk Eibachc0046862011-03-21 17:59:37 +0100165static int ads1015_get_channels_config_of(struct i2c_client *client)
166{
167 struct ads1015_data *data = i2c_get_clientdata(client);
168 struct device_node *node;
169
170 if (!client->dev.of_node
171 || !of_get_next_child(client->dev.of_node, NULL))
172 return -EINVAL;
173
174 for_each_child_of_node(client->dev.of_node, node) {
175 const __be32 *property;
176 int len;
177 unsigned int channel;
178 unsigned int pga = ADS1015_DEFAULT_PGA;
179 unsigned int data_rate = ADS1015_DEFAULT_DATA_RATE;
180
181 property = of_get_property(node, "reg", &len);
182 if (!property || len != sizeof(int)) {
183 dev_err(&client->dev, "invalid reg on %s\n",
184 node->full_name);
185 continue;
186 }
187
188 channel = be32_to_cpup(property);
189 if (channel > ADS1015_CHANNELS) {
190 dev_err(&client->dev,
191 "invalid channel index %d on %s\n",
192 channel, node->full_name);
193 continue;
194 }
195
196 property = of_get_property(node, "ti,gain", &len);
197 if (property && len == sizeof(int)) {
198 pga = be32_to_cpup(property);
199 if (pga > 6) {
200 dev_err(&client->dev,
201 "invalid gain on %s\n",
202 node->full_name);
203 }
204 }
205
206 property = of_get_property(node, "ti,datarate", &len);
207 if (property && len == sizeof(int)) {
208 data_rate = be32_to_cpup(property);
209 if (data_rate > 7) {
210 dev_err(&client->dev,
211 "invalid data_rate on %s\n",
212 node->full_name);
213 }
214 }
215
216 data->channel_data[channel].enabled = true;
217 data->channel_data[channel].pga = pga;
218 data->channel_data[channel].data_rate = data_rate;
219 }
220
221 return 0;
222}
Dirk Eibach8c22a8f2011-03-21 17:59:36 +0100223#endif
224
Dirk Eibachc0046862011-03-21 17:59:37 +0100225static void ads1015_get_channels_config(struct i2c_client *client)
226{
227 unsigned int k;
228 struct ads1015_data *data = i2c_get_clientdata(client);
229 struct ads1015_platform_data *pdata = dev_get_platdata(&client->dev);
230
Dirk Eibach8c22a8f2011-03-21 17:59:36 +0100231 /* prefer platform data */
Dirk Eibachc0046862011-03-21 17:59:37 +0100232 if (pdata) {
233 memcpy(data->channel_data, pdata->channel_data,
234 sizeof(data->channel_data));
235 return;
236 }
Dirk Eibach8c22a8f2011-03-21 17:59:36 +0100237
238#ifdef CONFIG_OF
Dirk Eibachc0046862011-03-21 17:59:37 +0100239 if (!ads1015_get_channels_config_of(client))
240 return;
Dirk Eibach8c22a8f2011-03-21 17:59:36 +0100241#endif
242
243 /* fallback on default configuration */
Dirk Eibachc0046862011-03-21 17:59:37 +0100244 for (k = 0; k < ADS1015_CHANNELS; ++k) {
245 data->channel_data[k].enabled = true;
246 data->channel_data[k].pga = ADS1015_DEFAULT_PGA;
247 data->channel_data[k].data_rate = ADS1015_DEFAULT_DATA_RATE;
248 }
Dirk Eibach8c22a8f2011-03-21 17:59:36 +0100249}
250
251static int ads1015_probe(struct i2c_client *client,
252 const struct i2c_device_id *id)
253{
254 struct ads1015_data *data;
255 int err;
Dirk Eibach8c22a8f2011-03-21 17:59:36 +0100256 unsigned int k;
Dirk Eibach8c22a8f2011-03-21 17:59:36 +0100257
258 data = kzalloc(sizeof(struct ads1015_data), GFP_KERNEL);
259 if (!data) {
260 err = -ENOMEM;
261 goto exit;
262 }
263
264 i2c_set_clientdata(client, data);
265 mutex_init(&data->update_lock);
266
267 /* build sysfs attribute group */
Dirk Eibachc0046862011-03-21 17:59:37 +0100268 ads1015_get_channels_config(client);
269 for (k = 0; k < ADS1015_CHANNELS; ++k) {
270 if (!data->channel_data[k].enabled)
Dirk Eibach8c22a8f2011-03-21 17:59:36 +0100271 continue;
Jean Delvarefdf241a2011-03-21 17:59:37 +0100272 err = device_create_file(&client->dev, &ads1015_in[k].dev_attr);
273 if (err)
Guenter Roeck363434b2012-02-22 08:13:52 -0800274 goto exit_remove;
Dirk Eibach8c22a8f2011-03-21 17:59:36 +0100275 }
Dirk Eibach8c22a8f2011-03-21 17:59:36 +0100276
277 data->hwmon_dev = hwmon_device_register(&client->dev);
278 if (IS_ERR(data->hwmon_dev)) {
279 err = PTR_ERR(data->hwmon_dev);
280 goto exit_remove;
281 }
282
283 return 0;
284
285exit_remove:
Dirk Eibachc0046862011-03-21 17:59:37 +0100286 for (k = 0; k < ADS1015_CHANNELS; ++k)
Jean Delvarefdf241a2011-03-21 17:59:37 +0100287 device_remove_file(&client->dev, &ads1015_in[k].dev_attr);
Dirk Eibach8c22a8f2011-03-21 17:59:36 +0100288 kfree(data);
289exit:
290 return err;
291}
292
293static const struct i2c_device_id ads1015_id[] = {
294 { "ads1015", 0 },
295 { }
296};
297MODULE_DEVICE_TABLE(i2c, ads1015_id);
298
299static struct i2c_driver ads1015_driver = {
300 .driver = {
301 .name = "ads1015",
302 },
303 .probe = ads1015_probe,
304 .remove = ads1015_remove,
305 .id_table = ads1015_id,
306};
307
Axel Linf0967ee2012-01-20 15:38:18 +0800308module_i2c_driver(ads1015_driver);
Dirk Eibach8c22a8f2011-03-21 17:59:36 +0100309
310MODULE_AUTHOR("Dirk Eibach <eibach@gdsys.de>");
311MODULE_DESCRIPTION("ADS1015 driver");
312MODULE_LICENSE("GPL");