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1/*
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
48/* Data rates in samples per second */
49static const unsigned int data_rate_table[8] = {
50 128, 250, 490, 920, 1600, 2400, 3300, 3300 };
51
52#define ADS1015_DEFAULT_CHANNELS 0xff
53#define ADS1015_DEFAULT_PGA 2
54#define ADS1015_DEFAULT_DATA_RATE 4
55
56struct ads1015_data {
57 struct device *hwmon_dev;
58 struct mutex update_lock; /* mutex protect updates */
59 struct ads1015_channel_data channel_data[ADS1015_CHANNELS];
60};
61
62static s32 ads1015_read_reg(struct i2c_client *client, unsigned int reg)
63{
64 s32 data = i2c_smbus_read_word_data(client, reg);
65
66 return (data < 0) ? data : swab16(data);
67}
68
69static s32 ads1015_write_reg(struct i2c_client *client, unsigned int reg,
70 u16 val)
71{
72 return i2c_smbus_write_word_data(client, reg, swab16(val));
73}
74
75static int ads1015_read_value(struct i2c_client *client, unsigned int channel,
76 int *value)
77{
78 u16 config;
79 s16 conversion;
80 struct ads1015_data *data = i2c_get_clientdata(client);
81 unsigned int pga = data->channel_data[channel].pga;
82 int fullscale;
83 unsigned int data_rate = data->channel_data[channel].data_rate;
84 unsigned int conversion_time_ms;
85 int res;
86
87 mutex_lock(&data->update_lock);
88
89 /* get channel parameters */
90 res = ads1015_read_reg(client, ADS1015_CONFIG);
91 if (res < 0)
92 goto err_unlock;
93 config = res;
94 fullscale = fullscale_table[pga];
95 conversion_time_ms = DIV_ROUND_UP(1000, data_rate_table[data_rate]);
96
97 /* setup and start single conversion */
98 config &= 0x001f;
99 config |= (1 << 15) | (1 << 8);
100 config |= (channel & 0x0007) << 12;
101 config |= (pga & 0x0007) << 9;
102 config |= (data_rate & 0x0007) << 5;
103
104 res = ads1015_write_reg(client, ADS1015_CONFIG, config);
105 if (res < 0)
106 goto err_unlock;
107
108 /* wait until conversion finished */
109 msleep(conversion_time_ms);
110 res = ads1015_read_reg(client, ADS1015_CONFIG);
111 if (res < 0)
112 goto err_unlock;
113 config = res;
114 if (!(config & (1 << 15))) {
115 /* conversion not finished in time */
116 res = -EIO;
117 goto err_unlock;
118 }
119
120 res = ads1015_read_reg(client, ADS1015_CONVERSION);
121 if (res < 0)
122 goto err_unlock;
123 conversion = res;
124
125 mutex_unlock(&data->update_lock);
126
127 *value = DIV_ROUND_CLOSEST(conversion * fullscale, 0x7ff0);
128
129 return 0;
130
131err_unlock:
132 mutex_unlock(&data->update_lock);
133 return res;
134}
135
136/* sysfs callback function */
137static ssize_t show_in(struct device *dev, struct device_attribute *da,
138 char *buf)
139{
140 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
141 struct i2c_client *client = to_i2c_client(dev);
142 int in;
143 int res;
144
145 res = ads1015_read_value(client, attr->index, &in);
146
147 return (res < 0) ? res : sprintf(buf, "%d\n", in);
148}
149
150static const struct sensor_device_attribute ads1015_in[] = {
151 SENSOR_ATTR(in0_input, S_IRUGO, show_in, NULL, 0),
152 SENSOR_ATTR(in1_input, S_IRUGO, show_in, NULL, 1),
153 SENSOR_ATTR(in2_input, S_IRUGO, show_in, NULL, 2),
154 SENSOR_ATTR(in3_input, S_IRUGO, show_in, NULL, 3),
155 SENSOR_ATTR(in4_input, S_IRUGO, show_in, NULL, 4),
156 SENSOR_ATTR(in5_input, S_IRUGO, show_in, NULL, 5),
157 SENSOR_ATTR(in6_input, S_IRUGO, show_in, NULL, 6),
158 SENSOR_ATTR(in7_input, S_IRUGO, show_in, NULL, 7),
159};
160
161/*
162 * Driver interface
163 */
164
165static int ads1015_remove(struct i2c_client *client)
166{
167 struct ads1015_data *data = i2c_get_clientdata(client);
168 int k;
169
170 hwmon_device_unregister(data->hwmon_dev);
171 for (k = 0; k < ADS1015_CHANNELS; ++k)
172 device_remove_file(&client->dev, &ads1015_in[k].dev_attr);
173 kfree(data);
174 return 0;
175}
176
177#ifdef CONFIG_OF
178static int ads1015_get_channels_config_of(struct i2c_client *client)
179{
180 struct ads1015_data *data = i2c_get_clientdata(client);
181 struct device_node *node;
182
183 if (!client->dev.of_node
184 || !of_get_next_child(client->dev.of_node, NULL))
185 return -EINVAL;
186
187 for_each_child_of_node(client->dev.of_node, node) {
188 const __be32 *property;
189 int len;
190 unsigned int channel;
191 unsigned int pga = ADS1015_DEFAULT_PGA;
192 unsigned int data_rate = ADS1015_DEFAULT_DATA_RATE;
193
194 property = of_get_property(node, "reg", &len);
195 if (!property || len != sizeof(int)) {
196 dev_err(&client->dev, "invalid reg on %s\n",
197 node->full_name);
198 continue;
199 }
200
201 channel = be32_to_cpup(property);
202 if (channel > ADS1015_CHANNELS) {
203 dev_err(&client->dev,
204 "invalid channel index %d on %s\n",
205 channel, node->full_name);
206 continue;
207 }
208
209 property = of_get_property(node, "ti,gain", &len);
210 if (property && len == sizeof(int)) {
211 pga = be32_to_cpup(property);
212 if (pga > 6) {
213 dev_err(&client->dev,
214 "invalid gain on %s\n",
215 node->full_name);
216 }
217 }
218
219 property = of_get_property(node, "ti,datarate", &len);
220 if (property && len == sizeof(int)) {
221 data_rate = be32_to_cpup(property);
222 if (data_rate > 7) {
223 dev_err(&client->dev,
224 "invalid data_rate on %s\n",
225 node->full_name);
226 }
227 }
228
229 data->channel_data[channel].enabled = true;
230 data->channel_data[channel].pga = pga;
231 data->channel_data[channel].data_rate = data_rate;
232 }
233
234 return 0;
235}
236#endif
237
238static void ads1015_get_channels_config(struct i2c_client *client)
239{
240 unsigned int k;
241 struct ads1015_data *data = i2c_get_clientdata(client);
242 struct ads1015_platform_data *pdata = dev_get_platdata(&client->dev);
243
244 /* prefer platform data */
245 if (pdata) {
246 memcpy(data->channel_data, pdata->channel_data,
247 sizeof(data->channel_data));
248 return;
249 }
250
251#ifdef CONFIG_OF
252 if (!ads1015_get_channels_config_of(client))
253 return;
254#endif
255
256 /* fallback on default configuration */
257 for (k = 0; k < ADS1015_CHANNELS; ++k) {
258 data->channel_data[k].enabled = true;
259 data->channel_data[k].pga = ADS1015_DEFAULT_PGA;
260 data->channel_data[k].data_rate = ADS1015_DEFAULT_DATA_RATE;
261 }
262}
263
264static int ads1015_probe(struct i2c_client *client,
265 const struct i2c_device_id *id)
266{
267 struct ads1015_data *data;
268 int err;
269 unsigned int k;
270
271 data = kzalloc(sizeof(struct ads1015_data), GFP_KERNEL);
272 if (!data) {
273 err = -ENOMEM;
274 goto exit;
275 }
276
277 i2c_set_clientdata(client, data);
278 mutex_init(&data->update_lock);
279
280 /* build sysfs attribute group */
281 ads1015_get_channels_config(client);
282 for (k = 0; k < ADS1015_CHANNELS; ++k) {
283 if (!data->channel_data[k].enabled)
284 continue;
285 err = device_create_file(&client->dev, &ads1015_in[k].dev_attr);
286 if (err)
287 goto exit_free;
288 }
289
290 data->hwmon_dev = hwmon_device_register(&client->dev);
291 if (IS_ERR(data->hwmon_dev)) {
292 err = PTR_ERR(data->hwmon_dev);
293 goto exit_remove;
294 }
295
296 return 0;
297
298exit_remove:
299 for (k = 0; k < ADS1015_CHANNELS; ++k)
300 device_remove_file(&client->dev, &ads1015_in[k].dev_attr);
301exit_free:
302 kfree(data);
303exit:
304 return err;
305}
306
307static const struct i2c_device_id ads1015_id[] = {
308 { "ads1015", 0 },
309 { }
310};
311MODULE_DEVICE_TABLE(i2c, ads1015_id);
312
313static struct i2c_driver ads1015_driver = {
314 .driver = {
315 .name = "ads1015",
316 },
317 .probe = ads1015_probe,
318 .remove = ads1015_remove,
319 .id_table = ads1015_id,
320};
321
322static int __init sensors_ads1015_init(void)
323{
324 return i2c_add_driver(&ads1015_driver);
325}
326
327static void __exit sensors_ads1015_exit(void)
328{
329 i2c_del_driver(&ads1015_driver);
330}
331
332MODULE_AUTHOR("Dirk Eibach <eibach@gdsys.de>");
333MODULE_DESCRIPTION("ADS1015 driver");
334MODULE_LICENSE("GPL");
335
336module_init(sensors_ads1015_init);
337module_exit(sensors_ads1015_exit);