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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 int ads1015_read_adc(struct i2c_client *client, unsigned int channel)
63{
64 u16 config;
65 struct ads1015_data *data = i2c_get_clientdata(client);
66 unsigned int pga = data->channel_data[channel].pga;
67 unsigned int data_rate = data->channel_data[channel].data_rate;
68 unsigned int conversion_time_ms;
69 int res;
70
71 mutex_lock(&data->update_lock);
72
73 /* get channel parameters */
74 res = i2c_smbus_read_word_swapped(client, ADS1015_CONFIG);
75 if (res < 0)
76 goto err_unlock;
77 config = res;
78 conversion_time_ms = DIV_ROUND_UP(1000, data_rate_table[data_rate]);
79
80 /* setup and start single conversion */
81 config &= 0x001f;
82 config |= (1 << 15) | (1 << 8);
83 config |= (channel & 0x0007) << 12;
84 config |= (pga & 0x0007) << 9;
85 config |= (data_rate & 0x0007) << 5;
86
87 res = i2c_smbus_write_word_swapped(client, ADS1015_CONFIG, config);
88 if (res < 0)
89 goto err_unlock;
90
91 /* wait until conversion finished */
92 msleep(conversion_time_ms);
93 res = i2c_smbus_read_word_swapped(client, ADS1015_CONFIG);
94 if (res < 0)
95 goto err_unlock;
96 config = res;
97 if (!(config & (1 << 15))) {
98 /* conversion not finished in time */
99 res = -EIO;
100 goto err_unlock;
101 }
102
103 res = i2c_smbus_read_word_swapped(client, ADS1015_CONVERSION);
104
105err_unlock:
106 mutex_unlock(&data->update_lock);
107 return res;
108}
109
110static int ads1015_reg_to_mv(struct i2c_client *client, unsigned int channel,
111 s16 reg)
112{
113 struct ads1015_data *data = i2c_get_clientdata(client);
114 unsigned int pga = data->channel_data[channel].pga;
115 int fullscale = fullscale_table[pga];
116
117 return DIV_ROUND_CLOSEST(reg * fullscale, 0x7ff0);
118}
119
120/* sysfs callback function */
121static ssize_t show_in(struct device *dev, struct device_attribute *da,
122 char *buf)
123{
124 struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
125 struct i2c_client *client = to_i2c_client(dev);
126 int res;
127 int index = attr->index;
128
129 res = ads1015_read_adc(client, index);
130 if (res < 0)
131 return res;
132
133 return sprintf(buf, "%d\n", ads1015_reg_to_mv(client, index, res));
134}
135
136static const struct sensor_device_attribute ads1015_in[] = {
137 SENSOR_ATTR(in0_input, S_IRUGO, show_in, NULL, 0),
138 SENSOR_ATTR(in1_input, S_IRUGO, show_in, NULL, 1),
139 SENSOR_ATTR(in2_input, S_IRUGO, show_in, NULL, 2),
140 SENSOR_ATTR(in3_input, S_IRUGO, show_in, NULL, 3),
141 SENSOR_ATTR(in4_input, S_IRUGO, show_in, NULL, 4),
142 SENSOR_ATTR(in5_input, S_IRUGO, show_in, NULL, 5),
143 SENSOR_ATTR(in6_input, S_IRUGO, show_in, NULL, 6),
144 SENSOR_ATTR(in7_input, S_IRUGO, show_in, NULL, 7),
145};
146
147/*
148 * Driver interface
149 */
150
151static int ads1015_remove(struct i2c_client *client)
152{
153 struct ads1015_data *data = i2c_get_clientdata(client);
154 int k;
155
156 hwmon_device_unregister(data->hwmon_dev);
157 for (k = 0; k < ADS1015_CHANNELS; ++k)
158 device_remove_file(&client->dev, &ads1015_in[k].dev_attr);
159 kfree(data);
160 return 0;
161}
162
163#ifdef CONFIG_OF
164static int ads1015_get_channels_config_of(struct i2c_client *client)
165{
166 struct ads1015_data *data = i2c_get_clientdata(client);
167 struct device_node *node;
168
169 if (!client->dev.of_node
170 || !of_get_next_child(client->dev.of_node, NULL))
171 return -EINVAL;
172
173 for_each_child_of_node(client->dev.of_node, node) {
174 const __be32 *property;
175 int len;
176 unsigned int channel;
177 unsigned int pga = ADS1015_DEFAULT_PGA;
178 unsigned int data_rate = ADS1015_DEFAULT_DATA_RATE;
179
180 property = of_get_property(node, "reg", &len);
181 if (!property || len != sizeof(int)) {
182 dev_err(&client->dev, "invalid reg on %s\n",
183 node->full_name);
184 continue;
185 }
186
187 channel = be32_to_cpup(property);
188 if (channel > ADS1015_CHANNELS) {
189 dev_err(&client->dev,
190 "invalid channel index %d on %s\n",
191 channel, node->full_name);
192 continue;
193 }
194
195 property = of_get_property(node, "ti,gain", &len);
196 if (property && len == sizeof(int)) {
197 pga = be32_to_cpup(property);
198 if (pga > 6) {
199 dev_err(&client->dev,
200 "invalid gain on %s\n",
201 node->full_name);
202 }
203 }
204
205 property = of_get_property(node, "ti,datarate", &len);
206 if (property && len == sizeof(int)) {
207 data_rate = be32_to_cpup(property);
208 if (data_rate > 7) {
209 dev_err(&client->dev,
210 "invalid data_rate on %s\n",
211 node->full_name);
212 }
213 }
214
215 data->channel_data[channel].enabled = true;
216 data->channel_data[channel].pga = pga;
217 data->channel_data[channel].data_rate = data_rate;
218 }
219
220 return 0;
221}
222#endif
223
224static void ads1015_get_channels_config(struct i2c_client *client)
225{
226 unsigned int k;
227 struct ads1015_data *data = i2c_get_clientdata(client);
228 struct ads1015_platform_data *pdata = dev_get_platdata(&client->dev);
229
230 /* prefer platform data */
231 if (pdata) {
232 memcpy(data->channel_data, pdata->channel_data,
233 sizeof(data->channel_data));
234 return;
235 }
236
237#ifdef CONFIG_OF
238 if (!ads1015_get_channels_config_of(client))
239 return;
240#endif
241
242 /* fallback on default configuration */
243 for (k = 0; k < ADS1015_CHANNELS; ++k) {
244 data->channel_data[k].enabled = true;
245 data->channel_data[k].pga = ADS1015_DEFAULT_PGA;
246 data->channel_data[k].data_rate = ADS1015_DEFAULT_DATA_RATE;
247 }
248}
249
250static int ads1015_probe(struct i2c_client *client,
251 const struct i2c_device_id *id)
252{
253 struct ads1015_data *data;
254 int err;
255 unsigned int k;
256
257 data = kzalloc(sizeof(struct ads1015_data), GFP_KERNEL);
258 if (!data) {
259 err = -ENOMEM;
260 goto exit;
261 }
262
263 i2c_set_clientdata(client, data);
264 mutex_init(&data->update_lock);
265
266 /* build sysfs attribute group */
267 ads1015_get_channels_config(client);
268 for (k = 0; k < ADS1015_CHANNELS; ++k) {
269 if (!data->channel_data[k].enabled)
270 continue;
271 err = device_create_file(&client->dev, &ads1015_in[k].dev_attr);
272 if (err)
273 goto exit_remove;
274 }
275
276 data->hwmon_dev = hwmon_device_register(&client->dev);
277 if (IS_ERR(data->hwmon_dev)) {
278 err = PTR_ERR(data->hwmon_dev);
279 goto exit_remove;
280 }
281
282 return 0;
283
284exit_remove:
285 for (k = 0; k < ADS1015_CHANNELS; ++k)
286 device_remove_file(&client->dev, &ads1015_in[k].dev_attr);
287 kfree(data);
288exit:
289 return err;
290}
291
292static const struct i2c_device_id ads1015_id[] = {
293 { "ads1015", 0 },
294 { }
295};
296MODULE_DEVICE_TABLE(i2c, ads1015_id);
297
298static struct i2c_driver ads1015_driver = {
299 .driver = {
300 .name = "ads1015",
301 },
302 .probe = ads1015_probe,
303 .remove = ads1015_remove,
304 .id_table = ads1015_id,
305};
306
307module_i2c_driver(ads1015_driver);
308
309MODULE_AUTHOR("Dirk Eibach <eibach@gdsys.de>");
310MODULE_DESCRIPTION("ADS1015 driver");
311MODULE_LICENSE("GPL");