summaryrefslogtreecommitdiffstats
path: root/drivers/hwmon/ads1015.c
blob: 7765e4f74ec56177ad8cc39476320d6d2436f719 (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
/*
 * ads1015.c - lm_sensors driver for ads1015 12-bit 4-input ADC
 * (C) Copyright 2010
 * Dirk Eibach, Guntermann & Drunck GmbH <eibach@gdsys.de>
 *
 * Based on the ads7828 driver by Steve Hardy.
 *
 * Datasheet available at: http://focus.ti.com/lit/ds/symlink/ads1015.pdf
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include <linux/module.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/delay.h>
#include <linux/i2c.h>
#include <linux/hwmon.h>
#include <linux/hwmon-sysfs.h>
#include <linux/err.h>
#include <linux/mutex.h>
#include <linux/of.h>

#include <linux/i2c/ads1015.h>

/* ADS1015 registers */
enum {
	ADS1015_CONVERSION = 0,
	ADS1015_CONFIG = 1,
};

/* PGA fullscale voltages in mV */
static const unsigned int fullscale_table[8] = {
	6144, 4096, 2048, 1024, 512, 256, 256, 256 };

/* Data rates in samples per second */
static const unsigned int data_rate_table[8] = {
	128, 250, 490, 920, 1600, 2400, 3300, 3300 };

#define ADS1015_DEFAULT_CHANNELS 0xff
#define ADS1015_DEFAULT_PGA 2
#define ADS1015_DEFAULT_DATA_RATE 4

struct ads1015_data {
	struct device *hwmon_dev;
	struct mutex update_lock; /* mutex protect updates */
	struct ads1015_channel_data channel_data[ADS1015_CHANNELS];
};

static int ads1015_read_value(struct i2c_client *client, unsigned int channel,
			      int *value)
{
	u16 config;
	s16 conversion;
	struct ads1015_data *data = i2c_get_clientdata(client);
	unsigned int pga = data->channel_data[channel].pga;
	int fullscale;
	unsigned int data_rate = data->channel_data[channel].data_rate;
	unsigned int conversion_time_ms;
	int res;

	mutex_lock(&data->update_lock);

	/* get channel parameters */
	res = i2c_smbus_read_word_swapped(client, ADS1015_CONFIG);
	if (res < 0)
		goto err_unlock;
	config = res;
	fullscale = fullscale_table[pga];
	conversion_time_ms = DIV_ROUND_UP(1000, data_rate_table[data_rate]);

	/* setup and start single conversion */
	config &= 0x001f;
	config |= (1 << 15) | (1 << 8);
	config |= (channel & 0x0007) << 12;
	config |= (pga & 0x0007) << 9;
	config |= (data_rate & 0x0007) << 5;

	res = i2c_smbus_write_word_swapped(client, ADS1015_CONFIG, config);
	if (res < 0)
		goto err_unlock;

	/* wait until conversion finished */
	msleep(conversion_time_ms);
	res = i2c_smbus_read_word_swapped(client, ADS1015_CONFIG);
	if (res < 0)
		goto err_unlock;
	config = res;
	if (!(config & (1 << 15))) {
		/* conversion not finished in time */
		res = -EIO;
		goto err_unlock;
	}

	res = i2c_smbus_read_word_swapped(client, ADS1015_CONVERSION);
	if (res < 0)
		goto err_unlock;
	conversion = res;

	mutex_unlock(&data->update_lock);

	*value = DIV_ROUND_CLOSEST(conversion * fullscale, 0x7ff0);

	return 0;

err_unlock:
	mutex_unlock(&data->update_lock);
	return res;
}

/* sysfs callback function */
static ssize_t show_in(struct device *dev, struct device_attribute *da,
	char *buf)
{
	struct sensor_device_attribute *attr = to_sensor_dev_attr(da);
	struct i2c_client *client = to_i2c_client(dev);
	int in;
	int res;

	res = ads1015_read_value(client, attr->index, &in);

	return (res < 0) ? res : sprintf(buf, "%d\n", in);
}

static const struct sensor_device_attribute ads1015_in[] = {
	SENSOR_ATTR(in0_input, S_IRUGO, show_in, NULL, 0),
	SENSOR_ATTR(in1_input, S_IRUGO, show_in, NULL, 1),
	SENSOR_ATTR(in2_input, S_IRUGO, show_in, NULL, 2),
	SENSOR_ATTR(in3_input, S_IRUGO, show_in, NULL, 3),
	SENSOR_ATTR(in4_input, S_IRUGO, show_in, NULL, 4),
	SENSOR_ATTR(in5_input, S_IRUGO, show_in, NULL, 5),
	SENSOR_ATTR(in6_input, S_IRUGO, show_in, NULL, 6),
	SENSOR_ATTR(in7_input, S_IRUGO, show_in, NULL, 7),
};

/*
 * Driver interface
 */

static int ads1015_remove(struct i2c_client *client)
{
	struct ads1015_data *data = i2c_get_clientdata(client);
	int k;

	hwmon_device_unregister(data->hwmon_dev);
	for (k = 0; k < ADS1015_CHANNELS; ++k)
		device_remove_file(&client->dev, &ads1015_in[k].dev_attr);
	kfree(data);
	return 0;
}

#ifdef CONFIG_OF
static int ads1015_get_channels_config_of(struct i2c_client *client)
{
	struct ads1015_data *data = i2c_get_clientdata(client);
	struct device_node *node;

	if (!client->dev.of_node
	    || !of_get_next_child(client->dev.of_node, NULL))
		return -EINVAL;

	for_each_child_of_node(client->dev.of_node, node) {
		const __be32 *property;
		int len;
		unsigned int channel;
		unsigned int pga = ADS1015_DEFAULT_PGA;
		unsigned int data_rate = ADS1015_DEFAULT_DATA_RATE;

		property = of_get_property(node, "reg", &len);
		if (!property || len != sizeof(int)) {
			dev_err(&client->dev, "invalid reg on %s\n",
				node->full_name);
			continue;
		}

		channel = be32_to_cpup(property);
		if (channel > ADS1015_CHANNELS) {
			dev_err(&client->dev,
				"invalid channel index %d on %s\n",
				channel, node->full_name);
			continue;
		}

		property = of_get_property(node, "ti,gain", &len);
		if (property && len == sizeof(int)) {
			pga = be32_to_cpup(property);
			if (pga > 6) {
				dev_err(&client->dev,
					"invalid gain on %s\n",
					node->full_name);
			}
		}

		property = of_get_property(node, "ti,datarate", &len);
		if (property && len == sizeof(int)) {
			data_rate = be32_to_cpup(property);
			if (data_rate > 7) {
				dev_err(&client->dev,
					"invalid data_rate on %s\n",
					node->full_name);
			}
		}

		data->channel_data[channel].enabled = true;
		data->channel_data[channel].pga = pga;
		data->channel_data[channel].data_rate = data_rate;
	}

	return 0;
}
#endif

static void ads1015_get_channels_config(struct i2c_client *client)
{
	unsigned int k;
	struct ads1015_data *data = i2c_get_clientdata(client);
	struct ads1015_platform_data *pdata = dev_get_platdata(&client->dev);

	/* prefer platform data */
	if (pdata) {
		memcpy(data->channel_data, pdata->channel_data,
		       sizeof(data->channel_data));
		return;
	}

#ifdef CONFIG_OF
	if (!ads1015_get_channels_config_of(client))
		return;
#endif

	/* fallback on default configuration */
	for (k = 0; k < ADS1015_CHANNELS; ++k) {
		data->channel_data[k].enabled = true;
		data->channel_data[k].pga = ADS1015_DEFAULT_PGA;
		data->channel_data[k].data_rate = ADS1015_DEFAULT_DATA_RATE;
	}
}

static int ads1015_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct ads1015_data *data;
	int err;
	unsigned int k;

	data = kzalloc(sizeof(struct ads1015_data), GFP_KERNEL);
	if (!data) {
		err = -ENOMEM;
		goto exit;
	}

	i2c_set_clientdata(client, data);
	mutex_init(&data->update_lock);

	/* build sysfs attribute group */
	ads1015_get_channels_config(client);
	for (k = 0; k < ADS1015_CHANNELS; ++k) {
		if (!data->channel_data[k].enabled)
			continue;
		err = device_create_file(&client->dev, &ads1015_in[k].dev_attr);
		if (err)
			goto exit_remove;
	}

	data->hwmon_dev = hwmon_device_register(&client->dev);
	if (IS_ERR(data->hwmon_dev)) {
		err = PTR_ERR(data->hwmon_dev);
		goto exit_remove;
	}

	return 0;

exit_remove:
	for (k = 0; k < ADS1015_CHANNELS; ++k)
		device_remove_file(&client->dev, &ads1015_in[k].dev_attr);
	kfree(data);
exit:
	return err;
}

static const struct i2c_device_id ads1015_id[] = {
	{ "ads1015", 0 },
	{ }
};
MODULE_DEVICE_TABLE(i2c, ads1015_id);

static struct i2c_driver ads1015_driver = {
	.driver = {
		.name = "ads1015",
	},
	.probe = ads1015_probe,
	.remove = ads1015_remove,
	.id_table = ads1015_id,
};

module_i2c_driver(ads1015_driver);

MODULE_AUTHOR("Dirk Eibach <eibach@gdsys.de>");
MODULE_DESCRIPTION("ADS1015 driver");
MODULE_LICENSE("GPL");
OpenPOWER on IntegriCloud