summaryrefslogtreecommitdiff
path: root/drivers/hwmon/ads1015.c
blob: fa02f20b79ff4e1ea1b93911f04eb23ccd7a0963 (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
/*
 * 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 };

#define ADS1015_CONFIG_CHANNELS 8
#define ADS1015_DEFAULT_CHANNELS 0xff

struct ads1015_data {
	struct device *hwmon_dev;
	struct mutex update_lock; /* mutex protect updates */
};

static s32 ads1015_read_reg(struct i2c_client *client, unsigned int reg)
{
	s32 data = i2c_smbus_read_word_data(client, reg);

	return (data < 0) ? data : swab16(data);
}

static s32 ads1015_write_reg(struct i2c_client *client, unsigned int reg,
			     u16 val)
{
	return i2c_smbus_write_word_data(client, reg, swab16(val));
}

static int ads1015_read_value(struct i2c_client *client, unsigned int channel,
			      int *value)
{
	u16 config;
	s16 conversion;
	unsigned int pga;
	int fullscale;
	unsigned int k;
	struct ads1015_data *data = i2c_get_clientdata(client);
	int res;

	mutex_lock(&data->update_lock);

	/* get fullscale voltage */
	res = ads1015_read_reg(client, ADS1015_CONFIG);
	if (res < 0)
		goto err_unlock;
	config = res;
	pga = (config >> 9) & 0x0007;
	fullscale = fullscale_table[pga];

	/* set channel and start single conversion */
	config &= ~(0x0007 << 12);
	config |= (1 << 15) | (1 << 8) | (channel & 0x0007) << 12;

	/* wait until conversion finished */
	res = ads1015_write_reg(client, ADS1015_CONFIG, config);
	if (res < 0)
		goto err_unlock;
	for (k = 0; k < 5; ++k) {
		msleep(1);
		res = ads1015_read_reg(client, ADS1015_CONFIG);
		if (res < 0)
			goto err_unlock;
		config = res;
		if (config & (1 << 15))
			break;
	}
	if (k == 5) {
		res = -EIO;
		goto err_unlock;
	}

	res = ads1015_read_reg(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_CONFIG_CHANNELS; ++k)
		device_remove_file(&client->dev, &ads1015_in[k].dev_attr);
	kfree(data);
	return 0;
}

static unsigned int ads1015_get_exported_channels(struct i2c_client *client)
{
	struct ads1015_platform_data *pdata = dev_get_platdata(&client->dev);
#ifdef CONFIG_OF
	struct device_node *np = client->dev.of_node;
	const __be32 *of_channels;
	int of_channels_size;
#endif

	/* prefer platform data */
	if (pdata)
		return pdata->exported_channels;

#ifdef CONFIG_OF
	/* fallback on OF */
	of_channels = of_get_property(np, "exported-channels",
				      &of_channels_size);
	if (of_channels && (of_channels_size == sizeof(*of_channels)))
		return be32_to_cpup(of_channels);
#endif

	/* fallback on default configuration */
	return ADS1015_DEFAULT_CHANNELS;
}

static int ads1015_probe(struct i2c_client *client,
			 const struct i2c_device_id *id)
{
	struct ads1015_data *data;
	int err;
	unsigned int exported_channels;
	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 */
	exported_channels = ads1015_get_exported_channels(client);
	for (k = 0; k < ADS1015_CONFIG_CHANNELS; ++k) {
		if (!(exported_channels & (1<<k)))
			continue;
		err = device_create_file(&client->dev, &ads1015_in[k].dev_attr);
		if (err)
			goto exit_free;
	}

	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_CONFIG_CHANNELS; ++k)
		device_remove_file(&client->dev, &ads1015_in[k].dev_attr);
exit_free:
	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,
};

static int __init sensors_ads1015_init(void)
{
	return i2c_add_driver(&ads1015_driver);
}

static void __exit sensors_ads1015_exit(void)
{
	i2c_del_driver(&ads1015_driver);
}

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

module_init(sensors_ads1015_init);
module_exit(sensors_ads1015_exit);