/drivers/hwmon/pcf8591.c

  1/*
  2    Copyright (C) 2001-2004 Aurelien Jarno <aurelien@aurel32.net>
  3    Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
  4    the help of Jean Delvare <khali@linux-fr.org>
  5
  6    This program is free software; you can redistribute it and/or modify
  7    it under the terms of the GNU General Public License as published by
  8    the Free Software Foundation; either version 2 of the License, or
  9    (at your option) any later version.
 10
 11    This program is distributed in the hope that it will be useful,
 12    but WITHOUT ANY WARRANTY; without even the implied warranty of
 13    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 14    GNU General Public License for more details.
 15
 16    You should have received a copy of the GNU General Public License
 17    along with this program; if not, write to the Free Software
 18    Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 19*/
 20
 21#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 22
 23#include <linux/module.h>
 24#include <linux/init.h>
 25#include <linux/slab.h>
 26#include <linux/i2c.h>
 27#include <linux/mutex.h>
 28#include <linux/err.h>
 29#include <linux/hwmon.h>
 30
 31/* Insmod parameters */
 32
 33static int input_mode;
 34module_param(input_mode, int, 0);
 35MODULE_PARM_DESC(input_mode,
 36	"Analog input mode:\n"
 37	" 0 = four single ended inputs\n"
 38	" 1 = three differential inputs\n"
 39	" 2 = single ended and differential mixed\n"
 40	" 3 = two differential inputs\n");
 41
 42/* The PCF8591 control byte
 43      7    6    5    4    3    2    1    0
 44   |  0 |AOEF|   AIP   |  0 |AINC|  AICH   | */
 45
 46/* Analog Output Enable Flag (analog output active if 1) */
 47#define PCF8591_CONTROL_AOEF		0x40
 48
 49/* Analog Input Programming
 50   0x00 = four single ended inputs
 51   0x10 = three differential inputs
 52   0x20 = single ended and differential mixed
 53   0x30 = two differential inputs */
 54#define PCF8591_CONTROL_AIP_MASK	0x30
 55
 56/* Autoincrement Flag (switch on if 1) */
 57#define PCF8591_CONTROL_AINC		0x04
 58
 59/* Channel selection
 60   0x00 = channel 0
 61   0x01 = channel 1
 62   0x02 = channel 2
 63   0x03 = channel 3 */
 64#define PCF8591_CONTROL_AICH_MASK	0x03
 65
 66/* Initial values */
 67#define PCF8591_INIT_CONTROL	((input_mode << 4) | PCF8591_CONTROL_AOEF)
 68#define PCF8591_INIT_AOUT	0	/* DAC out = 0 */
 69
 70/* Conversions */
 71#define REG_TO_SIGNED(reg)	(((reg) & 0x80)?((reg) - 256):(reg))
 72
 73struct pcf8591_data {
 74	struct device *hwmon_dev;
 75	struct mutex update_lock;
 76
 77	u8 control;
 78	u8 aout;
 79};
 80
 81static void pcf8591_init_client(struct i2c_client *client);
 82static int pcf8591_read_channel(struct device *dev, int channel);
 83
 84/* following are the sysfs callback functions */
 85#define show_in_channel(channel)					\
 86static ssize_t show_in##channel##_input(struct device *dev, struct device_attribute *attr, char *buf)	\
 87{									\
 88	return sprintf(buf, "%d\n", pcf8591_read_channel(dev, channel));\
 89}									\
 90static DEVICE_ATTR(in##channel##_input, S_IRUGO,			\
 91		   show_in##channel##_input, NULL);
 92
 93show_in_channel(0);
 94show_in_channel(1);
 95show_in_channel(2);
 96show_in_channel(3);
 97
 98static ssize_t show_out0_ouput(struct device *dev, struct device_attribute *attr, char *buf)
 99{
100	struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
101	return sprintf(buf, "%d\n", data->aout * 10);
102}
103
104static ssize_t set_out0_output(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
105{
106	unsigned int value;
107	struct i2c_client *client = to_i2c_client(dev);
108	struct pcf8591_data *data = i2c_get_clientdata(client);
109	if ((value = (simple_strtoul(buf, NULL, 10) + 5) / 10) <= 255) {
110		data->aout = value;
111		i2c_smbus_write_byte_data(client, data->control, data->aout);
112		return count;
113	}
114	return -EINVAL;
115}
116
117static DEVICE_ATTR(out0_output, S_IWUSR | S_IRUGO,
118		   show_out0_ouput, set_out0_output);
119
120static ssize_t show_out0_enable(struct device *dev, struct device_attribute *attr, char *buf)
121{
122	struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
123	return sprintf(buf, "%u\n", !(!(data->control & PCF8591_CONTROL_AOEF)));
124}
125
126static ssize_t set_out0_enable(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
127{
128	struct i2c_client *client = to_i2c_client(dev);
129	struct pcf8591_data *data = i2c_get_clientdata(client);
130	unsigned long val = simple_strtoul(buf, NULL, 10);
131
132	mutex_lock(&data->update_lock);
133	if (val)
134		data->control |= PCF8591_CONTROL_AOEF;
135	else
136		data->control &= ~PCF8591_CONTROL_AOEF;
137	i2c_smbus_write_byte(client, data->control);
138	mutex_unlock(&data->update_lock);
139	return count;
140}
141
142static DEVICE_ATTR(out0_enable, S_IWUSR | S_IRUGO,
143		   show_out0_enable, set_out0_enable);
144
145static struct attribute *pcf8591_attributes[] = {
146	&dev_attr_out0_enable.attr,
147	&dev_attr_out0_output.attr,
148	&dev_attr_in0_input.attr,
149	&dev_attr_in1_input.attr,
150	NULL
151};
152
153static const struct attribute_group pcf8591_attr_group = {
154	.attrs = pcf8591_attributes,
155};
156
157static struct attribute *pcf8591_attributes_opt[] = {
158	&dev_attr_in2_input.attr,
159	&dev_attr_in3_input.attr,
160	NULL
161};
162
163static const struct attribute_group pcf8591_attr_group_opt = {
164	.attrs = pcf8591_attributes_opt,
165};
166
167/*
168 * Real code
169 */
170
171static int pcf8591_probe(struct i2c_client *client,
172			 const struct i2c_device_id *id)
173{
174	struct pcf8591_data *data;
175	int err;
176
177	if (!(data = kzalloc(sizeof(struct pcf8591_data), GFP_KERNEL))) {
178		err = -ENOMEM;
179		goto exit;
180	}
181
182	i2c_set_clientdata(client, data);
183	mutex_init(&data->update_lock);
184
185	/* Initialize the PCF8591 chip */
186	pcf8591_init_client(client);
187
188	/* Register sysfs hooks */
189	err = sysfs_create_group(&client->dev.kobj, &pcf8591_attr_group);
190	if (err)
191		goto exit_kfree;
192
193	/* Register input2 if not in "two differential inputs" mode */
194	if (input_mode != 3) {
195		if ((err = device_create_file(&client->dev,
196					      &dev_attr_in2_input)))
197			goto exit_sysfs_remove;
198	}
199
200	/* Register input3 only in "four single ended inputs" mode */
201	if (input_mode == 0) {
202		if ((err = device_create_file(&client->dev,
203					      &dev_attr_in3_input)))
204			goto exit_sysfs_remove;
205	}
206
207	data->hwmon_dev = hwmon_device_register(&client->dev);
208	if (IS_ERR(data->hwmon_dev)) {
209		err = PTR_ERR(data->hwmon_dev);
210		goto exit_sysfs_remove;
211	}
212
213	return 0;
214
215exit_sysfs_remove:
216	sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
217	sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
218exit_kfree:
219	kfree(data);
220exit:
221	return err;
222}
223
224static int pcf8591_remove(struct i2c_client *client)
225{
226	struct pcf8591_data *data = i2c_get_clientdata(client);
227
228	hwmon_device_unregister(data->hwmon_dev);
229	sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
230	sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
231	kfree(i2c_get_clientdata(client));
232	return 0;
233}
234
235/* Called when we have found a new PCF8591. */
236static void pcf8591_init_client(struct i2c_client *client)
237{
238	struct pcf8591_data *data = i2c_get_clientdata(client);
239	data->control = PCF8591_INIT_CONTROL;
240	data->aout = PCF8591_INIT_AOUT;
241
242	i2c_smbus_write_byte_data(client, data->control, data->aout);
243
244	/* The first byte transmitted contains the conversion code of the
245	   previous read cycle. FLUSH IT! */
246	i2c_smbus_read_byte(client);
247}
248
249static int pcf8591_read_channel(struct device *dev, int channel)
250{
251	u8 value;
252	struct i2c_client *client = to_i2c_client(dev);
253	struct pcf8591_data *data = i2c_get_clientdata(client);
254
255	mutex_lock(&data->update_lock);
256
257	if ((data->control & PCF8591_CONTROL_AICH_MASK) != channel) {
258		data->control = (data->control & ~PCF8591_CONTROL_AICH_MASK)
259			      | channel;
260		i2c_smbus_write_byte(client, data->control);
261
262		/* The first byte transmitted contains the conversion code of
263		   the previous read cycle. FLUSH IT! */
264		i2c_smbus_read_byte(client);
265	}
266	value = i2c_smbus_read_byte(client);
267
268	mutex_unlock(&data->update_lock);
269
270	if ((channel == 2 && input_mode == 2) ||
271	    (channel != 3 && (input_mode == 1 || input_mode == 3)))
272		return (10 * REG_TO_SIGNED(value));
273	else
274		return (10 * value);
275}
276
277static const struct i2c_device_id pcf8591_id[] = {
278	{ "pcf8591", 0 },
279	{ }
280};
281MODULE_DEVICE_TABLE(i2c, pcf8591_id);
282
283static struct i2c_driver pcf8591_driver = {
284	.driver = {
285		.name	= "pcf8591",
286	},
287	.probe		= pcf8591_probe,
288	.remove		= pcf8591_remove,
289	.id_table	= pcf8591_id,
290};
291
292static int __init pcf8591_init(void)
293{
294	if (input_mode < 0 || input_mode > 3) {
295		pr_warn("invalid input_mode (%d)\n", input_mode);
296		input_mode = 0;
297	}
298	return i2c_add_driver(&pcf8591_driver);
299}
300
301static void __exit pcf8591_exit(void)
302{
303	i2c_del_driver(&pcf8591_driver);
304}
305
306MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>");
307MODULE_DESCRIPTION("PCF8591 driver");
308MODULE_LICENSE("GPL");
309
310module_init(pcf8591_init);
311module_exit(pcf8591_exit);