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 <jdelvare@suse.de>
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/*
43 * The PCF8591 control byte
44 *      7    6    5    4    3    2    1    0
45 *   |  0 |AOEF|   AIP   |  0 |AINC|  AICH   |
46 */
47
48/* Analog Output Enable Flag (analog output active if 1) */
49#define PCF8591_CONTROL_AOEF		0x40
50
51/*
52 * Analog Input Programming
53 * 0x00 = four single ended inputs
54 * 0x10 = three differential inputs
55 * 0x20 = single ended and differential mixed
56 * 0x30 = two differential inputs
57 */
58#define PCF8591_CONTROL_AIP_MASK	0x30
59
60/* Autoincrement Flag (switch on if 1) */
61#define PCF8591_CONTROL_AINC		0x04
62
63/*
64 * Channel selection
65 * 0x00 = channel 0
66 * 0x01 = channel 1
67 * 0x02 = channel 2
68 * 0x03 = channel 3
69 */
70#define PCF8591_CONTROL_AICH_MASK	0x03
71
72/* Initial values */
73#define PCF8591_INIT_CONTROL	((input_mode << 4) | PCF8591_CONTROL_AOEF)
74#define PCF8591_INIT_AOUT	0	/* DAC out = 0 */
75
76/* Conversions */
77#define REG_TO_SIGNED(reg)	(((reg) & 0x80) ? ((reg) - 256) : (reg))
78
79struct pcf8591_data {
80	struct device *hwmon_dev;
81	struct mutex update_lock;
82
83	u8 control;
84	u8 aout;
85};
86
87static void pcf8591_init_client(struct i2c_client *client);
88static int pcf8591_read_channel(struct device *dev, int channel);
89
90/* following are the sysfs callback functions */
91#define show_in_channel(channel)					\
92static ssize_t show_in##channel##_input(struct device *dev,		\
93					struct device_attribute *attr,	\
94					char *buf)			\
95{									\
96	return sprintf(buf, "%d\n", pcf8591_read_channel(dev, channel));\
97}									\
98static DEVICE_ATTR(in##channel##_input, S_IRUGO,			\
99		   show_in##channel##_input, NULL);
100
101show_in_channel(0);
102show_in_channel(1);
103show_in_channel(2);
104show_in_channel(3);
105
106static ssize_t show_out0_ouput(struct device *dev,
107			       struct device_attribute *attr, char *buf)
108{
109	struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
110	return sprintf(buf, "%d\n", data->aout * 10);
111}
112
113static ssize_t set_out0_output(struct device *dev,
114			       struct device_attribute *attr,
115			       const char *buf, size_t count)
116{
117	unsigned long val;
118	struct i2c_client *client = to_i2c_client(dev);
119	struct pcf8591_data *data = i2c_get_clientdata(client);
120	int err;
121
122	err = kstrtoul(buf, 10, &val);
123	if (err)
124		return err;
125
126	val /= 10;
127	if (val > 255)
128		return -EINVAL;
129
130	data->aout = val;
131	i2c_smbus_write_byte_data(client, data->control, data->aout);
132	return count;
133}
134
135static DEVICE_ATTR(out0_output, S_IWUSR | S_IRUGO,
136		   show_out0_ouput, set_out0_output);
137
138static ssize_t show_out0_enable(struct device *dev,
139				struct device_attribute *attr, char *buf)
140{
141	struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
142	return sprintf(buf, "%u\n", !(!(data->control & PCF8591_CONTROL_AOEF)));
143}
144
145static ssize_t set_out0_enable(struct device *dev,
146			       struct device_attribute *attr,
147			       const char *buf, size_t count)
148{
149	struct i2c_client *client = to_i2c_client(dev);
150	struct pcf8591_data *data = i2c_get_clientdata(client);
151	unsigned long val;
152	int err;
153
154	err = kstrtoul(buf, 10, &val);
155	if (err)
156		return err;
157
158	mutex_lock(&data->update_lock);
159	if (val)
160		data->control |= PCF8591_CONTROL_AOEF;
161	else
162		data->control &= ~PCF8591_CONTROL_AOEF;
163	i2c_smbus_write_byte(client, data->control);
164	mutex_unlock(&data->update_lock);
165	return count;
166}
167
168static DEVICE_ATTR(out0_enable, S_IWUSR | S_IRUGO,
169		   show_out0_enable, set_out0_enable);
170
171static struct attribute *pcf8591_attributes[] = {
172	&dev_attr_out0_enable.attr,
173	&dev_attr_out0_output.attr,
174	&dev_attr_in0_input.attr,
175	&dev_attr_in1_input.attr,
176	NULL
177};
178
179static const struct attribute_group pcf8591_attr_group = {
180	.attrs = pcf8591_attributes,
181};
182
183static struct attribute *pcf8591_attributes_opt[] = {
184	&dev_attr_in2_input.attr,
185	&dev_attr_in3_input.attr,
186	NULL
187};
188
189static const struct attribute_group pcf8591_attr_group_opt = {
190	.attrs = pcf8591_attributes_opt,
191};
192
193/*
194 * Real code
195 */
196
197static int pcf8591_probe(struct i2c_client *client,
198			 const struct i2c_device_id *id)
199{
200	struct pcf8591_data *data;
201	int err;
202
203	data = devm_kzalloc(&client->dev, sizeof(struct pcf8591_data),
204			    GFP_KERNEL);
205	if (!data)
206		return -ENOMEM;
207
208	i2c_set_clientdata(client, data);
209	mutex_init(&data->update_lock);
210
211	/* Initialize the PCF8591 chip */
212	pcf8591_init_client(client);
213
214	/* Register sysfs hooks */
215	err = sysfs_create_group(&client->dev.kobj, &pcf8591_attr_group);
216	if (err)
217		return err;
218
219	/* Register input2 if not in "two differential inputs" mode */
220	if (input_mode != 3) {
221		err = device_create_file(&client->dev, &dev_attr_in2_input);
222		if (err)
223			goto exit_sysfs_remove;
224	}
225
226	/* Register input3 only in "four single ended inputs" mode */
227	if (input_mode == 0) {
228		err = device_create_file(&client->dev, &dev_attr_in3_input);
229		if (err)
230			goto exit_sysfs_remove;
231	}
232
233	data->hwmon_dev = hwmon_device_register(&client->dev);
234	if (IS_ERR(data->hwmon_dev)) {
235		err = PTR_ERR(data->hwmon_dev);
236		goto exit_sysfs_remove;
237	}
238
239	return 0;
240
241exit_sysfs_remove:
242	sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
243	sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
244	return err;
245}
246
247static int pcf8591_remove(struct i2c_client *client)
248{
249	struct pcf8591_data *data = i2c_get_clientdata(client);
250
251	hwmon_device_unregister(data->hwmon_dev);
252	sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
253	sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
254	return 0;
255}
256
257/* Called when we have found a new PCF8591. */
258static void pcf8591_init_client(struct i2c_client *client)
259{
260	struct pcf8591_data *data = i2c_get_clientdata(client);
261	data->control = PCF8591_INIT_CONTROL;
262	data->aout = PCF8591_INIT_AOUT;
263
264	i2c_smbus_write_byte_data(client, data->control, data->aout);
265
266	/*
267	 * The first byte transmitted contains the conversion code of the
268	 * previous read cycle. FLUSH IT!
269	 */
270	i2c_smbus_read_byte(client);
271}
272
273static int pcf8591_read_channel(struct device *dev, int channel)
274{
275	u8 value;
276	struct i2c_client *client = to_i2c_client(dev);
277	struct pcf8591_data *data = i2c_get_clientdata(client);
278
279	mutex_lock(&data->update_lock);
280
281	if ((data->control & PCF8591_CONTROL_AICH_MASK) != channel) {
282		data->control = (data->control & ~PCF8591_CONTROL_AICH_MASK)
283			      | channel;
284		i2c_smbus_write_byte(client, data->control);
285
286		/*
287		 * The first byte transmitted contains the conversion code of
288		 * the previous read cycle. FLUSH IT!
289		 */
290		i2c_smbus_read_byte(client);
291	}
292	value = i2c_smbus_read_byte(client);
293
294	mutex_unlock(&data->update_lock);
295
296	if ((channel == 2 && input_mode == 2) ||
297	    (channel != 3 && (input_mode == 1 || input_mode == 3)))
298		return 10 * REG_TO_SIGNED(value);
299	else
300		return 10 * value;
301}
302
303static const struct i2c_device_id pcf8591_id[] = {
304	{ "pcf8591", 0 },
305	{ }
306};
307MODULE_DEVICE_TABLE(i2c, pcf8591_id);
308
309static struct i2c_driver pcf8591_driver = {
310	.driver = {
311		.name	= "pcf8591",
312	},
313	.probe		= pcf8591_probe,
314	.remove		= pcf8591_remove,
315	.id_table	= pcf8591_id,
316};
317
318static int __init pcf8591_init(void)
319{
320	if (input_mode < 0 || input_mode > 3) {
321		pr_warn("invalid input_mode (%d)\n", input_mode);
322		input_mode = 0;
323	}
324	return i2c_add_driver(&pcf8591_driver);
325}
326
327static void __exit pcf8591_exit(void)
328{
329	i2c_del_driver(&pcf8591_driver);
330}
331
332MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>");
333MODULE_DESCRIPTION("PCF8591 driver");
334MODULE_LICENSE("GPL");
335
336module_init(pcf8591_init);
337module_exit(pcf8591_exit);
338