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
33 static int input_mode;
34 module_param(input_mode, int, 0);
35 MODULE_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
79 struct pcf8591_data {
80 struct device *hwmon_dev;
81 struct mutex update_lock;
82
83 u8 control;
84 u8 aout;
85 };
86
87 static void pcf8591_init_client(struct i2c_client *client);
88 static int pcf8591_read_channel(struct device *dev, int channel);
89
90 /* following are the sysfs callback functions */
91 #define show_in_channel(channel) \
92 static 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 } \
98 static DEVICE_ATTR(in##channel##_input, S_IRUGO, \
99 show_in##channel##_input, NULL);
100
101 show_in_channel(0);
102 show_in_channel(1);
103 show_in_channel(2);
104 show_in_channel(3);
105
show_out0_ouput(struct device * dev,struct device_attribute * attr,char * buf)106 static 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
set_out0_output(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)113 static 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
135 static DEVICE_ATTR(out0_output, S_IWUSR | S_IRUGO,
136 show_out0_ouput, set_out0_output);
137
show_out0_enable(struct device * dev,struct device_attribute * attr,char * buf)138 static 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
set_out0_enable(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)145 static 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
168 static DEVICE_ATTR(out0_enable, S_IWUSR | S_IRUGO,
169 show_out0_enable, set_out0_enable);
170
171 static 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
179 static const struct attribute_group pcf8591_attr_group = {
180 .attrs = pcf8591_attributes,
181 };
182
183 static struct attribute *pcf8591_attributes_opt[] = {
184 &dev_attr_in2_input.attr,
185 &dev_attr_in3_input.attr,
186 NULL
187 };
188
189 static const struct attribute_group pcf8591_attr_group_opt = {
190 .attrs = pcf8591_attributes_opt,
191 };
192
193 /*
194 * Real code
195 */
196
pcf8591_probe(struct i2c_client * client,const struct i2c_device_id * id)197 static 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
241 exit_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
pcf8591_remove(struct i2c_client * client)247 static 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. */
pcf8591_init_client(struct i2c_client * client)258 static 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
pcf8591_read_channel(struct device * dev,int channel)273 static 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
303 static const struct i2c_device_id pcf8591_id[] = {
304 { "pcf8591", 0 },
305 { }
306 };
307 MODULE_DEVICE_TABLE(i2c, pcf8591_id);
308
309 static 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
pcf8591_init(void)318 static 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
pcf8591_exit(void)327 static void __exit pcf8591_exit(void)
328 {
329 i2c_del_driver(&pcf8591_driver);
330 }
331
332 MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>");
333 MODULE_DESCRIPTION("PCF8591 driver");
334 MODULE_LICENSE("GPL");
335
336 module_init(pcf8591_init);
337 module_exit(pcf8591_exit);
338