1 /*
2 pcf8591.c - Part of lm_sensors, Linux kernel modules for hardware
3 monitoring
4 Copyright (C) 2001-2004 Aurelien Jarno <aurelien@aurel32.net>
5 Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
6 the help of Jean Delvare <khali@linux-fr.org>
7
8 This program is free software; you can redistribute it and/or modify
9 it under the terms of the GNU General Public License as published by
10 the Free Software Foundation; either version 2 of the License, or
11 (at your option) any later version.
12
13 This program is distributed in the hope that it will be useful,
14 but WITHOUT ANY WARRANTY; without even the implied warranty of
15 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 GNU General Public License for more details.
17
18 You should have received a copy of the GNU General Public License
19 along with this program; if not, write to the Free Software
20 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
21 */
22
23 #include <linux/module.h>
24 #include <linux/init.h>
25 #include <linux/slab.h>
26 #include <linux/i2c.h>
27
28 /* Addresses to scan */
29 static unsigned short normal_i2c[] = { 0x48, 0x49, 0x4a, 0x4b, 0x4c,
30 0x4d, 0x4e, 0x4f, I2C_CLIENT_END };
31
32 /* Insmod parameters */
33 I2C_CLIENT_INSMOD_1(pcf8591);
34
35 static int input_mode;
36 module_param(input_mode, int, 0);
37 MODULE_PARM_DESC(input_mode,
38 "Analog input mode:\n"
39 " 0 = four single ended inputs\n"
40 " 1 = three differential inputs\n"
41 " 2 = single ended and differential mixed\n"
42 " 3 = two differential inputs\n");
43
44 /* The PCF8591 control byte
45 7 6 5 4 3 2 1 0
46 | 0 |AOEF| AIP | 0 |AINC| AICH | */
47
48 /* Analog Output Enable Flag (analog output active if 1) */
49 #define PCF8591_CONTROL_AOEF 0x40
50
51 /* Analog Input Programming
52 0x00 = four single ended inputs
53 0x10 = three differential inputs
54 0x20 = single ended and differential mixed
55 0x30 = two differential inputs */
56 #define PCF8591_CONTROL_AIP_MASK 0x30
57
58 /* Autoincrement Flag (switch on if 1) */
59 #define PCF8591_CONTROL_AINC 0x04
60
61 /* Channel selection
62 0x00 = channel 0
63 0x01 = channel 1
64 0x02 = channel 2
65 0x03 = channel 3 */
66 #define PCF8591_CONTROL_AICH_MASK 0x03
67
68 /* Initial values */
69 #define PCF8591_INIT_CONTROL ((input_mode << 4) | PCF8591_CONTROL_AOEF)
70 #define PCF8591_INIT_AOUT 0 /* DAC out = 0 */
71
72 /* Conversions */
73 #define REG_TO_SIGNED(reg) (((reg) & 0x80)?((reg) - 256):(reg))
74
75 struct pcf8591_data {
76 struct i2c_client client;
77 struct semaphore update_lock;
78
79 u8 control;
80 u8 aout;
81 };
82
83 static int pcf8591_attach_adapter(struct i2c_adapter *adapter);
84 static int pcf8591_detect(struct i2c_adapter *adapter, int address, int kind);
85 static int pcf8591_detach_client(struct i2c_client *client);
86 static void pcf8591_init_client(struct i2c_client *client);
87 static int pcf8591_read_channel(struct device *dev, int channel);
88
89 /* This is the driver that will be inserted */
90 static struct i2c_driver pcf8591_driver = {
91 .driver = {
92 .name = "pcf8591",
93 },
94 .id = I2C_DRIVERID_PCF8591,
95 .attach_adapter = pcf8591_attach_adapter,
96 .detach_client = pcf8591_detach_client,
97 };
98
99 /* following are the sysfs callback functions */
100 #define show_in_channel(channel) \
101 static ssize_t show_in##channel##_input(struct device *dev, struct device_attribute *attr, char *buf) \
102 { \
103 return sprintf(buf, "%d\n", pcf8591_read_channel(dev, channel));\
104 } \
105 static DEVICE_ATTR(in##channel##_input, S_IRUGO, \
106 show_in##channel##_input, NULL);
107
108 show_in_channel(0);
109 show_in_channel(1);
110 show_in_channel(2);
111 show_in_channel(3);
112
113 static ssize_t show_out0_ouput(struct device *dev, struct device_attribute *attr, char *buf)
114 {
115 struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
116 return sprintf(buf, "%d\n", data->aout * 10);
117 }
118
119 static ssize_t set_out0_output(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
120 {
121 unsigned int value;
122 struct i2c_client *client = to_i2c_client(dev);
123 struct pcf8591_data *data = i2c_get_clientdata(client);
124 if ((value = (simple_strtoul(buf, NULL, 10) + 5) / 10) <= 255) {
125 data->aout = value;
126 i2c_smbus_write_byte_data(client, data->control, data->aout);
127 return count;
128 }
129 return -EINVAL;
130 }
131
132 static DEVICE_ATTR(out0_output, S_IWUSR | S_IRUGO,
133 show_out0_ouput, set_out0_output);
134
135 static ssize_t show_out0_enable(struct device *dev, struct device_attribute *attr, char *buf)
136 {
137 struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
138 return sprintf(buf, "%u\n", !(!(data->control & PCF8591_CONTROL_AOEF)));
139 }
140
141 static ssize_t set_out0_enable(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
142 {
143 struct i2c_client *client = to_i2c_client(dev);
144 struct pcf8591_data *data = i2c_get_clientdata(client);
145 unsigned long val = simple_strtoul(buf, NULL, 10);
146
147 down(&data->update_lock);
148 if (val)
149 data->control |= PCF8591_CONTROL_AOEF;
150 else
151 data->control &= ~PCF8591_CONTROL_AOEF;
152 i2c_smbus_write_byte(client, data->control);
153 up(&data->update_lock);
154 return count;
155 }
156
157 static DEVICE_ATTR(out0_enable, S_IWUSR | S_IRUGO,
158 show_out0_enable, set_out0_enable);
159
160 /*
161 * Real code
162 */
163 static int pcf8591_attach_adapter(struct i2c_adapter *adapter)
164 {
165 return i2c_probe(adapter, &addr_data, pcf8591_detect);
166 }
167
168 /* This function is called by i2c_probe */
169 static int pcf8591_detect(struct i2c_adapter *adapter, int address, int kind)
170 {
171 struct i2c_client *new_client;
172 struct pcf8591_data *data;
173 int err = 0;
174
175 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE
176 | I2C_FUNC_SMBUS_WRITE_BYTE_DATA))
177 goto exit;
178
179 /* OK. For now, we presume we have a valid client. We now create the
180 client structure, even though we cannot fill it completely yet. */
181 if (!(data = kzalloc(sizeof(struct pcf8591_data), GFP_KERNEL))) {
182 err = -ENOMEM;
183 goto exit;
184 }
185
186 new_client = &data->client;
187 i2c_set_clientdata(new_client, data);
188 new_client->addr = address;
189 new_client->adapter = adapter;
190 new_client->driver = &pcf8591_driver;
191 new_client->flags = 0;
192
193 /* Now, we would do the remaining detection. But the PCF8591 is plainly
194 impossible to detect! Stupid chip. */
195
196 /* Determine the chip type - only one kind supported! */
197 if (kind <= 0)
198 kind = pcf8591;
199
200 /* Fill in the remaining client fields and put it into the global
201 list */
202 strlcpy(new_client->name, "pcf8591", I2C_NAME_SIZE);
203 init_MUTEX(&data->update_lock);
204
205 /* Tell the I2C layer a new client has arrived */
206 if ((err = i2c_attach_client(new_client)))
207 goto exit_kfree;
208
209 /* Initialize the PCF8591 chip */
210 pcf8591_init_client(new_client);
211
212 /* Register sysfs hooks */
213 device_create_file(&new_client->dev, &dev_attr_out0_enable);
214 device_create_file(&new_client->dev, &dev_attr_out0_output);
215 device_create_file(&new_client->dev, &dev_attr_in0_input);
216 device_create_file(&new_client->dev, &dev_attr_in1_input);
217
218 /* Register input2 if not in "two differential inputs" mode */
219 if (input_mode != 3 )
220 device_create_file(&new_client->dev, &dev_attr_in2_input);
221
222 /* Register input3 only in "four single ended inputs" mode */
223 if (input_mode == 0)
224 device_create_file(&new_client->dev, &dev_attr_in3_input);
225
226 return 0;
227
228 /* OK, this is not exactly good programming practice, usually. But it is
229 very code-efficient in this case. */
230
231 exit_kfree:
232 kfree(data);
233 exit:
234 return err;
235 }
236
237 static int pcf8591_detach_client(struct i2c_client *client)
238 {
239 int err;
240
241 if ((err = i2c_detach_client(client)))
242 return err;
243
244 kfree(i2c_get_clientdata(client));
245 return 0;
246 }
247
248 /* Called when we have found a new PCF8591. */
249 static void pcf8591_init_client(struct i2c_client *client)
250 {
251 struct pcf8591_data *data = i2c_get_clientdata(client);
252 data->control = PCF8591_INIT_CONTROL;
253 data->aout = PCF8591_INIT_AOUT;
254
255 i2c_smbus_write_byte_data(client, data->control, data->aout);
256
257 /* The first byte transmitted contains the conversion code of the
258 previous read cycle. FLUSH IT! */
259 i2c_smbus_read_byte(client);
260 }
261
262 static int pcf8591_read_channel(struct device *dev, int channel)
263 {
264 u8 value;
265 struct i2c_client *client = to_i2c_client(dev);
266 struct pcf8591_data *data = i2c_get_clientdata(client);
267
268 down(&data->update_lock);
269
270 if ((data->control & PCF8591_CONTROL_AICH_MASK) != channel) {
271 data->control = (data->control & ~PCF8591_CONTROL_AICH_MASK)
272 | channel;
273 i2c_smbus_write_byte(client, data->control);
274
275 /* The first byte transmitted contains the conversion code of
276 the previous read cycle. FLUSH IT! */
277 i2c_smbus_read_byte(client);
278 }
279 value = i2c_smbus_read_byte(client);
280
281 up(&data->update_lock);
282
283 if ((channel == 2 && input_mode == 2) ||
284 (channel != 3 && (input_mode == 1 || input_mode == 3)))
285 return (10 * REG_TO_SIGNED(value));
286 else
287 return (10 * value);
288 }
289
290 static int __init pcf8591_init(void)
291 {
292 if (input_mode < 0 || input_mode > 3) {
293 printk(KERN_WARNING "pcf8591: invalid input_mode (%d)\n",
294 input_mode);
295 input_mode = 0;
296 }
297 return i2c_add_driver(&pcf8591_driver);
298 }
299
300 static void __exit pcf8591_exit(void)
301 {
302 i2c_del_driver(&pcf8591_driver);
303 }
304
305 MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>");
306 MODULE_DESCRIPTION("PCF8591 driver");
307 MODULE_LICENSE("GPL");
308
309 module_init(pcf8591_init);
310 module_exit(pcf8591_exit);
311
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