1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Copyright (C) 2001-2004 Aurelien Jarno <aurelien@aurel32.net>
4 * Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
5 * the help of Jean Delvare <jdelvare@suse.de>
6 */
7
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9
10 #include <linux/module.h>
11 #include <linux/init.h>
12 #include <linux/slab.h>
13 #include <linux/i2c.h>
14 #include <linux/mutex.h>
15 #include <linux/err.h>
16 #include <linux/hwmon.h>
17 #include <linux/kstrtox.h>
18
19 /* Insmod parameters */
20
21 static int input_mode;
22 module_param(input_mode, int, 0);
23 MODULE_PARM_DESC(input_mode,
24 "Analog input mode:\n"
25 " 0 = four single ended inputs\n"
26 " 1 = three differential inputs\n"
27 " 2 = single ended and differential mixed\n"
28 " 3 = two differential inputs\n");
29
30 /*
31 * The PCF8591 control byte
32 * 7 6 5 4 3 2 1 0
33 * | 0 |AOEF| AIP | 0 |AINC| AICH |
34 */
35
36 /* Analog Output Enable Flag (analog output active if 1) */
37 #define PCF8591_CONTROL_AOEF 0x40
38
39 /*
40 * Analog Input Programming
41 * 0x00 = four single ended inputs
42 * 0x10 = three differential inputs
43 * 0x20 = single ended and differential mixed
44 * 0x30 = two differential inputs
45 */
46 #define PCF8591_CONTROL_AIP_MASK 0x30
47
48 /* Autoincrement Flag (switch on if 1) */
49 #define PCF8591_CONTROL_AINC 0x04
50
51 /*
52 * Channel selection
53 * 0x00 = channel 0
54 * 0x01 = channel 1
55 * 0x02 = channel 2
56 * 0x03 = channel 3
57 */
58 #define PCF8591_CONTROL_AICH_MASK 0x03
59
60 /* Initial values */
61 #define PCF8591_INIT_CONTROL ((input_mode << 4) | PCF8591_CONTROL_AOEF)
62 #define PCF8591_INIT_AOUT 0 /* DAC out = 0 */
63
64 /* Conversions */
65 #define REG_TO_SIGNED(reg) (((reg) & 0x80) ? ((reg) - 256) : (reg))
66
67 struct pcf8591_data {
68 struct device *hwmon_dev;
69 struct mutex update_lock;
70
71 u8 control;
72 u8 aout;
73 };
74
75 static void pcf8591_init_client(struct i2c_client *client);
76 static int pcf8591_read_channel(struct device *dev, int channel);
77
78 /* following are the sysfs callback functions */
79 #define show_in_channel(channel) \
80 static ssize_t show_in##channel##_input(struct device *dev, \
81 struct device_attribute *attr, \
82 char *buf) \
83 { \
84 return sprintf(buf, "%d\n", pcf8591_read_channel(dev, channel));\
85 } \
86 static DEVICE_ATTR(in##channel##_input, S_IRUGO, \
87 show_in##channel##_input, NULL);
88
89 show_in_channel(0);
90 show_in_channel(1);
91 show_in_channel(2);
92 show_in_channel(3);
93
out0_output_show(struct device * dev,struct device_attribute * attr,char * buf)94 static ssize_t out0_output_show(struct device *dev,
95 struct device_attribute *attr, char *buf)
96 {
97 struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
98 return sprintf(buf, "%d\n", data->aout * 10);
99 }
100
out0_output_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)101 static ssize_t out0_output_store(struct device *dev,
102 struct device_attribute *attr,
103 const char *buf, size_t count)
104 {
105 unsigned long val;
106 struct i2c_client *client = to_i2c_client(dev);
107 struct pcf8591_data *data = i2c_get_clientdata(client);
108 int err;
109
110 err = kstrtoul(buf, 10, &val);
111 if (err)
112 return err;
113
114 val /= 10;
115 if (val > 255)
116 return -EINVAL;
117
118 data->aout = val;
119 i2c_smbus_write_byte_data(client, data->control, data->aout);
120 return count;
121 }
122
123 static DEVICE_ATTR_RW(out0_output);
124
out0_enable_show(struct device * dev,struct device_attribute * attr,char * buf)125 static ssize_t out0_enable_show(struct device *dev,
126 struct device_attribute *attr, char *buf)
127 {
128 struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
129 return sprintf(buf, "%u\n", !(!(data->control & PCF8591_CONTROL_AOEF)));
130 }
131
out0_enable_store(struct device * dev,struct device_attribute * attr,const char * buf,size_t count)132 static ssize_t out0_enable_store(struct device *dev,
133 struct device_attribute *attr,
134 const char *buf, size_t count)
135 {
136 struct i2c_client *client = to_i2c_client(dev);
137 struct pcf8591_data *data = i2c_get_clientdata(client);
138 unsigned long val;
139 int err;
140
141 err = kstrtoul(buf, 10, &val);
142 if (err)
143 return err;
144
145 mutex_lock(&data->update_lock);
146 if (val)
147 data->control |= PCF8591_CONTROL_AOEF;
148 else
149 data->control &= ~PCF8591_CONTROL_AOEF;
150 i2c_smbus_write_byte(client, data->control);
151 mutex_unlock(&data->update_lock);
152 return count;
153 }
154
155 static DEVICE_ATTR_RW(out0_enable);
156
157 static struct attribute *pcf8591_attributes[] = {
158 &dev_attr_out0_enable.attr,
159 &dev_attr_out0_output.attr,
160 &dev_attr_in0_input.attr,
161 &dev_attr_in1_input.attr,
162 NULL
163 };
164
165 static const struct attribute_group pcf8591_attr_group = {
166 .attrs = pcf8591_attributes,
167 };
168
169 static struct attribute *pcf8591_attributes_opt[] = {
170 &dev_attr_in2_input.attr,
171 &dev_attr_in3_input.attr,
172 NULL
173 };
174
175 static const struct attribute_group pcf8591_attr_group_opt = {
176 .attrs = pcf8591_attributes_opt,
177 };
178
179 /*
180 * Real code
181 */
182
pcf8591_probe(struct i2c_client * client)183 static int pcf8591_probe(struct i2c_client *client)
184 {
185 struct pcf8591_data *data;
186 int err;
187
188 data = devm_kzalloc(&client->dev, sizeof(struct pcf8591_data),
189 GFP_KERNEL);
190 if (!data)
191 return -ENOMEM;
192
193 i2c_set_clientdata(client, data);
194 mutex_init(&data->update_lock);
195
196 /* Initialize the PCF8591 chip */
197 pcf8591_init_client(client);
198
199 /* Register sysfs hooks */
200 err = sysfs_create_group(&client->dev.kobj, &pcf8591_attr_group);
201 if (err)
202 return err;
203
204 /* Register input2 if not in "two differential inputs" mode */
205 if (input_mode != 3) {
206 err = device_create_file(&client->dev, &dev_attr_in2_input);
207 if (err)
208 goto exit_sysfs_remove;
209 }
210
211 /* Register input3 only in "four single ended inputs" mode */
212 if (input_mode == 0) {
213 err = device_create_file(&client->dev, &dev_attr_in3_input);
214 if (err)
215 goto exit_sysfs_remove;
216 }
217
218 data->hwmon_dev = hwmon_device_register(&client->dev);
219 if (IS_ERR(data->hwmon_dev)) {
220 err = PTR_ERR(data->hwmon_dev);
221 goto exit_sysfs_remove;
222 }
223
224 return 0;
225
226 exit_sysfs_remove:
227 sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
228 sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
229 return err;
230 }
231
pcf8591_remove(struct i2c_client * client)232 static void pcf8591_remove(struct i2c_client *client)
233 {
234 struct pcf8591_data *data = i2c_get_clientdata(client);
235
236 hwmon_device_unregister(data->hwmon_dev);
237 sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
238 sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
239 }
240
241 /* Called when we have found a new PCF8591. */
pcf8591_init_client(struct i2c_client * client)242 static void pcf8591_init_client(struct i2c_client *client)
243 {
244 struct pcf8591_data *data = i2c_get_clientdata(client);
245 data->control = PCF8591_INIT_CONTROL;
246 data->aout = PCF8591_INIT_AOUT;
247
248 i2c_smbus_write_byte_data(client, data->control, data->aout);
249
250 /*
251 * The first byte transmitted contains the conversion code of the
252 * previous read cycle. FLUSH IT!
253 */
254 i2c_smbus_read_byte(client);
255 }
256
pcf8591_read_channel(struct device * dev,int channel)257 static int pcf8591_read_channel(struct device *dev, int channel)
258 {
259 u8 value;
260 struct i2c_client *client = to_i2c_client(dev);
261 struct pcf8591_data *data = i2c_get_clientdata(client);
262
263 mutex_lock(&data->update_lock);
264
265 if ((data->control & PCF8591_CONTROL_AICH_MASK) != channel) {
266 data->control = (data->control & ~PCF8591_CONTROL_AICH_MASK)
267 | channel;
268 i2c_smbus_write_byte(client, data->control);
269
270 /*
271 * The first byte transmitted contains the conversion code of
272 * the previous read cycle. FLUSH IT!
273 */
274 i2c_smbus_read_byte(client);
275 }
276 value = i2c_smbus_read_byte(client);
277
278 mutex_unlock(&data->update_lock);
279
280 if ((channel == 2 && input_mode == 2) ||
281 (channel != 3 && (input_mode == 1 || input_mode == 3)))
282 return 10 * REG_TO_SIGNED(value);
283 else
284 return 10 * value;
285 }
286
287 static const struct i2c_device_id pcf8591_id[] = {
288 { "pcf8591", 0 },
289 { }
290 };
291 MODULE_DEVICE_TABLE(i2c, pcf8591_id);
292
293 static struct i2c_driver pcf8591_driver = {
294 .driver = {
295 .name = "pcf8591",
296 },
297 .probe = pcf8591_probe,
298 .remove = pcf8591_remove,
299 .id_table = pcf8591_id,
300 };
301
pcf8591_init(void)302 static int __init pcf8591_init(void)
303 {
304 if (input_mode < 0 || input_mode > 3) {
305 pr_warn("invalid input_mode (%d)\n", input_mode);
306 input_mode = 0;
307 }
308 return i2c_add_driver(&pcf8591_driver);
309 }
310
pcf8591_exit(void)311 static void __exit pcf8591_exit(void)
312 {
313 i2c_del_driver(&pcf8591_driver);
314 }
315
316 MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>");
317 MODULE_DESCRIPTION("PCF8591 driver");
318 MODULE_LICENSE("GPL");
319
320 module_init(pcf8591_init);
321 module_exit(pcf8591_exit);
322