xref: /kernel/linux/linux-6.6/drivers/hwmon/pcf8591.c (revision 62306a36) 
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
21static int input_mode;
22module_param(input_mode, int, 0);
23MODULE_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
67struct pcf8591_data {
68	struct device *hwmon_dev;
69	struct mutex update_lock;
70
71	u8 control;
72	u8 aout;
73};
74
75static void pcf8591_init_client(struct i2c_client *client);
76static int pcf8591_read_channel(struct device *dev, int channel);
77
78/* following are the sysfs callback functions */
79#define show_in_channel(channel)					\
80static 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}									\
86static DEVICE_ATTR(in##channel##_input, S_IRUGO,			\
87		   show_in##channel##_input, NULL);
88
89show_in_channel(0);
90show_in_channel(1);
91show_in_channel(2);
92show_in_channel(3);
93
94static 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
101static 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
123static DEVICE_ATTR_RW(out0_output);
124
125static 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
132static 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
155static DEVICE_ATTR_RW(out0_enable);
156
157static 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
165static const struct attribute_group pcf8591_attr_group = {
166	.attrs = pcf8591_attributes,
167};
168
169static struct attribute *pcf8591_attributes_opt[] = {
170	&dev_attr_in2_input.attr,
171	&dev_attr_in3_input.attr,
172	NULL
173};
174
175static const struct attribute_group pcf8591_attr_group_opt = {
176	.attrs = pcf8591_attributes_opt,
177};
178
179/*
180 * Real code
181 */
182
183static 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
226exit_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
232static 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. */
242static 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
257static 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
287static const struct i2c_device_id pcf8591_id[] = {
288	{ "pcf8591", 0 },
289	{ }
290};
291MODULE_DEVICE_TABLE(i2c, pcf8591_id);
292
293static 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
302static 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
311static void __exit pcf8591_exit(void)
312{
313	i2c_del_driver(&pcf8591_driver);
314}
315
316MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>");
317MODULE_DESCRIPTION("PCF8591 driver");
318MODULE_LICENSE("GPL");
319
320module_init(pcf8591_init);
321module_exit(pcf8591_exit);
322