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
18/* Insmod parameters */
19
20static int input_mode;
21module_param(input_mode, int, 0);
22MODULE_PARM_DESC(input_mode,
23	"Analog input mode:\n"
24	" 0 = four single ended inputs\n"
25	" 1 = three differential inputs\n"
26	" 2 = single ended and differential mixed\n"
27	" 3 = two differential inputs\n");
28
29/*
30 * The PCF8591 control byte
31 *      7    6    5    4    3    2    1    0
32 *   |  0 |AOEF|   AIP   |  0 |AINC|  AICH   |
33 */
34
35/* Analog Output Enable Flag (analog output active if 1) */
36#define PCF8591_CONTROL_AOEF		0x40
37
38/*
39 * Analog Input Programming
40 * 0x00 = four single ended inputs
41 * 0x10 = three differential inputs
42 * 0x20 = single ended and differential mixed
43 * 0x30 = two differential inputs
44 */
45#define PCF8591_CONTROL_AIP_MASK	0x30
46
47/* Autoincrement Flag (switch on if 1) */
48#define PCF8591_CONTROL_AINC		0x04
49
50/*
51 * Channel selection
52 * 0x00 = channel 0
53 * 0x01 = channel 1
54 * 0x02 = channel 2
55 * 0x03 = channel 3
56 */
57#define PCF8591_CONTROL_AICH_MASK	0x03
58
59/* Initial values */
60#define PCF8591_INIT_CONTROL	((input_mode << 4) | PCF8591_CONTROL_AOEF)
61#define PCF8591_INIT_AOUT	0	/* DAC out = 0 */
62
63/* Conversions */
64#define REG_TO_SIGNED(reg)	(((reg) & 0x80) ? ((reg) - 256) : (reg))
65
66struct pcf8591_data {
67	struct device *hwmon_dev;
68	struct mutex update_lock;
69
70	u8 control;
71	u8 aout;
72};
73
74static void pcf8591_init_client(struct i2c_client *client);
75static int pcf8591_read_channel(struct device *dev, int channel);
76
77/* following are the sysfs callback functions */
78#define show_in_channel(channel)					\
79static ssize_t show_in##channel##_input(struct device *dev,		\
80					struct device_attribute *attr,	\
81					char *buf)			\
82{									\
83	return sprintf(buf, "%d\n", pcf8591_read_channel(dev, channel));\
84}									\
85static DEVICE_ATTR(in##channel##_input, S_IRUGO,			\
86		   show_in##channel##_input, NULL);
87
88show_in_channel(0);
89show_in_channel(1);
90show_in_channel(2);
91show_in_channel(3);
92
93static ssize_t out0_output_show(struct device *dev,
94				struct device_attribute *attr, char *buf)
95{
96	struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
97	return sprintf(buf, "%d\n", data->aout * 10);
98}
99
100static ssize_t out0_output_store(struct device *dev,
101				 struct device_attribute *attr,
102				 const char *buf, size_t count)
103{
104	unsigned long val;
105	struct i2c_client *client = to_i2c_client(dev);
106	struct pcf8591_data *data = i2c_get_clientdata(client);
107	int err;
108
109	err = kstrtoul(buf, 10, &val);
110	if (err)
111		return err;
112
113	val /= 10;
114	if (val > 255)
115		return -EINVAL;
116
117	data->aout = val;
118	i2c_smbus_write_byte_data(client, data->control, data->aout);
119	return count;
120}
121
122static DEVICE_ATTR_RW(out0_output);
123
124static ssize_t out0_enable_show(struct device *dev,
125				struct device_attribute *attr, char *buf)
126{
127	struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
128	return sprintf(buf, "%u\n", !(!(data->control & PCF8591_CONTROL_AOEF)));
129}
130
131static ssize_t out0_enable_store(struct device *dev,
132				 struct device_attribute *attr,
133				 const char *buf, size_t count)
134{
135	struct i2c_client *client = to_i2c_client(dev);
136	struct pcf8591_data *data = i2c_get_clientdata(client);
137	unsigned long val;
138	int err;
139
140	err = kstrtoul(buf, 10, &val);
141	if (err)
142		return err;
143
144	mutex_lock(&data->update_lock);
145	if (val)
146		data->control |= PCF8591_CONTROL_AOEF;
147	else
148		data->control &= ~PCF8591_CONTROL_AOEF;
149	i2c_smbus_write_byte(client, data->control);
150	mutex_unlock(&data->update_lock);
151	return count;
152}
153
154static DEVICE_ATTR_RW(out0_enable);
155
156static struct attribute *pcf8591_attributes[] = {
157	&dev_attr_out0_enable.attr,
158	&dev_attr_out0_output.attr,
159	&dev_attr_in0_input.attr,
160	&dev_attr_in1_input.attr,
161	NULL
162};
163
164static const struct attribute_group pcf8591_attr_group = {
165	.attrs = pcf8591_attributes,
166};
167
168static struct attribute *pcf8591_attributes_opt[] = {
169	&dev_attr_in2_input.attr,
170	&dev_attr_in3_input.attr,
171	NULL
172};
173
174static const struct attribute_group pcf8591_attr_group_opt = {
175	.attrs = pcf8591_attributes_opt,
176};
177
178/*
179 * Real code
180 */
181
182static int pcf8591_probe(struct i2c_client *client)
183{
184	struct pcf8591_data *data;
185	int err;
186
187	data = devm_kzalloc(&client->dev, sizeof(struct pcf8591_data),
188			    GFP_KERNEL);
189	if (!data)
190		return -ENOMEM;
191
192	i2c_set_clientdata(client, data);
193	mutex_init(&data->update_lock);
194
195	/* Initialize the PCF8591 chip */
196	pcf8591_init_client(client);
197
198	/* Register sysfs hooks */
199	err = sysfs_create_group(&client->dev.kobj, &pcf8591_attr_group);
200	if (err)
201		return err;
202
203	/* Register input2 if not in "two differential inputs" mode */
204	if (input_mode != 3) {
205		err = device_create_file(&client->dev, &dev_attr_in2_input);
206		if (err)
207			goto exit_sysfs_remove;
208	}
209
210	/* Register input3 only in "four single ended inputs" mode */
211	if (input_mode == 0) {
212		err = device_create_file(&client->dev, &dev_attr_in3_input);
213		if (err)
214			goto exit_sysfs_remove;
215	}
216
217	data->hwmon_dev = hwmon_device_register(&client->dev);
218	if (IS_ERR(data->hwmon_dev)) {
219		err = PTR_ERR(data->hwmon_dev);
220		goto exit_sysfs_remove;
221	}
222
223	return 0;
224
225exit_sysfs_remove:
226	sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
227	sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
228	return err;
229}
230
231static int pcf8591_remove(struct i2c_client *client)
232{
233	struct pcf8591_data *data = i2c_get_clientdata(client);
234
235	hwmon_device_unregister(data->hwmon_dev);
236	sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
237	sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
238	return 0;
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_new	= 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