1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Maxim MAX197 A/D Converter driver
4 *
5 * Copyright (c) 2012 Savoir-faire Linux Inc.
6 *          Vivien Didelot <vivien.didelot@savoirfairelinux.com>
7 *
8 * For further information, see the Documentation/hwmon/max197.rst file.
9 */
10
11#include <linux/kernel.h>
12#include <linux/module.h>
13#include <linux/mod_devicetable.h>
14#include <linux/init.h>
15#include <linux/err.h>
16#include <linux/slab.h>
17#include <linux/mutex.h>
18#include <linux/device.h>
19#include <linux/sysfs.h>
20#include <linux/hwmon.h>
21#include <linux/hwmon-sysfs.h>
22#include <linux/platform_device.h>
23#include <linux/platform_data/max197.h>
24
25#define MAX199_LIMIT	4000		/* 4V */
26#define MAX197_LIMIT	10000		/* 10V */
27
28#define MAX197_NUM_CH	8		/* 8 Analog Input Channels */
29
30/* Control byte format */
31#define MAX197_BIP	(1 << 3)	/* Bipolarity */
32#define MAX197_RNG	(1 << 4)	/* Full range */
33
34#define MAX197_SCALE	12207		/* Scale coefficient for raw data */
35
36/* List of supported chips */
37enum max197_chips { max197, max199 };
38
39/**
40 * struct max197_data - device instance specific data
41 * @pdata:		Platform data.
42 * @hwmon_dev:		The hwmon device.
43 * @lock:		Read/Write mutex.
44 * @limit:		Max range value (10V for MAX197, 4V for MAX199).
45 * @scale:		Need to scale.
46 * @ctrl_bytes:		Channels control byte.
47 */
48struct max197_data {
49	struct max197_platform_data *pdata;
50	struct device *hwmon_dev;
51	struct mutex lock;
52	int limit;
53	bool scale;
54	u8 ctrl_bytes[MAX197_NUM_CH];
55};
56
57static inline void max197_set_unipolarity(struct max197_data *data, int channel)
58{
59	data->ctrl_bytes[channel] &= ~MAX197_BIP;
60}
61
62static inline void max197_set_bipolarity(struct max197_data *data, int channel)
63{
64	data->ctrl_bytes[channel] |= MAX197_BIP;
65}
66
67static inline void max197_set_half_range(struct max197_data *data, int channel)
68{
69	data->ctrl_bytes[channel] &= ~MAX197_RNG;
70}
71
72static inline void max197_set_full_range(struct max197_data *data, int channel)
73{
74	data->ctrl_bytes[channel] |= MAX197_RNG;
75}
76
77static inline bool max197_is_bipolar(struct max197_data *data, int channel)
78{
79	return data->ctrl_bytes[channel] & MAX197_BIP;
80}
81
82static inline bool max197_is_full_range(struct max197_data *data, int channel)
83{
84	return data->ctrl_bytes[channel] & MAX197_RNG;
85}
86
87/* Function called on read access on in{0,1,2,3,4,5,6,7}_{min,max} */
88static ssize_t max197_show_range(struct device *dev,
89				 struct device_attribute *devattr, char *buf)
90{
91	struct max197_data *data = dev_get_drvdata(dev);
92	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
93	int channel = attr->index;
94	bool is_min = attr->nr;
95	int range;
96
97	if (mutex_lock_interruptible(&data->lock))
98		return -ERESTARTSYS;
99
100	range = max197_is_full_range(data, channel) ?
101		data->limit : data->limit / 2;
102	if (is_min) {
103		if (max197_is_bipolar(data, channel))
104			range = -range;
105		else
106			range = 0;
107	}
108
109	mutex_unlock(&data->lock);
110
111	return sprintf(buf, "%d\n", range);
112}
113
114/* Function called on write access on in{0,1,2,3,4,5,6,7}_{min,max} */
115static ssize_t max197_store_range(struct device *dev,
116				  struct device_attribute *devattr,
117				  const char *buf, size_t count)
118{
119	struct max197_data *data = dev_get_drvdata(dev);
120	struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
121	int channel = attr->index;
122	bool is_min = attr->nr;
123	long value;
124	int half = data->limit / 2;
125	int full = data->limit;
126
127	if (kstrtol(buf, 10, &value))
128		return -EINVAL;
129
130	if (is_min) {
131		if (value <= -full)
132			value = -full;
133		else if (value < 0)
134			value = -half;
135		else
136			value = 0;
137	} else {
138		if (value >= full)
139			value = full;
140		else
141			value = half;
142	}
143
144	if (mutex_lock_interruptible(&data->lock))
145		return -ERESTARTSYS;
146
147	if (value == 0) {
148		/* We can deduce only the polarity */
149		max197_set_unipolarity(data, channel);
150	} else if (value == -half) {
151		max197_set_bipolarity(data, channel);
152		max197_set_half_range(data, channel);
153	} else if (value == -full) {
154		max197_set_bipolarity(data, channel);
155		max197_set_full_range(data, channel);
156	} else if (value == half) {
157		/* We can deduce only the range */
158		max197_set_half_range(data, channel);
159	} else if (value == full) {
160		/* We can deduce only the range */
161		max197_set_full_range(data, channel);
162	}
163
164	mutex_unlock(&data->lock);
165
166	return count;
167}
168
169/* Function called on read access on in{0,1,2,3,4,5,6,7}_input */
170static ssize_t max197_show_input(struct device *dev,
171				 struct device_attribute *devattr,
172				 char *buf)
173{
174	struct max197_data *data = dev_get_drvdata(dev);
175	struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
176	int channel = attr->index;
177	s32 value;
178	int ret;
179
180	if (mutex_lock_interruptible(&data->lock))
181		return -ERESTARTSYS;
182
183	ret = data->pdata->convert(data->ctrl_bytes[channel]);
184	if (ret < 0) {
185		dev_err(dev, "conversion failed\n");
186		goto unlock;
187	}
188	value = ret;
189
190	/*
191	 * Coefficient to apply on raw value.
192	 * See Table 1. Full Scale and Zero Scale in the MAX197 datasheet.
193	 */
194	if (data->scale) {
195		value *= MAX197_SCALE;
196		if (max197_is_full_range(data, channel))
197			value *= 2;
198		value /= 10000;
199	}
200
201	ret = sprintf(buf, "%d\n", value);
202
203unlock:
204	mutex_unlock(&data->lock);
205	return ret;
206}
207
208static ssize_t name_show(struct device *dev, struct device_attribute *attr,
209			 char *buf)
210{
211	struct platform_device *pdev = to_platform_device(dev);
212	return sprintf(buf, "%s\n", pdev->name);
213}
214
215#define MAX197_SENSOR_DEVICE_ATTR_CH(chan)				\
216	static SENSOR_DEVICE_ATTR(in##chan##_input, S_IRUGO,		\
217				  max197_show_input, NULL, chan);	\
218	static SENSOR_DEVICE_ATTR_2(in##chan##_min, S_IRUGO | S_IWUSR,	\
219				    max197_show_range,			\
220				    max197_store_range,			\
221				    true, chan);			\
222	static SENSOR_DEVICE_ATTR_2(in##chan##_max, S_IRUGO | S_IWUSR,	\
223				    max197_show_range,			\
224				    max197_store_range,			\
225				    false, chan)
226
227#define MAX197_SENSOR_DEV_ATTR_IN(chan)					\
228	&sensor_dev_attr_in##chan##_input.dev_attr.attr,		\
229	&sensor_dev_attr_in##chan##_max.dev_attr.attr,			\
230	&sensor_dev_attr_in##chan##_min.dev_attr.attr
231
232static DEVICE_ATTR_RO(name);
233
234MAX197_SENSOR_DEVICE_ATTR_CH(0);
235MAX197_SENSOR_DEVICE_ATTR_CH(1);
236MAX197_SENSOR_DEVICE_ATTR_CH(2);
237MAX197_SENSOR_DEVICE_ATTR_CH(3);
238MAX197_SENSOR_DEVICE_ATTR_CH(4);
239MAX197_SENSOR_DEVICE_ATTR_CH(5);
240MAX197_SENSOR_DEVICE_ATTR_CH(6);
241MAX197_SENSOR_DEVICE_ATTR_CH(7);
242
243static const struct attribute_group max197_sysfs_group = {
244	.attrs = (struct attribute *[]) {
245		&dev_attr_name.attr,
246		MAX197_SENSOR_DEV_ATTR_IN(0),
247		MAX197_SENSOR_DEV_ATTR_IN(1),
248		MAX197_SENSOR_DEV_ATTR_IN(2),
249		MAX197_SENSOR_DEV_ATTR_IN(3),
250		MAX197_SENSOR_DEV_ATTR_IN(4),
251		MAX197_SENSOR_DEV_ATTR_IN(5),
252		MAX197_SENSOR_DEV_ATTR_IN(6),
253		MAX197_SENSOR_DEV_ATTR_IN(7),
254		NULL
255	},
256};
257
258static int max197_probe(struct platform_device *pdev)
259{
260	int ch, ret;
261	struct max197_data *data;
262	struct max197_platform_data *pdata = dev_get_platdata(&pdev->dev);
263	enum max197_chips chip = platform_get_device_id(pdev)->driver_data;
264
265	if (pdata == NULL) {
266		dev_err(&pdev->dev, "no platform data supplied\n");
267		return -EINVAL;
268	}
269
270	if (pdata->convert == NULL) {
271		dev_err(&pdev->dev, "no convert function supplied\n");
272		return -EINVAL;
273	}
274
275	data = devm_kzalloc(&pdev->dev, sizeof(struct max197_data), GFP_KERNEL);
276	if (!data)
277		return -ENOMEM;
278
279	data->pdata = pdata;
280	mutex_init(&data->lock);
281
282	if (chip == max197) {
283		data->limit = MAX197_LIMIT;
284		data->scale = true;
285	} else {
286		data->limit = MAX199_LIMIT;
287		data->scale = false;
288	}
289
290	for (ch = 0; ch < MAX197_NUM_CH; ch++)
291		data->ctrl_bytes[ch] = (u8) ch;
292
293	platform_set_drvdata(pdev, data);
294
295	ret = sysfs_create_group(&pdev->dev.kobj, &max197_sysfs_group);
296	if (ret) {
297		dev_err(&pdev->dev, "sysfs create group failed\n");
298		return ret;
299	}
300
301	data->hwmon_dev = hwmon_device_register(&pdev->dev);
302	if (IS_ERR(data->hwmon_dev)) {
303		ret = PTR_ERR(data->hwmon_dev);
304		dev_err(&pdev->dev, "hwmon device register failed\n");
305		goto error;
306	}
307
308	return 0;
309
310error:
311	sysfs_remove_group(&pdev->dev.kobj, &max197_sysfs_group);
312	return ret;
313}
314
315static void max197_remove(struct platform_device *pdev)
316{
317	struct max197_data *data = platform_get_drvdata(pdev);
318
319	hwmon_device_unregister(data->hwmon_dev);
320	sysfs_remove_group(&pdev->dev.kobj, &max197_sysfs_group);
321}
322
323static const struct platform_device_id max197_device_ids[] = {
324	{ "max197", max197 },
325	{ "max199", max199 },
326	{ }
327};
328MODULE_DEVICE_TABLE(platform, max197_device_ids);
329
330static struct platform_driver max197_driver = {
331	.driver = {
332		.name = "max197",
333	},
334	.probe = max197_probe,
335	.remove_new = max197_remove,
336	.id_table = max197_device_ids,
337};
338module_platform_driver(max197_driver);
339
340MODULE_LICENSE("GPL");
341MODULE_AUTHOR("Savoir-faire Linux Inc. <kernel@savoirfairelinux.com>");
342MODULE_DESCRIPTION("Maxim MAX197 A/D Converter driver");
343