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