1/*
2 * Maxim MAX197 A/D Converter driver
3 *
4 * Copyright (c) 2012 Savoir-faire Linux Inc.
5 * Vivien Didelot <vivien.didelot@savoirfairelinux.com>
6 *
7 * This program is free software; you can redistribute it and/or modify
8 * it under the terms of the GNU General Public License version 2 as
9 * published by the Free Software Foundation.
10 *
11 * For further information, see the Documentation/hwmon/max197 file.
12 */
13
14#include <linux/kernel.h>
15#include <linux/module.h>
16#include <linux/mod_devicetable.h>
17#include <linux/init.h>
18#include <linux/err.h>
19#include <linux/slab.h>
20#include <linux/mutex.h>
21#include <linux/device.h>
22#include <linux/sysfs.h>
23#include <linux/hwmon.h>
24#include <linux/hwmon-sysfs.h>
25#include <linux/platform_device.h>
26#include <linux/platform_data/max197.h>
27
28#define MAX199_LIMIT 4000 /* 4V */
29#define MAX197_LIMIT 10000 /* 10V */
30
31#define MAX197_NUM_CH 8 /* 8 Analog Input Channels */
32
33/* Control byte format */
34#define MAX197_BIP (1 << 3) /* Bipolarity */
35#define MAX197_RNG (1 << 4) /* Full range */
36
37#define MAX197_SCALE 12207 /* Scale coefficient for raw data */
38
39/* List of supported chips */
40enum max197_chips { max197, max199 };
41
42/**
43 * struct max197_data - device instance specific data
44 * @pdata: Platform data.
45 * @hwmon_dev: The hwmon device.
46 * @lock: Read/Write mutex.
47 * @limit: Max range value (10V for MAX197, 4V for MAX199).
48 * @scale: Need to scale.
49 * @ctrl_bytes: Channels control byte.
50 */
51struct max197_data {
52 struct max197_platform_data *pdata;
53 struct device *hwmon_dev;
54 struct mutex lock;
55 int limit;
56 bool scale;
57 u8 ctrl_bytes[MAX197_NUM_CH];
58};
59
60static inline void max197_set_unipolarity(struct max197_data *data, int channel)
61{
62 data->ctrl_bytes[channel] &= ~MAX197_BIP;
63}
64
65static inline void max197_set_bipolarity(struct max197_data *data, int channel)
66{
67 data->ctrl_bytes[channel] |= MAX197_BIP;
68}
69
70static inline void max197_set_half_range(struct max197_data *data, int channel)
71{
72 data->ctrl_bytes[channel] &= ~MAX197_RNG;
73}
74
75static inline void max197_set_full_range(struct max197_data *data, int channel)
76{
77 data->ctrl_bytes[channel] |= MAX197_RNG;
78}
79
80static inline bool max197_is_bipolar(struct max197_data *data, int channel)
81{
82 return data->ctrl_bytes[channel] & MAX197_BIP;
83}
84
85static inline bool max197_is_full_range(struct max197_data *data, int channel)
86{
87 return data->ctrl_bytes[channel] & MAX197_RNG;
88}
89
90/* Function called on read access on in{0,1,2,3,4,5,6,7}_{min,max} */
91static ssize_t max197_show_range(struct device *dev,
92 struct device_attribute *devattr, char *buf)
93{
94 struct max197_data *data = dev_get_drvdata(dev);
95 struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
96 int channel = attr->index;
97 bool is_min = attr->nr;
98 int range;
99
100 if (mutex_lock_interruptible(&data->lock))
101 return -ERESTARTSYS;
102
103 range = max197_is_full_range(data, channel) ?
104 data->limit : data->limit / 2;
105 if (is_min) {
106 if (max197_is_bipolar(data, channel))
107 range = -range;
108 else
109 range = 0;
110 }
111
112 mutex_unlock(&data->lock);
113
114 return sprintf(buf, "%d\n", range);
115}
116
117/* Function called on write access on in{0,1,2,3,4,5,6,7}_{min,max} */
118static ssize_t max197_store_range(struct device *dev,
119 struct device_attribute *devattr,
120 const char *buf, size_t count)
121{
122 struct max197_data *data = dev_get_drvdata(dev);
123 struct sensor_device_attribute_2 *attr = to_sensor_dev_attr_2(devattr);
124 int channel = attr->index;
125 bool is_min = attr->nr;
126 long value;
127 int half = data->limit / 2;
128 int full = data->limit;
129
130 if (kstrtol(buf, 10, &value))
131 return -EINVAL;
132
133 if (is_min) {
134 if (value <= -full)
135 value = -full;
136 else if (value < 0)
137 value = -half;
138 else
139 value = 0;
140 } else {
141 if (value >= full)
142 value = full;
143 else
144 value = half;
145 }
146
147 if (mutex_lock_interruptible(&data->lock))
148 return -ERESTARTSYS;
149
150 if (value == 0) {
151 /* We can deduce only the polarity */
152 max197_set_unipolarity(data, channel);
153 } else if (value == -half) {
154 max197_set_bipolarity(data, channel);
155 max197_set_half_range(data, channel);
156 } else if (value == -full) {
157 max197_set_bipolarity(data, channel);
158 max197_set_full_range(data, channel);
159 } else if (value == half) {
160 /* We can deduce only the range */
161 max197_set_half_range(data, channel);
162 } else if (value == full) {
163 /* We can deduce only the range */
164 max197_set_full_range(data, channel);
165 }
166
167 mutex_unlock(&data->lock);
168
169 return count;
170}
171
172/* Function called on read access on in{0,1,2,3,4,5,6,7}_input */
173static ssize_t max197_show_input(struct device *dev,
174 struct device_attribute *devattr,
175 char *buf)
176{
177 struct max197_data *data = dev_get_drvdata(dev);
178 struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
179 int channel = attr->index;
180 s32 value;
181 int ret;
182
183 if (mutex_lock_interruptible(&data->lock))
184 return -ERESTARTSYS;
185
186 ret = data->pdata->convert(data->ctrl_bytes[channel]);
187 if (ret < 0) {
188 dev_err(dev, "conversion failed\n");
189 goto unlock;
190 }
191 value = ret;
192
193 /*
194 * Coefficient to apply on raw value.
195 * See Table 1. Full Scale and Zero Scale in the MAX197 datasheet.
196 */
197 if (data->scale) {
198 value *= MAX197_SCALE;
199 if (max197_is_full_range(data, channel))
200 value *= 2;
201 value /= 10000;
202 }
203
204 ret = sprintf(buf, "%d\n", value);
205
206unlock:
207 mutex_unlock(&data->lock);
208 return ret;
209}
210
211static ssize_t name_show(struct device *dev, struct device_attribute *attr,
212 char *buf)
213{
214 struct platform_device *pdev = to_platform_device(dev);
215 return sprintf(buf, "%s\n", pdev->name);
216}
217
218#define MAX197_SENSOR_DEVICE_ATTR_CH(chan) \
219 static SENSOR_DEVICE_ATTR(in##chan##_input, S_IRUGO, \
220 max197_show_input, NULL, chan); \
221 static SENSOR_DEVICE_ATTR_2(in##chan##_min, S_IRUGO | S_IWUSR, \
222 max197_show_range, \
223 max197_store_range, \
224 true, chan); \
225 static SENSOR_DEVICE_ATTR_2(in##chan##_max, S_IRUGO | S_IWUSR, \
226 max197_show_range, \
227 max197_store_range, \
228 false, chan)
229
230#define MAX197_SENSOR_DEV_ATTR_IN(chan) \
231 &sensor_dev_attr_in##chan##_input.dev_attr.attr, \
232 &sensor_dev_attr_in##chan##_max.dev_attr.attr, \
233 &sensor_dev_attr_in##chan##_min.dev_attr.attr
234
235static DEVICE_ATTR_RO(name);
236
237MAX197_SENSOR_DEVICE_ATTR_CH(0);
238MAX197_SENSOR_DEVICE_ATTR_CH(1);
239MAX197_SENSOR_DEVICE_ATTR_CH(2);
240MAX197_SENSOR_DEVICE_ATTR_CH(3);
241MAX197_SENSOR_DEVICE_ATTR_CH(4);
242MAX197_SENSOR_DEVICE_ATTR_CH(5);
243MAX197_SENSOR_DEVICE_ATTR_CH(6);
244MAX197_SENSOR_DEVICE_ATTR_CH(7);
245
246static const struct attribute_group max197_sysfs_group = {
247 .attrs = (struct attribute *[]) {
248 &dev_attr_name.attr,
249 MAX197_SENSOR_DEV_ATTR_IN(0),
250 MAX197_SENSOR_DEV_ATTR_IN(1),
251 MAX197_SENSOR_DEV_ATTR_IN(2),
252 MAX197_SENSOR_DEV_ATTR_IN(3),
253 MAX197_SENSOR_DEV_ATTR_IN(4),
254 MAX197_SENSOR_DEV_ATTR_IN(5),
255 MAX197_SENSOR_DEV_ATTR_IN(6),
256 MAX197_SENSOR_DEV_ATTR_IN(7),
257 NULL
258 },
259};
260
261static int max197_probe(struct platform_device *pdev)
262{
263 int ch, ret;
264 struct max197_data *data;
265 struct max197_platform_data *pdata = dev_get_platdata(&pdev->dev);
266 enum max197_chips chip = platform_get_device_id(pdev)->driver_data;
267
268 if (pdata == NULL) {
269 dev_err(&pdev->dev, "no platform data supplied\n");
270 return -EINVAL;
271 }
272
273 if (pdata->convert == NULL) {
274 dev_err(&pdev->dev, "no convert function supplied\n");
275 return -EINVAL;
276 }
277
278 data = devm_kzalloc(&pdev->dev, sizeof(struct max197_data), GFP_KERNEL);
279 if (!data)
280 return -ENOMEM;
281
282 data->pdata = pdata;
283 mutex_init(&data->lock);
284
285 if (chip == max197) {
286 data->limit = MAX197_LIMIT;
287 data->scale = true;
288 } else {
289 data->limit = MAX199_LIMIT;
290 data->scale = false;
291 }
292
293 for (ch = 0; ch < MAX197_NUM_CH; ch++)
294 data->ctrl_bytes[ch] = (u8) ch;
295
296 platform_set_drvdata(pdev, data);
297
298 ret = sysfs_create_group(&pdev->dev.kobj, &max197_sysfs_group);
299 if (ret) {
300 dev_err(&pdev->dev, "sysfs create group failed\n");
301 return ret;
302 }
303
304 data->hwmon_dev = hwmon_device_register(&pdev->dev);
305 if (IS_ERR(data->hwmon_dev)) {
306 ret = PTR_ERR(data->hwmon_dev);
307 dev_err(&pdev->dev, "hwmon device register failed\n");
308 goto error;
309 }
310
311 return 0;
312
313error:
314 sysfs_remove_group(&pdev->dev.kobj, &max197_sysfs_group);
315 return ret;
316}
317
318static int max197_remove(struct platform_device *pdev)
319{
320 struct max197_data *data = platform_get_drvdata(pdev);
321
322 hwmon_device_unregister(data->hwmon_dev);
323 sysfs_remove_group(&pdev->dev.kobj, &max197_sysfs_group);
324
325 return 0;
326}
327
328static const struct platform_device_id max197_device_ids[] = {
329 { "max197", max197 },
330 { "max199", max199 },
331 { }
332};
333MODULE_DEVICE_TABLE(platform, max197_device_ids);
334
335static struct platform_driver max197_driver = {
336 .driver = {
337 .name = "max197",
338 },
339 .probe = max197_probe,
340 .remove = max197_remove,
341 .id_table = max197_device_ids,
342};
343module_platform_driver(max197_driver);
344
345MODULE_LICENSE("GPL");
346MODULE_AUTHOR("Savoir-faire Linux Inc. <kernel@savoirfairelinux.com>");
347MODULE_DESCRIPTION("Maxim MAX197 A/D Converter driver");
348