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Ben Dooksbff78652009-07-18 10:12:28 +01001/* linux/drivers/hwmon/s3c-hwmon.c
2 *
3 * Copyright (C) 2005, 2008, 2009 Simtec Electronics
4 * http://armlinux.simtec.co.uk/
5 * Ben Dooks <ben@simtec.co.uk>
6 *
7 * S3C24XX/S3C64XX ADC hwmon support
8 *
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of the GNU General Public License version 2 as
11 * published by the Free Software Foundation.
12 *
13 * This program is distributed in the hope that it will be useful,
14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
16 * GNU General Public License for more details.
17 *
18 * You should have received a copy of the GNU General Public License
19 * along with this program; if not, write to the Free Software
20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
21*/
22
23#include <linux/module.h>
24#include <linux/slab.h>
25#include <linux/delay.h>
26#include <linux/io.h>
27#include <linux/init.h>
28#include <linux/err.h>
29#include <linux/clk.h>
30#include <linux/interrupt.h>
31#include <linux/platform_device.h>
32
33#include <linux/hwmon.h>
34#include <linux/hwmon-sysfs.h>
35
36#include <plat/adc.h>
37#include <plat/hwmon.h>
38
39struct s3c_hwmon_attr {
40 struct sensor_device_attribute in;
41 struct sensor_device_attribute label;
42 char in_name[12];
43 char label_name[12];
44};
45
46/**
47 * struct s3c_hwmon - ADC hwmon client information
48 * @lock: Access lock to serialise the conversions.
49 * @client: The client we registered with the S3C ADC core.
50 * @hwmon_dev: The hwmon device we created.
51 * @attr: The holders for the channel attributes.
52*/
53struct s3c_hwmon {
54 struct semaphore lock;
55 struct s3c_adc_client *client;
56 struct device *hwmon_dev;
57
58 struct s3c_hwmon_attr attrs[8];
59};
60
61/**
62 * s3c_hwmon_read_ch - read a value from a given adc channel.
63 * @dev: The device.
64 * @hwmon: Our state.
65 * @channel: The channel we're reading from.
66 *
67 * Read a value from the @channel with the proper locking and sleep until
68 * either the read completes or we timeout awaiting the ADC core to get
69 * back to us.
70 */
71static int s3c_hwmon_read_ch(struct device *dev,
72 struct s3c_hwmon *hwmon, int channel)
73{
74 int ret;
75
76 ret = down_interruptible(&hwmon->lock);
77 if (ret < 0)
78 return ret;
79
80 dev_dbg(dev, "reading channel %d\n", channel);
81
82 ret = s3c_adc_read(hwmon->client, channel);
83 up(&hwmon->lock);
84
85 return ret;
86}
87
88#ifdef CONFIG_SENSORS_S3C_RAW
89/**
90 * s3c_hwmon_show_raw - show a conversion from the raw channel number.
91 * @dev: The device that the attribute belongs to.
92 * @attr: The attribute being read.
93 * @buf: The result buffer.
94 *
95 * This show deals with the raw attribute, registered for each possible
96 * ADC channel. This does a conversion and returns the raw (un-scaled)
97 * value returned from the hardware.
98 */
99static ssize_t s3c_hwmon_show_raw(struct device *dev,
100 struct device_attribute *attr, char *buf)
101{
102 struct s3c_hwmon *adc = platform_get_drvdata(to_platform_device(dev));
103 struct sensor_device_attribute *sa = to_sensor_dev_attr(attr);
104 int ret;
105
106 ret = s3c_hwmon_read_ch(dev, adc, sa->index);
107
108 return (ret < 0) ? ret : snprintf(buf, PAGE_SIZE, "%d\n", ret);
109}
110
111#define DEF_ADC_ATTR(x) \
112 static SENSOR_DEVICE_ATTR(adc##x##_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, x)
113
114DEF_ADC_ATTR(0);
115DEF_ADC_ATTR(1);
116DEF_ADC_ATTR(2);
117DEF_ADC_ATTR(3);
118DEF_ADC_ATTR(4);
119DEF_ADC_ATTR(5);
120DEF_ADC_ATTR(6);
121DEF_ADC_ATTR(7);
122
123static struct attribute *s3c_hwmon_attrs[9] = {
124 &sensor_dev_attr_adc0_raw.dev_attr.attr,
125 &sensor_dev_attr_adc1_raw.dev_attr.attr,
126 &sensor_dev_attr_adc2_raw.dev_attr.attr,
127 &sensor_dev_attr_adc3_raw.dev_attr.attr,
128 &sensor_dev_attr_adc4_raw.dev_attr.attr,
129 &sensor_dev_attr_adc5_raw.dev_attr.attr,
130 &sensor_dev_attr_adc6_raw.dev_attr.attr,
131 &sensor_dev_attr_adc7_raw.dev_attr.attr,
132 NULL,
133};
134
135static struct attribute_group s3c_hwmon_attrgroup = {
136 .attrs = s3c_hwmon_attrs,
137};
138
139static inline int s3c_hwmon_add_raw(struct device *dev)
140{
141 return sysfs_create_group(&dev->kobj, &s3c_hwmon_attrgroup);
142}
143
144static inline void s3c_hwmon_remove_raw(struct device *dev)
145{
146 sysfs_remove_group(&dev->kobj, &s3c_hwmon_attrgroup);
147}
148
149#else
150
151static inline int s3c_hwmon_add_raw(struct device *dev) { return 0; }
152static inline void s3c_hwmon_remove_raw(struct device *dev) { }
153
154#endif /* CONFIG_SENSORS_S3C_RAW */
155
156/**
157 * s3c_hwmon_ch_show - show value of a given channel
158 * @dev: The device that the attribute belongs to.
159 * @attr: The attribute being read.
160 * @buf: The result buffer.
161 *
162 * Read a value from the ADC and scale it before returning it to the
163 * caller. The scale factor is gained from the channel configuration
164 * passed via the platform data when the device was registered.
165 */
166static ssize_t s3c_hwmon_ch_show(struct device *dev,
167 struct device_attribute *attr,
168 char *buf)
169{
170 struct sensor_device_attribute *sen_attr = to_sensor_dev_attr(attr);
171 struct s3c_hwmon *hwmon = platform_get_drvdata(to_platform_device(dev));
172 struct s3c_hwmon_pdata *pdata = dev->platform_data;
173 struct s3c_hwmon_chcfg *cfg;
174 int ret;
175
176 cfg = pdata->in[sen_attr->index];
177
178 ret = s3c_hwmon_read_ch(dev, hwmon, sen_attr->index);
179 if (ret < 0)
180 return ret;
181
182 ret *= cfg->mult;
183 ret = DIV_ROUND_CLOSEST(ret, cfg->div);
184
185 return snprintf(buf, PAGE_SIZE, "%d\n", ret);
186}
187
188/**
189 * s3c_hwmon_label_show - show label name of the given channel.
190 * @dev: The device that the attribute belongs to.
191 * @attr: The attribute being read.
192 * @buf: The result buffer.
193 *
194 * Return the label name of a given channel
195 */
196static ssize_t s3c_hwmon_label_show(struct device *dev,
197 struct device_attribute *attr,
198 char *buf)
199{
200 struct sensor_device_attribute *sen_attr = to_sensor_dev_attr(attr);
201 struct s3c_hwmon_pdata *pdata = dev->platform_data;
202 struct s3c_hwmon_chcfg *cfg;
203
204 cfg = pdata->in[sen_attr->index];
205
206 return snprintf(buf, PAGE_SIZE, "%s\n", cfg->name);
207}
208
209/**
210 * s3c_hwmon_create_attr - create hwmon attribute for given channel.
211 * @dev: The device to create the attribute on.
212 * @cfg: The channel configuration passed from the platform data.
213 * @channel: The ADC channel number to process.
214 *
215 * Create the scaled attribute for use with hwmon from the specified
216 * platform data in @pdata. The sysfs entry is handled by the routine
217 * s3c_hwmon_ch_show().
218 *
219 * The attribute name is taken from the configuration data if present
220 * otherwise the name is taken by concatenating in_ with the channel
221 * number.
222 */
223static int s3c_hwmon_create_attr(struct device *dev,
224 struct s3c_hwmon_chcfg *cfg,
225 struct s3c_hwmon_attr *attrs,
226 int channel)
227{
228 struct sensor_device_attribute *attr;
229 int ret;
230
231 snprintf(attrs->in_name, sizeof(attrs->in_name), "in%d_input", channel);
232
233 attr = &attrs->in;
234 attr->index = channel;
235 attr->dev_attr.attr.name = attrs->in_name;
236 attr->dev_attr.attr.mode = S_IRUGO;
237 attr->dev_attr.attr.owner = THIS_MODULE;
238 attr->dev_attr.show = s3c_hwmon_ch_show;
239
240 ret = device_create_file(dev, &attr->dev_attr);
241 if (ret < 0) {
242 dev_err(dev, "failed to create input attribute\n");
243 return ret;
244 }
245
246 /* if this has a name, add a label */
247 if (cfg->name) {
248 snprintf(attrs->label_name, sizeof(attrs->label_name),
249 "in%d_label", channel);
250
251 attr = &attrs->label;
252 attr->index = channel;
253 attr->dev_attr.attr.name = attrs->label_name;
254 attr->dev_attr.attr.mode = S_IRUGO;
255 attr->dev_attr.attr.owner = THIS_MODULE;
256 attr->dev_attr.show = s3c_hwmon_label_show;
257
258 ret = device_create_file(dev, &attr->dev_attr);
259 if (ret < 0) {
260 device_remove_file(dev, &attrs->in.dev_attr);
261 dev_err(dev, "failed to create label attribute\n");
262 }
263 }
264
265 return ret;
266}
267
268static void s3c_hwmon_remove_attr(struct device *dev,
269 struct s3c_hwmon_attr *attrs)
270{
271 device_remove_file(dev, &attrs->in.dev_attr);
272 device_remove_file(dev, &attrs->label.dev_attr);
273}
274
275/**
276 * s3c_hwmon_probe - device probe entry.
277 * @dev: The device being probed.
278*/
279static int __devinit s3c_hwmon_probe(struct platform_device *dev)
280{
281 struct s3c_hwmon_pdata *pdata = dev->dev.platform_data;
282 struct s3c_hwmon *hwmon;
283 int ret = 0;
284 int i;
285
286 if (!pdata) {
287 dev_err(&dev->dev, "no platform data supplied\n");
288 return -EINVAL;
289 }
290
291 hwmon = kzalloc(sizeof(struct s3c_hwmon), GFP_KERNEL);
292 if (hwmon == NULL) {
293 dev_err(&dev->dev, "no memory\n");
294 return -ENOMEM;
295 }
296
297 platform_set_drvdata(dev, hwmon);
298
299 init_MUTEX(&hwmon->lock);
300
301 /* Register with the core ADC driver. */
302
303 hwmon->client = s3c_adc_register(dev, NULL, NULL, 0);
304 if (IS_ERR(hwmon->client)) {
305 dev_err(&dev->dev, "cannot register adc\n");
306 ret = PTR_ERR(hwmon->client);
307 goto err_mem;
308 }
309
310 /* add attributes for our adc devices. */
311
312 ret = s3c_hwmon_add_raw(&dev->dev);
313 if (ret)
314 goto err_registered;
315
316 /* register with the hwmon core */
317
318 hwmon->hwmon_dev = hwmon_device_register(&dev->dev);
319 if (IS_ERR(hwmon->hwmon_dev)) {
320 dev_err(&dev->dev, "error registering with hwmon\n");
321 ret = PTR_ERR(hwmon->hwmon_dev);
322 goto err_raw_attribute;
323 }
324
325 for (i = 0; i < ARRAY_SIZE(pdata->in); i++) {
Ben Dooks6d905e62009-12-09 20:35:45 +0100326 struct s3c_hwmon_chcfg *cfg = pdata->in[i];
Ben Dooksbe4c23c2009-11-16 12:45:39 +0100327
328 if (!cfg)
Ben Dooksbff78652009-07-18 10:12:28 +0100329 continue;
330
Ben Dooksbe4c23c2009-11-16 12:45:39 +0100331 if (cfg->mult >= 0x10000)
Ben Dooksbff78652009-07-18 10:12:28 +0100332 dev_warn(&dev->dev,
333 "channel %d multiplier too large\n",
334 i);
335
Ben Dooks6d905e62009-12-09 20:35:45 +0100336 if (cfg->div == 0) {
Ben Dooksbe4c23c2009-11-16 12:45:39 +0100337 dev_err(&dev->dev, "channel %d divider zero\n", i);
338 continue;
339 }
340
Ben Dooksbff78652009-07-18 10:12:28 +0100341 ret = s3c_hwmon_create_attr(&dev->dev, pdata->in[i],
342 &hwmon->attrs[i], i);
343 if (ret) {
344 dev_err(&dev->dev,
345 "error creating channel %d\n", i);
346
347 for (i--; i >= 0; i--)
348 s3c_hwmon_remove_attr(&dev->dev,
349 &hwmon->attrs[i]);
350
351 goto err_hwmon_register;
352 }
353 }
354
355 return 0;
356
357 err_hwmon_register:
358 hwmon_device_unregister(hwmon->hwmon_dev);
359
360 err_raw_attribute:
361 s3c_hwmon_remove_raw(&dev->dev);
362
363 err_registered:
364 s3c_adc_release(hwmon->client);
365
366 err_mem:
367 kfree(hwmon);
368 return ret;
369}
370
371static int __devexit s3c_hwmon_remove(struct platform_device *dev)
372{
373 struct s3c_hwmon *hwmon = platform_get_drvdata(dev);
374 int i;
375
376 s3c_hwmon_remove_raw(&dev->dev);
377
378 for (i = 0; i < ARRAY_SIZE(hwmon->attrs); i++)
379 s3c_hwmon_remove_attr(&dev->dev, &hwmon->attrs[i]);
380
381 hwmon_device_unregister(hwmon->hwmon_dev);
382 s3c_adc_release(hwmon->client);
383
384 return 0;
385}
386
387static struct platform_driver s3c_hwmon_driver = {
388 .driver = {
389 .name = "s3c-hwmon",
390 .owner = THIS_MODULE,
391 },
392 .probe = s3c_hwmon_probe,
393 .remove = __devexit_p(s3c_hwmon_remove),
394};
395
396static int __init s3c_hwmon_init(void)
397{
398 return platform_driver_register(&s3c_hwmon_driver);
399}
400
401static void __exit s3c_hwmon_exit(void)
402{
403 platform_driver_unregister(&s3c_hwmon_driver);
404}
405
406module_init(s3c_hwmon_init);
407module_exit(s3c_hwmon_exit);
408
409MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
410MODULE_DESCRIPTION("S3C ADC HWMon driver");
411MODULE_LICENSE("GPL v2");
412MODULE_ALIAS("platform:s3c-hwmon");