1 /* 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
39 struct 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 */
53 struct s3c_hwmon {
54 struct mutex 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 */
s3c_hwmon_read_ch(struct device * dev,struct s3c_hwmon * hwmon,int channel)71 static int s3c_hwmon_read_ch(struct device *dev,
72 struct s3c_hwmon *hwmon, int channel)
73 {
74 int ret;
75
76 ret = mutex_lock_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 mutex_unlock(&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 */
s3c_hwmon_show_raw(struct device * dev,struct device_attribute * attr,char * buf)99 static 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
114 DEF_ADC_ATTR(0);
115 DEF_ADC_ATTR(1);
116 DEF_ADC_ATTR(2);
117 DEF_ADC_ATTR(3);
118 DEF_ADC_ATTR(4);
119 DEF_ADC_ATTR(5);
120 DEF_ADC_ATTR(6);
121 DEF_ADC_ATTR(7);
122
123 static 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
135 static struct attribute_group s3c_hwmon_attrgroup = {
136 .attrs = s3c_hwmon_attrs,
137 };
138
s3c_hwmon_add_raw(struct device * dev)139 static inline int s3c_hwmon_add_raw(struct device *dev)
140 {
141 return sysfs_create_group(&dev->kobj, &s3c_hwmon_attrgroup);
142 }
143
s3c_hwmon_remove_raw(struct device * dev)144 static inline void s3c_hwmon_remove_raw(struct device *dev)
145 {
146 sysfs_remove_group(&dev->kobj, &s3c_hwmon_attrgroup);
147 }
148
149 #else
150
s3c_hwmon_add_raw(struct device * dev)151 static inline int s3c_hwmon_add_raw(struct device *dev) { return 0; }
s3c_hwmon_remove_raw(struct device * dev)152 static 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 */
s3c_hwmon_ch_show(struct device * dev,struct device_attribute * attr,char * buf)166 static 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 */
s3c_hwmon_label_show(struct device * dev,struct device_attribute * attr,char * buf)196 static 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 */
s3c_hwmon_create_attr(struct device * dev,struct s3c_hwmon_chcfg * cfg,struct s3c_hwmon_attr * attrs,int channel)223 static 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 sysfs_attr_init(&attr->dev_attr.attr);
236 attr->dev_attr.attr.name = attrs->in_name;
237 attr->dev_attr.attr.mode = S_IRUGO;
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 sysfs_attr_init(&attr->dev_attr.attr);
254 attr->dev_attr.attr.name = attrs->label_name;
255 attr->dev_attr.attr.mode = S_IRUGO;
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
s3c_hwmon_remove_attr(struct device * dev,struct s3c_hwmon_attr * attrs)268 static 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 */
s3c_hwmon_probe(struct platform_device * dev)279 static 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 mutex_init(&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++) {
326 struct s3c_hwmon_chcfg *cfg = pdata->in[i];
327
328 if (!cfg)
329 continue;
330
331 if (cfg->mult >= 0x10000)
332 dev_warn(&dev->dev,
333 "channel %d multiplier too large\n",
334 i);
335
336 if (cfg->div == 0) {
337 dev_err(&dev->dev, "channel %d divider zero\n", i);
338 continue;
339 }
340
341 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
s3c_hwmon_remove(struct platform_device * dev)371 static 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
387 static 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
396 module_platform_driver(s3c_hwmon_driver);
397
398 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
399 MODULE_DESCRIPTION("S3C ADC HWMon driver");
400 MODULE_LICENSE("GPL v2");
401 MODULE_ALIAS("platform:s3c-hwmon");
402