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Linux/drivers/hwmon/s3c-hwmon.c

  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/io.h>
 26 #include <linux/init.h>
 27 #include <linux/err.h>
 28 #include <linux/clk.h>
 29 #include <linux/interrupt.h>
 30 #include <linux/platform_device.h>
 31 
 32 #include <linux/hwmon.h>
 33 #include <linux/hwmon-sysfs.h>
 34 
 35 #include <plat/adc.h>
 36 #include <linux/platform_data/hwmon-s3c.h>
 37 
 38 struct s3c_hwmon_attr {
 39         struct sensor_device_attribute  in;
 40         struct sensor_device_attribute  label;
 41         char                            in_name[12];
 42         char                            label_name[12];
 43 };
 44 
 45 /**
 46  * struct s3c_hwmon - ADC hwmon client information
 47  * @lock: Access lock to serialise the conversions.
 48  * @client: The client we registered with the S3C ADC core.
 49  * @hwmon_dev: The hwmon device we created.
 50  * @attr: The holders for the channel attributes.
 51 */
 52 struct s3c_hwmon {
 53         struct mutex            lock;
 54         struct s3c_adc_client   *client;
 55         struct device           *hwmon_dev;
 56 
 57         struct s3c_hwmon_attr   attrs[8];
 58 };
 59 
 60 /**
 61  * s3c_hwmon_read_ch - read a value from a given adc channel.
 62  * @dev: The device.
 63  * @hwmon: Our state.
 64  * @channel: The channel we're reading from.
 65  *
 66  * Read a value from the @channel with the proper locking and sleep until
 67  * either the read completes or we timeout awaiting the ADC core to get
 68  * back to us.
 69  */
 70 static int s3c_hwmon_read_ch(struct device *dev,
 71                              struct s3c_hwmon *hwmon, int channel)
 72 {
 73         int ret;
 74 
 75         ret = mutex_lock_interruptible(&hwmon->lock);
 76         if (ret < 0)
 77                 return ret;
 78 
 79         dev_dbg(dev, "reading channel %d\n", channel);
 80 
 81         ret = s3c_adc_read(hwmon->client, channel);
 82         mutex_unlock(&hwmon->lock);
 83 
 84         return ret;
 85 }
 86 
 87 #ifdef CONFIG_SENSORS_S3C_RAW
 88 /**
 89  * s3c_hwmon_show_raw - show a conversion from the raw channel number.
 90  * @dev: The device that the attribute belongs to.
 91  * @attr: The attribute being read.
 92  * @buf: The result buffer.
 93  *
 94  * This show deals with the raw attribute, registered for each possible
 95  * ADC channel. This does a conversion and returns the raw (un-scaled)
 96  * value returned from the hardware.
 97  */
 98 static ssize_t s3c_hwmon_show_raw(struct device *dev,
 99                                   struct device_attribute *attr, char *buf)
100 {
101         struct s3c_hwmon *adc = platform_get_drvdata(to_platform_device(dev));
102         struct sensor_device_attribute *sa = to_sensor_dev_attr(attr);
103         int ret;
104 
105         ret = s3c_hwmon_read_ch(dev, adc, sa->index);
106 
107         return  (ret < 0) ? ret : snprintf(buf, PAGE_SIZE, "%d\n", ret);
108 }
109 
110 static SENSOR_DEVICE_ATTR(adc0_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 0);
111 static SENSOR_DEVICE_ATTR(adc1_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 1);
112 static SENSOR_DEVICE_ATTR(adc2_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 2);
113 static SENSOR_DEVICE_ATTR(adc3_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 3);
114 static SENSOR_DEVICE_ATTR(adc4_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 4);
115 static SENSOR_DEVICE_ATTR(adc5_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 5);
116 static SENSOR_DEVICE_ATTR(adc6_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 6);
117 static SENSOR_DEVICE_ATTR(adc7_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 7);
118 
119 static struct attribute *s3c_hwmon_attrs[9] = {
120         &sensor_dev_attr_adc0_raw.dev_attr.attr,
121         &sensor_dev_attr_adc1_raw.dev_attr.attr,
122         &sensor_dev_attr_adc2_raw.dev_attr.attr,
123         &sensor_dev_attr_adc3_raw.dev_attr.attr,
124         &sensor_dev_attr_adc4_raw.dev_attr.attr,
125         &sensor_dev_attr_adc5_raw.dev_attr.attr,
126         &sensor_dev_attr_adc6_raw.dev_attr.attr,
127         &sensor_dev_attr_adc7_raw.dev_attr.attr,
128         NULL,
129 };
130 
131 static struct attribute_group s3c_hwmon_attrgroup = {
132         .attrs  = s3c_hwmon_attrs,
133 };
134 
135 static inline int s3c_hwmon_add_raw(struct device *dev)
136 {
137         return sysfs_create_group(&dev->kobj, &s3c_hwmon_attrgroup);
138 }
139 
140 static inline void s3c_hwmon_remove_raw(struct device *dev)
141 {
142         sysfs_remove_group(&dev->kobj, &s3c_hwmon_attrgroup);
143 }
144 
145 #else
146 
147 static inline int s3c_hwmon_add_raw(struct device *dev) { return 0; }
148 static inline void s3c_hwmon_remove_raw(struct device *dev) { }
149 
150 #endif /* CONFIG_SENSORS_S3C_RAW */
151 
152 /**
153  * s3c_hwmon_ch_show - show value of a given channel
154  * @dev: The device that the attribute belongs to.
155  * @attr: The attribute being read.
156  * @buf: The result buffer.
157  *
158  * Read a value from the ADC and scale it before returning it to the
159  * caller. The scale factor is gained from the channel configuration
160  * passed via the platform data when the device was registered.
161  */
162 static ssize_t s3c_hwmon_ch_show(struct device *dev,
163                                  struct device_attribute *attr,
164                                  char *buf)
165 {
166         struct sensor_device_attribute *sen_attr = to_sensor_dev_attr(attr);
167         struct s3c_hwmon *hwmon = platform_get_drvdata(to_platform_device(dev));
168         struct s3c_hwmon_pdata *pdata = dev_get_platdata(dev);
169         struct s3c_hwmon_chcfg *cfg;
170         int ret;
171 
172         cfg = pdata->in[sen_attr->index];
173 
174         ret = s3c_hwmon_read_ch(dev, hwmon, sen_attr->index);
175         if (ret < 0)
176                 return ret;
177 
178         ret *= cfg->mult;
179         ret = DIV_ROUND_CLOSEST(ret, cfg->div);
180 
181         return snprintf(buf, PAGE_SIZE, "%d\n", ret);
182 }
183 
184 /**
185  * s3c_hwmon_label_show - show label name of the given channel.
186  * @dev: The device that the attribute belongs to.
187  * @attr: The attribute being read.
188  * @buf: The result buffer.
189  *
190  * Return the label name of a given channel
191  */
192 static ssize_t s3c_hwmon_label_show(struct device *dev,
193                                     struct device_attribute *attr,
194                                     char *buf)
195 {
196         struct sensor_device_attribute *sen_attr = to_sensor_dev_attr(attr);
197         struct s3c_hwmon_pdata *pdata = dev_get_platdata(dev);
198         struct s3c_hwmon_chcfg *cfg;
199 
200         cfg = pdata->in[sen_attr->index];
201 
202         return snprintf(buf, PAGE_SIZE, "%s\n", cfg->name);
203 }
204 
205 /**
206  * s3c_hwmon_create_attr - create hwmon attribute for given channel.
207  * @dev: The device to create the attribute on.
208  * @cfg: The channel configuration passed from the platform data.
209  * @channel: The ADC channel number to process.
210  *
211  * Create the scaled attribute for use with hwmon from the specified
212  * platform data in @pdata. The sysfs entry is handled by the routine
213  * s3c_hwmon_ch_show().
214  *
215  * The attribute name is taken from the configuration data if present
216  * otherwise the name is taken by concatenating in_ with the channel
217  * number.
218  */
219 static int s3c_hwmon_create_attr(struct device *dev,
220                                  struct s3c_hwmon_chcfg *cfg,
221                                  struct s3c_hwmon_attr *attrs,
222                                  int channel)
223 {
224         struct sensor_device_attribute *attr;
225         int ret;
226 
227         snprintf(attrs->in_name, sizeof(attrs->in_name), "in%d_input", channel);
228 
229         attr = &attrs->in;
230         attr->index = channel;
231         sysfs_attr_init(&attr->dev_attr.attr);
232         attr->dev_attr.attr.name  = attrs->in_name;
233         attr->dev_attr.attr.mode  = S_IRUGO;
234         attr->dev_attr.show = s3c_hwmon_ch_show;
235 
236         ret =  device_create_file(dev, &attr->dev_attr);
237         if (ret < 0) {
238                 dev_err(dev, "failed to create input attribute\n");
239                 return ret;
240         }
241 
242         /* if this has a name, add a label */
243         if (cfg->name) {
244                 snprintf(attrs->label_name, sizeof(attrs->label_name),
245                          "in%d_label", channel);
246 
247                 attr = &attrs->label;
248                 attr->index = channel;
249                 sysfs_attr_init(&attr->dev_attr.attr);
250                 attr->dev_attr.attr.name  = attrs->label_name;
251                 attr->dev_attr.attr.mode  = S_IRUGO;
252                 attr->dev_attr.show = s3c_hwmon_label_show;
253 
254                 ret = device_create_file(dev, &attr->dev_attr);
255                 if (ret < 0) {
256                         device_remove_file(dev, &attrs->in.dev_attr);
257                         dev_err(dev, "failed to create label attribute\n");
258                 }
259         }
260 
261         return ret;
262 }
263 
264 static void s3c_hwmon_remove_attr(struct device *dev,
265                                   struct s3c_hwmon_attr *attrs)
266 {
267         device_remove_file(dev, &attrs->in.dev_attr);
268         device_remove_file(dev, &attrs->label.dev_attr);
269 }
270 
271 /**
272  * s3c_hwmon_probe - device probe entry.
273  * @dev: The device being probed.
274 */
275 static int s3c_hwmon_probe(struct platform_device *dev)
276 {
277         struct s3c_hwmon_pdata *pdata = dev_get_platdata(&dev->dev);
278         struct s3c_hwmon *hwmon;
279         int ret = 0;
280         int i;
281 
282         if (!pdata) {
283                 dev_err(&dev->dev, "no platform data supplied\n");
284                 return -EINVAL;
285         }
286 
287         hwmon = devm_kzalloc(&dev->dev, sizeof(struct s3c_hwmon), GFP_KERNEL);
288         if (hwmon == NULL)
289                 return -ENOMEM;
290 
291         platform_set_drvdata(dev, hwmon);
292 
293         mutex_init(&hwmon->lock);
294 
295         /* Register with the core ADC driver. */
296 
297         hwmon->client = s3c_adc_register(dev, NULL, NULL, 0);
298         if (IS_ERR(hwmon->client)) {
299                 dev_err(&dev->dev, "cannot register adc\n");
300                 return PTR_ERR(hwmon->client);
301         }
302 
303         /* add attributes for our adc devices. */
304 
305         ret = s3c_hwmon_add_raw(&dev->dev);
306         if (ret)
307                 goto err_registered;
308 
309         /* register with the hwmon core */
310 
311         hwmon->hwmon_dev = hwmon_device_register(&dev->dev);
312         if (IS_ERR(hwmon->hwmon_dev)) {
313                 dev_err(&dev->dev, "error registering with hwmon\n");
314                 ret = PTR_ERR(hwmon->hwmon_dev);
315                 goto err_raw_attribute;
316         }
317 
318         for (i = 0; i < ARRAY_SIZE(pdata->in); i++) {
319                 struct s3c_hwmon_chcfg *cfg = pdata->in[i];
320 
321                 if (!cfg)
322                         continue;
323 
324                 if (cfg->mult >= 0x10000)
325                         dev_warn(&dev->dev,
326                                  "channel %d multiplier too large\n",
327                                  i);
328 
329                 if (cfg->div == 0) {
330                         dev_err(&dev->dev, "channel %d divider zero\n", i);
331                         continue;
332                 }
333 
334                 ret = s3c_hwmon_create_attr(&dev->dev, pdata->in[i],
335                                             &hwmon->attrs[i], i);
336                 if (ret) {
337                         dev_err(&dev->dev,
338                                         "error creating channel %d\n", i);
339 
340                         for (i--; i >= 0; i--)
341                                 s3c_hwmon_remove_attr(&dev->dev,
342                                                               &hwmon->attrs[i]);
343 
344                         goto err_hwmon_register;
345                 }
346         }
347 
348         return 0;
349 
350  err_hwmon_register:
351         hwmon_device_unregister(hwmon->hwmon_dev);
352 
353  err_raw_attribute:
354         s3c_hwmon_remove_raw(&dev->dev);
355 
356  err_registered:
357         s3c_adc_release(hwmon->client);
358 
359         return ret;
360 }
361 
362 static int s3c_hwmon_remove(struct platform_device *dev)
363 {
364         struct s3c_hwmon *hwmon = platform_get_drvdata(dev);
365         int i;
366 
367         s3c_hwmon_remove_raw(&dev->dev);
368 
369         for (i = 0; i < ARRAY_SIZE(hwmon->attrs); i++)
370                 s3c_hwmon_remove_attr(&dev->dev, &hwmon->attrs[i]);
371 
372         hwmon_device_unregister(hwmon->hwmon_dev);
373         s3c_adc_release(hwmon->client);
374 
375         return 0;
376 }
377 
378 static struct platform_driver s3c_hwmon_driver = {
379         .driver = {
380                 .name           = "s3c-hwmon",
381                 .owner          = THIS_MODULE,
382         },
383         .probe          = s3c_hwmon_probe,
384         .remove         = s3c_hwmon_remove,
385 };
386 
387 module_platform_driver(s3c_hwmon_driver);
388 
389 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
390 MODULE_DESCRIPTION("S3C ADC HWMon driver");
391 MODULE_LICENSE("GPL v2");
392 MODULE_ALIAS("platform:s3c-hwmon");
393 

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