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/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  */
  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  */
  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
 139 static inline int s3c_hwmon_add_raw(struct device *dev)
 140 {
 141         return sysfs_create_group(&dev->kobj, &s3c_hwmon_attrgroup);
 142 }
 143
 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
 151 static inline int s3c_hwmon_add_raw(struct device *dev) { return 0; }
 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  */
 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  */
 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  */
 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
 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 */
 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
 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");