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 #define DEF_ADC_ATTR(x) \
 111         static SENSOR_DEVICE_ATTR(adc##x##_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, x)
 112
 113 DEF_ADC_ATTR(0);
 114 DEF_ADC_ATTR(1);
 115 DEF_ADC_ATTR(2);
 116 DEF_ADC_ATTR(3);
 117 DEF_ADC_ATTR(4);
 118 DEF_ADC_ATTR(5);
 119 DEF_ADC_ATTR(6);
 120 DEF_ADC_ATTR(7);
 121
 122 static struct attribute *s3c_hwmon_attrs[9] = {
 123         &sensor_dev_attr_adc0_raw.dev_attr.attr,
 124         &sensor_dev_attr_adc1_raw.dev_attr.attr,
 125         &sensor_dev_attr_adc2_raw.dev_attr.attr,
 126         &sensor_dev_attr_adc3_raw.dev_attr.attr,
 127         &sensor_dev_attr_adc4_raw.dev_attr.attr,
 128         &sensor_dev_attr_adc5_raw.dev_attr.attr,
 129         &sensor_dev_attr_adc6_raw.dev_attr.attr,
 130         &sensor_dev_attr_adc7_raw.dev_attr.attr,
 131         NULL,
 132 };
 133
 134 static struct attribute_group s3c_hwmon_attrgroup = {
 135         .attrs  = s3c_hwmon_attrs,
 136 };
 137
 138 static inline int s3c_hwmon_add_raw(struct device *dev)
 139 {
 140         return sysfs_create_group(&dev->kobj, &s3c_hwmon_attrgroup);
 141 }
 142
 143 static inline void s3c_hwmon_remove_raw(struct device *dev)
 144 {
 145         sysfs_remove_group(&dev->kobj, &s3c_hwmon_attrgroup);
 146 }
 147
 148 #else
 149
 150 static inline int s3c_hwmon_add_raw(struct device *dev) { return 0; }
 151 static inline void s3c_hwmon_remove_raw(struct device *dev) { }
 152
 153 #endif /* CONFIG_SENSORS_S3C_RAW */
 154
 155 /**
 156  * s3c_hwmon_ch_show - show value of a given channel
 157  * @dev: The device that the attribute belongs to.
 158  * @attr: The attribute being read.
 159  * @buf: The result buffer.
 160  *
 161  * Read a value from the ADC and scale it before returning it to the
 162  * caller. The scale factor is gained from the channel configuration
 163  * passed via the platform data when the device was registered.
 164  */
 165 static ssize_t s3c_hwmon_ch_show(struct device *dev,
 166                                  struct device_attribute *attr,
 167                                  char *buf)
 168 {
 169         struct sensor_device_attribute *sen_attr = to_sensor_dev_attr(attr);
 170         struct s3c_hwmon *hwmon = platform_get_drvdata(to_platform_device(dev));
 171         struct s3c_hwmon_pdata *pdata = dev->platform_data;
 172         struct s3c_hwmon_chcfg *cfg;
 173         int ret;
 174
 175         cfg = pdata->in[sen_attr->index];
 176
 177         ret = s3c_hwmon_read_ch(dev, hwmon, sen_attr->index);
 178         if (ret < 0)
 179                 return ret;
 180
 181         ret *= cfg->mult;
 182         ret = DIV_ROUND_CLOSEST(ret, cfg->div);
 183
 184         return snprintf(buf, PAGE_SIZE, "%d\n", ret);
 185 }
 186
 187 /**
 188  * s3c_hwmon_label_show - show label name of the given channel.
 189  * @dev: The device that the attribute belongs to.
 190  * @attr: The attribute being read.
 191  * @buf: The result buffer.
 192  *
 193  * Return the label name of a given channel
 194  */
 195 static ssize_t s3c_hwmon_label_show(struct device *dev,
 196                                     struct device_attribute *attr,
 197                                     char *buf)
 198 {
 199         struct sensor_device_attribute *sen_attr = to_sensor_dev_attr(attr);
 200         struct s3c_hwmon_pdata *pdata = dev->platform_data;
 201         struct s3c_hwmon_chcfg *cfg;
 202
 203         cfg = pdata->in[sen_attr->index];
 204
 205         return snprintf(buf, PAGE_SIZE, "%s\n", cfg->name);
 206 }
 207
 208 /**
 209  * s3c_hwmon_create_attr - create hwmon attribute for given channel.
 210  * @dev: The device to create the attribute on.
 211  * @cfg: The channel configuration passed from the platform data.
 212  * @channel: The ADC channel number to process.
 213  *
 214  * Create the scaled attribute for use with hwmon from the specified
 215  * platform data in @pdata. The sysfs entry is handled by the routine
 216  * s3c_hwmon_ch_show().
 217  *
 218  * The attribute name is taken from the configuration data if present
 219  * otherwise the name is taken by concatenating in_ with the channel
 220  * number.
 221  */
 222 static int s3c_hwmon_create_attr(struct device *dev,
 223                                  struct s3c_hwmon_chcfg *cfg,
 224                                  struct s3c_hwmon_attr *attrs,
 225                                  int channel)
 226 {
 227         struct sensor_device_attribute *attr;
 228         int ret;
 229
 230         snprintf(attrs->in_name, sizeof(attrs->in_name), "in%d_input", channel);
 231
 232         attr = &attrs->in;
 233         attr->index = channel;
 234         sysfs_attr_init(&attr->dev_attr.attr);
 235         attr->dev_attr.attr.name  = attrs->in_name;
 236         attr->dev_attr.attr.mode  = S_IRUGO;
 237         attr->dev_attr.show = s3c_hwmon_ch_show;
 238
 239         ret =  device_create_file(dev, &attr->dev_attr);
 240         if (ret < 0) {
 241                 dev_err(dev, "failed to create input attribute\n");
 242                 return ret;
 243         }
 244
 245         /* if this has a name, add a label */
 246         if (cfg->name) {
 247                 snprintf(attrs->label_name, sizeof(attrs->label_name),
 248                          "in%d_label", channel);
 249
 250                 attr = &attrs->label;
 251                 attr->index = channel;
 252                 sysfs_attr_init(&attr->dev_attr.attr);
 253                 attr->dev_attr.attr.name  = attrs->label_name;
 254                 attr->dev_attr.attr.mode  = S_IRUGO;
 255                 attr->dev_attr.show = s3c_hwmon_label_show;
 256
 257                 ret = device_create_file(dev, &attr->dev_attr);
 258                 if (ret < 0) {
 259                         device_remove_file(dev, &attrs->in.dev_attr);
 260                         dev_err(dev, "failed to create label attribute\n");
 261                 }
 262         }
 263
 264         return ret;
 265 }
 266
 267 static void s3c_hwmon_remove_attr(struct device *dev,
 268                                   struct s3c_hwmon_attr *attrs)
 269 {
 270         device_remove_file(dev, &attrs->in.dev_attr);
 271         device_remove_file(dev, &attrs->label.dev_attr);
 272 }
 273
 274 /**
 275  * s3c_hwmon_probe - device probe entry.
 276  * @dev: The device being probed.
 277 */
 278 static int s3c_hwmon_probe(struct platform_device *dev)
 279 {
 280         struct s3c_hwmon_pdata *pdata = dev->dev.platform_data;
 281         struct s3c_hwmon *hwmon;
 282         int ret = 0;
 283         int i;
 284
 285         if (!pdata) {
 286                 dev_err(&dev->dev, "no platform data supplied\n");
 287                 return -EINVAL;
 288         }
 289
 290         hwmon = devm_kzalloc(&dev->dev, sizeof(struct s3c_hwmon), GFP_KERNEL);
 291         if (hwmon == NULL) {
 292                 dev_err(&dev->dev, "no memory\n");
 293                 return -ENOMEM;
 294         }
 295
 296         platform_set_drvdata(dev, hwmon);
 297
 298         mutex_init(&hwmon->lock);
 299
 300         /* Register with the core ADC driver. */
 301
 302         hwmon->client = s3c_adc_register(dev, NULL, NULL, 0);
 303         if (IS_ERR(hwmon->client)) {
 304                 dev_err(&dev->dev, "cannot register adc\n");
 305                 return PTR_ERR(hwmon->client);
 306         }
 307
 308         /* add attributes for our adc devices. */
 309
 310         ret = s3c_hwmon_add_raw(&dev->dev);
 311         if (ret)
 312                 goto err_registered;
 313
 314         /* register with the hwmon core */
 315
 316         hwmon->hwmon_dev = hwmon_device_register(&dev->dev);
 317         if (IS_ERR(hwmon->hwmon_dev)) {
 318                 dev_err(&dev->dev, "error registering with hwmon\n");
 319                 ret = PTR_ERR(hwmon->hwmon_dev);
 320                 goto err_raw_attribute;
 321         }
 322
 323         for (i = 0; i < ARRAY_SIZE(pdata->in); i++) {
 324                 struct s3c_hwmon_chcfg *cfg = pdata->in[i];
 325
 326                 if (!cfg)
 327                         continue;
 328
 329                 if (cfg->mult >= 0x10000)
 330                         dev_warn(&dev->dev,
 331                                  "channel %d multiplier too large\n",
 332                                  i);
 333
 334                 if (cfg->div == 0) {
 335                         dev_err(&dev->dev, "channel %d divider zero\n", i);
 336                         continue;
 337                 }
 338
 339                 ret = s3c_hwmon_create_attr(&dev->dev, pdata->in[i],
 340                                             &hwmon->attrs[i], i);
 341                 if (ret) {
 342                         dev_err(&dev->dev,
 343                                         "error creating channel %d\n", i);
 344
 345                         for (i--; i >= 0; i--)
 346                                 s3c_hwmon_remove_attr(&dev->dev,
 347                                                               &hwmon->attrs[i]);
 348
 349                         goto err_hwmon_register;
 350                 }
 351         }
 352
 353         return 0;
 354
 355  err_hwmon_register:
 356         hwmon_device_unregister(hwmon->hwmon_dev);
 357
 358  err_raw_attribute:
 359         s3c_hwmon_remove_raw(&dev->dev);
 360
 361  err_registered:
 362         s3c_adc_release(hwmon->client);
 363
 364         return ret;
 365 }
 366
 367 static int s3c_hwmon_remove(struct platform_device *dev)
 368 {
 369         struct s3c_hwmon *hwmon = platform_get_drvdata(dev);
 370         int i;
 371
 372         s3c_hwmon_remove_raw(&dev->dev);
 373
 374         for (i = 0; i < ARRAY_SIZE(hwmon->attrs); i++)
 375                 s3c_hwmon_remove_attr(&dev->dev, &hwmon->attrs[i]);
 376
 377         hwmon_device_unregister(hwmon->hwmon_dev);
 378         s3c_adc_release(hwmon->client);
 379
 380         return 0;
 381 }
 382
 383 static struct platform_driver s3c_hwmon_driver = {
 384         .driver = {
 385                 .name           = "s3c-hwmon",
 386                 .owner          = THIS_MODULE,
 387         },
 388         .probe          = s3c_hwmon_probe,
 389         .remove         = s3c_hwmon_remove,
 390 };
 391
 392 module_platform_driver(s3c_hwmon_driver);
 393
 394 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
 395 MODULE_DESCRIPTION("S3C ADC HWMon driver");
 396 MODULE_LICENSE("GPL v2");
 397 MODULE_ALIAS("platform:s3c-hwmon");