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->platform_data;
 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->platform_data;
 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->dev.platform_data;
 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                 dev_err(&dev->dev, "no memory\n");
 290                 return -ENOMEM;
 291         }
 292
 293         platform_set_drvdata(dev, hwmon);
 294
 295         mutex_init(&hwmon->lock);
 296
 297         /* Register with the core ADC driver. */
 298
 299         hwmon->client = s3c_adc_register(dev, NULL, NULL, 0);
 300         if (IS_ERR(hwmon->client)) {
 301                 dev_err(&dev->dev, "cannot register adc\n");
 302                 return PTR_ERR(hwmon->client);
 303         }
 304
 305         /* add attributes for our adc devices. */
 306
 307         ret = s3c_hwmon_add_raw(&dev->dev);
 308         if (ret)
 309                 goto err_registered;
 310
 311         /* register with the hwmon core */
 312
 313         hwmon->hwmon_dev = hwmon_device_register(&dev->dev);
 314         if (IS_ERR(hwmon->hwmon_dev)) {
 315                 dev_err(&dev->dev, "error registering with hwmon\n");
 316                 ret = PTR_ERR(hwmon->hwmon_dev);
 317                 goto err_raw_attribute;
 318         }
 319
 320         for (i = 0; i < ARRAY_SIZE(pdata->in); i++) {
 321                 struct s3c_hwmon_chcfg *cfg = pdata->in[i];
 322
 323                 if (!cfg)
 324                         continue;
 325
 326                 if (cfg->mult >= 0x10000)
 327                         dev_warn(&dev->dev,
 328                                  "channel %d multiplier too large\n",
 329                                  i);
 330
 331                 if (cfg->div == 0) {
 332                         dev_err(&dev->dev, "channel %d divider zero\n", i);
 333                         continue;
 334                 }
 335
 336                 ret = s3c_hwmon_create_attr(&dev->dev, pdata->in[i],
 337                                             &hwmon->attrs[i], i);
 338                 if (ret) {
 339                         dev_err(&dev->dev,
 340                                         "error creating channel %d\n", i);
 341
 342                         for (i--; i >= 0; i--)
 343                                 s3c_hwmon_remove_attr(&dev->dev,
 344                                                               &hwmon->attrs[i]);
 345
 346                         goto err_hwmon_register;
 347                 }
 348         }
 349
 350         return 0;
 351
 352  err_hwmon_register:
 353         hwmon_device_unregister(hwmon->hwmon_dev);
 354
 355  err_raw_attribute:
 356         s3c_hwmon_remove_raw(&dev->dev);
 357
 358  err_registered:
 359         s3c_adc_release(hwmon->client);
 360
 361         return ret;
 362 }
 363
 364 static int s3c_hwmon_remove(struct platform_device *dev)
 365 {
 366         struct s3c_hwmon *hwmon = platform_get_drvdata(dev);
 367         int i;
 368
 369         s3c_hwmon_remove_raw(&dev->dev);
 370
 371         for (i = 0; i < ARRAY_SIZE(hwmon->attrs); i++)
 372                 s3c_hwmon_remove_attr(&dev->dev, &hwmon->attrs[i]);
 373
 374         hwmon_device_unregister(hwmon->hwmon_dev);
 375         s3c_adc_release(hwmon->client);
 376
 377         return 0;
 378 }
 379
 380 static struct platform_driver s3c_hwmon_driver = {
 381         .driver = {
 382                 .name           = "s3c-hwmon",
 383                 .owner          = THIS_MODULE,
 384         },
 385         .probe          = s3c_hwmon_probe,
 386         .remove         = s3c_hwmon_remove,
 387 };
 388
 389 module_platform_driver(s3c_hwmon_driver);
 390
 391 MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
 392 MODULE_DESCRIPTION("S3C ADC HWMon driver");
 393 MODULE_LICENSE("GPL v2");
 394 MODULE_ALIAS("platform:s3c-hwmon");