linux/drivers/hwmon/s3c-hwmon.c
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   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
  38struct 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*/
  52struct 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 */
  70static 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 */
  98static 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
 113DEF_ADC_ATTR(0);
 114DEF_ADC_ATTR(1);
 115DEF_ADC_ATTR(2);
 116DEF_ADC_ATTR(3);
 117DEF_ADC_ATTR(4);
 118DEF_ADC_ATTR(5);
 119DEF_ADC_ATTR(6);
 120DEF_ADC_ATTR(7);
 121
 122static 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
 134static struct attribute_group s3c_hwmon_attrgroup = {
 135        .attrs  = s3c_hwmon_attrs,
 136};
 137
 138static inline int s3c_hwmon_add_raw(struct device *dev)
 139{
 140        return sysfs_create_group(&dev->kobj, &s3c_hwmon_attrgroup);
 141}
 142
 143static inline void s3c_hwmon_remove_raw(struct device *dev)
 144{
 145        sysfs_remove_group(&dev->kobj, &s3c_hwmon_attrgroup);
 146}
 147
 148#else
 149
 150static inline int s3c_hwmon_add_raw(struct device *dev) { return 0; }
 151static 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 */
 165static 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 */
 195static 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 */
 222static 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
 267static 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*/
 278static 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
 367static 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
 383static 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
 392module_platform_driver(s3c_hwmon_driver);
 393
 394MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
 395MODULE_DESCRIPTION("S3C ADC HWMon driver");
 396MODULE_LICENSE("GPL v2");
 397MODULE_ALIAS("platform:s3c-hwmon");
 398
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