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
 110static SENSOR_DEVICE_ATTR(adc0_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 0);
 111static SENSOR_DEVICE_ATTR(adc1_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 1);
 112static SENSOR_DEVICE_ATTR(adc2_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 2);
 113static SENSOR_DEVICE_ATTR(adc3_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 3);
 114static SENSOR_DEVICE_ATTR(adc4_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 4);
 115static SENSOR_DEVICE_ATTR(adc5_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 5);
 116static SENSOR_DEVICE_ATTR(adc6_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 6);
 117static SENSOR_DEVICE_ATTR(adc7_raw, S_IRUGO, s3c_hwmon_show_raw, NULL, 7);
 118
 119static 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
 131static struct attribute_group s3c_hwmon_attrgroup = {
 132        .attrs  = s3c_hwmon_attrs,
 133};
 134
 135static inline int s3c_hwmon_add_raw(struct device *dev)
 136{
 137        return sysfs_create_group(&dev->kobj, &s3c_hwmon_attrgroup);
 138}
 139
 140static inline void s3c_hwmon_remove_raw(struct device *dev)
 141{
 142        sysfs_remove_group(&dev->kobj, &s3c_hwmon_attrgroup);
 143}
 144
 145#else
 146
 147static inline int s3c_hwmon_add_raw(struct device *dev) { return 0; }
 148static 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 */
 162static 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 */
 192static 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 */
 219static 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
 264static 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*/
 275static 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                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
 364static 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
 380static 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
 389module_platform_driver(s3c_hwmon_driver);
 390
 391MODULE_AUTHOR("Ben Dooks <ben@simtec.co.uk>");
 392MODULE_DESCRIPTION("S3C ADC HWMon driver");
 393MODULE_LICENSE("GPL v2");
 394MODULE_ALIAS("platform:s3c-hwmon");
 395
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