arch/arm/plat-s3c24xx/adc.c

   1 /* arch/arm/plat-s3c24xx/adc.c
   2  *
   3  * Copyright (c) 2008 Simtec Electronics
   4  *      http://armlinux.simtec.co.uk/
   5  *      Ben Dooks <ben@simtec.co.uk>, <ben-linux@fluff.org>
   6  *
   7  * S3C24XX ADC device core
   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 as published by
  11  * the Free Software Foundation; either version 2 of the License.
  12 */
  13
  14 #include <linux/module.h>
  15 #include <linux/kernel.h>
  16 #include <linux/platform_device.h>
  17 #include <linux/list.h>
  18 #include <linux/err.h>
  19 #include <linux/clk.h>
  20 #include <linux/interrupt.h>
  21 #include <linux/io.h>
  22
  23 #include <plat/regs-adc.h>
  24 #include <plat/adc.h>
  25
  26 /* This driver is designed to control the usage of the ADC block between
  27  * the touchscreen and any other drivers that may need to use it, such as
  28  * the hwmon driver.
  29  *
  30  * Priority will be given to the touchscreen driver, but as this itself is
  31  * rate limited it should not starve other requests which are processed in
  32  * order that they are received.
  33  *
  34  * Each user registers to get a client block which uniquely identifies it
  35  * and stores information such as the necessary functions to callback when
  36  * action is required.
  37  */
  38
  39 struct s3c_adc_client {
  40         struct platform_device  *pdev;
  41         struct list_head         pend;
  42         wait_queue_head_t       *wait;
  43
  44         unsigned int             nr_samples;
  45         int                      result;
  46         unsigned char            is_ts;
  47         unsigned char            channel;
  48
  49         void    (*select_cb)(struct s3c_adc_client *c, unsigned selected);
  50         void    (*convert_cb)(struct s3c_adc_client *c,
  51                               unsigned val1, unsigned val2,
  52                               unsigned *samples_left);
  53 };
  54
  55 struct adc_device {
  56         struct platform_device  *pdev;
  57         struct platform_device  *owner;
  58         struct clk              *clk;
  59         struct s3c_adc_client   *cur;
  60         struct s3c_adc_client   *ts_pend;
  61         void __iomem            *regs;
  62
  63         unsigned int             prescale;
  64
  65         int                      irq;
  66 };
  67
  68 static struct adc_device *adc_dev;
  69
  70 static LIST_HEAD(adc_pending);
  71
  72 #define adc_dbg(_adc, msg...) dev_dbg(&(_adc)->pdev->dev, msg)
  73
  74 static inline void s3c_adc_convert(struct adc_device *adc)
  75 {
  76         unsigned con = readl(adc->regs + S3C2410_ADCCON);
  77
  78         con |= S3C2410_ADCCON_ENABLE_START;
  79         writel(con, adc->regs + S3C2410_ADCCON);
  80 }
  81
  82 static inline void s3c_adc_select(struct adc_device *adc,
  83                                   struct s3c_adc_client *client)
  84 {
  85         unsigned con = readl(adc->regs + S3C2410_ADCCON);
  86
  87         client->select_cb(client, 1);
  88
  89         con &= ~S3C2410_ADCCON_MUXMASK;
  90         con &= ~S3C2410_ADCCON_STDBM;
  91         con &= ~S3C2410_ADCCON_STARTMASK;
  92
  93         if (!client->is_ts)
  94                 con |= S3C2410_ADCCON_SELMUX(client->channel);
  95
  96         writel(con, adc->regs + S3C2410_ADCCON);
  97 }
  98
  99 static void s3c_adc_dbgshow(struct adc_device *adc)
 100 {
 101         adc_dbg(adc, "CON=%08x, TSC=%08x, DLY=%08x\n",
 102                 readl(adc->regs + S3C2410_ADCCON),
 103                 readl(adc->regs + S3C2410_ADCTSC),
 104                 readl(adc->regs + S3C2410_ADCDLY));
 105 }
 106
 107 static void s3c_adc_try(struct adc_device *adc)
 108 {
 109         struct s3c_adc_client *next = adc->ts_pend;
 110
 111         if (!next && !list_empty(&adc_pending)) {
 112                 next = list_first_entry(&adc_pending,
 113                                         struct s3c_adc_client, pend);
 114                 list_del(&next->pend);
 115         } else
 116                 adc->ts_pend = NULL;
 117
 118         if (next) {
 119                 adc_dbg(adc, "new client is %p\n", next);
 120                 adc->cur = next;
 121                 s3c_adc_select(adc, next);
 122                 s3c_adc_convert(adc);
 123                 s3c_adc_dbgshow(adc);
 124         }
 125 }
 126
 127 int s3c_adc_start(struct s3c_adc_client *client,
 128                   unsigned int channel, unsigned int nr_samples)
 129 {
 130         struct adc_device *adc = adc_dev;
 131         unsigned long flags;
 132
 133         if (!adc) {
 134                 printk(KERN_ERR "%s: failed to find adc\n", __func__);
 135                 return -EINVAL;
 136         }
 137
 138         if (client->is_ts && adc->ts_pend)
 139                 return -EAGAIN;
 140
 141         local_irq_save(flags);
 142
 143         client->channel = channel;
 144         client->nr_samples = nr_samples;
 145
 146         if (client->is_ts)
 147                 adc->ts_pend = client;
 148         else
 149                 list_add_tail(&client->pend, &adc_pending);
 150
 151         if (!adc->cur)
 152                 s3c_adc_try(adc);
 153         local_irq_restore(flags);
 154
 155         return 0;
 156 }
 157 EXPORT_SYMBOL_GPL(s3c_adc_start);
 158
 159 static void s3c_convert_done(struct s3c_adc_client *client,
 160                              unsigned v, unsigned u, unsigned *left)
 161 {
 162         client->result = v;
 163         wake_up(client->wait);
 164 }
 165
 166 int s3c_adc_read(struct s3c_adc_client *client, unsigned int ch)
 167 {
 168         DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wake);
 169         int ret;
 170
 171         client->convert_cb = s3c_convert_done;
 172         client->wait = &wake;
 173         client->result = -1;
 174
 175         ret = s3c_adc_start(client, ch, 1);
 176         if (ret < 0)
 177                 goto err;
 178
 179         ret = wait_event_timeout(wake, client->result >= 0, HZ / 2);
 180         if (client->result < 0) {
 181                 ret = -ETIMEDOUT;
 182                 goto err;
 183         }
 184
 185         client->convert_cb = NULL;
 186         return client->result;
 187
 188 err:
 189         return ret;
 190 }
 191 EXPORT_SYMBOL_GPL(s3c_adc_convert);
 192
 193 static void s3c_adc_default_select(struct s3c_adc_client *client,
 194                                    unsigned select)
 195 {
 196 }
 197
 198 struct s3c_adc_client *s3c_adc_register(struct platform_device *pdev,
 199                                         void (*select)(struct s3c_adc_client *client,
 200                                                        unsigned int selected),
 201                                         void (*conv)(struct s3c_adc_client *client,
 202                                                      unsigned d0, unsigned d1,
 203                                                      unsigned *samples_left),
 204                                         unsigned int is_ts)
 205 {
 206         struct s3c_adc_client *client;
 207
 208         WARN_ON(!pdev);
 209
 210         if (!select)
 211                 select = s3c_adc_default_select;
 212
 213         if (!pdev)
 214                 return ERR_PTR(-EINVAL);
 215
 216         client = kzalloc(sizeof(struct s3c_adc_client), GFP_KERNEL);
 217         if (!client) {
 218                 dev_err(&pdev->dev, "no memory for adc client\n");
 219                 return ERR_PTR(-ENOMEM);
 220         }
 221
 222         client->pdev = pdev;
 223         client->is_ts = is_ts;
 224         client->select_cb = select;
 225         client->convert_cb = conv;
 226
 227         return client;
 228 }
 229 EXPORT_SYMBOL_GPL(s3c_adc_register);
 230
 231 void s3c_adc_release(struct s3c_adc_client *client)
 232 {
 233         /* We should really check that nothing is in progress. */
 234         if (adc_dev->cur == client)
 235                 adc_dev->cur = NULL;
 236         if (adc_dev->ts_pend == client)
 237                 adc_dev->ts_pend = NULL;
 238         else {
 239                 struct list_head *p, *n;
 240                 struct s3c_adc_client *tmp;
 241
 242                 list_for_each_safe(p, n, &adc_pending) {
 243                         tmp = list_entry(p, struct s3c_adc_client, pend);
 244                         if (tmp == client)
 245                                 list_del(&tmp->pend);
 246                 }
 247         }
 248
 249         if (adc_dev->cur == NULL)
 250                 s3c_adc_try(adc_dev);
 251         kfree(client);
 252 }
 253 EXPORT_SYMBOL_GPL(s3c_adc_release);
 254
 255 static irqreturn_t s3c_adc_irq(int irq, void *pw)
 256 {
 257         struct adc_device *adc = pw;
 258         struct s3c_adc_client *client = adc->cur;
 259         unsigned long flags;
 260         unsigned data0, data1;
 261
 262         if (!client) {
 263                 dev_warn(&adc->pdev->dev, "%s: no adc pending\n", __func__);
 264                 return IRQ_HANDLED;
 265         }
 266
 267         data0 = readl(adc->regs + S3C2410_ADCDAT0);
 268         data1 = readl(adc->regs + S3C2410_ADCDAT1);
 269         adc_dbg(adc, "read %d: 0x%04x, 0x%04x\n", client->nr_samples, data0, data1);
 270
 271         client->nr_samples--;
 272
 273         if (client->convert_cb)
 274                 (client->convert_cb)(client, data0 & 0x3ff, data1 & 0x3ff,
 275                                      &client->nr_samples);
 276
 277         if (client->nr_samples > 0) {
 278                 /* fire another conversion for this */
 279
 280                 client->select_cb(client, 1);
 281                 s3c_adc_convert(adc);
 282         } else {
 283                 local_irq_save(flags);
 284                 (client->select_cb)(client, 0);
 285                 adc->cur = NULL;
 286
 287                 s3c_adc_try(adc);
 288                 local_irq_restore(flags);
 289         }
 290
 291         return IRQ_HANDLED;
 292 }
 293
 294 static int s3c_adc_probe(struct platform_device *pdev)
 295 {
 296         struct device *dev = &pdev->dev;
 297         struct adc_device *adc;
 298         struct resource *regs;
 299         int ret;
 300
 301         adc = kzalloc(sizeof(struct adc_device), GFP_KERNEL);
 302         if (adc == NULL) {
 303                 dev_err(dev, "failed to allocate adc_device\n");
 304                 return -ENOMEM;
 305         }
 306
 307         adc->pdev = pdev;
 308         adc->prescale = S3C2410_ADCCON_PRSCVL(49);
 309
 310         adc->irq = platform_get_irq(pdev, 1);
 311         if (adc->irq <= 0) {
 312                 dev_err(dev, "failed to get adc irq\n");
 313                 ret = -ENOENT;
 314                 goto err_alloc;
 315         }
 316
 317         ret = request_irq(adc->irq, s3c_adc_irq, 0, dev_name(dev), adc);
 318         if (ret < 0) {
 319                 dev_err(dev, "failed to attach adc irq\n");
 320                 goto err_alloc;
 321         }
 322
 323         adc->clk = clk_get(dev, "adc");
 324         if (IS_ERR(adc->clk)) {
 325                 dev_err(dev, "failed to get adc clock\n");
 326                 ret = PTR_ERR(adc->clk);
 327                 goto err_irq;
 328         }
 329
 330         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 331         if (!regs) {
 332                 dev_err(dev, "failed to find registers\n");
 333                 ret = -ENXIO;
 334                 goto err_clk;
 335         }
 336
 337         adc->regs = ioremap(regs->start, resource_size(regs));
 338         if (!adc->regs) {
 339                 dev_err(dev, "failed to map registers\n");
 340                 ret = -ENXIO;
 341                 goto err_clk;
 342         }
 343
 344         clk_enable(adc->clk);
 345
 346         writel(adc->prescale | S3C2410_ADCCON_PRSCEN,
 347                adc->regs + S3C2410_ADCCON);
 348
 349         dev_info(dev, "attached adc driver\n");
 350
 351         platform_set_drvdata(pdev, adc);
 352         adc_dev = adc;
 353
 354         return 0;
 355
 356  err_clk:
 357         clk_put(adc->clk);
 358
 359  err_irq:
 360         free_irq(adc->irq, adc);
 361
 362  err_alloc:
 363         kfree(adc);
 364         return ret;
 365 }
 366
 367 static int s3c_adc_remove(struct platform_device *pdev)
 368 {
 369         struct adc_device *adc = platform_get_drvdata(pdev);
 370
 371         iounmap(adc->regs);
 372         free_irq(adc->irq, adc);
 373         clk_disable(adc->clk);
 374         clk_put(adc->clk);
 375         kfree(adc);
 376
 377         return 0;
 378 }
 379
 380 #ifdef CONFIG_PM
 381 static int s3c_adc_suspend(struct platform_device *pdev, pm_message_t state)
 382 {
 383         struct adc_device *adc = platform_get_drvdata(pdev);
 384         u32 con;
 385
 386         con = readl(adc->regs + S3C2410_ADCCON);
 387         con |= S3C2410_ADCCON_STDBM;
 388         writel(con, adc->regs + S3C2410_ADCCON);
 389
 390         clk_disable(adc->clk);
 391
 392         return 0;
 393 }
 394
 395 static int s3c_adc_resume(struct platform_device *pdev)
 396 {
 397         struct adc_device *adc = platform_get_drvdata(pdev);
 398
 399         clk_enable(adc->clk);
 400
 401         writel(adc->prescale | S3C2410_ADCCON_PRSCEN,
 402                adc->regs + S3C2410_ADCCON);
 403
 404         return 0;
 405 }
 406
 407 #else
 408 #define s3c_adc_suspend NULL
 409 #define s3c_adc_resume NULL
 410 #endif
 411
 412 static struct platform_driver s3c_adc_driver = {
 413         .driver         = {
 414                 .name   = "s3c24xx-adc",
 415                 .owner  = THIS_MODULE,
 416         },
 417         .probe          = s3c_adc_probe,
 418         .remove         = __devexit_p(s3c_adc_remove),
 419         .suspend        = s3c_adc_suspend,
 420         .resume         = s3c_adc_resume,
 421 };
 422
 423 static int __init adc_init(void)
 424 {
 425         int ret;
 426
 427         ret = platform_driver_register(&s3c_adc_driver);
 428         if (ret)
 429                 printk(KERN_ERR "%s: failed to add adc driver\n", __func__);
 430
 431         return ret;
 432 }
 433
 434 arch_initcall(adc_init);