arch/arm/plat-samsung/adc.c

   1 /* arch/arm/plat-samsung/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  * Samsung 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/sched.h>
  18 #include <linux/list.h>
  19 #include <linux/slab.h>
  20 #include <linux/err.h>
  21 #include <linux/clk.h>
  22 #include <linux/interrupt.h>
  23 #include <linux/io.h>
  24 #include <linux/regulator/consumer.h>
  25
  26 #include <plat/regs-adc.h>
  27 #include <plat/adc.h>
  28
  29 /* This driver is designed to control the usage of the ADC block between
  30  * the touchscreen and any other drivers that may need to use it, such as
  31  * the hwmon driver.
  32  *
  33  * Priority will be given to the touchscreen driver, but as this itself is
  34  * rate limited it should not starve other requests which are processed in
  35  * order that they are received.
  36  *
  37  * Each user registers to get a client block which uniquely identifies it
  38  * and stores information such as the necessary functions to callback when
  39  * action is required.
  40  */
  41
  42 enum s3c_cpu_type {
  43         TYPE_ADCV1, /* S3C24XX */
  44         TYPE_ADCV2, /* S3C64XX, S5P64X0, S5PC100 */
  45         TYPE_ADCV3, /* S5PV210, S5PC110, EXYNOS4210 */
  46 };
  47
  48 struct s3c_adc_client {
  49         struct platform_device  *pdev;
  50         struct list_head         pend;
  51         wait_queue_head_t       *wait;
  52
  53         unsigned int             nr_samples;
  54         int                      result;
  55         unsigned char            is_ts;
  56         unsigned char            channel;
  57
  58         void    (*select_cb)(struct s3c_adc_client *c, unsigned selected);
  59         void    (*convert_cb)(struct s3c_adc_client *c,
  60                               unsigned val1, unsigned val2,
  61                               unsigned *samples_left);
  62 };
  63
  64 struct adc_device {
  65         struct platform_device  *pdev;
  66         struct platform_device  *owner;
  67         struct clk              *clk;
  68         struct s3c_adc_client   *cur;
  69         struct s3c_adc_client   *ts_pend;
  70         void __iomem            *regs;
  71         spinlock_t               lock;
  72
  73         unsigned int             prescale;
  74
  75         int                      irq;
  76         struct regulator        *vdd;
  77 };
  78
  79 static struct adc_device *adc_dev;
  80
  81 static LIST_HEAD(adc_pending);  /* protected by adc_device.lock */
  82
  83 #define adc_dbg(_adc, msg...) dev_dbg(&(_adc)->pdev->dev, msg)
  84
  85 static inline void s3c_adc_convert(struct adc_device *adc)
  86 {
  87         unsigned con = readl(adc->regs + S3C2410_ADCCON);
  88
  89         con |= S3C2410_ADCCON_ENABLE_START;
  90         writel(con, adc->regs + S3C2410_ADCCON);
  91 }
  92
  93 static inline void s3c_adc_select(struct adc_device *adc,
  94                                   struct s3c_adc_client *client)
  95 {
  96         unsigned con = readl(adc->regs + S3C2410_ADCCON);
  97         enum s3c_cpu_type cpu = platform_get_device_id(adc->pdev)->driver_data;
  98
  99         client->select_cb(client, 1);
 100
 101         con &= ~S3C2410_ADCCON_MUXMASK;
 102         con &= ~S3C2410_ADCCON_STDBM;
 103         con &= ~S3C2410_ADCCON_STARTMASK;
 104
 105         if (!client->is_ts) {
 106                 if (cpu == TYPE_ADCV3)
 107                         writel(client->channel & 0xf, adc->regs + S5P_ADCMUX);
 108                 else
 109                         con |= S3C2410_ADCCON_SELMUX(client->channel);
 110         }
 111
 112         writel(con, adc->regs + S3C2410_ADCCON);
 113 }
 114
 115 static void s3c_adc_dbgshow(struct adc_device *adc)
 116 {
 117         adc_dbg(adc, "CON=%08x, TSC=%08x, DLY=%08x\n",
 118                 readl(adc->regs + S3C2410_ADCCON),
 119                 readl(adc->regs + S3C2410_ADCTSC),
 120                 readl(adc->regs + S3C2410_ADCDLY));
 121 }
 122
 123 static void s3c_adc_try(struct adc_device *adc)
 124 {
 125         struct s3c_adc_client *next = adc->ts_pend;
 126
 127         if (!next && !list_empty(&adc_pending)) {
 128                 next = list_first_entry(&adc_pending,
 129                                         struct s3c_adc_client, pend);
 130                 list_del(&next->pend);
 131         } else
 132                 adc->ts_pend = NULL;
 133
 134         if (next) {
 135                 adc_dbg(adc, "new client is %p\n", next);
 136                 adc->cur = next;
 137                 s3c_adc_select(adc, next);
 138                 s3c_adc_convert(adc);
 139                 s3c_adc_dbgshow(adc);
 140         }
 141 }
 142
 143 int s3c_adc_start(struct s3c_adc_client *client,
 144                   unsigned int channel, unsigned int nr_samples)
 145 {
 146         struct adc_device *adc = adc_dev;
 147         unsigned long flags;
 148
 149         if (!adc) {
 150                 printk(KERN_ERR "%s: failed to find adc\n", __func__);
 151                 return -EINVAL;
 152         }
 153
 154         if (client->is_ts && adc->ts_pend)
 155                 return -EAGAIN;
 156
 157         spin_lock_irqsave(&adc->lock, flags);
 158
 159         client->channel = channel;
 160         client->nr_samples = nr_samples;
 161
 162         if (client->is_ts)
 163                 adc->ts_pend = client;
 164         else
 165                 list_add_tail(&client->pend, &adc_pending);
 166
 167         if (!adc->cur)
 168                 s3c_adc_try(adc);
 169
 170         spin_unlock_irqrestore(&adc->lock, flags);
 171
 172         return 0;
 173 }
 174 EXPORT_SYMBOL_GPL(s3c_adc_start);
 175
 176 static void s3c_convert_done(struct s3c_adc_client *client,
 177                              unsigned v, unsigned u, unsigned *left)
 178 {
 179         client->result = v;
 180         wake_up(client->wait);
 181 }
 182
 183 int s3c_adc_read(struct s3c_adc_client *client, unsigned int ch)
 184 {
 185         DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wake);
 186         int ret;
 187
 188         client->convert_cb = s3c_convert_done;
 189         client->wait = &wake;
 190         client->result = -1;
 191
 192         ret = s3c_adc_start(client, ch, 1);
 193         if (ret < 0)
 194                 goto err;
 195
 196         ret = wait_event_timeout(wake, client->result >= 0, HZ / 2);
 197         if (client->result < 0) {
 198                 ret = -ETIMEDOUT;
 199                 goto err;
 200         }
 201
 202         client->convert_cb = NULL;
 203         return client->result;
 204
 205 err:
 206         return ret;
 207 }
 208 EXPORT_SYMBOL_GPL(s3c_adc_read);
 209
 210 static void s3c_adc_default_select(struct s3c_adc_client *client,
 211                                    unsigned select)
 212 {
 213 }
 214
 215 struct s3c_adc_client *s3c_adc_register(struct platform_device *pdev,
 216                                         void (*select)(struct s3c_adc_client *client,
 217                                                        unsigned int selected),
 218                                         void (*conv)(struct s3c_adc_client *client,
 219                                                      unsigned d0, unsigned d1,
 220                                                      unsigned *samples_left),
 221                                         unsigned int is_ts)
 222 {
 223         struct s3c_adc_client *client;
 224
 225         WARN_ON(!pdev);
 226
 227         if (!select)
 228                 select = s3c_adc_default_select;
 229
 230         if (!pdev)
 231                 return ERR_PTR(-EINVAL);
 232
 233         client = kzalloc(sizeof(struct s3c_adc_client), GFP_KERNEL);
 234         if (!client) {
 235                 dev_err(&pdev->dev, "no memory for adc client\n");
 236                 return ERR_PTR(-ENOMEM);
 237         }
 238
 239         client->pdev = pdev;
 240         client->is_ts = is_ts;
 241         client->select_cb = select;
 242         client->convert_cb = conv;
 243
 244         return client;
 245 }
 246 EXPORT_SYMBOL_GPL(s3c_adc_register);
 247
 248 void s3c_adc_release(struct s3c_adc_client *client)
 249 {
 250         unsigned long flags;
 251
 252         spin_lock_irqsave(&adc_dev->lock, flags);
 253
 254         /* We should really check that nothing is in progress. */
 255         if (adc_dev->cur == client)
 256                 adc_dev->cur = NULL;
 257         if (adc_dev->ts_pend == client)
 258                 adc_dev->ts_pend = NULL;
 259         else {
 260                 struct list_head *p, *n;
 261                 struct s3c_adc_client *tmp;
 262
 263                 list_for_each_safe(p, n, &adc_pending) {
 264                         tmp = list_entry(p, struct s3c_adc_client, pend);
 265                         if (tmp == client)
 266                                 list_del(&tmp->pend);
 267                 }
 268         }
 269
 270         if (adc_dev->cur == NULL)
 271                 s3c_adc_try(adc_dev);
 272
 273         spin_unlock_irqrestore(&adc_dev->lock, flags);
 274         kfree(client);
 275 }
 276 EXPORT_SYMBOL_GPL(s3c_adc_release);
 277
 278 static irqreturn_t s3c_adc_irq(int irq, void *pw)
 279 {
 280         struct adc_device *adc = pw;
 281         struct s3c_adc_client *client = adc->cur;
 282         enum s3c_cpu_type cpu = platform_get_device_id(adc->pdev)->driver_data;
 283         unsigned data0, data1;
 284
 285         if (!client) {
 286                 dev_warn(&adc->pdev->dev, "%s: no adc pending\n", __func__);
 287                 goto exit;
 288         }
 289
 290         data0 = readl(adc->regs + S3C2410_ADCDAT0);
 291         data1 = readl(adc->regs + S3C2410_ADCDAT1);
 292         adc_dbg(adc, "read %d: 0x%04x, 0x%04x\n", client->nr_samples, data0, data1);
 293
 294         client->nr_samples--;
 295
 296         if (cpu != TYPE_ADCV1) {
 297                 /* S3C64XX/S5P ADC resolution is 12-bit */
 298                 data0 &= 0xfff;
 299                 data1 &= 0xfff;
 300         } else {
 301                 data0 &= 0x3ff;
 302                 data1 &= 0x3ff;
 303         }
 304
 305         if (client->convert_cb)
 306                 (client->convert_cb)(client, data0, data1, &client->nr_samples);
 307
 308         if (client->nr_samples > 0) {
 309                 /* fire another conversion for this */
 310
 311                 client->select_cb(client, 1);
 312                 s3c_adc_convert(adc);
 313         } else {
 314                 spin_lock(&adc->lock);
 315                 (client->select_cb)(client, 0);
 316                 adc->cur = NULL;
 317
 318                 s3c_adc_try(adc);
 319                 spin_unlock(&adc->lock);
 320         }
 321
 322 exit:
 323         if (cpu != TYPE_ADCV1) {
 324                 /* Clear ADC interrupt */
 325                 writel(0, adc->regs + S3C64XX_ADCCLRINT);
 326         }
 327         return IRQ_HANDLED;
 328 }
 329
 330 static int s3c_adc_probe(struct platform_device *pdev)
 331 {
 332         struct device *dev = &pdev->dev;
 333         struct adc_device *adc;
 334         struct resource *regs;
 335         int ret;
 336         unsigned tmp;
 337
 338         adc = kzalloc(sizeof(struct adc_device), GFP_KERNEL);
 339         if (adc == NULL) {
 340                 dev_err(dev, "failed to allocate adc_device\n");
 341                 return -ENOMEM;
 342         }
 343
 344         spin_lock_init(&adc->lock);
 345
 346         adc->pdev = pdev;
 347         adc->prescale = S3C2410_ADCCON_PRSCVL(49);
 348
 349         adc->vdd = regulator_get(dev, "vdd");
 350         if (IS_ERR(adc->vdd)) {
 351                 dev_err(dev, "operating without regulator \"vdd\" .\n");
 352                 ret = PTR_ERR(adc->vdd);
 353                 goto err_alloc;
 354         }
 355
 356         adc->irq = platform_get_irq(pdev, 1);
 357         if (adc->irq <= 0) {
 358                 dev_err(dev, "failed to get adc irq\n");
 359                 ret = -ENOENT;
 360                 goto err_reg;
 361         }
 362
 363         ret = request_irq(adc->irq, s3c_adc_irq, 0, dev_name(dev), adc);
 364         if (ret < 0) {
 365                 dev_err(dev, "failed to attach adc irq\n");
 366                 goto err_reg;
 367         }
 368
 369         adc->clk = clk_get(dev, "adc");
 370         if (IS_ERR(adc->clk)) {
 371                 dev_err(dev, "failed to get adc clock\n");
 372                 ret = PTR_ERR(adc->clk);
 373                 goto err_irq;
 374         }
 375
 376         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 377         if (!regs) {
 378                 dev_err(dev, "failed to find registers\n");
 379                 ret = -ENXIO;
 380                 goto err_clk;
 381         }
 382
 383         adc->regs = ioremap(regs->start, resource_size(regs));
 384         if (!adc->regs) {
 385                 dev_err(dev, "failed to map registers\n");
 386                 ret = -ENXIO;
 387                 goto err_clk;
 388         }
 389
 390         ret = regulator_enable(adc->vdd);
 391         if (ret)
 392                 goto err_ioremap;
 393
 394         clk_enable(adc->clk);
 395
 396         tmp = adc->prescale | S3C2410_ADCCON_PRSCEN;
 397         if (platform_get_device_id(pdev)->driver_data != TYPE_ADCV1) {
 398                 /* Enable 12-bit ADC resolution */
 399                 tmp |= S3C64XX_ADCCON_RESSEL;
 400         }
 401         writel(tmp, adc->regs + S3C2410_ADCCON);
 402
 403         dev_info(dev, "attached adc driver\n");
 404
 405         platform_set_drvdata(pdev, adc);
 406         adc_dev = adc;
 407
 408         return 0;
 409
 410  err_ioremap:
 411         iounmap(adc->regs);
 412  err_clk:
 413         clk_put(adc->clk);
 414
 415  err_irq:
 416         free_irq(adc->irq, adc);
 417  err_reg:
 418         regulator_put(adc->vdd);
 419  err_alloc:
 420         kfree(adc);
 421         return ret;
 422 }
 423
 424 static int __devexit s3c_adc_remove(struct platform_device *pdev)
 425 {
 426         struct adc_device *adc = platform_get_drvdata(pdev);
 427
 428         iounmap(adc->regs);
 429         free_irq(adc->irq, adc);
 430         clk_disable(adc->clk);
 431         regulator_disable(adc->vdd);
 432         regulator_put(adc->vdd);
 433         clk_put(adc->clk);
 434         kfree(adc);
 435
 436         return 0;
 437 }
 438
 439 #ifdef CONFIG_PM
 440 static int s3c_adc_suspend(struct device *dev)
 441 {
 442         struct platform_device *pdev = container_of(dev,
 443                         struct platform_device, dev);
 444         struct adc_device *adc = platform_get_drvdata(pdev);
 445         unsigned long flags;
 446         u32 con;
 447
 448         spin_lock_irqsave(&adc->lock, flags);
 449
 450         con = readl(adc->regs + S3C2410_ADCCON);
 451         con |= S3C2410_ADCCON_STDBM;
 452         writel(con, adc->regs + S3C2410_ADCCON);
 453
 454         disable_irq(adc->irq);
 455         spin_unlock_irqrestore(&adc->lock, flags);
 456         clk_disable(adc->clk);
 457         regulator_disable(adc->vdd);
 458
 459         return 0;
 460 }
 461
 462 static int s3c_adc_resume(struct device *dev)
 463 {
 464         struct platform_device *pdev = container_of(dev,
 465                         struct platform_device, dev);
 466         struct adc_device *adc = platform_get_drvdata(pdev);
 467         int ret;
 468         unsigned long tmp;
 469
 470         ret = regulator_enable(adc->vdd);
 471         if (ret)
 472                 return ret;
 473         clk_enable(adc->clk);
 474         enable_irq(adc->irq);
 475
 476         tmp = adc->prescale | S3C2410_ADCCON_PRSCEN;
 477         /* Enable 12-bit ADC resolution */
 478         if (platform_get_device_id(pdev)->driver_data != TYPE_ADCV1)
 479                 tmp |= S3C64XX_ADCCON_RESSEL;
 480         writel(tmp, adc->regs + S3C2410_ADCCON);
 481
 482         return 0;
 483 }
 484
 485 #else
 486 #define s3c_adc_suspend NULL
 487 #define s3c_adc_resume NULL
 488 #endif
 489
 490 static struct platform_device_id s3c_adc_driver_ids[] = {
 491         {
 492                 .name           = "s3c24xx-adc",
 493                 .driver_data    = TYPE_ADCV1,
 494         }, {
 495                 .name           = "s3c64xx-adc",
 496                 .driver_data    = TYPE_ADCV2,
 497         }, {
 498                 .name           = "samsung-adc-v3",
 499                 .driver_data    = TYPE_ADCV3,
 500         },
 501         { }
 502 };
 503 MODULE_DEVICE_TABLE(platform, s3c_adc_driver_ids);
 504
 505 static const struct dev_pm_ops adc_pm_ops = {
 506         .suspend        = s3c_adc_suspend,
 507         .resume         = s3c_adc_resume,
 508 };
 509
 510 static struct platform_driver s3c_adc_driver = {
 511         .id_table       = s3c_adc_driver_ids,
 512         .driver         = {
 513                 .name   = "s3c-adc",
 514                 .owner  = THIS_MODULE,
 515                 .pm     = &adc_pm_ops,
 516         },
 517         .probe          = s3c_adc_probe,
 518         .remove         = __devexit_p(s3c_adc_remove),
 519 };
 520
 521 static int __init adc_init(void)
 522 {
 523         int ret;
 524
 525         ret = platform_driver_register(&s3c_adc_driver);
 526         if (ret)
 527                 printk(KERN_ERR "%s: failed to add adc driver\n", __func__);
 528
 529         return ret;
 530 }
 531
 532 module_init(adc_init);