arch/arm/plat-samsung/adc.c

   1 // SPDX-License-Identifier: GPL-1.0+
   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 #include <linux/module.h>
  10 #include <linux/kernel.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/sched.h>
  13 #include <linux/list.h>
  14 #include <linux/slab.h>
  15 #include <linux/err.h>
  16 #include <linux/clk.h>
  17 #include <linux/interrupt.h>
  18 #include <linux/io.h>
  19 #include <linux/regulator/consumer.h>
  20
  21 #include <plat/regs-adc.h>
  22 #include <plat/adc.h>
  23
  24 /* This driver is designed to control the usage of the ADC block between
  25  * the touchscreen and any other drivers that may need to use it, such as
  26  * the hwmon driver.
  27  *
  28  * Priority will be given to the touchscreen driver, but as this itself is
  29  * rate limited it should not starve other requests which are processed in
  30  * order that they are received.
  31  *
  32  * Each user registers to get a client block which uniquely identifies it
  33  * and stores information such as the necessary functions to callback when
  34  * action is required.
  35  */
  36
  37 enum s3c_cpu_type {
  38         TYPE_ADCV1, /* S3C24XX */
  39         TYPE_ADCV11, /* S3C2443 */
  40         TYPE_ADCV12, /* S3C2416, S3C2450 */
  41         TYPE_ADCV2, /* S3C64XX */
  42         TYPE_ADCV3, /* S5PV210, S5PC110, EXYNOS4210 */
  43 };
  44
  45 struct s3c_adc_client {
  46         struct platform_device  *pdev;
  47         struct list_head         pend;
  48         wait_queue_head_t       *wait;
  49
  50         unsigned int             nr_samples;
  51         int                      result;
  52         unsigned char            is_ts;
  53         unsigned char            channel;
  54
  55         void    (*select_cb)(struct s3c_adc_client *c, unsigned selected);
  56         void    (*convert_cb)(struct s3c_adc_client *c,
  57                               unsigned val1, unsigned val2,
  58                               unsigned *samples_left);
  59 };
  60
  61 struct adc_device {
  62         struct platform_device  *pdev;
  63         struct platform_device  *owner;
  64         struct clk              *clk;
  65         struct s3c_adc_client   *cur;
  66         struct s3c_adc_client   *ts_pend;
  67         void __iomem            *regs;
  68         spinlock_t               lock;
  69
  70         unsigned int             prescale;
  71
  72         int                      irq;
  73         struct regulator        *vdd;
  74 };
  75
  76 static struct adc_device *adc_dev;
  77
  78 static LIST_HEAD(adc_pending);  /* protected by adc_device.lock */
  79
  80 #define adc_dbg(_adc, msg...) dev_dbg(&(_adc)->pdev->dev, msg)
  81
  82 static inline void s3c_adc_convert(struct adc_device *adc)
  83 {
  84         unsigned con = readl(adc->regs + S3C2410_ADCCON);
  85
  86         con |= S3C2410_ADCCON_ENABLE_START;
  87         writel(con, adc->regs + S3C2410_ADCCON);
  88 }
  89
  90 static inline void s3c_adc_select(struct adc_device *adc,
  91                                   struct s3c_adc_client *client)
  92 {
  93         unsigned con = readl(adc->regs + S3C2410_ADCCON);
  94         enum s3c_cpu_type cpu = platform_get_device_id(adc->pdev)->driver_data;
  95
  96         client->select_cb(client, 1);
  97
  98         if (cpu == TYPE_ADCV1 || cpu == TYPE_ADCV2)
  99                 con &= ~S3C2410_ADCCON_MUXMASK;
 100         con &= ~S3C2410_ADCCON_STDBM;
 101         con &= ~S3C2410_ADCCON_STARTMASK;
 102
 103         if (!client->is_ts) {
 104                 if (cpu == TYPE_ADCV3)
 105                         writel(client->channel & 0xf, adc->regs + S5P_ADCMUX);
 106                 else if (cpu == TYPE_ADCV11 || cpu == TYPE_ADCV12)
 107                         writel(client->channel & 0xf,
 108                                                 adc->regs + S3C2443_ADCMUX);
 109                 else
 110                         con |= S3C2410_ADCCON_SELMUX(client->channel);
 111         }
 112
 113         writel(con, adc->regs + S3C2410_ADCCON);
 114 }
 115
 116 static void s3c_adc_dbgshow(struct adc_device *adc)
 117 {
 118         adc_dbg(adc, "CON=%08x, TSC=%08x, DLY=%08x\n",
 119                 readl(adc->regs + S3C2410_ADCCON),
 120                 readl(adc->regs + S3C2410_ADCTSC),
 121                 readl(adc->regs + S3C2410_ADCDLY));
 122 }
 123
 124 static void s3c_adc_try(struct adc_device *adc)
 125 {
 126         struct s3c_adc_client *next = adc->ts_pend;
 127
 128         if (!next && !list_empty(&adc_pending)) {
 129                 next = list_first_entry(&adc_pending,
 130                                         struct s3c_adc_client, pend);
 131                 list_del(&next->pend);
 132         } else
 133                 adc->ts_pend = NULL;
 134
 135         if (next) {
 136                 adc_dbg(adc, "new client is %p\n", next);
 137                 adc->cur = next;
 138                 s3c_adc_select(adc, next);
 139                 s3c_adc_convert(adc);
 140                 s3c_adc_dbgshow(adc);
 141         }
 142 }
 143
 144 int s3c_adc_start(struct s3c_adc_client *client,
 145                   unsigned int channel, unsigned int nr_samples)
 146 {
 147         struct adc_device *adc = adc_dev;
 148         unsigned long flags;
 149
 150         if (!adc) {
 151                 printk(KERN_ERR "%s: failed to find adc\n", __func__);
 152                 return -EINVAL;
 153         }
 154
 155         spin_lock_irqsave(&adc->lock, flags);
 156
 157         if (client->is_ts && adc->ts_pend) {
 158                 spin_unlock_irqrestore(&adc->lock, flags);
 159                 return -EAGAIN;
 160         }
 161
 162         client->channel = channel;
 163         client->nr_samples = nr_samples;
 164
 165         if (client->is_ts)
 166                 adc->ts_pend = client;
 167         else
 168                 list_add_tail(&client->pend, &adc_pending);
 169
 170         if (!adc->cur)
 171                 s3c_adc_try(adc);
 172
 173         spin_unlock_irqrestore(&adc->lock, flags);
 174
 175         return 0;
 176 }
 177 EXPORT_SYMBOL_GPL(s3c_adc_start);
 178
 179 static void s3c_convert_done(struct s3c_adc_client *client,
 180                              unsigned v, unsigned u, unsigned *left)
 181 {
 182         client->result = v;
 183         wake_up(client->wait);
 184 }
 185
 186 int s3c_adc_read(struct s3c_adc_client *client, unsigned int ch)
 187 {
 188         DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wake);
 189         int ret;
 190
 191         client->convert_cb = s3c_convert_done;
 192         client->wait = &wake;
 193         client->result = -1;
 194
 195         ret = s3c_adc_start(client, ch, 1);
 196         if (ret < 0)
 197                 goto err;
 198
 199         ret = wait_event_timeout(wake, client->result >= 0, HZ / 2);
 200         if (client->result < 0) {
 201                 ret = -ETIMEDOUT;
 202                 goto err;
 203         }
 204
 205         client->convert_cb = NULL;
 206         return client->result;
 207
 208 err:
 209         return ret;
 210 }
 211 EXPORT_SYMBOL_GPL(s3c_adc_read);
 212
 213 static void s3c_adc_default_select(struct s3c_adc_client *client,
 214                                    unsigned select)
 215 {
 216 }
 217
 218 struct s3c_adc_client *s3c_adc_register(struct platform_device *pdev,
 219                                         void (*select)(struct s3c_adc_client *client,
 220                                                        unsigned int selected),
 221                                         void (*conv)(struct s3c_adc_client *client,
 222                                                      unsigned d0, unsigned d1,
 223                                                      unsigned *samples_left),
 224                                         unsigned int is_ts)
 225 {
 226         struct s3c_adc_client *client;
 227
 228         WARN_ON(!pdev);
 229
 230         if (!select)
 231                 select = s3c_adc_default_select;
 232
 233         if (!pdev)
 234                 return ERR_PTR(-EINVAL);
 235
 236         client = kzalloc(sizeof(*client), GFP_KERNEL);
 237         if (!client)
 238                 return ERR_PTR(-ENOMEM);
 239
 240         client->pdev = pdev;
 241         client->is_ts = is_ts;
 242         client->select_cb = select;
 243         client->convert_cb = conv;
 244
 245         return client;
 246 }
 247 EXPORT_SYMBOL_GPL(s3c_adc_register);
 248
 249 void s3c_adc_release(struct s3c_adc_client *client)
 250 {
 251         unsigned long flags;
 252
 253         spin_lock_irqsave(&adc_dev->lock, flags);
 254
 255         /* We should really check that nothing is in progress. */
 256         if (adc_dev->cur == client)
 257                 adc_dev->cur = NULL;
 258         if (adc_dev->ts_pend == client)
 259                 adc_dev->ts_pend = NULL;
 260         else {
 261                 struct list_head *p, *n;
 262                 struct s3c_adc_client *tmp;
 263
 264                 list_for_each_safe(p, n, &adc_pending) {
 265                         tmp = list_entry(p, struct s3c_adc_client, pend);
 266                         if (tmp == client)
 267                                 list_del(&tmp->pend);
 268                 }
 269         }
 270
 271         if (adc_dev->cur == NULL)
 272                 s3c_adc_try(adc_dev);
 273
 274         spin_unlock_irqrestore(&adc_dev->lock, flags);
 275         kfree(client);
 276 }
 277 EXPORT_SYMBOL_GPL(s3c_adc_release);
 278
 279 static irqreturn_t s3c_adc_irq(int irq, void *pw)
 280 {
 281         struct adc_device *adc = pw;
 282         struct s3c_adc_client *client = adc->cur;
 283         enum s3c_cpu_type cpu = platform_get_device_id(adc->pdev)->driver_data;
 284         unsigned data0, data1;
 285
 286         if (!client) {
 287                 dev_warn(&adc->pdev->dev, "%s: no adc pending\n", __func__);
 288                 goto exit;
 289         }
 290
 291         data0 = readl(adc->regs + S3C2410_ADCDAT0);
 292         data1 = readl(adc->regs + S3C2410_ADCDAT1);
 293         adc_dbg(adc, "read %d: 0x%04x, 0x%04x\n", client->nr_samples, data0, data1);
 294
 295         client->nr_samples--;
 296
 297         if (cpu == TYPE_ADCV1 || cpu == TYPE_ADCV11) {
 298                 data0 &= 0x3ff;
 299                 data1 &= 0x3ff;
 300         } else {
 301                 /* S3C2416/S3C64XX/S5P ADC resolution is 12-bit */
 302                 data0 &= 0xfff;
 303                 data1 &= 0xfff;
 304         }
 305
 306         if (client->convert_cb)
 307                 (client->convert_cb)(client, data0, data1, &client->nr_samples);
 308
 309         if (client->nr_samples > 0) {
 310                 /* fire another conversion for this */
 311
 312                 client->select_cb(client, 1);
 313                 s3c_adc_convert(adc);
 314         } else {
 315                 spin_lock(&adc->lock);
 316                 (client->select_cb)(client, 0);
 317                 adc->cur = NULL;
 318
 319                 s3c_adc_try(adc);
 320                 spin_unlock(&adc->lock);
 321         }
 322
 323 exit:
 324         if (cpu == TYPE_ADCV2 || cpu == TYPE_ADCV3) {
 325                 /* Clear ADC interrupt */
 326                 writel(0, adc->regs + S3C64XX_ADCCLRINT);
 327         }
 328         return IRQ_HANDLED;
 329 }
 330
 331 static int s3c_adc_probe(struct platform_device *pdev)
 332 {
 333         struct device *dev = &pdev->dev;
 334         struct adc_device *adc;
 335         struct resource *regs;
 336         enum s3c_cpu_type cpu = platform_get_device_id(pdev)->driver_data;
 337         int ret;
 338         unsigned tmp;
 339
 340         adc = devm_kzalloc(dev, sizeof(*adc), GFP_KERNEL);
 341         if (!adc)
 342                 return -ENOMEM;
 343
 344         spin_lock_init(&adc->lock);
 345
 346         adc->pdev = pdev;
 347         adc->prescale = S3C2410_ADCCON_PRSCVL(49);
 348
 349         adc->vdd = devm_regulator_get(dev, "vdd");
 350         if (IS_ERR(adc->vdd)) {
 351                 dev_err(dev, "operating without regulator \"vdd\" .\n");
 352                 return PTR_ERR(adc->vdd);
 353         }
 354
 355         adc->irq = platform_get_irq(pdev, 1);
 356         if (adc->irq <= 0) {
 357                 dev_err(dev, "failed to get adc irq\n");
 358                 return -ENOENT;
 359         }
 360
 361         ret = devm_request_irq(dev, adc->irq, s3c_adc_irq, 0, dev_name(dev),
 362                                 adc);
 363         if (ret < 0) {
 364                 dev_err(dev, "failed to attach adc irq\n");
 365                 return ret;
 366         }
 367
 368         adc->clk = devm_clk_get(dev, "adc");
 369         if (IS_ERR(adc->clk)) {
 370                 dev_err(dev, "failed to get adc clock\n");
 371                 return PTR_ERR(adc->clk);
 372         }
 373
 374         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 375         adc->regs = devm_ioremap_resource(dev, regs);
 376         if (IS_ERR(adc->regs))
 377                 return PTR_ERR(adc->regs);
 378
 379         ret = regulator_enable(adc->vdd);
 380         if (ret)
 381                 return ret;
 382
 383         clk_prepare_enable(adc->clk);
 384
 385         tmp = adc->prescale | S3C2410_ADCCON_PRSCEN;
 386
 387         /* Enable 12-bit ADC resolution */
 388         if (cpu == TYPE_ADCV12)
 389                 tmp |= S3C2416_ADCCON_RESSEL;
 390         if (cpu == TYPE_ADCV2 || cpu == TYPE_ADCV3)
 391                 tmp |= S3C64XX_ADCCON_RESSEL;
 392
 393         writel(tmp, adc->regs + S3C2410_ADCCON);
 394
 395         dev_info(dev, "attached adc driver\n");
 396
 397         platform_set_drvdata(pdev, adc);
 398         adc_dev = adc;
 399
 400         return 0;
 401 }
 402
 403 static int s3c_adc_remove(struct platform_device *pdev)
 404 {
 405         struct adc_device *adc = platform_get_drvdata(pdev);
 406
 407         clk_disable_unprepare(adc->clk);
 408         regulator_disable(adc->vdd);
 409
 410         return 0;
 411 }
 412
 413 #ifdef CONFIG_PM
 414 static int s3c_adc_suspend(struct device *dev)
 415 {
 416         struct adc_device *adc = dev_get_drvdata(dev);
 417         unsigned long flags;
 418         u32 con;
 419
 420         spin_lock_irqsave(&adc->lock, flags);
 421
 422         con = readl(adc->regs + S3C2410_ADCCON);
 423         con |= S3C2410_ADCCON_STDBM;
 424         writel(con, adc->regs + S3C2410_ADCCON);
 425
 426         disable_irq(adc->irq);
 427         spin_unlock_irqrestore(&adc->lock, flags);
 428         clk_disable(adc->clk);
 429         regulator_disable(adc->vdd);
 430
 431         return 0;
 432 }
 433
 434 static int s3c_adc_resume(struct device *dev)
 435 {
 436         struct platform_device *pdev = to_platform_device(dev);
 437         struct adc_device *adc = platform_get_drvdata(pdev);
 438         enum s3c_cpu_type cpu = platform_get_device_id(pdev)->driver_data;
 439         int ret;
 440         unsigned long tmp;
 441
 442         ret = regulator_enable(adc->vdd);
 443         if (ret)
 444                 return ret;
 445         clk_enable(adc->clk);
 446         enable_irq(adc->irq);
 447
 448         tmp = adc->prescale | S3C2410_ADCCON_PRSCEN;
 449
 450         /* Enable 12-bit ADC resolution */
 451         if (cpu == TYPE_ADCV12)
 452                 tmp |= S3C2416_ADCCON_RESSEL;
 453         if (cpu == TYPE_ADCV2 || cpu == TYPE_ADCV3)
 454                 tmp |= S3C64XX_ADCCON_RESSEL;
 455
 456         writel(tmp, adc->regs + S3C2410_ADCCON);
 457
 458         return 0;
 459 }
 460
 461 #else
 462 #define s3c_adc_suspend NULL
 463 #define s3c_adc_resume NULL
 464 #endif
 465
 466 static const struct platform_device_id s3c_adc_driver_ids[] = {
 467         {
 468                 .name           = "s3c24xx-adc",
 469                 .driver_data    = TYPE_ADCV1,
 470         }, {
 471                 .name           = "s3c2443-adc",
 472                 .driver_data    = TYPE_ADCV11,
 473         }, {
 474                 .name           = "s3c2416-adc",
 475                 .driver_data    = TYPE_ADCV12,
 476         }, {
 477                 .name           = "s3c64xx-adc",
 478                 .driver_data    = TYPE_ADCV2,
 479         }, {
 480                 .name           = "samsung-adc-v3",
 481                 .driver_data    = TYPE_ADCV3,
 482         },
 483         { }
 484 };
 485 MODULE_DEVICE_TABLE(platform, s3c_adc_driver_ids);
 486
 487 static const struct dev_pm_ops adc_pm_ops = {
 488         .suspend        = s3c_adc_suspend,
 489         .resume         = s3c_adc_resume,
 490 };
 491
 492 static struct platform_driver s3c_adc_driver = {
 493         .id_table       = s3c_adc_driver_ids,
 494         .driver         = {
 495                 .name   = "s3c-adc",
 496                 .pm     = &adc_pm_ops,
 497         },
 498         .probe          = s3c_adc_probe,
 499         .remove         = s3c_adc_remove,
 500 };
 501
 502 static int __init adc_init(void)
 503 {
 504         int ret;
 505
 506         ret = platform_driver_register(&s3c_adc_driver);
 507         if (ret)
 508                 printk(KERN_ERR "%s: failed to add adc driver\n", __func__);
 509
 510         return ret;
 511 }
 512
 513 module_init(adc_init);