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/mod_devicetable.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/sched.h>
  14 #include <linux/list.h>
  15 #include <linux/slab.h>
  16 #include <linux/err.h>
  17 #include <linux/clk.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/io.h>
  20 #include <linux/regulator/consumer.h>
  21
  22 #include <plat/regs-adc.h>
  23 #include <plat/adc.h>
  24
  25 /* This driver is designed to control the usage of the ADC block between
  26  * the touchscreen and any other drivers that may need to use it, such as
  27  * the hwmon driver.
  28  *
  29  * Priority will be given to the touchscreen driver, but as this itself is
  30  * rate limited it should not starve other requests which are processed in
  31  * order that they are received.
  32  *
  33  * Each user registers to get a client block which uniquely identifies it
  34  * and stores information such as the necessary functions to callback when
  35  * action is required.
  36  */
  37
  38 enum s3c_cpu_type {
  39         TYPE_ADCV1, /* S3C24XX */
  40         TYPE_ADCV11, /* S3C2443 */
  41         TYPE_ADCV12, /* S3C2416, S3C2450 */
  42         TYPE_ADCV2, /* S3C64XX */
  43         TYPE_ADCV3, /* S5PV210, S5PC110, Exynos4210 */
  44 };
  45
  46 struct s3c_adc_client {
  47         struct platform_device  *pdev;
  48         struct list_head         pend;
  49         wait_queue_head_t       *wait;
  50
  51         unsigned int             nr_samples;
  52         int                      result;
  53         unsigned char            is_ts;
  54         unsigned char            channel;
  55
  56         void    (*select_cb)(struct s3c_adc_client *c, unsigned selected);
  57         void    (*convert_cb)(struct s3c_adc_client *c,
  58                               unsigned val1, unsigned val2,
  59                               unsigned *samples_left);
  60 };
  61
  62 struct adc_device {
  63         struct platform_device  *pdev;
  64         struct platform_device  *owner;
  65         struct clk              *clk;
  66         struct s3c_adc_client   *cur;
  67         struct s3c_adc_client   *ts_pend;
  68         void __iomem            *regs;
  69         spinlock_t               lock;
  70
  71         unsigned int             prescale;
  72
  73         int                      irq;
  74         struct regulator        *vdd;
  75 };
  76
  77 static struct adc_device *adc_dev;
  78
  79 static LIST_HEAD(adc_pending);  /* protected by adc_device.lock */
  80
  81 #define adc_dbg(_adc, msg...) dev_dbg(&(_adc)->pdev->dev, msg)
  82
  83 static inline void s3c_adc_convert(struct adc_device *adc)
  84 {
  85         unsigned con = readl(adc->regs + S3C2410_ADCCON);
  86
  87         con |= S3C2410_ADCCON_ENABLE_START;
  88         writel(con, adc->regs + S3C2410_ADCCON);
  89 }
  90
  91 static inline void s3c_adc_select(struct adc_device *adc,
  92                                   struct s3c_adc_client *client)
  93 {
  94         unsigned con = readl(adc->regs + S3C2410_ADCCON);
  95         enum s3c_cpu_type cpu = platform_get_device_id(adc->pdev)->driver_data;
  96
  97         client->select_cb(client, 1);
  98
  99         if (cpu == TYPE_ADCV1 || cpu == TYPE_ADCV2)
 100                 con &= ~S3C2410_ADCCON_MUXMASK;
 101         con &= ~S3C2410_ADCCON_STDBM;
 102         con &= ~S3C2410_ADCCON_STARTMASK;
 103
 104         if (!client->is_ts) {
 105                 if (cpu == TYPE_ADCV3)
 106                         writel(client->channel & 0xf, adc->regs + S5P_ADCMUX);
 107                 else if (cpu == TYPE_ADCV11 || cpu == TYPE_ADCV12)
 108                         writel(client->channel & 0xf,
 109                                                 adc->regs + S3C2443_ADCMUX);
 110                 else
 111                         con |= S3C2410_ADCCON_SELMUX(client->channel);
 112         }
 113
 114         writel(con, adc->regs + S3C2410_ADCCON);
 115 }
 116
 117 static void s3c_adc_dbgshow(struct adc_device *adc)
 118 {
 119         adc_dbg(adc, "CON=%08x, TSC=%08x, DLY=%08x\n",
 120                 readl(adc->regs + S3C2410_ADCCON),
 121                 readl(adc->regs + S3C2410_ADCTSC),
 122                 readl(adc->regs + S3C2410_ADCDLY));
 123 }
 124
 125 static void s3c_adc_try(struct adc_device *adc)
 126 {
 127         struct s3c_adc_client *next = adc->ts_pend;
 128
 129         if (!next && !list_empty(&adc_pending)) {
 130                 next = list_first_entry(&adc_pending,
 131                                         struct s3c_adc_client, pend);
 132                 list_del(&next->pend);
 133         } else
 134                 adc->ts_pend = NULL;
 135
 136         if (next) {
 137                 adc_dbg(adc, "new client is %p\n", next);
 138                 adc->cur = next;
 139                 s3c_adc_select(adc, next);
 140                 s3c_adc_convert(adc);
 141                 s3c_adc_dbgshow(adc);
 142         }
 143 }
 144
 145 int s3c_adc_start(struct s3c_adc_client *client,
 146                   unsigned int channel, unsigned int nr_samples)
 147 {
 148         struct adc_device *adc = adc_dev;
 149         unsigned long flags;
 150
 151         if (!adc) {
 152                 printk(KERN_ERR "%s: failed to find adc\n", __func__);
 153                 return -EINVAL;
 154         }
 155
 156         spin_lock_irqsave(&adc->lock, flags);
 157
 158         if (client->is_ts && adc->ts_pend) {
 159                 spin_unlock_irqrestore(&adc->lock, flags);
 160                 return -EAGAIN;
 161         }
 162
 163         client->channel = channel;
 164         client->nr_samples = nr_samples;
 165
 166         if (client->is_ts)
 167                 adc->ts_pend = client;
 168         else
 169                 list_add_tail(&client->pend, &adc_pending);
 170
 171         if (!adc->cur)
 172                 s3c_adc_try(adc);
 173
 174         spin_unlock_irqrestore(&adc->lock, flags);
 175
 176         return 0;
 177 }
 178 EXPORT_SYMBOL_GPL(s3c_adc_start);
 179
 180 static void s3c_convert_done(struct s3c_adc_client *client,
 181                              unsigned v, unsigned u, unsigned *left)
 182 {
 183         client->result = v;
 184         wake_up(client->wait);
 185 }
 186
 187 int s3c_adc_read(struct s3c_adc_client *client, unsigned int ch)
 188 {
 189         DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wake);
 190         int ret;
 191
 192         client->convert_cb = s3c_convert_done;
 193         client->wait = &wake;
 194         client->result = -1;
 195
 196         ret = s3c_adc_start(client, ch, 1);
 197         if (ret < 0)
 198                 goto err;
 199
 200         ret = wait_event_timeout(wake, client->result >= 0, HZ / 2);
 201         if (client->result < 0) {
 202                 ret = -ETIMEDOUT;
 203                 goto err;
 204         }
 205
 206         client->convert_cb = NULL;
 207         return client->result;
 208
 209 err:
 210         return ret;
 211 }
 212 EXPORT_SYMBOL_GPL(s3c_adc_read);
 213
 214 static void s3c_adc_default_select(struct s3c_adc_client *client,
 215                                    unsigned select)
 216 {
 217 }
 218
 219 struct s3c_adc_client *s3c_adc_register(struct platform_device *pdev,
 220                                         void (*select)(struct s3c_adc_client *client,
 221                                                        unsigned int selected),
 222                                         void (*conv)(struct s3c_adc_client *client,
 223                                                      unsigned d0, unsigned d1,
 224                                                      unsigned *samples_left),
 225                                         unsigned int is_ts)
 226 {
 227         struct s3c_adc_client *client;
 228
 229         WARN_ON(!pdev);
 230
 231         if (!select)
 232                 select = s3c_adc_default_select;
 233
 234         if (!pdev)
 235                 return ERR_PTR(-EINVAL);
 236
 237         client = kzalloc(sizeof(*client), GFP_KERNEL);
 238         if (!client)
 239                 return ERR_PTR(-ENOMEM);
 240
 241         client->pdev = pdev;
 242         client->is_ts = is_ts;
 243         client->select_cb = select;
 244         client->convert_cb = conv;
 245
 246         return client;
 247 }
 248 EXPORT_SYMBOL_GPL(s3c_adc_register);
 249
 250 void s3c_adc_release(struct s3c_adc_client *client)
 251 {
 252         unsigned long flags;
 253
 254         spin_lock_irqsave(&adc_dev->lock, flags);
 255
 256         /* We should really check that nothing is in progress. */
 257         if (adc_dev->cur == client)
 258                 adc_dev->cur = NULL;
 259         if (adc_dev->ts_pend == client)
 260                 adc_dev->ts_pend = NULL;
 261         else {
 262                 struct list_head *p, *n;
 263                 struct s3c_adc_client *tmp;
 264
 265                 list_for_each_safe(p, n, &adc_pending) {
 266                         tmp = list_entry(p, struct s3c_adc_client, pend);
 267                         if (tmp == client)
 268                                 list_del(&tmp->pend);
 269                 }
 270         }
 271
 272         if (adc_dev->cur == NULL)
 273                 s3c_adc_try(adc_dev);
 274
 275         spin_unlock_irqrestore(&adc_dev->lock, flags);
 276         kfree(client);
 277 }
 278 EXPORT_SYMBOL_GPL(s3c_adc_release);
 279
 280 static irqreturn_t s3c_adc_irq(int irq, void *pw)
 281 {
 282         struct adc_device *adc = pw;
 283         struct s3c_adc_client *client = adc->cur;
 284         enum s3c_cpu_type cpu = platform_get_device_id(adc->pdev)->driver_data;
 285         unsigned data0, data1;
 286
 287         if (!client) {
 288                 dev_warn(&adc->pdev->dev, "%s: no adc pending\n", __func__);
 289                 goto exit;
 290         }
 291
 292         data0 = readl(adc->regs + S3C2410_ADCDAT0);
 293         data1 = readl(adc->regs + S3C2410_ADCDAT1);
 294         adc_dbg(adc, "read %d: 0x%04x, 0x%04x\n", client->nr_samples, data0, data1);
 295
 296         client->nr_samples--;
 297
 298         if (cpu == TYPE_ADCV1 || cpu == TYPE_ADCV11) {
 299                 data0 &= 0x3ff;
 300                 data1 &= 0x3ff;
 301         } else {
 302                 /* S3C2416/S3C64XX/S5P ADC resolution is 12-bit */
 303                 data0 &= 0xfff;
 304                 data1 &= 0xfff;
 305         }
 306
 307         if (client->convert_cb)
 308                 (client->convert_cb)(client, data0, data1, &client->nr_samples);
 309
 310         if (client->nr_samples > 0) {
 311                 /* fire another conversion for this */
 312
 313                 client->select_cb(client, 1);
 314                 s3c_adc_convert(adc);
 315         } else {
 316                 spin_lock(&adc->lock);
 317                 (client->select_cb)(client, 0);
 318                 adc->cur = NULL;
 319
 320                 s3c_adc_try(adc);
 321                 spin_unlock(&adc->lock);
 322         }
 323
 324 exit:
 325         if (cpu == TYPE_ADCV2 || cpu == TYPE_ADCV3) {
 326                 /* Clear ADC interrupt */
 327                 writel(0, adc->regs + S3C64XX_ADCCLRINT);
 328         }
 329         return IRQ_HANDLED;
 330 }
 331
 332 static int s3c_adc_probe(struct platform_device *pdev)
 333 {
 334         struct device *dev = &pdev->dev;
 335         struct adc_device *adc;
 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                 return -ENOENT;
 358
 359         ret = devm_request_irq(dev, adc->irq, s3c_adc_irq, 0, dev_name(dev),
 360                                 adc);
 361         if (ret < 0) {
 362                 dev_err(dev, "failed to attach adc irq\n");
 363                 return ret;
 364         }
 365
 366         adc->clk = devm_clk_get(dev, "adc");
 367         if (IS_ERR(adc->clk)) {
 368                 dev_err(dev, "failed to get adc clock\n");
 369                 return PTR_ERR(adc->clk);
 370         }
 371
 372         adc->regs = devm_platform_ioremap_resource(pdev, 0);
 373         if (IS_ERR(adc->regs))
 374                 return PTR_ERR(adc->regs);
 375
 376         ret = regulator_enable(adc->vdd);
 377         if (ret)
 378                 return ret;
 379
 380         clk_prepare_enable(adc->clk);
 381
 382         tmp = adc->prescale | S3C2410_ADCCON_PRSCEN;
 383
 384         /* Enable 12-bit ADC resolution */
 385         if (cpu == TYPE_ADCV12)
 386                 tmp |= S3C2416_ADCCON_RESSEL;
 387         if (cpu == TYPE_ADCV2 || cpu == TYPE_ADCV3)
 388                 tmp |= S3C64XX_ADCCON_RESSEL;
 389
 390         writel(tmp, adc->regs + S3C2410_ADCCON);
 391
 392         dev_info(dev, "attached adc driver\n");
 393
 394         platform_set_drvdata(pdev, adc);
 395         adc_dev = adc;
 396
 397         return 0;
 398 }
 399
 400 static int s3c_adc_remove(struct platform_device *pdev)
 401 {
 402         struct adc_device *adc = platform_get_drvdata(pdev);
 403
 404         clk_disable_unprepare(adc->clk);
 405         regulator_disable(adc->vdd);
 406
 407         return 0;
 408 }
 409
 410 #ifdef CONFIG_PM
 411 static int s3c_adc_suspend(struct device *dev)
 412 {
 413         struct adc_device *adc = dev_get_drvdata(dev);
 414         unsigned long flags;
 415         u32 con;
 416
 417         spin_lock_irqsave(&adc->lock, flags);
 418
 419         con = readl(adc->regs + S3C2410_ADCCON);
 420         con |= S3C2410_ADCCON_STDBM;
 421         writel(con, adc->regs + S3C2410_ADCCON);
 422
 423         disable_irq(adc->irq);
 424         spin_unlock_irqrestore(&adc->lock, flags);
 425         clk_disable(adc->clk);
 426         regulator_disable(adc->vdd);
 427
 428         return 0;
 429 }
 430
 431 static int s3c_adc_resume(struct device *dev)
 432 {
 433         struct platform_device *pdev = to_platform_device(dev);
 434         struct adc_device *adc = platform_get_drvdata(pdev);
 435         enum s3c_cpu_type cpu = platform_get_device_id(pdev)->driver_data;
 436         int ret;
 437         unsigned long tmp;
 438
 439         ret = regulator_enable(adc->vdd);
 440         if (ret)
 441                 return ret;
 442         clk_enable(adc->clk);
 443         enable_irq(adc->irq);
 444
 445         tmp = adc->prescale | S3C2410_ADCCON_PRSCEN;
 446
 447         /* Enable 12-bit ADC resolution */
 448         if (cpu == TYPE_ADCV12)
 449                 tmp |= S3C2416_ADCCON_RESSEL;
 450         if (cpu == TYPE_ADCV2 || cpu == TYPE_ADCV3)
 451                 tmp |= S3C64XX_ADCCON_RESSEL;
 452
 453         writel(tmp, adc->regs + S3C2410_ADCCON);
 454
 455         return 0;
 456 }
 457
 458 #else
 459 #define s3c_adc_suspend NULL
 460 #define s3c_adc_resume NULL
 461 #endif
 462
 463 static const struct platform_device_id s3c_adc_driver_ids[] = {
 464         {
 465                 .name           = "s3c24xx-adc",
 466                 .driver_data    = TYPE_ADCV1,
 467         }, {
 468                 .name           = "s3c2443-adc",
 469                 .driver_data    = TYPE_ADCV11,
 470         }, {
 471                 .name           = "s3c2416-adc",
 472                 .driver_data    = TYPE_ADCV12,
 473         }, {
 474                 .name           = "s3c64xx-adc",
 475                 .driver_data    = TYPE_ADCV2,
 476         }, {
 477                 .name           = "samsung-adc-v3",
 478                 .driver_data    = TYPE_ADCV3,
 479         },
 480         { }
 481 };
 482 MODULE_DEVICE_TABLE(platform, s3c_adc_driver_ids);
 483
 484 static const struct dev_pm_ops adc_pm_ops = {
 485         .suspend        = s3c_adc_suspend,
 486         .resume         = s3c_adc_resume,
 487 };
 488
 489 static struct platform_driver s3c_adc_driver = {
 490         .id_table       = s3c_adc_driver_ids,
 491         .driver         = {
 492                 .name   = "s3c-adc",
 493                 .pm     = &adc_pm_ops,
 494         },
 495         .probe          = s3c_adc_probe,
 496         .remove         = s3c_adc_remove,
 497 };
 498
 499 static int __init adc_init(void)
 500 {
 501         int ret;
 502
 503         ret = platform_driver_register(&s3c_adc_driver);
 504         if (ret)
 505                 printk(KERN_ERR "%s: failed to add adc driver\n", __func__);
 506
 507         return ret;
 508 }
 509
 510 module_init(adc_init);