linux/arch/arm/plat-samsung/adc.c
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   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
  42enum s3c_cpu_type {
  43        TYPE_ADCV1, /* S3C24XX */
  44        TYPE_ADCV11, /* S3C2443 */
  45        TYPE_ADCV12, /* S3C2416, S3C2450 */
  46        TYPE_ADCV2, /* S3C64XX, S5P64X0, S5PC100 */
  47        TYPE_ADCV3, /* S5PV210, S5PC110, EXYNOS4210 */
  48};
  49
  50struct s3c_adc_client {
  51        struct platform_device  *pdev;
  52        struct list_head         pend;
  53        wait_queue_head_t       *wait;
  54
  55        unsigned int             nr_samples;
  56        int                      result;
  57        unsigned char            is_ts;
  58        unsigned char            channel;
  59
  60        void    (*select_cb)(struct s3c_adc_client *c, unsigned selected);
  61        void    (*convert_cb)(struct s3c_adc_client *c,
  62                              unsigned val1, unsigned val2,
  63                              unsigned *samples_left);
  64};
  65
  66struct adc_device {
  67        struct platform_device  *pdev;
  68        struct platform_device  *owner;
  69        struct clk              *clk;
  70        struct s3c_adc_client   *cur;
  71        struct s3c_adc_client   *ts_pend;
  72        void __iomem            *regs;
  73        spinlock_t               lock;
  74
  75        unsigned int             prescale;
  76
  77        int                      irq;
  78        struct regulator        *vdd;
  79};
  80
  81static struct adc_device *adc_dev;
  82
  83static LIST_HEAD(adc_pending);  /* protected by adc_device.lock */
  84
  85#define adc_dbg(_adc, msg...) dev_dbg(&(_adc)->pdev->dev, msg)
  86
  87static inline void s3c_adc_convert(struct adc_device *adc)
  88{
  89        unsigned con = readl(adc->regs + S3C2410_ADCCON);
  90
  91        con |= S3C2410_ADCCON_ENABLE_START;
  92        writel(con, adc->regs + S3C2410_ADCCON);
  93}
  94
  95static inline void s3c_adc_select(struct adc_device *adc,
  96                                  struct s3c_adc_client *client)
  97{
  98        unsigned con = readl(adc->regs + S3C2410_ADCCON);
  99        enum s3c_cpu_type cpu = platform_get_device_id(adc->pdev)->driver_data;
 100
 101        client->select_cb(client, 1);
 102
 103        if (cpu == TYPE_ADCV1 || cpu == TYPE_ADCV2)
 104                con &= ~S3C2410_ADCCON_MUXMASK;
 105        con &= ~S3C2410_ADCCON_STDBM;
 106        con &= ~S3C2410_ADCCON_STARTMASK;
 107
 108        if (!client->is_ts) {
 109                if (cpu == TYPE_ADCV3)
 110                        writel(client->channel & 0xf, adc->regs + S5P_ADCMUX);
 111                else if (cpu == TYPE_ADCV11 || cpu == TYPE_ADCV12)
 112                        writel(client->channel & 0xf,
 113                                                adc->regs + S3C2443_ADCMUX);
 114                else
 115                        con |= S3C2410_ADCCON_SELMUX(client->channel);
 116        }
 117
 118        writel(con, adc->regs + S3C2410_ADCCON);
 119}
 120
 121static void s3c_adc_dbgshow(struct adc_device *adc)
 122{
 123        adc_dbg(adc, "CON=%08x, TSC=%08x, DLY=%08x\n",
 124                readl(adc->regs + S3C2410_ADCCON),
 125                readl(adc->regs + S3C2410_ADCTSC),
 126                readl(adc->regs + S3C2410_ADCDLY));
 127}
 128
 129static void s3c_adc_try(struct adc_device *adc)
 130{
 131        struct s3c_adc_client *next = adc->ts_pend;
 132
 133        if (!next && !list_empty(&adc_pending)) {
 134                next = list_first_entry(&adc_pending,
 135                                        struct s3c_adc_client, pend);
 136                list_del(&next->pend);
 137        } else
 138                adc->ts_pend = NULL;
 139
 140        if (next) {
 141                adc_dbg(adc, "new client is %p\n", next);
 142                adc->cur = next;
 143                s3c_adc_select(adc, next);
 144                s3c_adc_convert(adc);
 145                s3c_adc_dbgshow(adc);
 146        }
 147}
 148
 149int s3c_adc_start(struct s3c_adc_client *client,
 150                  unsigned int channel, unsigned int nr_samples)
 151{
 152        struct adc_device *adc = adc_dev;
 153        unsigned long flags;
 154
 155        if (!adc) {
 156                printk(KERN_ERR "%s: failed to find adc\n", __func__);
 157                return -EINVAL;
 158        }
 159
 160        spin_lock_irqsave(&adc->lock, flags);
 161
 162        if (client->is_ts && adc->ts_pend) {
 163                spin_unlock_irqrestore(&adc->lock, flags);
 164                return -EAGAIN;
 165        }
 166
 167        client->channel = channel;
 168        client->nr_samples = nr_samples;
 169
 170        if (client->is_ts)
 171                adc->ts_pend = client;
 172        else
 173                list_add_tail(&client->pend, &adc_pending);
 174
 175        if (!adc->cur)
 176                s3c_adc_try(adc);
 177
 178        spin_unlock_irqrestore(&adc->lock, flags);
 179
 180        return 0;
 181}
 182EXPORT_SYMBOL_GPL(s3c_adc_start);
 183
 184static void s3c_convert_done(struct s3c_adc_client *client,
 185                             unsigned v, unsigned u, unsigned *left)
 186{
 187        client->result = v;
 188        wake_up(client->wait);
 189}
 190
 191int s3c_adc_read(struct s3c_adc_client *client, unsigned int ch)
 192{
 193        DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wake);
 194        int ret;
 195
 196        client->convert_cb = s3c_convert_done;
 197        client->wait = &wake;
 198        client->result = -1;
 199
 200        ret = s3c_adc_start(client, ch, 1);
 201        if (ret < 0)
 202                goto err;
 203
 204        ret = wait_event_timeout(wake, client->result >= 0, HZ / 2);
 205        if (client->result < 0) {
 206                ret = -ETIMEDOUT;
 207                goto err;
 208        }
 209
 210        client->convert_cb = NULL;
 211        return client->result;
 212
 213err:
 214        return ret;
 215}
 216EXPORT_SYMBOL_GPL(s3c_adc_read);
 217
 218static void s3c_adc_default_select(struct s3c_adc_client *client,
 219                                   unsigned select)
 220{
 221}
 222
 223struct s3c_adc_client *s3c_adc_register(struct platform_device *pdev,
 224                                        void (*select)(struct s3c_adc_client *client,
 225                                                       unsigned int selected),
 226                                        void (*conv)(struct s3c_adc_client *client,
 227                                                     unsigned d0, unsigned d1,
 228                                                     unsigned *samples_left),
 229                                        unsigned int is_ts)
 230{
 231        struct s3c_adc_client *client;
 232
 233        WARN_ON(!pdev);
 234
 235        if (!select)
 236                select = s3c_adc_default_select;
 237
 238        if (!pdev)
 239                return ERR_PTR(-EINVAL);
 240
 241        client = kzalloc(sizeof(struct s3c_adc_client), GFP_KERNEL);
 242        if (!client) {
 243                dev_err(&pdev->dev, "no memory for adc client\n");
 244                return ERR_PTR(-ENOMEM);
 245        }
 246
 247        client->pdev = pdev;
 248        client->is_ts = is_ts;
 249        client->select_cb = select;
 250        client->convert_cb = conv;
 251
 252        return client;
 253}
 254EXPORT_SYMBOL_GPL(s3c_adc_register);
 255
 256void s3c_adc_release(struct s3c_adc_client *client)
 257{
 258        unsigned long flags;
 259
 260        spin_lock_irqsave(&adc_dev->lock, flags);
 261
 262        /* We should really check that nothing is in progress. */
 263        if (adc_dev->cur == client)
 264                adc_dev->cur = NULL;
 265        if (adc_dev->ts_pend == client)
 266                adc_dev->ts_pend = NULL;
 267        else {
 268                struct list_head *p, *n;
 269                struct s3c_adc_client *tmp;
 270
 271                list_for_each_safe(p, n, &adc_pending) {
 272                        tmp = list_entry(p, struct s3c_adc_client, pend);
 273                        if (tmp == client)
 274                                list_del(&tmp->pend);
 275                }
 276        }
 277
 278        if (adc_dev->cur == NULL)
 279                s3c_adc_try(adc_dev);
 280
 281        spin_unlock_irqrestore(&adc_dev->lock, flags);
 282        kfree(client);
 283}
 284EXPORT_SYMBOL_GPL(s3c_adc_release);
 285
 286static irqreturn_t s3c_adc_irq(int irq, void *pw)
 287{
 288        struct adc_device *adc = pw;
 289        struct s3c_adc_client *client = adc->cur;
 290        enum s3c_cpu_type cpu = platform_get_device_id(adc->pdev)->driver_data;
 291        unsigned data0, data1;
 292
 293        if (!client) {
 294                dev_warn(&adc->pdev->dev, "%s: no adc pending\n", __func__);
 295                goto exit;
 296        }
 297
 298        data0 = readl(adc->regs + S3C2410_ADCDAT0);
 299        data1 = readl(adc->regs + S3C2410_ADCDAT1);
 300        adc_dbg(adc, "read %d: 0x%04x, 0x%04x\n", client->nr_samples, data0, data1);
 301
 302        client->nr_samples--;
 303
 304        if (cpu == TYPE_ADCV1 || cpu == TYPE_ADCV11) {
 305                data0 &= 0x3ff;
 306                data1 &= 0x3ff;
 307        } else {
 308                /* S3C2416/S3C64XX/S5P ADC resolution is 12-bit */
 309                data0 &= 0xfff;
 310                data1 &= 0xfff;
 311        }
 312
 313        if (client->convert_cb)
 314                (client->convert_cb)(client, data0, data1, &client->nr_samples);
 315
 316        if (client->nr_samples > 0) {
 317                /* fire another conversion for this */
 318
 319                client->select_cb(client, 1);
 320                s3c_adc_convert(adc);
 321        } else {
 322                spin_lock(&adc->lock);
 323                (client->select_cb)(client, 0);
 324                adc->cur = NULL;
 325
 326                s3c_adc_try(adc);
 327                spin_unlock(&adc->lock);
 328        }
 329
 330exit:
 331        if (cpu == TYPE_ADCV2 || cpu == TYPE_ADCV3) {
 332                /* Clear ADC interrupt */
 333                writel(0, adc->regs + S3C64XX_ADCCLRINT);
 334        }
 335        return IRQ_HANDLED;
 336}
 337
 338static int s3c_adc_probe(struct platform_device *pdev)
 339{
 340        struct device *dev = &pdev->dev;
 341        struct adc_device *adc;
 342        struct resource *regs;
 343        enum s3c_cpu_type cpu = platform_get_device_id(pdev)->driver_data;
 344        int ret;
 345        unsigned tmp;
 346
 347        adc = devm_kzalloc(dev, sizeof(struct adc_device), GFP_KERNEL);
 348        if (adc == NULL) {
 349                dev_err(dev, "failed to allocate adc_device\n");
 350                return -ENOMEM;
 351        }
 352
 353        spin_lock_init(&adc->lock);
 354
 355        adc->pdev = pdev;
 356        adc->prescale = S3C2410_ADCCON_PRSCVL(49);
 357
 358        adc->vdd = devm_regulator_get(dev, "vdd");
 359        if (IS_ERR(adc->vdd)) {
 360                dev_err(dev, "operating without regulator \"vdd\" .\n");
 361                return PTR_ERR(adc->vdd);
 362        }
 363
 364        adc->irq = platform_get_irq(pdev, 1);
 365        if (adc->irq <= 0) {
 366                dev_err(dev, "failed to get adc irq\n");
 367                return -ENOENT;
 368        }
 369
 370        ret = devm_request_irq(dev, adc->irq, s3c_adc_irq, 0, dev_name(dev),
 371                                adc);
 372        if (ret < 0) {
 373                dev_err(dev, "failed to attach adc irq\n");
 374                return ret;
 375        }
 376
 377        adc->clk = devm_clk_get(dev, "adc");
 378        if (IS_ERR(adc->clk)) {
 379                dev_err(dev, "failed to get adc clock\n");
 380                return PTR_ERR(adc->clk);
 381        }
 382
 383        regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 384        if (!regs) {
 385                dev_err(dev, "failed to find registers\n");
 386                return -ENXIO;
 387        }
 388
 389        adc->regs = devm_ioremap_resource(dev, regs);
 390        if (IS_ERR(adc->regs))
 391                return PTR_ERR(adc->regs);
 392
 393        ret = regulator_enable(adc->vdd);
 394        if (ret)
 395                return ret;
 396
 397        clk_enable(adc->clk);
 398
 399        tmp = adc->prescale | S3C2410_ADCCON_PRSCEN;
 400
 401        /* Enable 12-bit ADC resolution */
 402        if (cpu == TYPE_ADCV12)
 403                tmp |= S3C2416_ADCCON_RESSEL;
 404        if (cpu == TYPE_ADCV2 || cpu == TYPE_ADCV3)
 405                tmp |= S3C64XX_ADCCON_RESSEL;
 406
 407        writel(tmp, adc->regs + S3C2410_ADCCON);
 408
 409        dev_info(dev, "attached adc driver\n");
 410
 411        platform_set_drvdata(pdev, adc);
 412        adc_dev = adc;
 413
 414        return 0;
 415}
 416
 417static int s3c_adc_remove(struct platform_device *pdev)
 418{
 419        struct adc_device *adc = platform_get_drvdata(pdev);
 420
 421        clk_disable(adc->clk);
 422        regulator_disable(adc->vdd);
 423
 424        return 0;
 425}
 426
 427#ifdef CONFIG_PM
 428static int s3c_adc_suspend(struct device *dev)
 429{
 430        struct platform_device *pdev = container_of(dev,
 431                        struct platform_device, dev);
 432        struct adc_device *adc = platform_get_drvdata(pdev);
 433        unsigned long flags;
 434        u32 con;
 435
 436        spin_lock_irqsave(&adc->lock, flags);
 437
 438        con = readl(adc->regs + S3C2410_ADCCON);
 439        con |= S3C2410_ADCCON_STDBM;
 440        writel(con, adc->regs + S3C2410_ADCCON);
 441
 442        disable_irq(adc->irq);
 443        spin_unlock_irqrestore(&adc->lock, flags);
 444        clk_disable(adc->clk);
 445        regulator_disable(adc->vdd);
 446
 447        return 0;
 448}
 449
 450static int s3c_adc_resume(struct device *dev)
 451{
 452        struct platform_device *pdev = container_of(dev,
 453                        struct platform_device, dev);
 454        struct adc_device *adc = platform_get_drvdata(pdev);
 455        enum s3c_cpu_type cpu = platform_get_device_id(pdev)->driver_data;
 456        int ret;
 457        unsigned long tmp;
 458
 459        ret = regulator_enable(adc->vdd);
 460        if (ret)
 461                return ret;
 462        clk_enable(adc->clk);
 463        enable_irq(adc->irq);
 464
 465        tmp = adc->prescale | S3C2410_ADCCON_PRSCEN;
 466
 467        /* Enable 12-bit ADC resolution */
 468        if (cpu == TYPE_ADCV12)
 469                tmp |= S3C2416_ADCCON_RESSEL;
 470        if (cpu == TYPE_ADCV2 || cpu == TYPE_ADCV3)
 471                tmp |= S3C64XX_ADCCON_RESSEL;
 472
 473        writel(tmp, adc->regs + S3C2410_ADCCON);
 474
 475        return 0;
 476}
 477
 478#else
 479#define s3c_adc_suspend NULL
 480#define s3c_adc_resume NULL
 481#endif
 482
 483static struct platform_device_id s3c_adc_driver_ids[] = {
 484        {
 485                .name           = "s3c24xx-adc",
 486                .driver_data    = TYPE_ADCV1,
 487        }, {
 488                .name           = "s3c2443-adc",
 489                .driver_data    = TYPE_ADCV11,
 490        }, {
 491                .name           = "s3c2416-adc",
 492                .driver_data    = TYPE_ADCV12,
 493        }, {
 494                .name           = "s3c64xx-adc",
 495                .driver_data    = TYPE_ADCV2,
 496        }, {
 497                .name           = "samsung-adc-v3",
 498                .driver_data    = TYPE_ADCV3,
 499        },
 500        { }
 501};
 502MODULE_DEVICE_TABLE(platform, s3c_adc_driver_ids);
 503
 504static const struct dev_pm_ops adc_pm_ops = {
 505        .suspend        = s3c_adc_suspend,
 506        .resume         = s3c_adc_resume,
 507};
 508
 509static struct platform_driver s3c_adc_driver = {
 510        .id_table       = s3c_adc_driver_ids,
 511        .driver         = {
 512                .name   = "s3c-adc",
 513                .owner  = THIS_MODULE,
 514                .pm     = &adc_pm_ops,
 515        },
 516        .probe          = s3c_adc_probe,
 517        .remove         = s3c_adc_remove,
 518};
 519
 520static int __init adc_init(void)
 521{
 522        int ret;
 523
 524        ret = platform_driver_register(&s3c_adc_driver);
 525        if (ret)
 526                printk(KERN_ERR "%s: failed to add adc driver\n", __func__);
 527
 528        return ret;
 529}
 530
 531module_init(adc_init);
 532