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