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