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