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 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         kfree(client);
 194 }
 195 EXPORT_SYMBOL_GPL(s3c_adc_release);
 196
 197 static irqreturn_t s3c_adc_irq(int irq, void *pw)
 198 {
 199         struct adc_device *adc = pw;
 200         struct s3c_adc_client *client = adc->cur;
 201         unsigned long flags;
 202         unsigned data0, data1;
 203
 204         if (!client) {
 205                 dev_warn(&adc->pdev->dev, "%s: no adc pending\n", __func__);
 206                 return IRQ_HANDLED;
 207         }
 208
 209         data0 = readl(adc->regs + S3C2410_ADCDAT0);
 210         data1 = readl(adc->regs + S3C2410_ADCDAT1);
 211         adc_dbg(adc, "read %d: 0x%04x, 0x%04x\n", client->nr_samples, data0, data1);
 212
 213         (client->convert_cb)(data0 & 0x3ff, data1 & 0x3ff);
 214
 215         if (--client->nr_samples > 0) {
 216                 /* fire another conversion for this */
 217
 218                 client->select_cb(1);
 219                 s3c_adc_convert(adc);
 220         } else {
 221                 local_irq_save(flags);
 222                 (client->select_cb)(0);
 223                 adc->cur = NULL;
 224
 225                 s3c_adc_try(adc);
 226                 local_irq_restore(flags);
 227         }
 228
 229         return IRQ_HANDLED;
 230 }
 231
 232 static int s3c_adc_probe(struct platform_device *pdev)
 233 {
 234         struct device *dev = &pdev->dev;
 235         struct adc_device *adc;
 236         struct resource *regs;
 237         int ret;
 238
 239         adc = kzalloc(sizeof(struct adc_device), GFP_KERNEL);
 240         if (adc == NULL) {
 241                 dev_err(dev, "failed to allocate adc_device\n");
 242                 return -ENOMEM;
 243         }
 244
 245         adc->pdev = pdev;
 246         adc->prescale = S3C2410_ADCCON_PRSCVL(49);
 247
 248         adc->irq = platform_get_irq(pdev, 1);
 249         if (adc->irq <= 0) {
 250                 dev_err(dev, "failed to get adc irq\n");
 251                 ret = -ENOENT;
 252                 goto err_alloc;
 253         }
 254
 255         ret = request_irq(adc->irq, s3c_adc_irq, 0, dev_name(dev), adc);
 256         if (ret < 0) {
 257                 dev_err(dev, "failed to attach adc irq\n");
 258                 goto err_alloc;
 259         }
 260
 261         adc->clk = clk_get(dev, "adc");
 262         if (IS_ERR(adc->clk)) {
 263                 dev_err(dev, "failed to get adc clock\n");
 264                 ret = PTR_ERR(adc->clk);
 265                 goto err_irq;
 266         }
 267
 268         regs = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 269         if (!regs) {
 270                 dev_err(dev, "failed to find registers\n");
 271                 ret = -ENXIO;
 272                 goto err_clk;
 273         }
 274
 275         adc->regs = ioremap(regs->start, resource_size(regs));
 276         if (!adc->regs) {
 277                 dev_err(dev, "failed to map registers\n");
 278                 ret = -ENXIO;
 279                 goto err_clk;
 280         }
 281
 282         clk_enable(adc->clk);
 283
 284         writel(adc->prescale | S3C2410_ADCCON_PRSCEN,
 285                adc->regs + S3C2410_ADCCON);
 286
 287         dev_info(dev, "attached adc driver\n");
 288
 289         platform_set_drvdata(pdev, adc);
 290         adc_dev = adc;
 291
 292         return 0;
 293
 294  err_clk:
 295         clk_put(adc->clk);
 296
 297  err_irq:
 298         free_irq(adc->irq, adc);
 299
 300  err_alloc:
 301         kfree(adc);
 302         return ret;
 303 }
 304
 305 static int s3c_adc_remove(struct platform_device *pdev)
 306 {
 307         struct adc_device *adc = platform_get_drvdata(pdev);
 308
 309         iounmap(adc->regs);
 310         free_irq(adc->irq, adc);
 311         clk_disable(adc->clk);
 312         clk_put(adc->clk);
 313         kfree(adc);
 314
 315         return 0;
 316 }
 317
 318 #ifdef CONFIG_PM
 319 static int s3c_adc_suspend(struct platform_device *pdev, pm_message_t state)
 320 {
 321         struct adc_device *adc = platform_get_drvdata(pdev);
 322         u32 con;
 323
 324         con = readl(adc->regs + S3C2410_ADCCON);
 325         con |= S3C2410_ADCCON_STDBM;
 326         writel(con, adc->regs + S3C2410_ADCCON);
 327
 328         clk_disable(adc->clk);
 329
 330         return 0;
 331 }
 332
 333 static int s3c_adc_resume(struct platform_device *pdev)
 334 {
 335         struct adc_device *adc = platform_get_drvdata(pdev);
 336
 337         clk_enable(adc->clk);
 338
 339         writel(adc->prescale | S3C2410_ADCCON_PRSCEN,
 340                adc->regs + S3C2410_ADCCON);
 341
 342         return 0;
 343 }
 344
 345 #else
 346 #define s3c_adc_suspend NULL
 347 #define s3c_adc_resume NULL
 348 #endif
 349
 350 static struct platform_driver s3c_adc_driver = {
 351         .driver         = {
 352                 .name   = "s3c24xx-adc",
 353                 .owner  = THIS_MODULE,
 354         },
 355         .probe          = s3c_adc_probe,
 356         .remove         = __devexit_p(s3c_adc_remove),
 357         .suspend        = s3c_adc_suspend,
 358         .resume         = s3c_adc_resume,
 359 };
 360
 361 static int __init adc_init(void)
 362 {
 363         int ret;
 364
 365         ret = platform_driver_register(&s3c_adc_driver);
 366         if (ret)
 367                 printk(KERN_ERR "%s: failed to add adc driver\n", __func__);
 368
 369         return ret;
 370 }
 371
 372 arch_initcall(adc_init);