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 25#include <plat/regs-adc.h> 26#include <plat/adc.h> 27 28/* This driver is designed to control the usage of the ADC block between 29 * the touchscreen and any other drivers that may need to use it, such as 30 * the hwmon driver. 31 * 32 * Priority will be given to the touchscreen driver, but as this itself is 33 * rate limited it should not starve other requests which are processed in 34 * order that they are received. 35 * 36 * Each user registers to get a client block which uniquely identifies it 37 * and stores information such as the necessary functions to callback when 38 * action is required. 39 */ 40 41enum s3c_cpu_type { 42 TYPE_S3C24XX, 43 TYPE_S3C64XX 44}; 45 46struct s3c_adc_client { 47 struct platform_device *pdev; 48 struct list_head pend; 49 wait_queue_head_t *wait; 50 51 unsigned int nr_samples; 52 int result; 53 unsigned char is_ts; 54 unsigned char channel; 55 56 void (*select_cb)(struct s3c_adc_client *c, unsigned selected); 57 void (*convert_cb)(struct s3c_adc_client *c, 58 unsigned val1, unsigned val2, 59 unsigned *samples_left); 60}; 61 62struct adc_device { 63 struct platform_device *pdev; 64 struct platform_device *owner; 65 struct clk *clk; 66 struct s3c_adc_client *cur; 67 struct s3c_adc_client *ts_pend; 68 void __iomem *regs; 69 spinlock_t lock; 70 71 unsigned int prescale; 72 73 int irq; 74}; 75 76static struct adc_device *adc_dev; 77 78static LIST_HEAD(adc_pending); /* protected by adc_device.lock */ 79 80#define adc_dbg(_adc, msg...) dev_dbg(&(_adc)->pdev->dev, msg) 81 82static inline void s3c_adc_convert(struct adc_device *adc) 83{ 84 unsigned con = readl(adc->regs + S3C2410_ADCCON); 85 86 con |= S3C2410_ADCCON_ENABLE_START; 87 writel(con, adc->regs + S3C2410_ADCCON); 88} 89 90static inline void s3c_adc_select(struct adc_device *adc, 91 struct s3c_adc_client *client) 92{ 93 unsigned con = readl(adc->regs + S3C2410_ADCCON); 94 95 client->select_cb(client, 1); 96 97 con &= ~S3C2410_ADCCON_MUXMASK; 98 con &= ~S3C2410_ADCCON_STDBM; 99 con &= ~S3C2410_ADCCON_STARTMASK; 100 101 if (!client->is_ts) 102 con |= S3C2410_ADCCON_SELMUX(client->channel); 103 104 writel(con, adc->regs + S3C2410_ADCCON); 105} 106 107static void s3c_adc_dbgshow(struct adc_device *adc) 108{ 109 adc_dbg(adc, "CON=%08x, TSC=%08x, DLY=%08x\n", 110 readl(adc->regs + S3C2410_ADCCON), 111 readl(adc->regs + S3C2410_ADCTSC), 112 readl(adc->regs + S3C2410_ADCDLY)); 113} 114 115static void s3c_adc_try(struct adc_device *adc) 116{ 117 struct s3c_adc_client *next = adc->ts_pend; 118 119 if (!next && !list_empty(&adc_pending)) { 120 next = list_first_entry(&adc_pending, 121 struct s3c_adc_client, pend); 122 list_del(&next->pend); 123 } else 124 adc->ts_pend = NULL; 125 126 if (next) { 127 adc_dbg(adc, "new client is %p\n", next); 128 adc->cur = next; 129 s3c_adc_select(adc, next); 130 s3c_adc_convert(adc); 131 s3c_adc_dbgshow(adc); 132 } 133} 134 135int s3c_adc_start(struct s3c_adc_client *client, 136 unsigned int channel, unsigned int nr_samples) 137{ 138 struct adc_device *adc = adc_dev; 139 unsigned long flags; 140 141 if (!adc) { 142 printk(KERN_ERR "%s: failed to find adc\n", __func__); 143 return -EINVAL; 144 } 145 146 if (client->is_ts && adc->ts_pend) 147 return -EAGAIN; 148 149 spin_lock_irqsave(&adc->lock, flags); 150 151 client->channel = channel; 152 client->nr_samples = nr_samples; 153 154 if (client->is_ts) 155 adc->ts_pend = client; 156 else 157 list_add_tail(&client->pend, &adc_pending); 158 159 if (!adc->cur) 160 s3c_adc_try(adc); 161 162 spin_unlock_irqrestore(&adc->lock, flags); 163 164 return 0; 165} 166EXPORT_SYMBOL_GPL(s3c_adc_start); 167 168static void s3c_convert_done(struct s3c_adc_client *client, 169 unsigned v, unsigned u, unsigned *left) 170{ 171 client->result = v; 172 wake_up(client->wait); 173} 174 175int s3c_adc_read(struct s3c_adc_client *client, unsigned int ch) 176{ 177 DECLARE_WAIT_QUEUE_HEAD_ONSTACK(wake); 178 int ret; 179 180 client->convert_cb = s3c_convert_done; 181 client->wait = &wake; 182 client->result = -1; 183 184 ret = s3c_adc_start(client, ch, 1); 185 if (ret < 0) 186 goto err; 187 188 ret = wait_event_timeout(wake, client->result >= 0, HZ / 2); 189 if (client->result < 0) { 190 ret = -ETIMEDOUT; 191 goto err; 192 } 193 194 client->convert_cb = NULL; 195 return client->result; 196 197err: 198 return ret; 199} 200EXPORT_SYMBOL_GPL(s3c_adc_read); 201 202static void s3c_adc_default_select(struct s3c_adc_client *client, 203 unsigned select) 204{ 205} 206 207struct s3c_adc_client *s3c_adc_register(struct platform_device *pdev, 208 void (*select)(struct s3c_adc_client *client, 209 unsigned int selected), 210 void (*conv)(struct s3c_adc_client *client, 211 unsigned d0, unsigned d1, 212 unsigned *samples_left), 213 unsigned int is_ts) 214{ 215 struct s3c_adc_client *client; 216 217 WARN_ON(!pdev); 218 219 if (!select) 220 select = s3c_adc_default_select; 221 222 if (!pdev) 223 return ERR_PTR(-EINVAL); 224 225 client = kzalloc(sizeof(struct s3c_adc_client), GFP_KERNEL); 226 if (!client) { 227 dev_err(&pdev->dev, "no memory for adc client\n"); 228 return ERR_PTR(-ENOMEM); 229 } 230 231 client->pdev = pdev; 232 client->is_ts = is_ts; 233 client->select_cb = select; 234 client->convert_cb = conv; 235 236 return client; 237} 238EXPORT_SYMBOL_GPL(s3c_adc_register); 239 240void s3c_adc_release(struct s3c_adc_client *client) 241{ 242 unsigned long flags; 243 244 spin_lock_irqsave(&adc_dev->lock, flags); 245 246 /* We should really check that nothing is in progress. */ 247 if (adc_dev->cur == client) 248 adc_dev->cur = NULL; 249 if (adc_dev->ts_pend == client) 250 adc_dev->ts_pend = NULL; 251 else { 252 struct list_head *p, *n; 253 struct s3c_adc_client *tmp; 254 255 list_for_each_safe(p, n, &adc_pending) { 256 tmp = list_entry(p, struct s3c_adc_client, pend); 257 if (tmp == client) 258 list_del(&tmp->pend); 259 } 260 } 261 262 if (adc_dev->cur == NULL) 263 s3c_adc_try(adc_dev); 264 265 spin_unlock_irqrestore(&adc_dev->lock, flags); 266 kfree(client); 267} 268EXPORT_SYMBOL_GPL(s3c_adc_release); 269 270static irqreturn_t s3c_adc_irq(int irq, void *pw) 271{ 272 struct adc_device *adc = pw; 273 struct s3c_adc_client *client = adc->cur; 274 enum s3c_cpu_type cpu = platform_get_device_id(adc->pdev)->driver_data; 275 unsigned data0, data1; 276 277 if (!client) { 278 dev_warn(&adc->pdev->dev, "%s: no adc pending\n", __func__); 279 goto exit; 280 } 281 282 data0 = readl(adc->regs + S3C2410_ADCDAT0); 283 data1 = readl(adc->regs + S3C2410_ADCDAT1); 284 adc_dbg(adc, "read %d: 0x%04x, 0x%04x\n", client->nr_samples, data0, data1); 285 286 client->nr_samples--; 287 288 if (cpu == TYPE_S3C64XX) { 289 /* S3C64XX ADC resolution is 12-bit */ 290 data0 &= 0xfff; 291 data1 &= 0xfff; 292 } else { 293 data0 &= 0x3ff; 294 data1 &= 0x3ff; 295 } 296 297 if (client->convert_cb) 298 (client->convert_cb)(client, data0, data1, &client->nr_samples); 299 300 if (client->nr_samples > 0) { 301 /* fire another conversion for this */ 302 303 client->select_cb(client, 1); 304 s3c_adc_convert(adc); 305 } else { 306 spin_lock(&adc->lock); 307 (client->select_cb)(client, 0); 308 adc->cur = NULL; 309 310 s3c_adc_try(adc); 311 spin_unlock(&adc->lock); 312 } 313 314exit: 315 if (cpu == TYPE_S3C64XX) { 316 /* Clear ADC interrupt */ 317 writel(0, adc->regs + S3C64XX_ADCCLRINT); 318 } 319 return IRQ_HANDLED; 320} 321 322static int s3c_adc_probe(struct platform_device *pdev) 323{ 324 struct device *dev = &pdev->dev; 325 struct adc_device *adc; 326 struct resource *regs; 327 int ret; 328 unsigned tmp; 329 330 adc = kzalloc(sizeof(struct adc_device), GFP_KERNEL); 331 if (adc == NULL) { 332 dev_err(dev, "failed to allocate adc_device\n"); 333 return -ENOMEM; 334 } 335 336 spin_lock_init(&adc->lock); 337 338 adc->pdev = pdev; 339 adc->prescale = S3C2410_ADCCON_PRSCVL(49); 340 341 adc->irq = platform_get_irq(pdev, 1); 342 if (adc->irq <= 0) { 343 dev_err(dev, "failed to get adc irq\n"); 344 ret = -ENOENT; 345 goto err_alloc; 346 } 347 348 ret = request_irq(adc->irq, s3c_adc_irq, 0, dev_name(dev), adc); 349 if (ret < 0) { 350 dev_err(dev, "failed to attach adc irq\n"); 351 goto err_alloc; 352 } 353 354 adc->clk = clk_get(dev, "adc"); 355 if (IS_ERR(adc->clk)) { 356 dev_err(dev, "failed to get adc clock\n"); 357 ret = PTR_ERR(adc->clk); 358 goto err_irq; 359 } 360 361 regs = platform_get_resource(pdev, IORESOURCE_MEM, 0); 362 if (!regs) { 363 dev_err(dev, "failed to find registers\n"); 364 ret = -ENXIO; 365 goto err_clk; 366 } 367 368 adc->regs = ioremap(regs->start, resource_size(regs)); 369 if (!adc->regs) { 370 dev_err(dev, "failed to map registers\n"); 371 ret = -ENXIO; 372 goto err_clk; 373 } 374 375 clk_enable(adc->clk); 376 377 tmp = adc->prescale | S3C2410_ADCCON_PRSCEN; 378 if (platform_get_device_id(pdev)->driver_data == TYPE_S3C64XX) { 379 /* Enable 12-bit ADC resolution */ 380 tmp |= S3C64XX_ADCCON_RESSEL; 381 } 382 writel(tmp, adc->regs + S3C2410_ADCCON); 383 384 dev_info(dev, "attached adc driver\n"); 385 386 platform_set_drvdata(pdev, adc); 387 adc_dev = adc; 388 389 return 0; 390 391 err_clk: 392 clk_put(adc->clk); 393 394 err_irq: 395 free_irq(adc->irq, adc); 396 397 err_alloc: 398 kfree(adc); 399 return ret; 400} 401 402static int __devexit s3c_adc_remove(struct platform_device *pdev) 403{ 404 struct adc_device *adc = platform_get_drvdata(pdev); 405 406 iounmap(adc->regs); 407 free_irq(adc->irq, adc); 408 clk_disable(adc->clk); 409 clk_put(adc->clk); 410 kfree(adc); 411 412 return 0; 413} 414 415#ifdef CONFIG_PM 416static int s3c_adc_suspend(struct platform_device *pdev, pm_message_t state) 417{ 418 struct adc_device *adc = platform_get_drvdata(pdev); 419 unsigned long flags; 420 u32 con; 421 422 spin_lock_irqsave(&adc->lock, flags); 423 424 con = readl(adc->regs + S3C2410_ADCCON); 425 con |= S3C2410_ADCCON_STDBM; 426 writel(con, adc->regs + S3C2410_ADCCON); 427 428 disable_irq(adc->irq); 429 spin_unlock_irqrestore(&adc->lock, flags); 430 clk_disable(adc->clk); 431 432 return 0; 433} 434 435static int s3c_adc_resume(struct platform_device *pdev) 436{ 437 struct adc_device *adc = platform_get_drvdata(pdev); 438 439 clk_enable(adc->clk); 440 enable_irq(adc->irq); 441 442 writel(adc->prescale | S3C2410_ADCCON_PRSCEN, 443 adc->regs + S3C2410_ADCCON); 444 445 return 0; 446} 447 448#else 449#define s3c_adc_suspend NULL 450#define s3c_adc_resume NULL 451#endif 452 453static struct platform_device_id s3c_adc_driver_ids[] = { 454 { 455 .name = "s3c24xx-adc", 456 .driver_data = TYPE_S3C24XX, 457 }, { 458 .name = "s3c64xx-adc", 459 .driver_data = TYPE_S3C64XX, 460 }, 461 { } 462}; 463MODULE_DEVICE_TABLE(platform, s3c_adc_driver_ids); 464 465static struct platform_driver s3c_adc_driver = { 466 .id_table = s3c_adc_driver_ids, 467 .driver = { 468 .name = "s3c-adc", 469 .owner = THIS_MODULE, 470 }, 471 .probe = s3c_adc_probe, 472 .remove = __devexit_p(s3c_adc_remove), 473 .suspend = s3c_adc_suspend, 474 .resume = s3c_adc_resume, 475}; 476 477static int __init adc_init(void) 478{ 479 int ret; 480 481 ret = platform_driver_register(&s3c_adc_driver); 482 if (ret) 483 printk(KERN_ERR "%s: failed to add adc driver\n", __func__); 484 485 return ret; 486} 487 488arch_initcall(adc_init); 489