1 /* 2 * TI ADC MFD driver 3 * 4 * Copyright (C) 2012 Texas Instruments Incorporated - http://www.ti.com/ 5 * 6 * This program is free software; you can redistribute it and/or 7 * modify it under the terms of the GNU General Public License as 8 * published by the Free Software Foundation version 2. 9 * 10 * This program is distributed "as is" WITHOUT ANY WARRANTY of any 11 * kind, whether express or implied; without even the implied warranty 12 * of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 13 * GNU General Public License for more details. 14 */ 15 16 #include <linux/kernel.h> 17 #include <linux/err.h> 18 #include <linux/module.h> 19 #include <linux/slab.h> 20 #include <linux/interrupt.h> 21 #include <linux/platform_device.h> 22 #include <linux/io.h> 23 #include <linux/iio/iio.h> 24 #include <linux/of.h> 25 #include <linux/of_device.h> 26 #include <linux/iio/machine.h> 27 #include <linux/iio/driver.h> 28 29 #include <linux/mfd/ti_am335x_tscadc.h> 30 #include <linux/iio/buffer.h> 31 #include <linux/iio/kfifo_buf.h> 32 33 struct tiadc_device { 34 struct ti_tscadc_dev *mfd_tscadc; 35 int channels; 36 u8 channel_line[8]; 37 u8 channel_step[8]; 38 int buffer_en_ch_steps; 39 u16 data[8]; 40 u32 open_delay[8], sample_delay[8], step_avg[8]; 41 }; 42 43 static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg) 44 { 45 return readl(adc->mfd_tscadc->tscadc_base + reg); 46 } 47 48 static void tiadc_writel(struct tiadc_device *adc, unsigned int reg, 49 unsigned int val) 50 { 51 writel(val, adc->mfd_tscadc->tscadc_base + reg); 52 } 53 54 static u32 get_adc_step_mask(struct tiadc_device *adc_dev) 55 { 56 u32 step_en; 57 58 step_en = ((1 << adc_dev->channels) - 1); 59 step_en <<= TOTAL_STEPS - adc_dev->channels + 1; 60 return step_en; 61 } 62 63 static u32 get_adc_chan_step_mask(struct tiadc_device *adc_dev, 64 struct iio_chan_spec const *chan) 65 { 66 int i; 67 68 for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) { 69 if (chan->channel == adc_dev->channel_line[i]) { 70 u32 step; 71 72 step = adc_dev->channel_step[i]; 73 /* +1 for the charger */ 74 return 1 << (step + 1); 75 } 76 } 77 WARN_ON(1); 78 return 0; 79 } 80 81 static u32 get_adc_step_bit(struct tiadc_device *adc_dev, int chan) 82 { 83 return 1 << adc_dev->channel_step[chan]; 84 } 85 86 static void tiadc_step_config(struct iio_dev *indio_dev) 87 { 88 struct tiadc_device *adc_dev = iio_priv(indio_dev); 89 struct device *dev = adc_dev->mfd_tscadc->dev; 90 unsigned int stepconfig; 91 int i, steps = 0; 92 93 /* 94 * There are 16 configurable steps and 8 analog input 95 * lines available which are shared between Touchscreen and ADC. 96 * 97 * Steps forwards i.e. from 0 towards 16 are used by ADC 98 * depending on number of input lines needed. 99 * Channel would represent which analog input 100 * needs to be given to ADC to digitalize data. 101 */ 102 103 104 for (i = 0; i < adc_dev->channels; i++) { 105 int chan; 106 107 chan = adc_dev->channel_line[i]; 108 109 if (adc_dev->step_avg[i] > STEPCONFIG_AVG_16) { 110 dev_warn(dev, "chan %d step_avg truncating to %d\n", 111 chan, STEPCONFIG_AVG_16); 112 adc_dev->step_avg[i] = STEPCONFIG_AVG_16; 113 } 114 115 if (adc_dev->step_avg[i]) 116 stepconfig = 117 STEPCONFIG_AVG(ffs(adc_dev->step_avg[i]) - 1) | 118 STEPCONFIG_FIFO1; 119 else 120 stepconfig = STEPCONFIG_FIFO1; 121 122 if (iio_buffer_enabled(indio_dev)) 123 stepconfig |= STEPCONFIG_MODE_SWCNT; 124 125 tiadc_writel(adc_dev, REG_STEPCONFIG(steps), 126 stepconfig | STEPCONFIG_INP(chan)); 127 128 if (adc_dev->open_delay[i] > STEPDELAY_OPEN_MASK) { 129 dev_warn(dev, "chan %d open delay truncating to 0x3FFFF\n", 130 chan); 131 adc_dev->open_delay[i] = STEPDELAY_OPEN_MASK; 132 } 133 134 if (adc_dev->sample_delay[i] > 0xFF) { 135 dev_warn(dev, "chan %d sample delay truncating to 0xFF\n", 136 chan); 137 adc_dev->sample_delay[i] = 0xFF; 138 } 139 140 tiadc_writel(adc_dev, REG_STEPDELAY(steps), 141 STEPDELAY_OPEN(adc_dev->open_delay[i]) | 142 STEPDELAY_SAMPLE(adc_dev->sample_delay[i])); 143 144 adc_dev->channel_step[i] = steps; 145 steps++; 146 } 147 } 148 149 static irqreturn_t tiadc_irq_h(int irq, void *private) 150 { 151 struct iio_dev *indio_dev = private; 152 struct tiadc_device *adc_dev = iio_priv(indio_dev); 153 unsigned int status, config; 154 status = tiadc_readl(adc_dev, REG_IRQSTATUS); 155 156 /* 157 * ADC and touchscreen share the IRQ line. 158 * FIFO0 interrupts are used by TSC. Handle FIFO1 IRQs here only 159 */ 160 if (status & IRQENB_FIFO1OVRRUN) { 161 /* FIFO Overrun. Clear flag. Disable/Enable ADC to recover */ 162 config = tiadc_readl(adc_dev, REG_CTRL); 163 config &= ~(CNTRLREG_TSCSSENB); 164 tiadc_writel(adc_dev, REG_CTRL, config); 165 tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1OVRRUN 166 | IRQENB_FIFO1UNDRFLW | IRQENB_FIFO1THRES); 167 tiadc_writel(adc_dev, REG_CTRL, (config | CNTRLREG_TSCSSENB)); 168 return IRQ_HANDLED; 169 } else if (status & IRQENB_FIFO1THRES) { 170 /* Disable irq and wake worker thread */ 171 tiadc_writel(adc_dev, REG_IRQCLR, IRQENB_FIFO1THRES); 172 return IRQ_WAKE_THREAD; 173 } 174 175 return IRQ_NONE; 176 } 177 178 static irqreturn_t tiadc_worker_h(int irq, void *private) 179 { 180 struct iio_dev *indio_dev = private; 181 struct tiadc_device *adc_dev = iio_priv(indio_dev); 182 int i, k, fifo1count, read; 183 u16 *data = adc_dev->data; 184 185 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); 186 for (k = 0; k < fifo1count; k = k + i) { 187 for (i = 0; i < (indio_dev->scan_bytes)/2; i++) { 188 read = tiadc_readl(adc_dev, REG_FIFO1); 189 data[i] = read & FIFOREAD_DATA_MASK; 190 } 191 iio_push_to_buffers(indio_dev, (u8 *) data); 192 } 193 194 tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES); 195 tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES); 196 197 return IRQ_HANDLED; 198 } 199 200 static int tiadc_buffer_preenable(struct iio_dev *indio_dev) 201 { 202 struct tiadc_device *adc_dev = iio_priv(indio_dev); 203 int i, fifo1count, read; 204 205 tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES | 206 IRQENB_FIFO1OVRRUN | 207 IRQENB_FIFO1UNDRFLW)); 208 209 /* Flush FIFO. Needed in corner cases in simultaneous tsc/adc use */ 210 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); 211 for (i = 0; i < fifo1count; i++) 212 read = tiadc_readl(adc_dev, REG_FIFO1); 213 214 return 0; 215 } 216 217 static int tiadc_buffer_postenable(struct iio_dev *indio_dev) 218 { 219 struct tiadc_device *adc_dev = iio_priv(indio_dev); 220 unsigned int enb = 0; 221 u8 bit; 222 223 tiadc_step_config(indio_dev); 224 for_each_set_bit(bit, indio_dev->active_scan_mask, adc_dev->channels) 225 enb |= (get_adc_step_bit(adc_dev, bit) << 1); 226 adc_dev->buffer_en_ch_steps = enb; 227 228 am335x_tsc_se_set_cache(adc_dev->mfd_tscadc, enb); 229 230 tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES 231 | IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW); 232 tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES 233 | IRQENB_FIFO1OVRRUN); 234 235 return 0; 236 } 237 238 static int tiadc_buffer_predisable(struct iio_dev *indio_dev) 239 { 240 struct tiadc_device *adc_dev = iio_priv(indio_dev); 241 int fifo1count, i, read; 242 243 tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES | 244 IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW)); 245 am335x_tsc_se_clr(adc_dev->mfd_tscadc, adc_dev->buffer_en_ch_steps); 246 adc_dev->buffer_en_ch_steps = 0; 247 248 /* Flush FIFO of leftover data in the time it takes to disable adc */ 249 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); 250 for (i = 0; i < fifo1count; i++) 251 read = tiadc_readl(adc_dev, REG_FIFO1); 252 253 return 0; 254 } 255 256 static int tiadc_buffer_postdisable(struct iio_dev *indio_dev) 257 { 258 tiadc_step_config(indio_dev); 259 260 return 0; 261 } 262 263 static const struct iio_buffer_setup_ops tiadc_buffer_setup_ops = { 264 .preenable = &tiadc_buffer_preenable, 265 .postenable = &tiadc_buffer_postenable, 266 .predisable = &tiadc_buffer_predisable, 267 .postdisable = &tiadc_buffer_postdisable, 268 }; 269 270 static int tiadc_iio_buffered_hardware_setup(struct iio_dev *indio_dev, 271 irqreturn_t (*pollfunc_bh)(int irq, void *p), 272 irqreturn_t (*pollfunc_th)(int irq, void *p), 273 int irq, 274 unsigned long flags, 275 const struct iio_buffer_setup_ops *setup_ops) 276 { 277 struct iio_buffer *buffer; 278 int ret; 279 280 buffer = iio_kfifo_allocate(); 281 if (!buffer) 282 return -ENOMEM; 283 284 iio_device_attach_buffer(indio_dev, buffer); 285 286 ret = request_threaded_irq(irq, pollfunc_th, pollfunc_bh, 287 flags, indio_dev->name, indio_dev); 288 if (ret) 289 goto error_kfifo_free; 290 291 indio_dev->setup_ops = setup_ops; 292 indio_dev->modes |= INDIO_BUFFER_HARDWARE; 293 294 return 0; 295 296 error_kfifo_free: 297 iio_kfifo_free(indio_dev->buffer); 298 return ret; 299 } 300 301 static void tiadc_iio_buffered_hardware_remove(struct iio_dev *indio_dev) 302 { 303 struct tiadc_device *adc_dev = iio_priv(indio_dev); 304 305 free_irq(adc_dev->mfd_tscadc->irq, indio_dev); 306 iio_kfifo_free(indio_dev->buffer); 307 } 308 309 310 static const char * const chan_name_ain[] = { 311 "AIN0", 312 "AIN1", 313 "AIN2", 314 "AIN3", 315 "AIN4", 316 "AIN5", 317 "AIN6", 318 "AIN7", 319 }; 320 321 static int tiadc_channel_init(struct iio_dev *indio_dev, int channels) 322 { 323 struct tiadc_device *adc_dev = iio_priv(indio_dev); 324 struct iio_chan_spec *chan_array; 325 struct iio_chan_spec *chan; 326 int i; 327 328 indio_dev->num_channels = channels; 329 chan_array = kcalloc(channels, 330 sizeof(struct iio_chan_spec), GFP_KERNEL); 331 if (chan_array == NULL) 332 return -ENOMEM; 333 334 chan = chan_array; 335 for (i = 0; i < channels; i++, chan++) { 336 337 chan->type = IIO_VOLTAGE; 338 chan->indexed = 1; 339 chan->channel = adc_dev->channel_line[i]; 340 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW); 341 chan->datasheet_name = chan_name_ain[chan->channel]; 342 chan->scan_index = i; 343 chan->scan_type.sign = 'u'; 344 chan->scan_type.realbits = 12; 345 chan->scan_type.storagebits = 16; 346 } 347 348 indio_dev->channels = chan_array; 349 350 return 0; 351 } 352 353 static void tiadc_channels_remove(struct iio_dev *indio_dev) 354 { 355 kfree(indio_dev->channels); 356 } 357 358 static int tiadc_read_raw(struct iio_dev *indio_dev, 359 struct iio_chan_spec const *chan, 360 int *val, int *val2, long mask) 361 { 362 struct tiadc_device *adc_dev = iio_priv(indio_dev); 363 int i, map_val; 364 unsigned int fifo1count, read, stepid; 365 bool found = false; 366 u32 step_en; 367 unsigned long timeout; 368 369 if (iio_buffer_enabled(indio_dev)) 370 return -EBUSY; 371 372 step_en = get_adc_chan_step_mask(adc_dev, chan); 373 if (!step_en) 374 return -EINVAL; 375 376 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); 377 while (fifo1count--) 378 tiadc_readl(adc_dev, REG_FIFO1); 379 380 am335x_tsc_se_set_once(adc_dev->mfd_tscadc, step_en); 381 382 timeout = jiffies + usecs_to_jiffies 383 (IDLE_TIMEOUT * adc_dev->channels); 384 /* Wait for Fifo threshold interrupt */ 385 while (1) { 386 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); 387 if (fifo1count) 388 break; 389 390 if (time_after(jiffies, timeout)) { 391 am335x_tsc_se_adc_done(adc_dev->mfd_tscadc); 392 return -EAGAIN; 393 } 394 } 395 map_val = adc_dev->channel_step[chan->scan_index]; 396 397 /* 398 * We check the complete FIFO. We programmed just one entry but in case 399 * something went wrong we left empty handed (-EAGAIN previously) and 400 * then the value apeared somehow in the FIFO we would have two entries. 401 * Therefore we read every item and keep only the latest version of the 402 * requested channel. 403 */ 404 for (i = 0; i < fifo1count; i++) { 405 read = tiadc_readl(adc_dev, REG_FIFO1); 406 stepid = read & FIFOREAD_CHNLID_MASK; 407 stepid = stepid >> 0x10; 408 409 if (stepid == map_val) { 410 read = read & FIFOREAD_DATA_MASK; 411 found = true; 412 *val = (u16) read; 413 } 414 } 415 am335x_tsc_se_adc_done(adc_dev->mfd_tscadc); 416 417 if (found == false) 418 return -EBUSY; 419 return IIO_VAL_INT; 420 } 421 422 static const struct iio_info tiadc_info = { 423 .read_raw = &tiadc_read_raw, 424 .driver_module = THIS_MODULE, 425 }; 426 427 static int tiadc_parse_dt(struct platform_device *pdev, 428 struct tiadc_device *adc_dev) 429 { 430 struct device_node *node = pdev->dev.of_node; 431 struct property *prop; 432 const __be32 *cur; 433 int channels = 0; 434 u32 val; 435 436 of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) { 437 adc_dev->channel_line[channels] = val; 438 439 /* Set Default values for optional DT parameters */ 440 adc_dev->open_delay[channels] = STEPCONFIG_OPENDLY; 441 adc_dev->sample_delay[channels] = STEPCONFIG_SAMPLEDLY; 442 adc_dev->step_avg[channels] = 16; 443 444 channels++; 445 } 446 447 of_property_read_u32_array(node, "ti,chan-step-avg", 448 adc_dev->step_avg, channels); 449 of_property_read_u32_array(node, "ti,chan-step-opendelay", 450 adc_dev->open_delay, channels); 451 of_property_read_u32_array(node, "ti,chan-step-sampledelay", 452 adc_dev->sample_delay, channels); 453 454 adc_dev->channels = channels; 455 return 0; 456 } 457 458 static int tiadc_probe(struct platform_device *pdev) 459 { 460 struct iio_dev *indio_dev; 461 struct tiadc_device *adc_dev; 462 struct device_node *node = pdev->dev.of_node; 463 int err; 464 465 if (!node) { 466 dev_err(&pdev->dev, "Could not find valid DT data.\n"); 467 return -EINVAL; 468 } 469 470 indio_dev = devm_iio_device_alloc(&pdev->dev, 471 sizeof(struct tiadc_device)); 472 if (indio_dev == NULL) { 473 dev_err(&pdev->dev, "failed to allocate iio device\n"); 474 return -ENOMEM; 475 } 476 adc_dev = iio_priv(indio_dev); 477 478 adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev); 479 tiadc_parse_dt(pdev, adc_dev); 480 481 indio_dev->dev.parent = &pdev->dev; 482 indio_dev->name = dev_name(&pdev->dev); 483 indio_dev->modes = INDIO_DIRECT_MODE; 484 indio_dev->info = &tiadc_info; 485 486 tiadc_step_config(indio_dev); 487 tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD); 488 489 err = tiadc_channel_init(indio_dev, adc_dev->channels); 490 if (err < 0) 491 return err; 492 493 err = tiadc_iio_buffered_hardware_setup(indio_dev, 494 &tiadc_worker_h, 495 &tiadc_irq_h, 496 adc_dev->mfd_tscadc->irq, 497 IRQF_SHARED, 498 &tiadc_buffer_setup_ops); 499 500 if (err) 501 goto err_free_channels; 502 503 err = iio_device_register(indio_dev); 504 if (err) 505 goto err_buffer_unregister; 506 507 platform_set_drvdata(pdev, indio_dev); 508 509 return 0; 510 511 err_buffer_unregister: 512 tiadc_iio_buffered_hardware_remove(indio_dev); 513 err_free_channels: 514 tiadc_channels_remove(indio_dev); 515 return err; 516 } 517 518 static int tiadc_remove(struct platform_device *pdev) 519 { 520 struct iio_dev *indio_dev = platform_get_drvdata(pdev); 521 struct tiadc_device *adc_dev = iio_priv(indio_dev); 522 u32 step_en; 523 524 iio_device_unregister(indio_dev); 525 tiadc_iio_buffered_hardware_remove(indio_dev); 526 tiadc_channels_remove(indio_dev); 527 528 step_en = get_adc_step_mask(adc_dev); 529 am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en); 530 531 return 0; 532 } 533 534 #ifdef CONFIG_PM 535 static int tiadc_suspend(struct device *dev) 536 { 537 struct iio_dev *indio_dev = dev_get_drvdata(dev); 538 struct tiadc_device *adc_dev = iio_priv(indio_dev); 539 struct ti_tscadc_dev *tscadc_dev; 540 unsigned int idle; 541 542 tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev)); 543 if (!device_may_wakeup(tscadc_dev->dev)) { 544 idle = tiadc_readl(adc_dev, REG_CTRL); 545 idle &= ~(CNTRLREG_TSCSSENB); 546 tiadc_writel(adc_dev, REG_CTRL, (idle | 547 CNTRLREG_POWERDOWN)); 548 } 549 550 return 0; 551 } 552 553 static int tiadc_resume(struct device *dev) 554 { 555 struct iio_dev *indio_dev = dev_get_drvdata(dev); 556 struct tiadc_device *adc_dev = iio_priv(indio_dev); 557 unsigned int restore; 558 559 /* Make sure ADC is powered up */ 560 restore = tiadc_readl(adc_dev, REG_CTRL); 561 restore &= ~(CNTRLREG_POWERDOWN); 562 tiadc_writel(adc_dev, REG_CTRL, restore); 563 564 tiadc_step_config(indio_dev); 565 am335x_tsc_se_set_cache(adc_dev->mfd_tscadc, 566 adc_dev->buffer_en_ch_steps); 567 return 0; 568 } 569 570 static const struct dev_pm_ops tiadc_pm_ops = { 571 .suspend = tiadc_suspend, 572 .resume = tiadc_resume, 573 }; 574 #define TIADC_PM_OPS (&tiadc_pm_ops) 575 #else 576 #define TIADC_PM_OPS NULL 577 #endif 578 579 static const struct of_device_id ti_adc_dt_ids[] = { 580 { .compatible = "ti,am3359-adc", }, 581 { } 582 }; 583 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids); 584 585 static struct platform_driver tiadc_driver = { 586 .driver = { 587 .name = "TI-am335x-adc", 588 .pm = TIADC_PM_OPS, 589 .of_match_table = ti_adc_dt_ids, 590 }, 591 .probe = tiadc_probe, 592 .remove = tiadc_remove, 593 }; 594 module_platform_driver(tiadc_driver); 595 596 MODULE_DESCRIPTION("TI ADC controller driver"); 597 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>"); 598 MODULE_LICENSE("GPL"); 599