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_SOFTWARE; 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, sizeof(*chan_array), GFP_KERNEL); 330 if (chan_array == NULL) 331 return -ENOMEM; 332 333 chan = chan_array; 334 for (i = 0; i < channels; i++, chan++) { 335 336 chan->type = IIO_VOLTAGE; 337 chan->indexed = 1; 338 chan->channel = adc_dev->channel_line[i]; 339 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW); 340 chan->datasheet_name = chan_name_ain[chan->channel]; 341 chan->scan_index = i; 342 chan->scan_type.sign = 'u'; 343 chan->scan_type.realbits = 12; 344 chan->scan_type.storagebits = 16; 345 } 346 347 indio_dev->channels = chan_array; 348 349 return 0; 350 } 351 352 static void tiadc_channels_remove(struct iio_dev *indio_dev) 353 { 354 kfree(indio_dev->channels); 355 } 356 357 static int tiadc_read_raw(struct iio_dev *indio_dev, 358 struct iio_chan_spec const *chan, 359 int *val, int *val2, long mask) 360 { 361 struct tiadc_device *adc_dev = iio_priv(indio_dev); 362 int i, map_val; 363 unsigned int fifo1count, read, stepid; 364 bool found = false; 365 u32 step_en; 366 unsigned long timeout; 367 368 if (iio_buffer_enabled(indio_dev)) 369 return -EBUSY; 370 371 step_en = get_adc_chan_step_mask(adc_dev, chan); 372 if (!step_en) 373 return -EINVAL; 374 375 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); 376 while (fifo1count--) 377 tiadc_readl(adc_dev, REG_FIFO1); 378 379 am335x_tsc_se_set_once(adc_dev->mfd_tscadc, step_en); 380 381 timeout = jiffies + usecs_to_jiffies 382 (IDLE_TIMEOUT * adc_dev->channels); 383 /* Wait for Fifo threshold interrupt */ 384 while (1) { 385 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); 386 if (fifo1count) 387 break; 388 389 if (time_after(jiffies, timeout)) { 390 am335x_tsc_se_adc_done(adc_dev->mfd_tscadc); 391 return -EAGAIN; 392 } 393 } 394 map_val = adc_dev->channel_step[chan->scan_index]; 395 396 /* 397 * We check the complete FIFO. We programmed just one entry but in case 398 * something went wrong we left empty handed (-EAGAIN previously) and 399 * then the value apeared somehow in the FIFO we would have two entries. 400 * Therefore we read every item and keep only the latest version of the 401 * requested channel. 402 */ 403 for (i = 0; i < fifo1count; i++) { 404 read = tiadc_readl(adc_dev, REG_FIFO1); 405 stepid = read & FIFOREAD_CHNLID_MASK; 406 stepid = stepid >> 0x10; 407 408 if (stepid == map_val) { 409 read = read & FIFOREAD_DATA_MASK; 410 found = true; 411 *val = (u16) read; 412 } 413 } 414 am335x_tsc_se_adc_done(adc_dev->mfd_tscadc); 415 416 if (found == false) 417 return -EBUSY; 418 return IIO_VAL_INT; 419 } 420 421 static const struct iio_info tiadc_info = { 422 .read_raw = &tiadc_read_raw, 423 .driver_module = THIS_MODULE, 424 }; 425 426 static int tiadc_parse_dt(struct platform_device *pdev, 427 struct tiadc_device *adc_dev) 428 { 429 struct device_node *node = pdev->dev.of_node; 430 struct property *prop; 431 const __be32 *cur; 432 int channels = 0; 433 u32 val; 434 435 of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) { 436 adc_dev->channel_line[channels] = val; 437 438 /* Set Default values for optional DT parameters */ 439 adc_dev->open_delay[channels] = STEPCONFIG_OPENDLY; 440 adc_dev->sample_delay[channels] = STEPCONFIG_SAMPLEDLY; 441 adc_dev->step_avg[channels] = 16; 442 443 channels++; 444 } 445 446 of_property_read_u32_array(node, "ti,chan-step-avg", 447 adc_dev->step_avg, channels); 448 of_property_read_u32_array(node, "ti,chan-step-opendelay", 449 adc_dev->open_delay, channels); 450 of_property_read_u32_array(node, "ti,chan-step-sampledelay", 451 adc_dev->sample_delay, channels); 452 453 adc_dev->channels = channels; 454 return 0; 455 } 456 457 static int tiadc_probe(struct platform_device *pdev) 458 { 459 struct iio_dev *indio_dev; 460 struct tiadc_device *adc_dev; 461 struct device_node *node = pdev->dev.of_node; 462 int err; 463 464 if (!node) { 465 dev_err(&pdev->dev, "Could not find valid DT data.\n"); 466 return -EINVAL; 467 } 468 469 indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*indio_dev)); 470 if (indio_dev == NULL) { 471 dev_err(&pdev->dev, "failed to allocate iio device\n"); 472 return -ENOMEM; 473 } 474 adc_dev = iio_priv(indio_dev); 475 476 adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev); 477 tiadc_parse_dt(pdev, adc_dev); 478 479 indio_dev->dev.parent = &pdev->dev; 480 indio_dev->name = dev_name(&pdev->dev); 481 indio_dev->modes = INDIO_DIRECT_MODE; 482 indio_dev->info = &tiadc_info; 483 484 tiadc_step_config(indio_dev); 485 tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD); 486 487 err = tiadc_channel_init(indio_dev, adc_dev->channels); 488 if (err < 0) 489 return err; 490 491 err = tiadc_iio_buffered_hardware_setup(indio_dev, 492 &tiadc_worker_h, 493 &tiadc_irq_h, 494 adc_dev->mfd_tscadc->irq, 495 IRQF_SHARED, 496 &tiadc_buffer_setup_ops); 497 498 if (err) 499 goto err_free_channels; 500 501 err = iio_device_register(indio_dev); 502 if (err) 503 goto err_buffer_unregister; 504 505 platform_set_drvdata(pdev, indio_dev); 506 507 return 0; 508 509 err_buffer_unregister: 510 tiadc_iio_buffered_hardware_remove(indio_dev); 511 err_free_channels: 512 tiadc_channels_remove(indio_dev); 513 return err; 514 } 515 516 static int tiadc_remove(struct platform_device *pdev) 517 { 518 struct iio_dev *indio_dev = platform_get_drvdata(pdev); 519 struct tiadc_device *adc_dev = iio_priv(indio_dev); 520 u32 step_en; 521 522 iio_device_unregister(indio_dev); 523 tiadc_iio_buffered_hardware_remove(indio_dev); 524 tiadc_channels_remove(indio_dev); 525 526 step_en = get_adc_step_mask(adc_dev); 527 am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en); 528 529 return 0; 530 } 531 532 #ifdef CONFIG_PM 533 static int tiadc_suspend(struct device *dev) 534 { 535 struct iio_dev *indio_dev = dev_get_drvdata(dev); 536 struct tiadc_device *adc_dev = iio_priv(indio_dev); 537 struct ti_tscadc_dev *tscadc_dev; 538 unsigned int idle; 539 540 tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev)); 541 if (!device_may_wakeup(tscadc_dev->dev)) { 542 idle = tiadc_readl(adc_dev, REG_CTRL); 543 idle &= ~(CNTRLREG_TSCSSENB); 544 tiadc_writel(adc_dev, REG_CTRL, (idle | 545 CNTRLREG_POWERDOWN)); 546 } 547 548 return 0; 549 } 550 551 static int tiadc_resume(struct device *dev) 552 { 553 struct iio_dev *indio_dev = dev_get_drvdata(dev); 554 struct tiadc_device *adc_dev = iio_priv(indio_dev); 555 unsigned int restore; 556 557 /* Make sure ADC is powered up */ 558 restore = tiadc_readl(adc_dev, REG_CTRL); 559 restore &= ~(CNTRLREG_POWERDOWN); 560 tiadc_writel(adc_dev, REG_CTRL, restore); 561 562 tiadc_step_config(indio_dev); 563 am335x_tsc_se_set_cache(adc_dev->mfd_tscadc, 564 adc_dev->buffer_en_ch_steps); 565 return 0; 566 } 567 568 static const struct dev_pm_ops tiadc_pm_ops = { 569 .suspend = tiadc_suspend, 570 .resume = tiadc_resume, 571 }; 572 #define TIADC_PM_OPS (&tiadc_pm_ops) 573 #else 574 #define TIADC_PM_OPS NULL 575 #endif 576 577 static const struct of_device_id ti_adc_dt_ids[] = { 578 { .compatible = "ti,am3359-adc", }, 579 { } 580 }; 581 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids); 582 583 static struct platform_driver tiadc_driver = { 584 .driver = { 585 .name = "TI-am335x-adc", 586 .pm = TIADC_PM_OPS, 587 .of_match_table = ti_adc_dt_ids, 588 }, 589 .probe = tiadc_probe, 590 .remove = tiadc_remove, 591 }; 592 module_platform_driver(tiadc_driver); 593 594 MODULE_DESCRIPTION("TI ADC controller driver"); 595 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>"); 596 MODULE_LICENSE("GPL"); 597