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