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