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 return 0; 268 269 error_kfifo_free: 270 iio_kfifo_free(indio_dev->buffer); 271 return ret; 272 } 273 274 static void tiadc_iio_buffered_hardware_remove(struct iio_dev *indio_dev) 275 { 276 struct tiadc_device *adc_dev = iio_priv(indio_dev); 277 278 free_irq(adc_dev->mfd_tscadc->irq, indio_dev); 279 iio_kfifo_free(indio_dev->buffer); 280 } 281 282 283 static const char * const chan_name_ain[] = { 284 "AIN0", 285 "AIN1", 286 "AIN2", 287 "AIN3", 288 "AIN4", 289 "AIN5", 290 "AIN6", 291 "AIN7", 292 }; 293 294 static int tiadc_channel_init(struct iio_dev *indio_dev, int channels) 295 { 296 struct tiadc_device *adc_dev = iio_priv(indio_dev); 297 struct iio_chan_spec *chan_array; 298 struct iio_chan_spec *chan; 299 int i; 300 301 indio_dev->num_channels = channels; 302 chan_array = kcalloc(channels, 303 sizeof(struct iio_chan_spec), GFP_KERNEL); 304 if (chan_array == NULL) 305 return -ENOMEM; 306 307 chan = chan_array; 308 for (i = 0; i < channels; i++, chan++) { 309 310 chan->type = IIO_VOLTAGE; 311 chan->indexed = 1; 312 chan->channel = adc_dev->channel_line[i]; 313 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW); 314 chan->datasheet_name = chan_name_ain[chan->channel]; 315 chan->scan_index = i; 316 chan->scan_type.sign = 'u'; 317 chan->scan_type.realbits = 12; 318 chan->scan_type.storagebits = 16; 319 } 320 321 indio_dev->channels = chan_array; 322 323 return 0; 324 } 325 326 static void tiadc_channels_remove(struct iio_dev *indio_dev) 327 { 328 kfree(indio_dev->channels); 329 } 330 331 static int tiadc_read_raw(struct iio_dev *indio_dev, 332 struct iio_chan_spec const *chan, 333 int *val, int *val2, long mask) 334 { 335 struct tiadc_device *adc_dev = iio_priv(indio_dev); 336 int i, map_val; 337 unsigned int fifo1count, read, stepid; 338 bool found = false; 339 u32 step_en; 340 unsigned long timeout; 341 342 if (iio_buffer_enabled(indio_dev)) 343 return -EBUSY; 344 345 step_en = get_adc_chan_step_mask(adc_dev, chan); 346 if (!step_en) 347 return -EINVAL; 348 349 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); 350 while (fifo1count--) 351 tiadc_readl(adc_dev, REG_FIFO1); 352 353 am335x_tsc_se_set_once(adc_dev->mfd_tscadc, step_en); 354 355 timeout = jiffies + usecs_to_jiffies 356 (IDLE_TIMEOUT * adc_dev->channels); 357 /* Wait for Fifo threshold interrupt */ 358 while (1) { 359 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); 360 if (fifo1count) 361 break; 362 363 if (time_after(jiffies, timeout)) { 364 am335x_tsc_se_adc_done(adc_dev->mfd_tscadc); 365 return -EAGAIN; 366 } 367 } 368 map_val = adc_dev->channel_step[chan->scan_index]; 369 370 /* 371 * We check the complete FIFO. We programmed just one entry but in case 372 * something went wrong we left empty handed (-EAGAIN previously) and 373 * then the value apeared somehow in the FIFO we would have two entries. 374 * Therefore we read every item and keep only the latest version of the 375 * requested channel. 376 */ 377 for (i = 0; i < fifo1count; i++) { 378 read = tiadc_readl(adc_dev, REG_FIFO1); 379 stepid = read & FIFOREAD_CHNLID_MASK; 380 stepid = stepid >> 0x10; 381 382 if (stepid == map_val) { 383 read = read & FIFOREAD_DATA_MASK; 384 found = true; 385 *val = (u16) read; 386 } 387 } 388 am335x_tsc_se_adc_done(adc_dev->mfd_tscadc); 389 390 if (found == false) 391 return -EBUSY; 392 return IIO_VAL_INT; 393 } 394 395 static const struct iio_info tiadc_info = { 396 .read_raw = &tiadc_read_raw, 397 .driver_module = THIS_MODULE, 398 }; 399 400 static int tiadc_probe(struct platform_device *pdev) 401 { 402 struct iio_dev *indio_dev; 403 struct tiadc_device *adc_dev; 404 struct device_node *node = pdev->dev.of_node; 405 struct property *prop; 406 const __be32 *cur; 407 int err; 408 u32 val; 409 int channels = 0; 410 411 if (!node) { 412 dev_err(&pdev->dev, "Could not find valid DT data.\n"); 413 return -EINVAL; 414 } 415 416 indio_dev = devm_iio_device_alloc(&pdev->dev, 417 sizeof(struct tiadc_device)); 418 if (indio_dev == NULL) { 419 dev_err(&pdev->dev, "failed to allocate iio device\n"); 420 return -ENOMEM; 421 } 422 adc_dev = iio_priv(indio_dev); 423 424 adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev); 425 426 of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) { 427 adc_dev->channel_line[channels] = val; 428 channels++; 429 } 430 adc_dev->channels = channels; 431 432 indio_dev->dev.parent = &pdev->dev; 433 indio_dev->name = dev_name(&pdev->dev); 434 indio_dev->modes = INDIO_DIRECT_MODE; 435 indio_dev->info = &tiadc_info; 436 437 tiadc_step_config(indio_dev); 438 tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD); 439 440 err = tiadc_channel_init(indio_dev, adc_dev->channels); 441 if (err < 0) 442 return err; 443 444 err = tiadc_iio_buffered_hardware_setup(indio_dev, 445 &tiadc_worker_h, 446 &tiadc_irq_h, 447 adc_dev->mfd_tscadc->irq, 448 IRQF_SHARED, 449 &tiadc_buffer_setup_ops); 450 451 if (err) 452 goto err_free_channels; 453 454 err = iio_device_register(indio_dev); 455 if (err) 456 goto err_buffer_unregister; 457 458 platform_set_drvdata(pdev, indio_dev); 459 460 return 0; 461 462 err_buffer_unregister: 463 tiadc_iio_buffered_hardware_remove(indio_dev); 464 err_free_channels: 465 tiadc_channels_remove(indio_dev); 466 return err; 467 } 468 469 static int tiadc_remove(struct platform_device *pdev) 470 { 471 struct iio_dev *indio_dev = platform_get_drvdata(pdev); 472 struct tiadc_device *adc_dev = iio_priv(indio_dev); 473 u32 step_en; 474 475 iio_device_unregister(indio_dev); 476 tiadc_iio_buffered_hardware_remove(indio_dev); 477 tiadc_channels_remove(indio_dev); 478 479 step_en = get_adc_step_mask(adc_dev); 480 am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en); 481 482 return 0; 483 } 484 485 #ifdef CONFIG_PM 486 static int tiadc_suspend(struct device *dev) 487 { 488 struct iio_dev *indio_dev = dev_get_drvdata(dev); 489 struct tiadc_device *adc_dev = iio_priv(indio_dev); 490 struct ti_tscadc_dev *tscadc_dev; 491 unsigned int idle; 492 493 tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev)); 494 if (!device_may_wakeup(tscadc_dev->dev)) { 495 idle = tiadc_readl(adc_dev, REG_CTRL); 496 idle &= ~(CNTRLREG_TSCSSENB); 497 tiadc_writel(adc_dev, REG_CTRL, (idle | 498 CNTRLREG_POWERDOWN)); 499 } 500 501 return 0; 502 } 503 504 static int tiadc_resume(struct device *dev) 505 { 506 struct iio_dev *indio_dev = dev_get_drvdata(dev); 507 struct tiadc_device *adc_dev = iio_priv(indio_dev); 508 unsigned int restore; 509 510 /* Make sure ADC is powered up */ 511 restore = tiadc_readl(adc_dev, REG_CTRL); 512 restore &= ~(CNTRLREG_POWERDOWN); 513 tiadc_writel(adc_dev, REG_CTRL, restore); 514 515 tiadc_step_config(indio_dev); 516 am335x_tsc_se_set_cache(adc_dev->mfd_tscadc, 517 adc_dev->buffer_en_ch_steps); 518 return 0; 519 } 520 521 static const struct dev_pm_ops tiadc_pm_ops = { 522 .suspend = tiadc_suspend, 523 .resume = tiadc_resume, 524 }; 525 #define TIADC_PM_OPS (&tiadc_pm_ops) 526 #else 527 #define TIADC_PM_OPS NULL 528 #endif 529 530 static const struct of_device_id ti_adc_dt_ids[] = { 531 { .compatible = "ti,am3359-adc", }, 532 { } 533 }; 534 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids); 535 536 static struct platform_driver tiadc_driver = { 537 .driver = { 538 .name = "TI-am335x-adc", 539 .pm = TIADC_PM_OPS, 540 .of_match_table = ti_adc_dt_ids, 541 }, 542 .probe = tiadc_probe, 543 .remove = tiadc_remove, 544 }; 545 module_platform_driver(tiadc_driver); 546 547 MODULE_DESCRIPTION("TI ADC controller driver"); 548 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>"); 549 MODULE_LICENSE("GPL"); 550