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