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 #include <linux/iio/trigger.h> 34 #include <linux/iio/trigger_consumer.h> 35 #include <linux/iio/triggered_buffer.h> 36 37 struct tiadc_device { 38 struct ti_tscadc_dev *mfd_tscadc; 39 int channels; 40 u8 channel_line[8]; 41 u8 channel_step[8]; 42 int buffer_en_ch_steps; 43 struct iio_trigger *trig; 44 u16 data[8]; 45 }; 46 47 static unsigned int tiadc_readl(struct tiadc_device *adc, unsigned int reg) 48 { 49 return readl(adc->mfd_tscadc->tscadc_base + reg); 50 } 51 52 static void tiadc_writel(struct tiadc_device *adc, unsigned int reg, 53 unsigned int val) 54 { 55 writel(val, adc->mfd_tscadc->tscadc_base + reg); 56 } 57 58 static u32 get_adc_step_mask(struct tiadc_device *adc_dev) 59 { 60 u32 step_en; 61 62 step_en = ((1 << adc_dev->channels) - 1); 63 step_en <<= TOTAL_STEPS - adc_dev->channels + 1; 64 return step_en; 65 } 66 67 static u32 get_adc_step_bit(struct tiadc_device *adc_dev, int chan) 68 { 69 return 1 << adc_dev->channel_step[chan]; 70 } 71 72 static void tiadc_step_config(struct iio_dev *indio_dev) 73 { 74 struct tiadc_device *adc_dev = iio_priv(indio_dev); 75 unsigned int stepconfig; 76 int i, steps; 77 78 /* 79 * There are 16 configurable steps and 8 analog input 80 * lines available which are shared between Touchscreen and ADC. 81 * 82 * Steps backwards i.e. from 16 towards 0 are used by ADC 83 * depending on number of input lines needed. 84 * Channel would represent which analog input 85 * needs to be given to ADC to digitalize data. 86 */ 87 88 steps = TOTAL_STEPS - adc_dev->channels; 89 if (iio_buffer_enabled(indio_dev)) 90 stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1 91 | STEPCONFIG_MODE_SWCNT; 92 else 93 stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1; 94 95 for (i = 0; i < adc_dev->channels; i++) { 96 int chan; 97 98 chan = adc_dev->channel_line[i]; 99 tiadc_writel(adc_dev, REG_STEPCONFIG(steps), 100 stepconfig | STEPCONFIG_INP(chan)); 101 tiadc_writel(adc_dev, REG_STEPDELAY(steps), 102 STEPCONFIG_OPENDLY); 103 adc_dev->channel_step[i] = steps; 104 steps++; 105 } 106 } 107 108 static irqreturn_t tiadc_irq_h(int irq, void *private) 109 { 110 struct iio_dev *indio_dev = private; 111 struct tiadc_device *adc_dev = iio_priv(indio_dev); 112 unsigned int status, config; 113 status = tiadc_readl(adc_dev, REG_IRQSTATUS); 114 115 /* 116 * ADC and touchscreen share the IRQ line. 117 * FIFO0 interrupts are used by TSC. Handle FIFO1 IRQs here only 118 */ 119 if (status & IRQENB_FIFO1OVRRUN) { 120 /* FIFO Overrun. Clear flag. Disable/Enable ADC to recover */ 121 config = tiadc_readl(adc_dev, REG_CTRL); 122 config &= ~(CNTRLREG_TSCSSENB); 123 tiadc_writel(adc_dev, REG_CTRL, config); 124 tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1OVRRUN 125 | IRQENB_FIFO1UNDRFLW | IRQENB_FIFO1THRES); 126 tiadc_writel(adc_dev, REG_CTRL, (config | CNTRLREG_TSCSSENB)); 127 return IRQ_HANDLED; 128 } else if (status & IRQENB_FIFO1THRES) { 129 /* Disable irq and wake worker thread */ 130 tiadc_writel(adc_dev, REG_IRQCLR, IRQENB_FIFO1THRES); 131 return IRQ_WAKE_THREAD; 132 } 133 134 return IRQ_NONE; 135 } 136 137 static irqreturn_t tiadc_worker_h(int irq, void *private) 138 { 139 struct iio_dev *indio_dev = private; 140 struct tiadc_device *adc_dev = iio_priv(indio_dev); 141 int i, k, fifo1count, read; 142 u16 *data = adc_dev->data; 143 144 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); 145 for (k = 0; k < fifo1count; k = k + i) { 146 for (i = 0; i < (indio_dev->scan_bytes)/2; i++) { 147 read = tiadc_readl(adc_dev, REG_FIFO1); 148 data[i] = read & FIFOREAD_DATA_MASK; 149 } 150 iio_push_to_buffers(indio_dev, (u8 *) data); 151 } 152 153 tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES); 154 tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES); 155 156 return IRQ_HANDLED; 157 } 158 159 static int tiadc_buffer_preenable(struct iio_dev *indio_dev) 160 { 161 struct tiadc_device *adc_dev = iio_priv(indio_dev); 162 int i, fifo1count, read; 163 164 tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES | 165 IRQENB_FIFO1OVRRUN | 166 IRQENB_FIFO1UNDRFLW)); 167 168 /* Flush FIFO. Needed in corner cases in simultaneous tsc/adc use */ 169 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); 170 for (i = 0; i < fifo1count; i++) 171 read = tiadc_readl(adc_dev, REG_FIFO1); 172 173 return iio_sw_buffer_preenable(indio_dev); 174 } 175 176 static int tiadc_buffer_postenable(struct iio_dev *indio_dev) 177 { 178 struct tiadc_device *adc_dev = iio_priv(indio_dev); 179 struct iio_buffer *buffer = indio_dev->buffer; 180 unsigned int enb = 0; 181 u8 bit; 182 183 tiadc_step_config(indio_dev); 184 for_each_set_bit(bit, buffer->scan_mask, adc_dev->channels) 185 enb |= (get_adc_step_bit(adc_dev, bit) << 1); 186 adc_dev->buffer_en_ch_steps = enb; 187 188 am335x_tsc_se_set(adc_dev->mfd_tscadc, enb); 189 190 tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES 191 | IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW); 192 tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES 193 | IRQENB_FIFO1OVRRUN); 194 195 return 0; 196 } 197 198 static int tiadc_buffer_predisable(struct iio_dev *indio_dev) 199 { 200 struct tiadc_device *adc_dev = iio_priv(indio_dev); 201 int fifo1count, i, read; 202 203 tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES | 204 IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW)); 205 am335x_tsc_se_clr(adc_dev->mfd_tscadc, adc_dev->buffer_en_ch_steps); 206 207 /* Flush FIFO of leftover data in the time it takes to disable adc */ 208 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); 209 for (i = 0; i < fifo1count; i++) 210 read = tiadc_readl(adc_dev, REG_FIFO1); 211 212 return 0; 213 } 214 215 static int tiadc_buffer_postdisable(struct iio_dev *indio_dev) 216 { 217 tiadc_step_config(indio_dev); 218 219 return 0; 220 } 221 222 static const struct iio_buffer_setup_ops tiadc_buffer_setup_ops = { 223 .preenable = &tiadc_buffer_preenable, 224 .postenable = &tiadc_buffer_postenable, 225 .predisable = &tiadc_buffer_predisable, 226 .postdisable = &tiadc_buffer_postdisable, 227 }; 228 229 int tiadc_iio_buffered_hardware_setup(struct iio_dev *indio_dev, 230 irqreturn_t (*pollfunc_bh)(int irq, void *p), 231 irqreturn_t (*pollfunc_th)(int irq, void *p), 232 int irq, 233 unsigned long flags, 234 const struct iio_buffer_setup_ops *setup_ops) 235 { 236 int ret; 237 238 indio_dev->buffer = iio_kfifo_allocate(indio_dev); 239 if (!indio_dev->buffer) 240 return -ENOMEM; 241 242 ret = request_threaded_irq(irq, pollfunc_th, pollfunc_bh, 243 flags, indio_dev->name, indio_dev); 244 if (ret) 245 goto error_kfifo_free; 246 247 indio_dev->setup_ops = setup_ops; 248 indio_dev->modes |= INDIO_BUFFER_HARDWARE; 249 250 ret = iio_buffer_register(indio_dev, 251 indio_dev->channels, 252 indio_dev->num_channels); 253 if (ret) 254 goto error_free_irq; 255 256 return 0; 257 258 error_free_irq: 259 free_irq(irq, indio_dev); 260 error_kfifo_free: 261 iio_kfifo_free(indio_dev->buffer); 262 return ret; 263 } 264 265 static void tiadc_iio_buffered_hardware_remove(struct iio_dev *indio_dev) 266 { 267 struct tiadc_device *adc_dev = iio_priv(indio_dev); 268 269 free_irq(adc_dev->mfd_tscadc->irq, indio_dev); 270 iio_kfifo_free(indio_dev->buffer); 271 iio_buffer_unregister(indio_dev); 272 } 273 274 275 static const char * const chan_name_ain[] = { 276 "AIN0", 277 "AIN1", 278 "AIN2", 279 "AIN3", 280 "AIN4", 281 "AIN5", 282 "AIN6", 283 "AIN7", 284 }; 285 286 static int tiadc_channel_init(struct iio_dev *indio_dev, int channels) 287 { 288 struct tiadc_device *adc_dev = iio_priv(indio_dev); 289 struct iio_chan_spec *chan_array; 290 struct iio_chan_spec *chan; 291 int i; 292 293 indio_dev->num_channels = channels; 294 chan_array = kcalloc(channels, 295 sizeof(struct iio_chan_spec), GFP_KERNEL); 296 if (chan_array == NULL) 297 return -ENOMEM; 298 299 chan = chan_array; 300 for (i = 0; i < channels; i++, chan++) { 301 302 chan->type = IIO_VOLTAGE; 303 chan->indexed = 1; 304 chan->channel = adc_dev->channel_line[i]; 305 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW); 306 chan->datasheet_name = chan_name_ain[chan->channel]; 307 chan->scan_index = i; 308 chan->scan_type.sign = 'u'; 309 chan->scan_type.realbits = 12; 310 chan->scan_type.storagebits = 16; 311 } 312 313 indio_dev->channels = chan_array; 314 315 return 0; 316 } 317 318 static void tiadc_channels_remove(struct iio_dev *indio_dev) 319 { 320 kfree(indio_dev->channels); 321 } 322 323 static int tiadc_read_raw(struct iio_dev *indio_dev, 324 struct iio_chan_spec const *chan, 325 int *val, int *val2, long mask) 326 { 327 struct tiadc_device *adc_dev = iio_priv(indio_dev); 328 int i, map_val; 329 unsigned int fifo1count, read, stepid; 330 u32 step = UINT_MAX; 331 bool found = false; 332 u32 step_en; 333 unsigned long timeout = jiffies + usecs_to_jiffies 334 (IDLE_TIMEOUT * adc_dev->channels); 335 336 if (iio_buffer_enabled(indio_dev)) 337 return -EBUSY; 338 339 step_en = get_adc_step_mask(adc_dev); 340 am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en); 341 342 /* Wait for ADC sequencer to complete sampling */ 343 while (tiadc_readl(adc_dev, REG_ADCFSM) & SEQ_STATUS) { 344 if (time_after(jiffies, timeout)) 345 return -EAGAIN; 346 } 347 map_val = chan->channel + TOTAL_CHANNELS; 348 349 /* 350 * When the sub-system is first enabled, 351 * the sequencer will always start with the 352 * lowest step (1) and continue until step (16). 353 * For ex: If we have enabled 4 ADC channels and 354 * currently use only 1 out of them, the 355 * sequencer still configures all the 4 steps, 356 * leading to 3 unwanted data. 357 * Hence we need to flush out this data. 358 */ 359 360 for (i = 0; i < ARRAY_SIZE(adc_dev->channel_step); i++) { 361 if (chan->channel == adc_dev->channel_line[i]) { 362 step = adc_dev->channel_step[i]; 363 break; 364 } 365 } 366 if (WARN_ON_ONCE(step == UINT_MAX)) 367 return -EINVAL; 368 369 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); 370 for (i = 0; i < fifo1count; i++) { 371 read = tiadc_readl(adc_dev, REG_FIFO1); 372 stepid = read & FIFOREAD_CHNLID_MASK; 373 stepid = stepid >> 0x10; 374 375 if (stepid == map_val) { 376 read = read & FIFOREAD_DATA_MASK; 377 found = true; 378 *val = (u16) read; 379 } 380 } 381 382 if (found == false) 383 return -EBUSY; 384 return IIO_VAL_INT; 385 } 386 387 static const struct iio_info tiadc_info = { 388 .read_raw = &tiadc_read_raw, 389 .driver_module = THIS_MODULE, 390 }; 391 392 static int tiadc_probe(struct platform_device *pdev) 393 { 394 struct iio_dev *indio_dev; 395 struct tiadc_device *adc_dev; 396 struct device_node *node = pdev->dev.of_node; 397 struct property *prop; 398 const __be32 *cur; 399 int err; 400 u32 val; 401 int channels = 0; 402 403 if (!node) { 404 dev_err(&pdev->dev, "Could not find valid DT data.\n"); 405 return -EINVAL; 406 } 407 408 indio_dev = devm_iio_device_alloc(&pdev->dev, 409 sizeof(struct tiadc_device)); 410 if (indio_dev == NULL) { 411 dev_err(&pdev->dev, "failed to allocate iio device\n"); 412 return -ENOMEM; 413 } 414 adc_dev = iio_priv(indio_dev); 415 416 adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev); 417 418 of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) { 419 adc_dev->channel_line[channels] = val; 420 channels++; 421 } 422 adc_dev->channels = channels; 423 424 indio_dev->dev.parent = &pdev->dev; 425 indio_dev->name = dev_name(&pdev->dev); 426 indio_dev->modes = INDIO_DIRECT_MODE; 427 indio_dev->info = &tiadc_info; 428 429 tiadc_step_config(indio_dev); 430 tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD); 431 432 err = tiadc_channel_init(indio_dev, adc_dev->channels); 433 if (err < 0) 434 return err; 435 436 err = tiadc_iio_buffered_hardware_setup(indio_dev, 437 &tiadc_worker_h, 438 &tiadc_irq_h, 439 adc_dev->mfd_tscadc->irq, 440 IRQF_SHARED, 441 &tiadc_buffer_setup_ops); 442 443 if (err) 444 goto err_free_channels; 445 446 err = iio_device_register(indio_dev); 447 if (err) 448 goto err_buffer_unregister; 449 450 platform_set_drvdata(pdev, indio_dev); 451 452 return 0; 453 454 err_buffer_unregister: 455 tiadc_iio_buffered_hardware_remove(indio_dev); 456 err_free_channels: 457 tiadc_channels_remove(indio_dev); 458 return err; 459 } 460 461 static int tiadc_remove(struct platform_device *pdev) 462 { 463 struct iio_dev *indio_dev = platform_get_drvdata(pdev); 464 struct tiadc_device *adc_dev = iio_priv(indio_dev); 465 u32 step_en; 466 467 iio_device_unregister(indio_dev); 468 tiadc_iio_buffered_hardware_remove(indio_dev); 469 tiadc_channels_remove(indio_dev); 470 471 step_en = get_adc_step_mask(adc_dev); 472 am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en); 473 474 return 0; 475 } 476 477 #ifdef CONFIG_PM 478 static int tiadc_suspend(struct device *dev) 479 { 480 struct iio_dev *indio_dev = dev_get_drvdata(dev); 481 struct tiadc_device *adc_dev = iio_priv(indio_dev); 482 struct ti_tscadc_dev *tscadc_dev; 483 unsigned int idle; 484 485 tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev)); 486 if (!device_may_wakeup(tscadc_dev->dev)) { 487 idle = tiadc_readl(adc_dev, REG_CTRL); 488 idle &= ~(CNTRLREG_TSCSSENB); 489 tiadc_writel(adc_dev, REG_CTRL, (idle | 490 CNTRLREG_POWERDOWN)); 491 } 492 493 return 0; 494 } 495 496 static int tiadc_resume(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 unsigned int restore; 501 502 /* Make sure ADC is powered up */ 503 restore = tiadc_readl(adc_dev, REG_CTRL); 504 restore &= ~(CNTRLREG_POWERDOWN); 505 tiadc_writel(adc_dev, REG_CTRL, restore); 506 507 tiadc_step_config(indio_dev); 508 509 return 0; 510 } 511 512 static const struct dev_pm_ops tiadc_pm_ops = { 513 .suspend = tiadc_suspend, 514 .resume = tiadc_resume, 515 }; 516 #define TIADC_PM_OPS (&tiadc_pm_ops) 517 #else 518 #define TIADC_PM_OPS NULL 519 #endif 520 521 static const struct of_device_id ti_adc_dt_ids[] = { 522 { .compatible = "ti,am3359-adc", }, 523 { } 524 }; 525 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids); 526 527 static struct platform_driver tiadc_driver = { 528 .driver = { 529 .name = "TI-am335x-adc", 530 .owner = THIS_MODULE, 531 .pm = TIADC_PM_OPS, 532 .of_match_table = of_match_ptr(ti_adc_dt_ids), 533 }, 534 .probe = tiadc_probe, 535 .remove = tiadc_remove, 536 }; 537 module_platform_driver(tiadc_driver); 538 539 MODULE_DESCRIPTION("TI ADC controller driver"); 540 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>"); 541 MODULE_LICENSE("GPL"); 542