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_step_bit(struct tiadc_device *adc_dev, int chan) 64 { 65 return 1 << adc_dev->channel_step[chan]; 66 } 67 68 static void tiadc_step_config(struct iio_dev *indio_dev) 69 { 70 struct tiadc_device *adc_dev = iio_priv(indio_dev); 71 unsigned int stepconfig; 72 int i, steps; 73 74 /* 75 * There are 16 configurable steps and 8 analog input 76 * lines available which are shared between Touchscreen and ADC. 77 * 78 * Steps backwards i.e. from 16 towards 0 are used by ADC 79 * depending on number of input lines needed. 80 * Channel would represent which analog input 81 * needs to be given to ADC to digitalize data. 82 */ 83 84 steps = TOTAL_STEPS - adc_dev->channels; 85 if (iio_buffer_enabled(indio_dev)) 86 stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1 87 | STEPCONFIG_MODE_SWCNT; 88 else 89 stepconfig = STEPCONFIG_AVG_16 | STEPCONFIG_FIFO1; 90 91 for (i = 0; i < adc_dev->channels; i++) { 92 int chan; 93 94 chan = adc_dev->channel_line[i]; 95 tiadc_writel(adc_dev, REG_STEPCONFIG(steps), 96 stepconfig | STEPCONFIG_INP(chan)); 97 tiadc_writel(adc_dev, REG_STEPDELAY(steps), 98 STEPCONFIG_OPENDLY); 99 adc_dev->channel_step[i] = steps; 100 steps++; 101 } 102 } 103 104 static irqreturn_t tiadc_irq_h(int irq, void *private) 105 { 106 struct iio_dev *indio_dev = private; 107 struct tiadc_device *adc_dev = iio_priv(indio_dev); 108 unsigned int status, config; 109 status = tiadc_readl(adc_dev, REG_IRQSTATUS); 110 111 /* 112 * ADC and touchscreen share the IRQ line. 113 * FIFO0 interrupts are used by TSC. Handle FIFO1 IRQs here only 114 */ 115 if (status & IRQENB_FIFO1OVRRUN) { 116 /* FIFO Overrun. Clear flag. Disable/Enable ADC to recover */ 117 config = tiadc_readl(adc_dev, REG_CTRL); 118 config &= ~(CNTRLREG_TSCSSENB); 119 tiadc_writel(adc_dev, REG_CTRL, config); 120 tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1OVRRUN 121 | IRQENB_FIFO1UNDRFLW | IRQENB_FIFO1THRES); 122 tiadc_writel(adc_dev, REG_CTRL, (config | CNTRLREG_TSCSSENB)); 123 return IRQ_HANDLED; 124 } else if (status & IRQENB_FIFO1THRES) { 125 /* Disable irq and wake worker thread */ 126 tiadc_writel(adc_dev, REG_IRQCLR, IRQENB_FIFO1THRES); 127 return IRQ_WAKE_THREAD; 128 } 129 130 return IRQ_NONE; 131 } 132 133 static irqreturn_t tiadc_worker_h(int irq, void *private) 134 { 135 struct iio_dev *indio_dev = private; 136 struct tiadc_device *adc_dev = iio_priv(indio_dev); 137 int i, k, fifo1count, read; 138 u16 *data = adc_dev->data; 139 140 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); 141 for (k = 0; k < fifo1count; k = k + i) { 142 for (i = 0; i < (indio_dev->scan_bytes)/2; i++) { 143 read = tiadc_readl(adc_dev, REG_FIFO1); 144 data[i] = read & FIFOREAD_DATA_MASK; 145 } 146 iio_push_to_buffers(indio_dev, (u8 *) data); 147 } 148 149 tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES); 150 tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES); 151 152 return IRQ_HANDLED; 153 } 154 155 static int tiadc_buffer_preenable(struct iio_dev *indio_dev) 156 { 157 struct tiadc_device *adc_dev = iio_priv(indio_dev); 158 int i, fifo1count, read; 159 160 tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES | 161 IRQENB_FIFO1OVRRUN | 162 IRQENB_FIFO1UNDRFLW)); 163 164 /* Flush FIFO. Needed in corner cases in simultaneous tsc/adc use */ 165 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); 166 for (i = 0; i < fifo1count; i++) 167 read = tiadc_readl(adc_dev, REG_FIFO1); 168 169 return 0; 170 } 171 172 static int tiadc_buffer_postenable(struct iio_dev *indio_dev) 173 { 174 struct tiadc_device *adc_dev = iio_priv(indio_dev); 175 struct iio_buffer *buffer = indio_dev->buffer; 176 unsigned int enb = 0; 177 u8 bit; 178 179 tiadc_step_config(indio_dev); 180 for_each_set_bit(bit, buffer->scan_mask, adc_dev->channels) 181 enb |= (get_adc_step_bit(adc_dev, bit) << 1); 182 adc_dev->buffer_en_ch_steps = enb; 183 184 am335x_tsc_se_set(adc_dev->mfd_tscadc, enb); 185 186 tiadc_writel(adc_dev, REG_IRQSTATUS, IRQENB_FIFO1THRES 187 | IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW); 188 tiadc_writel(adc_dev, REG_IRQENABLE, IRQENB_FIFO1THRES 189 | IRQENB_FIFO1OVRRUN); 190 191 return 0; 192 } 193 194 static int tiadc_buffer_predisable(struct iio_dev *indio_dev) 195 { 196 struct tiadc_device *adc_dev = iio_priv(indio_dev); 197 int fifo1count, i, read; 198 199 tiadc_writel(adc_dev, REG_IRQCLR, (IRQENB_FIFO1THRES | 200 IRQENB_FIFO1OVRRUN | IRQENB_FIFO1UNDRFLW)); 201 am335x_tsc_se_clr(adc_dev->mfd_tscadc, adc_dev->buffer_en_ch_steps); 202 203 /* Flush FIFO of leftover data in the time it takes to disable adc */ 204 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); 205 for (i = 0; i < fifo1count; i++) 206 read = tiadc_readl(adc_dev, REG_FIFO1); 207 208 return 0; 209 } 210 211 static int tiadc_buffer_postdisable(struct iio_dev *indio_dev) 212 { 213 tiadc_step_config(indio_dev); 214 215 return 0; 216 } 217 218 static const struct iio_buffer_setup_ops tiadc_buffer_setup_ops = { 219 .preenable = &tiadc_buffer_preenable, 220 .postenable = &tiadc_buffer_postenable, 221 .predisable = &tiadc_buffer_predisable, 222 .postdisable = &tiadc_buffer_postdisable, 223 }; 224 225 static int tiadc_iio_buffered_hardware_setup(struct iio_dev *indio_dev, 226 irqreturn_t (*pollfunc_bh)(int irq, void *p), 227 irqreturn_t (*pollfunc_th)(int irq, void *p), 228 int irq, 229 unsigned long flags, 230 const struct iio_buffer_setup_ops *setup_ops) 231 { 232 int ret; 233 234 indio_dev->buffer = iio_kfifo_allocate(indio_dev); 235 if (!indio_dev->buffer) 236 return -ENOMEM; 237 238 ret = request_threaded_irq(irq, pollfunc_th, pollfunc_bh, 239 flags, indio_dev->name, indio_dev); 240 if (ret) 241 goto error_kfifo_free; 242 243 indio_dev->setup_ops = setup_ops; 244 indio_dev->modes |= INDIO_BUFFER_HARDWARE; 245 246 ret = iio_buffer_register(indio_dev, 247 indio_dev->channels, 248 indio_dev->num_channels); 249 if (ret) 250 goto error_free_irq; 251 252 return 0; 253 254 error_free_irq: 255 free_irq(irq, indio_dev); 256 error_kfifo_free: 257 iio_kfifo_free(indio_dev->buffer); 258 return ret; 259 } 260 261 static void tiadc_iio_buffered_hardware_remove(struct iio_dev *indio_dev) 262 { 263 struct tiadc_device *adc_dev = iio_priv(indio_dev); 264 265 free_irq(adc_dev->mfd_tscadc->irq, indio_dev); 266 iio_kfifo_free(indio_dev->buffer); 267 iio_buffer_unregister(indio_dev); 268 } 269 270 271 static const char * const chan_name_ain[] = { 272 "AIN0", 273 "AIN1", 274 "AIN2", 275 "AIN3", 276 "AIN4", 277 "AIN5", 278 "AIN6", 279 "AIN7", 280 }; 281 282 static int tiadc_channel_init(struct iio_dev *indio_dev, int channels) 283 { 284 struct tiadc_device *adc_dev = iio_priv(indio_dev); 285 struct iio_chan_spec *chan_array; 286 struct iio_chan_spec *chan; 287 int i; 288 289 indio_dev->num_channels = channels; 290 chan_array = kcalloc(channels, 291 sizeof(struct iio_chan_spec), GFP_KERNEL); 292 if (chan_array == NULL) 293 return -ENOMEM; 294 295 chan = chan_array; 296 for (i = 0; i < channels; i++, chan++) { 297 298 chan->type = IIO_VOLTAGE; 299 chan->indexed = 1; 300 chan->channel = adc_dev->channel_line[i]; 301 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW); 302 chan->datasheet_name = chan_name_ain[chan->channel]; 303 chan->scan_index = i; 304 chan->scan_type.sign = 'u'; 305 chan->scan_type.realbits = 12; 306 chan->scan_type.storagebits = 16; 307 } 308 309 indio_dev->channels = chan_array; 310 311 return 0; 312 } 313 314 static void tiadc_channels_remove(struct iio_dev *indio_dev) 315 { 316 kfree(indio_dev->channels); 317 } 318 319 static int tiadc_read_raw(struct iio_dev *indio_dev, 320 struct iio_chan_spec const *chan, 321 int *val, int *val2, long mask) 322 { 323 struct tiadc_device *adc_dev = iio_priv(indio_dev); 324 int i, map_val; 325 unsigned int fifo1count, read, stepid; 326 bool found = false; 327 u32 step_en; 328 unsigned long timeout = jiffies + usecs_to_jiffies 329 (IDLE_TIMEOUT * adc_dev->channels); 330 331 if (iio_buffer_enabled(indio_dev)) 332 return -EBUSY; 333 334 step_en = get_adc_step_mask(adc_dev); 335 am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en); 336 337 /* Wait for ADC sequencer to complete sampling */ 338 while (tiadc_readl(adc_dev, REG_ADCFSM) & SEQ_STATUS) { 339 if (time_after(jiffies, timeout)) 340 return -EAGAIN; 341 } 342 map_val = chan->channel + TOTAL_CHANNELS; 343 344 /* 345 * When the sub-system is first enabled, 346 * the sequencer will always start with the 347 * lowest step (1) and continue until step (16). 348 * For ex: If we have enabled 4 ADC channels and 349 * currently use only 1 out of them, the 350 * sequencer still configures all the 4 steps, 351 * leading to 3 unwanted data. 352 * Hence we need to flush out this data. 353 */ 354 355 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); 356 for (i = 0; i < fifo1count; i++) { 357 read = tiadc_readl(adc_dev, REG_FIFO1); 358 stepid = read & FIFOREAD_CHNLID_MASK; 359 stepid = stepid >> 0x10; 360 361 if (stepid == map_val) { 362 read = read & FIFOREAD_DATA_MASK; 363 found = true; 364 *val = (u16) read; 365 } 366 } 367 368 if (found == false) 369 return -EBUSY; 370 return IIO_VAL_INT; 371 } 372 373 static const struct iio_info tiadc_info = { 374 .read_raw = &tiadc_read_raw, 375 .driver_module = THIS_MODULE, 376 }; 377 378 static int tiadc_probe(struct platform_device *pdev) 379 { 380 struct iio_dev *indio_dev; 381 struct tiadc_device *adc_dev; 382 struct device_node *node = pdev->dev.of_node; 383 struct property *prop; 384 const __be32 *cur; 385 int err; 386 u32 val; 387 int channels = 0; 388 389 if (!node) { 390 dev_err(&pdev->dev, "Could not find valid DT data.\n"); 391 return -EINVAL; 392 } 393 394 indio_dev = devm_iio_device_alloc(&pdev->dev, 395 sizeof(struct tiadc_device)); 396 if (indio_dev == NULL) { 397 dev_err(&pdev->dev, "failed to allocate iio device\n"); 398 return -ENOMEM; 399 } 400 adc_dev = iio_priv(indio_dev); 401 402 adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev); 403 404 of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) { 405 adc_dev->channel_line[channels] = val; 406 channels++; 407 } 408 adc_dev->channels = channels; 409 410 indio_dev->dev.parent = &pdev->dev; 411 indio_dev->name = dev_name(&pdev->dev); 412 indio_dev->modes = INDIO_DIRECT_MODE; 413 indio_dev->info = &tiadc_info; 414 415 tiadc_step_config(indio_dev); 416 tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD); 417 418 err = tiadc_channel_init(indio_dev, adc_dev->channels); 419 if (err < 0) 420 return err; 421 422 err = tiadc_iio_buffered_hardware_setup(indio_dev, 423 &tiadc_worker_h, 424 &tiadc_irq_h, 425 adc_dev->mfd_tscadc->irq, 426 IRQF_SHARED, 427 &tiadc_buffer_setup_ops); 428 429 if (err) 430 goto err_free_channels; 431 432 err = iio_device_register(indio_dev); 433 if (err) 434 goto err_buffer_unregister; 435 436 platform_set_drvdata(pdev, indio_dev); 437 438 return 0; 439 440 err_buffer_unregister: 441 tiadc_iio_buffered_hardware_remove(indio_dev); 442 err_free_channels: 443 tiadc_channels_remove(indio_dev); 444 return err; 445 } 446 447 static int tiadc_remove(struct platform_device *pdev) 448 { 449 struct iio_dev *indio_dev = platform_get_drvdata(pdev); 450 struct tiadc_device *adc_dev = iio_priv(indio_dev); 451 u32 step_en; 452 453 iio_device_unregister(indio_dev); 454 tiadc_iio_buffered_hardware_remove(indio_dev); 455 tiadc_channels_remove(indio_dev); 456 457 step_en = get_adc_step_mask(adc_dev); 458 am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en); 459 460 return 0; 461 } 462 463 #ifdef CONFIG_PM 464 static int tiadc_suspend(struct device *dev) 465 { 466 struct iio_dev *indio_dev = dev_get_drvdata(dev); 467 struct tiadc_device *adc_dev = iio_priv(indio_dev); 468 struct ti_tscadc_dev *tscadc_dev; 469 unsigned int idle; 470 471 tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev)); 472 if (!device_may_wakeup(tscadc_dev->dev)) { 473 idle = tiadc_readl(adc_dev, REG_CTRL); 474 idle &= ~(CNTRLREG_TSCSSENB); 475 tiadc_writel(adc_dev, REG_CTRL, (idle | 476 CNTRLREG_POWERDOWN)); 477 } 478 479 return 0; 480 } 481 482 static int tiadc_resume(struct device *dev) 483 { 484 struct iio_dev *indio_dev = dev_get_drvdata(dev); 485 struct tiadc_device *adc_dev = iio_priv(indio_dev); 486 unsigned int restore; 487 488 /* Make sure ADC is powered up */ 489 restore = tiadc_readl(adc_dev, REG_CTRL); 490 restore &= ~(CNTRLREG_POWERDOWN); 491 tiadc_writel(adc_dev, REG_CTRL, restore); 492 493 tiadc_step_config(indio_dev); 494 495 return 0; 496 } 497 498 static const struct dev_pm_ops tiadc_pm_ops = { 499 .suspend = tiadc_suspend, 500 .resume = tiadc_resume, 501 }; 502 #define TIADC_PM_OPS (&tiadc_pm_ops) 503 #else 504 #define TIADC_PM_OPS NULL 505 #endif 506 507 static const struct of_device_id ti_adc_dt_ids[] = { 508 { .compatible = "ti,am3359-adc", }, 509 { } 510 }; 511 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids); 512 513 static struct platform_driver tiadc_driver = { 514 .driver = { 515 .name = "TI-am335x-adc", 516 .owner = THIS_MODULE, 517 .pm = TIADC_PM_OPS, 518 .of_match_table = of_match_ptr(ti_adc_dt_ids), 519 }, 520 .probe = tiadc_probe, 521 .remove = tiadc_remove, 522 }; 523 module_platform_driver(tiadc_driver); 524 525 MODULE_DESCRIPTION("TI ADC controller driver"); 526 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>"); 527 MODULE_LICENSE("GPL"); 528