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 struct iio_buffer *buffer; 233 int ret; 234 235 buffer = iio_kfifo_allocate(indio_dev); 236 if (!buffer) 237 return -ENOMEM; 238 239 iio_device_attach_buffer(indio_dev, buffer); 240 241 ret = request_threaded_irq(irq, pollfunc_th, pollfunc_bh, 242 flags, indio_dev->name, indio_dev); 243 if (ret) 244 goto error_kfifo_free; 245 246 indio_dev->setup_ops = setup_ops; 247 indio_dev->modes |= INDIO_BUFFER_HARDWARE; 248 249 ret = iio_buffer_register(indio_dev, 250 indio_dev->channels, 251 indio_dev->num_channels); 252 if (ret) 253 goto error_free_irq; 254 255 return 0; 256 257 error_free_irq: 258 free_irq(irq, indio_dev); 259 error_kfifo_free: 260 iio_kfifo_free(indio_dev->buffer); 261 return ret; 262 } 263 264 static void tiadc_iio_buffered_hardware_remove(struct iio_dev *indio_dev) 265 { 266 struct tiadc_device *adc_dev = iio_priv(indio_dev); 267 268 free_irq(adc_dev->mfd_tscadc->irq, indio_dev); 269 iio_kfifo_free(indio_dev->buffer); 270 iio_buffer_unregister(indio_dev); 271 } 272 273 274 static const char * const chan_name_ain[] = { 275 "AIN0", 276 "AIN1", 277 "AIN2", 278 "AIN3", 279 "AIN4", 280 "AIN5", 281 "AIN6", 282 "AIN7", 283 }; 284 285 static int tiadc_channel_init(struct iio_dev *indio_dev, int channels) 286 { 287 struct tiadc_device *adc_dev = iio_priv(indio_dev); 288 struct iio_chan_spec *chan_array; 289 struct iio_chan_spec *chan; 290 int i; 291 292 indio_dev->num_channels = channels; 293 chan_array = kcalloc(channels, 294 sizeof(struct iio_chan_spec), GFP_KERNEL); 295 if (chan_array == NULL) 296 return -ENOMEM; 297 298 chan = chan_array; 299 for (i = 0; i < channels; i++, chan++) { 300 301 chan->type = IIO_VOLTAGE; 302 chan->indexed = 1; 303 chan->channel = adc_dev->channel_line[i]; 304 chan->info_mask_separate = BIT(IIO_CHAN_INFO_RAW); 305 chan->datasheet_name = chan_name_ain[chan->channel]; 306 chan->scan_index = i; 307 chan->scan_type.sign = 'u'; 308 chan->scan_type.realbits = 12; 309 chan->scan_type.storagebits = 16; 310 } 311 312 indio_dev->channels = chan_array; 313 314 return 0; 315 } 316 317 static void tiadc_channels_remove(struct iio_dev *indio_dev) 318 { 319 kfree(indio_dev->channels); 320 } 321 322 static int tiadc_read_raw(struct iio_dev *indio_dev, 323 struct iio_chan_spec const *chan, 324 int *val, int *val2, long mask) 325 { 326 struct tiadc_device *adc_dev = iio_priv(indio_dev); 327 int i, map_val; 328 unsigned int fifo1count, read, stepid; 329 bool found = false; 330 u32 step_en; 331 unsigned long timeout = jiffies + usecs_to_jiffies 332 (IDLE_TIMEOUT * adc_dev->channels); 333 334 if (iio_buffer_enabled(indio_dev)) 335 return -EBUSY; 336 337 step_en = get_adc_step_mask(adc_dev); 338 am335x_tsc_se_set(adc_dev->mfd_tscadc, step_en); 339 340 /* Wait for ADC sequencer to complete sampling */ 341 while (tiadc_readl(adc_dev, REG_ADCFSM) & SEQ_STATUS) { 342 if (time_after(jiffies, timeout)) 343 return -EAGAIN; 344 } 345 map_val = chan->channel + TOTAL_CHANNELS; 346 347 /* 348 * When the sub-system is first enabled, 349 * the sequencer will always start with the 350 * lowest step (1) and continue until step (16). 351 * For ex: If we have enabled 4 ADC channels and 352 * currently use only 1 out of them, the 353 * sequencer still configures all the 4 steps, 354 * leading to 3 unwanted data. 355 * Hence we need to flush out this data. 356 */ 357 358 fifo1count = tiadc_readl(adc_dev, REG_FIFO1CNT); 359 for (i = 0; i < fifo1count; i++) { 360 read = tiadc_readl(adc_dev, REG_FIFO1); 361 stepid = read & FIFOREAD_CHNLID_MASK; 362 stepid = stepid >> 0x10; 363 364 if (stepid == map_val) { 365 read = read & FIFOREAD_DATA_MASK; 366 found = true; 367 *val = (u16) read; 368 } 369 } 370 371 if (found == false) 372 return -EBUSY; 373 return IIO_VAL_INT; 374 } 375 376 static const struct iio_info tiadc_info = { 377 .read_raw = &tiadc_read_raw, 378 .driver_module = THIS_MODULE, 379 }; 380 381 static int tiadc_probe(struct platform_device *pdev) 382 { 383 struct iio_dev *indio_dev; 384 struct tiadc_device *adc_dev; 385 struct device_node *node = pdev->dev.of_node; 386 struct property *prop; 387 const __be32 *cur; 388 int err; 389 u32 val; 390 int channels = 0; 391 392 if (!node) { 393 dev_err(&pdev->dev, "Could not find valid DT data.\n"); 394 return -EINVAL; 395 } 396 397 indio_dev = devm_iio_device_alloc(&pdev->dev, 398 sizeof(struct tiadc_device)); 399 if (indio_dev == NULL) { 400 dev_err(&pdev->dev, "failed to allocate iio device\n"); 401 return -ENOMEM; 402 } 403 adc_dev = iio_priv(indio_dev); 404 405 adc_dev->mfd_tscadc = ti_tscadc_dev_get(pdev); 406 407 of_property_for_each_u32(node, "ti,adc-channels", prop, cur, val) { 408 adc_dev->channel_line[channels] = val; 409 channels++; 410 } 411 adc_dev->channels = channels; 412 413 indio_dev->dev.parent = &pdev->dev; 414 indio_dev->name = dev_name(&pdev->dev); 415 indio_dev->modes = INDIO_DIRECT_MODE; 416 indio_dev->info = &tiadc_info; 417 418 tiadc_step_config(indio_dev); 419 tiadc_writel(adc_dev, REG_FIFO1THR, FIFO1_THRESHOLD); 420 421 err = tiadc_channel_init(indio_dev, adc_dev->channels); 422 if (err < 0) 423 return err; 424 425 err = tiadc_iio_buffered_hardware_setup(indio_dev, 426 &tiadc_worker_h, 427 &tiadc_irq_h, 428 adc_dev->mfd_tscadc->irq, 429 IRQF_SHARED, 430 &tiadc_buffer_setup_ops); 431 432 if (err) 433 goto err_free_channels; 434 435 err = iio_device_register(indio_dev); 436 if (err) 437 goto err_buffer_unregister; 438 439 platform_set_drvdata(pdev, indio_dev); 440 441 return 0; 442 443 err_buffer_unregister: 444 tiadc_iio_buffered_hardware_remove(indio_dev); 445 err_free_channels: 446 tiadc_channels_remove(indio_dev); 447 return err; 448 } 449 450 static int tiadc_remove(struct platform_device *pdev) 451 { 452 struct iio_dev *indio_dev = platform_get_drvdata(pdev); 453 struct tiadc_device *adc_dev = iio_priv(indio_dev); 454 u32 step_en; 455 456 iio_device_unregister(indio_dev); 457 tiadc_iio_buffered_hardware_remove(indio_dev); 458 tiadc_channels_remove(indio_dev); 459 460 step_en = get_adc_step_mask(adc_dev); 461 am335x_tsc_se_clr(adc_dev->mfd_tscadc, step_en); 462 463 return 0; 464 } 465 466 #ifdef CONFIG_PM 467 static int tiadc_suspend(struct device *dev) 468 { 469 struct iio_dev *indio_dev = dev_get_drvdata(dev); 470 struct tiadc_device *adc_dev = iio_priv(indio_dev); 471 struct ti_tscadc_dev *tscadc_dev; 472 unsigned int idle; 473 474 tscadc_dev = ti_tscadc_dev_get(to_platform_device(dev)); 475 if (!device_may_wakeup(tscadc_dev->dev)) { 476 idle = tiadc_readl(adc_dev, REG_CTRL); 477 idle &= ~(CNTRLREG_TSCSSENB); 478 tiadc_writel(adc_dev, REG_CTRL, (idle | 479 CNTRLREG_POWERDOWN)); 480 } 481 482 return 0; 483 } 484 485 static int tiadc_resume(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 unsigned int restore; 490 491 /* Make sure ADC is powered up */ 492 restore = tiadc_readl(adc_dev, REG_CTRL); 493 restore &= ~(CNTRLREG_POWERDOWN); 494 tiadc_writel(adc_dev, REG_CTRL, restore); 495 496 tiadc_step_config(indio_dev); 497 498 return 0; 499 } 500 501 static const struct dev_pm_ops tiadc_pm_ops = { 502 .suspend = tiadc_suspend, 503 .resume = tiadc_resume, 504 }; 505 #define TIADC_PM_OPS (&tiadc_pm_ops) 506 #else 507 #define TIADC_PM_OPS NULL 508 #endif 509 510 static const struct of_device_id ti_adc_dt_ids[] = { 511 { .compatible = "ti,am3359-adc", }, 512 { } 513 }; 514 MODULE_DEVICE_TABLE(of, ti_adc_dt_ids); 515 516 static struct platform_driver tiadc_driver = { 517 .driver = { 518 .name = "TI-am335x-adc", 519 .owner = THIS_MODULE, 520 .pm = TIADC_PM_OPS, 521 .of_match_table = ti_adc_dt_ids, 522 }, 523 .probe = tiadc_probe, 524 .remove = tiadc_remove, 525 }; 526 module_platform_driver(tiadc_driver); 527 528 MODULE_DESCRIPTION("TI ADC controller driver"); 529 MODULE_AUTHOR("Rachna Patil <rachna@ti.com>"); 530 MODULE_LICENSE("GPL"); 531