drivers/mfd/ezx-pcap.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Driver for Motorola PCAP2 as present in EZX phones
   4  *
   5  * Copyright (C) 2006 Harald Welte <laforge@openezx.org>
   6  * Copyright (C) 2009 Daniel Ribeiro <drwyrm@gmail.com>
   7  */
   8
   9 #include <linux/module.h>
  10 #include <linux/kernel.h>
  11 #include <linux/platform_device.h>
  12 #include <linux/interrupt.h>
  13 #include <linux/irq.h>
  14 #include <linux/mfd/ezx-pcap.h>
  15 #include <linux/spi/spi.h>
  16 #include <linux/gpio.h>
  17 #include <linux/slab.h>
  18
  19 #define PCAP_ADC_MAXQ           8
  20 struct pcap_adc_request {
  21         u8 bank;
  22         u8 ch[2];
  23         u32 flags;
  24         void (*callback)(void *, u16[]);
  25         void *data;
  26 };
  27
  28 struct pcap_adc_sync_request {
  29         u16 res[2];
  30         struct completion completion;
  31 };
  32
  33 struct pcap_chip {
  34         struct spi_device *spi;
  35
  36         /* IO */
  37         u32 buf;
  38         spinlock_t io_lock;
  39
  40         /* IRQ */
  41         unsigned int irq_base;
  42         u32 msr;
  43         struct work_struct isr_work;
  44         struct work_struct msr_work;
  45         struct workqueue_struct *workqueue;
  46
  47         /* ADC */
  48         struct pcap_adc_request *adc_queue[PCAP_ADC_MAXQ];
  49         u8 adc_head;
  50         u8 adc_tail;
  51         spinlock_t adc_lock;
  52 };
  53
  54 /* IO */
  55 static int ezx_pcap_putget(struct pcap_chip *pcap, u32 *data)
  56 {
  57         struct spi_transfer t;
  58         struct spi_message m;
  59         int status;
  60
  61         memset(&t, 0, sizeof(t));
  62         spi_message_init(&m);
  63         t.len = sizeof(u32);
  64         spi_message_add_tail(&t, &m);
  65
  66         pcap->buf = *data;
  67         t.tx_buf = (u8 *) &pcap->buf;
  68         t.rx_buf = (u8 *) &pcap->buf;
  69         status = spi_sync(pcap->spi, &m);
  70
  71         if (status == 0)
  72                 *data = pcap->buf;
  73
  74         return status;
  75 }
  76
  77 int ezx_pcap_write(struct pcap_chip *pcap, u8 reg_num, u32 value)
  78 {
  79         unsigned long flags;
  80         int ret;
  81
  82         spin_lock_irqsave(&pcap->io_lock, flags);
  83         value &= PCAP_REGISTER_VALUE_MASK;
  84         value |= PCAP_REGISTER_WRITE_OP_BIT
  85                 | (reg_num << PCAP_REGISTER_ADDRESS_SHIFT);
  86         ret = ezx_pcap_putget(pcap, &value);
  87         spin_unlock_irqrestore(&pcap->io_lock, flags);
  88
  89         return ret;
  90 }
  91 EXPORT_SYMBOL_GPL(ezx_pcap_write);
  92
  93 int ezx_pcap_read(struct pcap_chip *pcap, u8 reg_num, u32 *value)
  94 {
  95         unsigned long flags;
  96         int ret;
  97
  98         spin_lock_irqsave(&pcap->io_lock, flags);
  99         *value = PCAP_REGISTER_READ_OP_BIT
 100                 | (reg_num << PCAP_REGISTER_ADDRESS_SHIFT);
 101
 102         ret = ezx_pcap_putget(pcap, value);
 103         spin_unlock_irqrestore(&pcap->io_lock, flags);
 104
 105         return ret;
 106 }
 107 EXPORT_SYMBOL_GPL(ezx_pcap_read);
 108
 109 int ezx_pcap_set_bits(struct pcap_chip *pcap, u8 reg_num, u32 mask, u32 val)
 110 {
 111         unsigned long flags;
 112         int ret;
 113         u32 tmp = PCAP_REGISTER_READ_OP_BIT |
 114                 (reg_num << PCAP_REGISTER_ADDRESS_SHIFT);
 115
 116         spin_lock_irqsave(&pcap->io_lock, flags);
 117         ret = ezx_pcap_putget(pcap, &tmp);
 118         if (ret)
 119                 goto out_unlock;
 120
 121         tmp &= (PCAP_REGISTER_VALUE_MASK & ~mask);
 122         tmp |= (val & mask) | PCAP_REGISTER_WRITE_OP_BIT |
 123                 (reg_num << PCAP_REGISTER_ADDRESS_SHIFT);
 124
 125         ret = ezx_pcap_putget(pcap, &tmp);
 126 out_unlock:
 127         spin_unlock_irqrestore(&pcap->io_lock, flags);
 128
 129         return ret;
 130 }
 131 EXPORT_SYMBOL_GPL(ezx_pcap_set_bits);
 132
 133 /* IRQ */
 134 int irq_to_pcap(struct pcap_chip *pcap, int irq)
 135 {
 136         return irq - pcap->irq_base;
 137 }
 138 EXPORT_SYMBOL_GPL(irq_to_pcap);
 139
 140 int pcap_to_irq(struct pcap_chip *pcap, int irq)
 141 {
 142         return pcap->irq_base + irq;
 143 }
 144 EXPORT_SYMBOL_GPL(pcap_to_irq);
 145
 146 static void pcap_mask_irq(struct irq_data *d)
 147 {
 148         struct pcap_chip *pcap = irq_data_get_irq_chip_data(d);
 149
 150         pcap->msr |= 1 << irq_to_pcap(pcap, d->irq);
 151         queue_work(pcap->workqueue, &pcap->msr_work);
 152 }
 153
 154 static void pcap_unmask_irq(struct irq_data *d)
 155 {
 156         struct pcap_chip *pcap = irq_data_get_irq_chip_data(d);
 157
 158         pcap->msr &= ~(1 << irq_to_pcap(pcap, d->irq));
 159         queue_work(pcap->workqueue, &pcap->msr_work);
 160 }
 161
 162 static struct irq_chip pcap_irq_chip = {
 163         .name           = "pcap",
 164         .irq_disable    = pcap_mask_irq,
 165         .irq_mask       = pcap_mask_irq,
 166         .irq_unmask     = pcap_unmask_irq,
 167 };
 168
 169 static void pcap_msr_work(struct work_struct *work)
 170 {
 171         struct pcap_chip *pcap = container_of(work, struct pcap_chip, msr_work);
 172
 173         ezx_pcap_write(pcap, PCAP_REG_MSR, pcap->msr);
 174 }
 175
 176 static void pcap_isr_work(struct work_struct *work)
 177 {
 178         struct pcap_chip *pcap = container_of(work, struct pcap_chip, isr_work);
 179         struct pcap_platform_data *pdata = dev_get_platdata(&pcap->spi->dev);
 180         u32 msr, isr, int_sel, service;
 181         int irq;
 182
 183         do {
 184                 ezx_pcap_read(pcap, PCAP_REG_MSR, &msr);
 185                 ezx_pcap_read(pcap, PCAP_REG_ISR, &isr);
 186
 187                 /* We can't service/ack irqs that are assigned to port 2 */
 188                 if (!(pdata->config & PCAP_SECOND_PORT)) {
 189                         ezx_pcap_read(pcap, PCAP_REG_INT_SEL, &int_sel);
 190                         isr &= ~int_sel;
 191                 }
 192
 193                 ezx_pcap_write(pcap, PCAP_REG_MSR, isr | msr);
 194                 ezx_pcap_write(pcap, PCAP_REG_ISR, isr);
 195
 196                 local_irq_disable();
 197                 service = isr & ~msr;
 198                 for (irq = pcap->irq_base; service; service >>= 1, irq++) {
 199                         if (service & 1)
 200                                 generic_handle_irq(irq);
 201                 }
 202                 local_irq_enable();
 203                 ezx_pcap_write(pcap, PCAP_REG_MSR, pcap->msr);
 204         } while (gpio_get_value(pdata->gpio));
 205 }
 206
 207 static void pcap_irq_handler(struct irq_desc *desc)
 208 {
 209         struct pcap_chip *pcap = irq_desc_get_handler_data(desc);
 210
 211         desc->irq_data.chip->irq_ack(&desc->irq_data);
 212         queue_work(pcap->workqueue, &pcap->isr_work);
 213 }
 214
 215 /* ADC */
 216 void pcap_set_ts_bits(struct pcap_chip *pcap, u32 bits)
 217 {
 218         unsigned long flags;
 219         u32 tmp;
 220
 221         spin_lock_irqsave(&pcap->adc_lock, flags);
 222         ezx_pcap_read(pcap, PCAP_REG_ADC, &tmp);
 223         tmp &= ~(PCAP_ADC_TS_M_MASK | PCAP_ADC_TS_REF_LOWPWR);
 224         tmp |= bits & (PCAP_ADC_TS_M_MASK | PCAP_ADC_TS_REF_LOWPWR);
 225         ezx_pcap_write(pcap, PCAP_REG_ADC, tmp);
 226         spin_unlock_irqrestore(&pcap->adc_lock, flags);
 227 }
 228 EXPORT_SYMBOL_GPL(pcap_set_ts_bits);
 229
 230 static void pcap_disable_adc(struct pcap_chip *pcap)
 231 {
 232         u32 tmp;
 233
 234         ezx_pcap_read(pcap, PCAP_REG_ADC, &tmp);
 235         tmp &= ~(PCAP_ADC_ADEN|PCAP_ADC_BATT_I_ADC|PCAP_ADC_BATT_I_POLARITY);
 236         ezx_pcap_write(pcap, PCAP_REG_ADC, tmp);
 237 }
 238
 239 static void pcap_adc_trigger(struct pcap_chip *pcap)
 240 {
 241         unsigned long flags;
 242         u32 tmp;
 243         u8 head;
 244
 245         spin_lock_irqsave(&pcap->adc_lock, flags);
 246         head = pcap->adc_head;
 247         if (!pcap->adc_queue[head]) {
 248                 /* queue is empty, save power */
 249                 pcap_disable_adc(pcap);
 250                 spin_unlock_irqrestore(&pcap->adc_lock, flags);
 251                 return;
 252         }
 253         /* start conversion on requested bank, save TS_M bits */
 254         ezx_pcap_read(pcap, PCAP_REG_ADC, &tmp);
 255         tmp &= (PCAP_ADC_TS_M_MASK | PCAP_ADC_TS_REF_LOWPWR);
 256         tmp |= pcap->adc_queue[head]->flags | PCAP_ADC_ADEN;
 257
 258         if (pcap->adc_queue[head]->bank == PCAP_ADC_BANK_1)
 259                 tmp |= PCAP_ADC_AD_SEL1;
 260
 261         ezx_pcap_write(pcap, PCAP_REG_ADC, tmp);
 262         spin_unlock_irqrestore(&pcap->adc_lock, flags);
 263         ezx_pcap_write(pcap, PCAP_REG_ADR, PCAP_ADR_ASC);
 264 }
 265
 266 static irqreturn_t pcap_adc_irq(int irq, void *_pcap)
 267 {
 268         struct pcap_chip *pcap = _pcap;
 269         struct pcap_adc_request *req;
 270         u16 res[2];
 271         u32 tmp;
 272
 273         spin_lock(&pcap->adc_lock);
 274         req = pcap->adc_queue[pcap->adc_head];
 275
 276         if (WARN(!req, "adc irq without pending request\n")) {
 277                 spin_unlock(&pcap->adc_lock);
 278                 return IRQ_HANDLED;
 279         }
 280
 281         /* read requested channels results */
 282         ezx_pcap_read(pcap, PCAP_REG_ADC, &tmp);
 283         tmp &= ~(PCAP_ADC_ADA1_MASK | PCAP_ADC_ADA2_MASK);
 284         tmp |= (req->ch[0] << PCAP_ADC_ADA1_SHIFT);
 285         tmp |= (req->ch[1] << PCAP_ADC_ADA2_SHIFT);
 286         ezx_pcap_write(pcap, PCAP_REG_ADC, tmp);
 287         ezx_pcap_read(pcap, PCAP_REG_ADR, &tmp);
 288         res[0] = (tmp & PCAP_ADR_ADD1_MASK) >> PCAP_ADR_ADD1_SHIFT;
 289         res[1] = (tmp & PCAP_ADR_ADD2_MASK) >> PCAP_ADR_ADD2_SHIFT;
 290
 291         pcap->adc_queue[pcap->adc_head] = NULL;
 292         pcap->adc_head = (pcap->adc_head + 1) & (PCAP_ADC_MAXQ - 1);
 293         spin_unlock(&pcap->adc_lock);
 294
 295         /* pass the results and release memory */
 296         req->callback(req->data, res);
 297         kfree(req);
 298
 299         /* trigger next conversion (if any) on queue */
 300         pcap_adc_trigger(pcap);
 301
 302         return IRQ_HANDLED;
 303 }
 304
 305 int pcap_adc_async(struct pcap_chip *pcap, u8 bank, u32 flags, u8 ch[],
 306                                                 void *callback, void *data)
 307 {
 308         struct pcap_adc_request *req;
 309         unsigned long irq_flags;
 310
 311         /* This will be freed after we have a result */
 312         req = kmalloc(sizeof(struct pcap_adc_request), GFP_KERNEL);
 313         if (!req)
 314                 return -ENOMEM;
 315
 316         req->bank = bank;
 317         req->flags = flags;
 318         req->ch[0] = ch[0];
 319         req->ch[1] = ch[1];
 320         req->callback = callback;
 321         req->data = data;
 322
 323         spin_lock_irqsave(&pcap->adc_lock, irq_flags);
 324         if (pcap->adc_queue[pcap->adc_tail]) {
 325                 spin_unlock_irqrestore(&pcap->adc_lock, irq_flags);
 326                 kfree(req);
 327                 return -EBUSY;
 328         }
 329         pcap->adc_queue[pcap->adc_tail] = req;
 330         pcap->adc_tail = (pcap->adc_tail + 1) & (PCAP_ADC_MAXQ - 1);
 331         spin_unlock_irqrestore(&pcap->adc_lock, irq_flags);
 332
 333         /* start conversion */
 334         pcap_adc_trigger(pcap);
 335
 336         return 0;
 337 }
 338 EXPORT_SYMBOL_GPL(pcap_adc_async);
 339
 340 static void pcap_adc_sync_cb(void *param, u16 res[])
 341 {
 342         struct pcap_adc_sync_request *req = param;
 343
 344         req->res[0] = res[0];
 345         req->res[1] = res[1];
 346         complete(&req->completion);
 347 }
 348
 349 int pcap_adc_sync(struct pcap_chip *pcap, u8 bank, u32 flags, u8 ch[],
 350                                                                 u16 res[])
 351 {
 352         struct pcap_adc_sync_request sync_data;
 353         int ret;
 354
 355         init_completion(&sync_data.completion);
 356         ret = pcap_adc_async(pcap, bank, flags, ch, pcap_adc_sync_cb,
 357                                                                 &sync_data);
 358         if (ret)
 359                 return ret;
 360         wait_for_completion(&sync_data.completion);
 361         res[0] = sync_data.res[0];
 362         res[1] = sync_data.res[1];
 363
 364         return 0;
 365 }
 366 EXPORT_SYMBOL_GPL(pcap_adc_sync);
 367
 368 /* subdevs */
 369 static int pcap_remove_subdev(struct device *dev, void *unused)
 370 {
 371         platform_device_unregister(to_platform_device(dev));
 372         return 0;
 373 }
 374
 375 static int pcap_add_subdev(struct pcap_chip *pcap,
 376                                                 struct pcap_subdev *subdev)
 377 {
 378         struct platform_device *pdev;
 379         int ret;
 380
 381         pdev = platform_device_alloc(subdev->name, subdev->id);
 382         if (!pdev)
 383                 return -ENOMEM;
 384
 385         pdev->dev.parent = &pcap->spi->dev;
 386         pdev->dev.platform_data = subdev->platform_data;
 387
 388         ret = platform_device_add(pdev);
 389         if (ret)
 390                 platform_device_put(pdev);
 391
 392         return ret;
 393 }
 394
 395 static int ezx_pcap_remove(struct spi_device *spi)
 396 {
 397         struct pcap_chip *pcap = spi_get_drvdata(spi);
 398         unsigned long flags;
 399         int i;
 400
 401         /* remove all registered subdevs */
 402         device_for_each_child(&spi->dev, NULL, pcap_remove_subdev);
 403
 404         /* cleanup ADC */
 405         spin_lock_irqsave(&pcap->adc_lock, flags);
 406         for (i = 0; i < PCAP_ADC_MAXQ; i++)
 407                 kfree(pcap->adc_queue[i]);
 408         spin_unlock_irqrestore(&pcap->adc_lock, flags);
 409
 410         /* cleanup irqchip */
 411         for (i = pcap->irq_base; i < (pcap->irq_base + PCAP_NIRQS); i++)
 412                 irq_set_chip_and_handler(i, NULL, NULL);
 413
 414         destroy_workqueue(pcap->workqueue);
 415
 416         return 0;
 417 }
 418
 419 static int ezx_pcap_probe(struct spi_device *spi)
 420 {
 421         struct pcap_platform_data *pdata = dev_get_platdata(&spi->dev);
 422         struct pcap_chip *pcap;
 423         int i, adc_irq;
 424         int ret = -ENODEV;
 425
 426         /* platform data is required */
 427         if (!pdata)
 428                 goto ret;
 429
 430         pcap = devm_kzalloc(&spi->dev, sizeof(*pcap), GFP_KERNEL);
 431         if (!pcap) {
 432                 ret = -ENOMEM;
 433                 goto ret;
 434         }
 435
 436         spin_lock_init(&pcap->io_lock);
 437         spin_lock_init(&pcap->adc_lock);
 438         INIT_WORK(&pcap->isr_work, pcap_isr_work);
 439         INIT_WORK(&pcap->msr_work, pcap_msr_work);
 440         spi_set_drvdata(spi, pcap);
 441
 442         /* setup spi */
 443         spi->bits_per_word = 32;
 444         spi->mode = SPI_MODE_0 | (pdata->config & PCAP_CS_AH ? SPI_CS_HIGH : 0);
 445         ret = spi_setup(spi);
 446         if (ret)
 447                 goto ret;
 448
 449         pcap->spi = spi;
 450
 451         /* setup irq */
 452         pcap->irq_base = pdata->irq_base;
 453         pcap->workqueue = create_singlethread_workqueue("pcapd");
 454         if (!pcap->workqueue) {
 455                 ret = -ENOMEM;
 456                 dev_err(&spi->dev, "can't create pcap thread\n");
 457                 goto ret;
 458         }
 459
 460         /* redirect interrupts to AP, except adcdone2 */
 461         if (!(pdata->config & PCAP_SECOND_PORT))
 462                 ezx_pcap_write(pcap, PCAP_REG_INT_SEL,
 463                                         (1 << PCAP_IRQ_ADCDONE2));
 464
 465         /* setup irq chip */
 466         for (i = pcap->irq_base; i < (pcap->irq_base + PCAP_NIRQS); i++) {
 467                 irq_set_chip_and_handler(i, &pcap_irq_chip, handle_simple_irq);
 468                 irq_set_chip_data(i, pcap);
 469                 irq_clear_status_flags(i, IRQ_NOREQUEST | IRQ_NOPROBE);
 470         }
 471
 472         /* mask/ack all PCAP interrupts */
 473         ezx_pcap_write(pcap, PCAP_REG_MSR, PCAP_MASK_ALL_INTERRUPT);
 474         ezx_pcap_write(pcap, PCAP_REG_ISR, PCAP_CLEAR_INTERRUPT_REGISTER);
 475         pcap->msr = PCAP_MASK_ALL_INTERRUPT;
 476
 477         irq_set_irq_type(spi->irq, IRQ_TYPE_EDGE_RISING);
 478         irq_set_chained_handler_and_data(spi->irq, pcap_irq_handler, pcap);
 479         irq_set_irq_wake(spi->irq, 1);
 480
 481         /* ADC */
 482         adc_irq = pcap_to_irq(pcap, (pdata->config & PCAP_SECOND_PORT) ?
 483                                         PCAP_IRQ_ADCDONE2 : PCAP_IRQ_ADCDONE);
 484
 485         ret = devm_request_irq(&spi->dev, adc_irq, pcap_adc_irq, 0, "ADC",
 486                                 pcap);
 487         if (ret)
 488                 goto free_irqchip;
 489
 490         /* setup subdevs */
 491         for (i = 0; i < pdata->num_subdevs; i++) {
 492                 ret = pcap_add_subdev(pcap, &pdata->subdevs[i]);
 493                 if (ret)
 494                         goto remove_subdevs;
 495         }
 496
 497         /* board specific quirks */
 498         if (pdata->init)
 499                 pdata->init(pcap);
 500
 501         return 0;
 502
 503 remove_subdevs:
 504         device_for_each_child(&spi->dev, NULL, pcap_remove_subdev);
 505 free_irqchip:
 506         for (i = pcap->irq_base; i < (pcap->irq_base + PCAP_NIRQS); i++)
 507                 irq_set_chip_and_handler(i, NULL, NULL);
 508 /* destroy_workqueue: */
 509         destroy_workqueue(pcap->workqueue);
 510 ret:
 511         return ret;
 512 }
 513
 514 static struct spi_driver ezxpcap_driver = {
 515         .probe  = ezx_pcap_probe,
 516         .remove = ezx_pcap_remove,
 517         .driver = {
 518                 .name   = "ezx-pcap",
 519         },
 520 };
 521
 522 static int __init ezx_pcap_init(void)
 523 {
 524         return spi_register_driver(&ezxpcap_driver);
 525 }
 526
 527 static void __exit ezx_pcap_exit(void)
 528 {
 529         spi_unregister_driver(&ezxpcap_driver);
 530 }
 531
 532 subsys_initcall(ezx_pcap_init);
 533 module_exit(ezx_pcap_exit);
 534
 535 MODULE_LICENSE("GPL");
 536 MODULE_AUTHOR("Daniel Ribeiro / Harald Welte");
 537 MODULE_DESCRIPTION("Motorola PCAP2 ASIC Driver");
 538 MODULE_ALIAS("spi:ezx-pcap");