drivers/i2c/busses/i2c-at91.c

   1 /*
   2  *  i2c Support for Atmel's AT91 Two-Wire Interface (TWI)
   3  *
   4  *  Copyright (C) 2011 Weinmann Medical GmbH
   5  *  Author: Nikolaus Voss <n.voss@weinmann.de>
   6  *
   7  *  Evolved from original work by:
   8  *  Copyright (C) 2004 Rick Bronson
   9  *  Converted to 2.6 by Andrew Victor <andrew@sanpeople.com>
  10  *
  11  *  Borrowed heavily from original work by:
  12  *  Copyright (C) 2000 Philip Edelbrock <phil@stimpy.netroedge.com>
  13  *
  14  *  This program is free software; you can redistribute it and/or modify
  15  *  it under the terms of the GNU General Public License as published by
  16  *  the Free Software Foundation; either version 2 of the License, or
  17  *  (at your option) any later version.
  18  */
  19
  20 #include <linux/clk.h>
  21 #include <linux/completion.h>
  22 #include <linux/dma-mapping.h>
  23 #include <linux/dmaengine.h>
  24 #include <linux/err.h>
  25 #include <linux/i2c.h>
  26 #include <linux/interrupt.h>
  27 #include <linux/io.h>
  28 #include <linux/module.h>
  29 #include <linux/of.h>
  30 #include <linux/of_device.h>
  31 #include <linux/platform_device.h>
  32 #include <linux/slab.h>
  33 #include <linux/platform_data/dma-atmel.h>
  34 #include <linux/pm_runtime.h>
  35 #include <linux/pinctrl/consumer.h>
  36
  37 #define DEFAULT_TWI_CLK_HZ              100000          /* max 400 Kbits/s */
  38 #define AT91_I2C_TIMEOUT        msecs_to_jiffies(100)   /* transfer timeout */
  39 #define AT91_I2C_DMA_THRESHOLD  8                       /* enable DMA if transfer size is bigger than this threshold */
  40 #define AUTOSUSPEND_TIMEOUT             2000
  41
  42 /* AT91 TWI register definitions */
  43 #define AT91_TWI_CR             0x0000  /* Control Register */
  44 #define AT91_TWI_START          0x0001  /* Send a Start Condition */
  45 #define AT91_TWI_STOP           0x0002  /* Send a Stop Condition */
  46 #define AT91_TWI_MSEN           0x0004  /* Master Transfer Enable */
  47 #define AT91_TWI_SVDIS          0x0020  /* Slave Transfer Disable */
  48 #define AT91_TWI_QUICK          0x0040  /* SMBus quick command */
  49 #define AT91_TWI_SWRST          0x0080  /* Software Reset */
  50
  51 #define AT91_TWI_MMR            0x0004  /* Master Mode Register */
  52 #define AT91_TWI_IADRSZ_1       0x0100  /* Internal Device Address Size */
  53 #define AT91_TWI_MREAD          0x1000  /* Master Read Direction */
  54
  55 #define AT91_TWI_IADR           0x000c  /* Internal Address Register */
  56
  57 #define AT91_TWI_CWGR           0x0010  /* Clock Waveform Generator Reg */
  58
  59 #define AT91_TWI_SR             0x0020  /* Status Register */
  60 #define AT91_TWI_TXCOMP         0x0001  /* Transmission Complete */
  61 #define AT91_TWI_RXRDY          0x0002  /* Receive Holding Register Ready */
  62 #define AT91_TWI_TXRDY          0x0004  /* Transmit Holding Register Ready */
  63
  64 #define AT91_TWI_OVRE           0x0040  /* Overrun Error */
  65 #define AT91_TWI_UNRE           0x0080  /* Underrun Error */
  66 #define AT91_TWI_NACK           0x0100  /* Not Acknowledged */
  67
  68 #define AT91_TWI_IER            0x0024  /* Interrupt Enable Register */
  69 #define AT91_TWI_IDR            0x0028  /* Interrupt Disable Register */
  70 #define AT91_TWI_IMR            0x002c  /* Interrupt Mask Register */
  71 #define AT91_TWI_RHR            0x0030  /* Receive Holding Register */
  72 #define AT91_TWI_THR            0x0034  /* Transmit Holding Register */
  73
  74 struct at91_twi_pdata {
  75         unsigned clk_max_div;
  76         unsigned clk_offset;
  77         bool has_unre_flag;
  78         struct at_dma_slave dma_slave;
  79 };
  80
  81 struct at91_twi_dma {
  82         struct dma_chan *chan_rx;
  83         struct dma_chan *chan_tx;
  84         struct scatterlist sg;
  85         struct dma_async_tx_descriptor *data_desc;
  86         enum dma_data_direction direction;
  87         bool buf_mapped;
  88         bool xfer_in_progress;
  89 };
  90
  91 struct at91_twi_dev {
  92         struct device *dev;
  93         void __iomem *base;
  94         struct completion cmd_complete;
  95         struct clk *clk;
  96         u8 *buf;
  97         size_t buf_len;
  98         struct i2c_msg *msg;
  99         int irq;
 100         unsigned imr;
 101         unsigned transfer_status;
 102         struct i2c_adapter adapter;
 103         unsigned twi_cwgr_reg;
 104         struct at91_twi_pdata *pdata;
 105         bool use_dma;
 106         bool recv_len_abort;
 107         struct at91_twi_dma dma;
 108 };
 109
 110 static unsigned at91_twi_read(struct at91_twi_dev *dev, unsigned reg)
 111 {
 112         return readl_relaxed(dev->base + reg);
 113 }
 114
 115 static void at91_twi_write(struct at91_twi_dev *dev, unsigned reg, unsigned val)
 116 {
 117         writel_relaxed(val, dev->base + reg);
 118 }
 119
 120 static void at91_disable_twi_interrupts(struct at91_twi_dev *dev)
 121 {
 122         at91_twi_write(dev, AT91_TWI_IDR,
 123                        AT91_TWI_TXCOMP | AT91_TWI_RXRDY | AT91_TWI_TXRDY);
 124 }
 125
 126 static void at91_twi_irq_save(struct at91_twi_dev *dev)
 127 {
 128         dev->imr = at91_twi_read(dev, AT91_TWI_IMR) & 0x7;
 129         at91_disable_twi_interrupts(dev);
 130 }
 131
 132 static void at91_twi_irq_restore(struct at91_twi_dev *dev)
 133 {
 134         at91_twi_write(dev, AT91_TWI_IER, dev->imr);
 135 }
 136
 137 static void at91_init_twi_bus(struct at91_twi_dev *dev)
 138 {
 139         at91_disable_twi_interrupts(dev);
 140         at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SWRST);
 141         at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_MSEN);
 142         at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_SVDIS);
 143         at91_twi_write(dev, AT91_TWI_CWGR, dev->twi_cwgr_reg);
 144 }
 145
 146 /*
 147  * Calculate symmetric clock as stated in datasheet:
 148  * twi_clk = F_MAIN / (2 * (cdiv * (1 << ckdiv) + offset))
 149  */
 150 static void at91_calc_twi_clock(struct at91_twi_dev *dev, int twi_clk)
 151 {
 152         int ckdiv, cdiv, div;
 153         struct at91_twi_pdata *pdata = dev->pdata;
 154         int offset = pdata->clk_offset;
 155         int max_ckdiv = pdata->clk_max_div;
 156
 157         div = max(0, (int)DIV_ROUND_UP(clk_get_rate(dev->clk),
 158                                        2 * twi_clk) - offset);
 159         ckdiv = fls(div >> 8);
 160         cdiv = div >> ckdiv;
 161
 162         if (ckdiv > max_ckdiv) {
 163                 dev_warn(dev->dev, "%d exceeds ckdiv max value which is %d.\n",
 164                          ckdiv, max_ckdiv);
 165                 ckdiv = max_ckdiv;
 166                 cdiv = 255;
 167         }
 168
 169         dev->twi_cwgr_reg = (ckdiv << 16) | (cdiv << 8) | cdiv;
 170         dev_dbg(dev->dev, "cdiv %d ckdiv %d\n", cdiv, ckdiv);
 171 }
 172
 173 static void at91_twi_dma_cleanup(struct at91_twi_dev *dev)
 174 {
 175         struct at91_twi_dma *dma = &dev->dma;
 176
 177         at91_twi_irq_save(dev);
 178
 179         if (dma->xfer_in_progress) {
 180                 if (dma->direction == DMA_FROM_DEVICE)
 181                         dmaengine_terminate_all(dma->chan_rx);
 182                 else
 183                         dmaengine_terminate_all(dma->chan_tx);
 184                 dma->xfer_in_progress = false;
 185         }
 186         if (dma->buf_mapped) {
 187                 dma_unmap_single(dev->dev, sg_dma_address(&dma->sg),
 188                                  dev->buf_len, dma->direction);
 189                 dma->buf_mapped = false;
 190         }
 191
 192         at91_twi_irq_restore(dev);
 193 }
 194
 195 static void at91_twi_write_next_byte(struct at91_twi_dev *dev)
 196 {
 197         if (dev->buf_len <= 0)
 198                 return;
 199
 200         at91_twi_write(dev, AT91_TWI_THR, *dev->buf);
 201
 202         /* send stop when last byte has been written */
 203         if (--dev->buf_len == 0)
 204                 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
 205
 206         dev_dbg(dev->dev, "wrote 0x%x, to go %d\n", *dev->buf, dev->buf_len);
 207
 208         ++dev->buf;
 209 }
 210
 211 static void at91_twi_write_data_dma_callback(void *data)
 212 {
 213         struct at91_twi_dev *dev = (struct at91_twi_dev *)data;
 214
 215         dma_unmap_single(dev->dev, sg_dma_address(&dev->dma.sg),
 216                          dev->buf_len, DMA_TO_DEVICE);
 217
 218         at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
 219 }
 220
 221 static void at91_twi_write_data_dma(struct at91_twi_dev *dev)
 222 {
 223         dma_addr_t dma_addr;
 224         struct dma_async_tx_descriptor *txdesc;
 225         struct at91_twi_dma *dma = &dev->dma;
 226         struct dma_chan *chan_tx = dma->chan_tx;
 227
 228         if (dev->buf_len <= 0)
 229                 return;
 230
 231         dma->direction = DMA_TO_DEVICE;
 232
 233         at91_twi_irq_save(dev);
 234         dma_addr = dma_map_single(dev->dev, dev->buf, dev->buf_len,
 235                                   DMA_TO_DEVICE);
 236         if (dma_mapping_error(dev->dev, dma_addr)) {
 237                 dev_err(dev->dev, "dma map failed\n");
 238                 return;
 239         }
 240         dma->buf_mapped = true;
 241         at91_twi_irq_restore(dev);
 242         sg_dma_len(&dma->sg) = dev->buf_len;
 243         sg_dma_address(&dma->sg) = dma_addr;
 244
 245         txdesc = dmaengine_prep_slave_sg(chan_tx, &dma->sg, 1, DMA_MEM_TO_DEV,
 246                                          DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 247         if (!txdesc) {
 248                 dev_err(dev->dev, "dma prep slave sg failed\n");
 249                 goto error;
 250         }
 251
 252         txdesc->callback = at91_twi_write_data_dma_callback;
 253         txdesc->callback_param = dev;
 254
 255         dma->xfer_in_progress = true;
 256         dmaengine_submit(txdesc);
 257         dma_async_issue_pending(chan_tx);
 258
 259         return;
 260
 261 error:
 262         at91_twi_dma_cleanup(dev);
 263 }
 264
 265 static void at91_twi_read_next_byte(struct at91_twi_dev *dev)
 266 {
 267         if (dev->buf_len <= 0)
 268                 return;
 269
 270         *dev->buf = at91_twi_read(dev, AT91_TWI_RHR) & 0xff;
 271         --dev->buf_len;
 272
 273         /* return if aborting, we only needed to read RHR to clear RXRDY*/
 274         if (dev->recv_len_abort)
 275                 return;
 276
 277         /* handle I2C_SMBUS_BLOCK_DATA */
 278         if (unlikely(dev->msg->flags & I2C_M_RECV_LEN)) {
 279                 /* ensure length byte is a valid value */
 280                 if (*dev->buf <= I2C_SMBUS_BLOCK_MAX && *dev->buf > 0) {
 281                         dev->msg->flags &= ~I2C_M_RECV_LEN;
 282                         dev->buf_len += *dev->buf;
 283                         dev->msg->len = dev->buf_len + 1;
 284                         dev_dbg(dev->dev, "received block length %d\n",
 285                                          dev->buf_len);
 286                 } else {
 287                         /* abort and send the stop by reading one more byte */
 288                         dev->recv_len_abort = true;
 289                         dev->buf_len = 1;
 290                 }
 291         }
 292
 293         /* send stop if second but last byte has been read */
 294         if (dev->buf_len == 1)
 295                 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_STOP);
 296
 297         dev_dbg(dev->dev, "read 0x%x, to go %d\n", *dev->buf, dev->buf_len);
 298
 299         ++dev->buf;
 300 }
 301
 302 static void at91_twi_read_data_dma_callback(void *data)
 303 {
 304         struct at91_twi_dev *dev = (struct at91_twi_dev *)data;
 305
 306         dma_unmap_single(dev->dev, sg_dma_address(&dev->dma.sg),
 307                          dev->buf_len, DMA_FROM_DEVICE);
 308
 309         /* The last two bytes have to be read without using dma */
 310         dev->buf += dev->buf_len - 2;
 311         dev->buf_len = 2;
 312         at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_RXRDY);
 313 }
 314
 315 static void at91_twi_read_data_dma(struct at91_twi_dev *dev)
 316 {
 317         dma_addr_t dma_addr;
 318         struct dma_async_tx_descriptor *rxdesc;
 319         struct at91_twi_dma *dma = &dev->dma;
 320         struct dma_chan *chan_rx = dma->chan_rx;
 321
 322         dma->direction = DMA_FROM_DEVICE;
 323
 324         /* Keep in mind that we won't use dma to read the last two bytes */
 325         at91_twi_irq_save(dev);
 326         dma_addr = dma_map_single(dev->dev, dev->buf, dev->buf_len - 2,
 327                                   DMA_FROM_DEVICE);
 328         if (dma_mapping_error(dev->dev, dma_addr)) {
 329                 dev_err(dev->dev, "dma map failed\n");
 330                 return;
 331         }
 332         dma->buf_mapped = true;
 333         at91_twi_irq_restore(dev);
 334         dma->sg.dma_address = dma_addr;
 335         sg_dma_len(&dma->sg) = dev->buf_len - 2;
 336
 337         rxdesc = dmaengine_prep_slave_sg(chan_rx, &dma->sg, 1, DMA_DEV_TO_MEM,
 338                                          DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
 339         if (!rxdesc) {
 340                 dev_err(dev->dev, "dma prep slave sg failed\n");
 341                 goto error;
 342         }
 343
 344         rxdesc->callback = at91_twi_read_data_dma_callback;
 345         rxdesc->callback_param = dev;
 346
 347         dma->xfer_in_progress = true;
 348         dmaengine_submit(rxdesc);
 349         dma_async_issue_pending(dma->chan_rx);
 350
 351         return;
 352
 353 error:
 354         at91_twi_dma_cleanup(dev);
 355 }
 356
 357 static irqreturn_t atmel_twi_interrupt(int irq, void *dev_id)
 358 {
 359         struct at91_twi_dev *dev = dev_id;
 360         const unsigned status = at91_twi_read(dev, AT91_TWI_SR);
 361         const unsigned irqstatus = status & at91_twi_read(dev, AT91_TWI_IMR);
 362
 363         if (!irqstatus)
 364                 return IRQ_NONE;
 365         else if (irqstatus & AT91_TWI_RXRDY)
 366                 at91_twi_read_next_byte(dev);
 367         else if (irqstatus & AT91_TWI_TXRDY)
 368                 at91_twi_write_next_byte(dev);
 369
 370         /* catch error flags */
 371         dev->transfer_status |= status;
 372
 373         if (irqstatus & AT91_TWI_TXCOMP) {
 374                 at91_disable_twi_interrupts(dev);
 375                 complete(&dev->cmd_complete);
 376         }
 377
 378         return IRQ_HANDLED;
 379 }
 380
 381 static int at91_do_twi_transfer(struct at91_twi_dev *dev)
 382 {
 383         int ret;
 384         bool has_unre_flag = dev->pdata->has_unre_flag;
 385
 386         dev_dbg(dev->dev, "transfer: %s %d bytes.\n",
 387                 (dev->msg->flags & I2C_M_RD) ? "read" : "write", dev->buf_len);
 388
 389         reinit_completion(&dev->cmd_complete);
 390         dev->transfer_status = 0;
 391
 392         if (!dev->buf_len) {
 393                 at91_twi_write(dev, AT91_TWI_CR, AT91_TWI_QUICK);
 394                 at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_TXCOMP);
 395         } else if (dev->msg->flags & I2C_M_RD) {
 396                 unsigned start_flags = AT91_TWI_START;
 397
 398                 if (at91_twi_read(dev, AT91_TWI_SR) & AT91_TWI_RXRDY) {
 399                         dev_err(dev->dev, "RXRDY still set!");
 400                         at91_twi_read(dev, AT91_TWI_RHR);
 401                 }
 402
 403                 /* if only one byte is to be read, immediately stop transfer */
 404                 if (dev->buf_len <= 1 && !(dev->msg->flags & I2C_M_RECV_LEN))
 405                         start_flags |= AT91_TWI_STOP;
 406                 at91_twi_write(dev, AT91_TWI_CR, start_flags);
 407                 /*
 408                  * When using dma, the last byte has to be read manually in
 409                  * order to not send the stop command too late and then
 410                  * to receive extra data. In practice, there are some issues
 411                  * if you use the dma to read n-1 bytes because of latency.
 412                  * Reading n-2 bytes with dma and the two last ones manually
 413                  * seems to be the best solution.
 414                  */
 415                 if (dev->use_dma && (dev->buf_len > AT91_I2C_DMA_THRESHOLD)) {
 416                         at91_twi_read_data_dma(dev);
 417                         /*
 418                          * It is important to enable TXCOMP irq here because
 419                          * doing it only when transferring the last two bytes
 420                          * will mask NACK errors since TXCOMP is set when a
 421                          * NACK occurs.
 422                          */
 423                         at91_twi_write(dev, AT91_TWI_IER,
 424                                AT91_TWI_TXCOMP);
 425                 } else
 426                         at91_twi_write(dev, AT91_TWI_IER,
 427                                AT91_TWI_TXCOMP | AT91_TWI_RXRDY);
 428         } else {
 429                 if (dev->use_dma && (dev->buf_len > AT91_I2C_DMA_THRESHOLD)) {
 430                         at91_twi_write_data_dma(dev);
 431                         at91_twi_write(dev, AT91_TWI_IER, AT91_TWI_TXCOMP);
 432                 } else {
 433                         at91_twi_write_next_byte(dev);
 434                         at91_twi_write(dev, AT91_TWI_IER,
 435                                 AT91_TWI_TXCOMP | AT91_TWI_TXRDY);
 436                 }
 437         }
 438
 439         ret = wait_for_completion_timeout(&dev->cmd_complete,
 440                                              dev->adapter.timeout);
 441         if (ret == 0) {
 442                 dev_err(dev->dev, "controller timed out\n");
 443                 at91_init_twi_bus(dev);
 444                 ret = -ETIMEDOUT;
 445                 goto error;
 446         }
 447         if (dev->transfer_status & AT91_TWI_NACK) {
 448                 dev_dbg(dev->dev, "received nack\n");
 449                 ret = -EREMOTEIO;
 450                 goto error;
 451         }
 452         if (dev->transfer_status & AT91_TWI_OVRE) {
 453                 dev_err(dev->dev, "overrun while reading\n");
 454                 ret = -EIO;
 455                 goto error;
 456         }
 457         if (has_unre_flag && dev->transfer_status & AT91_TWI_UNRE) {
 458                 dev_err(dev->dev, "underrun while writing\n");
 459                 ret = -EIO;
 460                 goto error;
 461         }
 462         if (dev->recv_len_abort) {
 463                 dev_err(dev->dev, "invalid smbus block length recvd\n");
 464                 ret = -EPROTO;
 465                 goto error;
 466         }
 467
 468         dev_dbg(dev->dev, "transfer complete\n");
 469
 470         return 0;
 471
 472 error:
 473         at91_twi_dma_cleanup(dev);
 474         return ret;
 475 }
 476
 477 static int at91_twi_xfer(struct i2c_adapter *adap, struct i2c_msg *msg, int num)
 478 {
 479         struct at91_twi_dev *dev = i2c_get_adapdata(adap);
 480         int ret;
 481         unsigned int_addr_flag = 0;
 482         struct i2c_msg *m_start = msg;
 483
 484         dev_dbg(&adap->dev, "at91_xfer: processing %d messages:\n", num);
 485
 486         ret = pm_runtime_get_sync(dev->dev);
 487         if (ret < 0)
 488                 goto out;
 489
 490         if (num == 2) {
 491                 int internal_address = 0;
 492                 int i;
 493
 494                 /* 1st msg is put into the internal address, start with 2nd */
 495                 m_start = &msg[1];
 496                 for (i = 0; i < msg->len; ++i) {
 497                         const unsigned addr = msg->buf[msg->len - 1 - i];
 498
 499                         internal_address |= addr << (8 * i);
 500                         int_addr_flag += AT91_TWI_IADRSZ_1;
 501                 }
 502                 at91_twi_write(dev, AT91_TWI_IADR, internal_address);
 503         }
 504
 505         at91_twi_write(dev, AT91_TWI_MMR, (m_start->addr << 16) | int_addr_flag
 506                        | ((m_start->flags & I2C_M_RD) ? AT91_TWI_MREAD : 0));
 507
 508         dev->buf_len = m_start->len;
 509         dev->buf = m_start->buf;
 510         dev->msg = m_start;
 511         dev->recv_len_abort = false;
 512
 513         ret = at91_do_twi_transfer(dev);
 514
 515         ret = (ret < 0) ? ret : num;
 516 out:
 517         pm_runtime_mark_last_busy(dev->dev);
 518         pm_runtime_put_autosuspend(dev->dev);
 519
 520         return ret;
 521 }
 522
 523 /*
 524  * The hardware can handle at most two messages concatenated by a
 525  * repeated start via it's internal address feature.
 526  */
 527 static struct i2c_adapter_quirks at91_twi_quirks = {
 528         .flags = I2C_AQ_COMB | I2C_AQ_COMB_WRITE_FIRST | I2C_AQ_COMB_SAME_ADDR,
 529         .max_comb_1st_msg_len = 3,
 530 };
 531
 532 static u32 at91_twi_func(struct i2c_adapter *adapter)
 533 {
 534         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL
 535                 | I2C_FUNC_SMBUS_READ_BLOCK_DATA;
 536 }
 537
 538 static struct i2c_algorithm at91_twi_algorithm = {
 539         .master_xfer    = at91_twi_xfer,
 540         .functionality  = at91_twi_func,
 541 };
 542
 543 static struct at91_twi_pdata at91rm9200_config = {
 544         .clk_max_div = 5,
 545         .clk_offset = 3,
 546         .has_unre_flag = true,
 547 };
 548
 549 static struct at91_twi_pdata at91sam9261_config = {
 550         .clk_max_div = 5,
 551         .clk_offset = 4,
 552         .has_unre_flag = false,
 553 };
 554
 555 static struct at91_twi_pdata at91sam9260_config = {
 556         .clk_max_div = 7,
 557         .clk_offset = 4,
 558         .has_unre_flag = false,
 559 };
 560
 561 static struct at91_twi_pdata at91sam9g20_config = {
 562         .clk_max_div = 7,
 563         .clk_offset = 4,
 564         .has_unre_flag = false,
 565 };
 566
 567 static struct at91_twi_pdata at91sam9g10_config = {
 568         .clk_max_div = 7,
 569         .clk_offset = 4,
 570         .has_unre_flag = false,
 571 };
 572
 573 static const struct platform_device_id at91_twi_devtypes[] = {
 574         {
 575                 .name = "i2c-at91rm9200",
 576                 .driver_data = (unsigned long) &at91rm9200_config,
 577         }, {
 578                 .name = "i2c-at91sam9261",
 579                 .driver_data = (unsigned long) &at91sam9261_config,
 580         }, {
 581                 .name = "i2c-at91sam9260",
 582                 .driver_data = (unsigned long) &at91sam9260_config,
 583         }, {
 584                 .name = "i2c-at91sam9g20",
 585                 .driver_data = (unsigned long) &at91sam9g20_config,
 586         }, {
 587                 .name = "i2c-at91sam9g10",
 588                 .driver_data = (unsigned long) &at91sam9g10_config,
 589         }, {
 590                 /* sentinel */
 591         }
 592 };
 593
 594 #if defined(CONFIG_OF)
 595 static struct at91_twi_pdata at91sam9x5_config = {
 596         .clk_max_div = 7,
 597         .clk_offset = 4,
 598         .has_unre_flag = false,
 599 };
 600
 601 static const struct of_device_id atmel_twi_dt_ids[] = {
 602         {
 603                 .compatible = "atmel,at91rm9200-i2c",
 604                 .data = &at91rm9200_config,
 605         } , {
 606                 .compatible = "atmel,at91sam9260-i2c",
 607                 .data = &at91sam9260_config,
 608         } , {
 609                 .compatible = "atmel,at91sam9261-i2c",
 610                 .data = &at91sam9261_config,
 611         } , {
 612                 .compatible = "atmel,at91sam9g20-i2c",
 613                 .data = &at91sam9g20_config,
 614         } , {
 615                 .compatible = "atmel,at91sam9g10-i2c",
 616                 .data = &at91sam9g10_config,
 617         }, {
 618                 .compatible = "atmel,at91sam9x5-i2c",
 619                 .data = &at91sam9x5_config,
 620         }, {
 621                 /* sentinel */
 622         }
 623 };
 624 MODULE_DEVICE_TABLE(of, atmel_twi_dt_ids);
 625 #endif
 626
 627 static int at91_twi_configure_dma(struct at91_twi_dev *dev, u32 phy_addr)
 628 {
 629         int ret = 0;
 630         struct dma_slave_config slave_config;
 631         struct at91_twi_dma *dma = &dev->dma;
 632
 633         memset(&slave_config, 0, sizeof(slave_config));
 634         slave_config.src_addr = (dma_addr_t)phy_addr + AT91_TWI_RHR;
 635         slave_config.src_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
 636         slave_config.src_maxburst = 1;
 637         slave_config.dst_addr = (dma_addr_t)phy_addr + AT91_TWI_THR;
 638         slave_config.dst_addr_width = DMA_SLAVE_BUSWIDTH_1_BYTE;
 639         slave_config.dst_maxburst = 1;
 640         slave_config.device_fc = false;
 641
 642         dma->chan_tx = dma_request_slave_channel_reason(dev->dev, "tx");
 643         if (IS_ERR(dma->chan_tx)) {
 644                 ret = PTR_ERR(dma->chan_tx);
 645                 dma->chan_tx = NULL;
 646                 goto error;
 647         }
 648
 649         dma->chan_rx = dma_request_slave_channel_reason(dev->dev, "rx");
 650         if (IS_ERR(dma->chan_rx)) {
 651                 ret = PTR_ERR(dma->chan_rx);
 652                 dma->chan_rx = NULL;
 653                 goto error;
 654         }
 655
 656         slave_config.direction = DMA_MEM_TO_DEV;
 657         if (dmaengine_slave_config(dma->chan_tx, &slave_config)) {
 658                 dev_err(dev->dev, "failed to configure tx channel\n");
 659                 ret = -EINVAL;
 660                 goto error;
 661         }
 662
 663         slave_config.direction = DMA_DEV_TO_MEM;
 664         if (dmaengine_slave_config(dma->chan_rx, &slave_config)) {
 665                 dev_err(dev->dev, "failed to configure rx channel\n");
 666                 ret = -EINVAL;
 667                 goto error;
 668         }
 669
 670         sg_init_table(&dma->sg, 1);
 671         dma->buf_mapped = false;
 672         dma->xfer_in_progress = false;
 673         dev->use_dma = true;
 674
 675         dev_info(dev->dev, "using %s (tx) and %s (rx) for DMA transfers\n",
 676                  dma_chan_name(dma->chan_tx), dma_chan_name(dma->chan_rx));
 677
 678         return ret;
 679
 680 error:
 681         if (ret != -EPROBE_DEFER)
 682                 dev_info(dev->dev, "can't use DMA, error %d\n", ret);
 683         if (dma->chan_rx)
 684                 dma_release_channel(dma->chan_rx);
 685         if (dma->chan_tx)
 686                 dma_release_channel(dma->chan_tx);
 687         return ret;
 688 }
 689
 690 static struct at91_twi_pdata *at91_twi_get_driver_data(
 691                                         struct platform_device *pdev)
 692 {
 693         if (pdev->dev.of_node) {
 694                 const struct of_device_id *match;
 695                 match = of_match_node(atmel_twi_dt_ids, pdev->dev.of_node);
 696                 if (!match)
 697                         return NULL;
 698                 return (struct at91_twi_pdata *)match->data;
 699         }
 700         return (struct at91_twi_pdata *) platform_get_device_id(pdev)->driver_data;
 701 }
 702
 703 static int at91_twi_probe(struct platform_device *pdev)
 704 {
 705         struct at91_twi_dev *dev;
 706         struct resource *mem;
 707         int rc;
 708         u32 phy_addr;
 709         u32 bus_clk_rate;
 710
 711         dev = devm_kzalloc(&pdev->dev, sizeof(*dev), GFP_KERNEL);
 712         if (!dev)
 713                 return -ENOMEM;
 714         init_completion(&dev->cmd_complete);
 715         dev->dev = &pdev->dev;
 716
 717         mem = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 718         if (!mem)
 719                 return -ENODEV;
 720         phy_addr = mem->start;
 721
 722         dev->pdata = at91_twi_get_driver_data(pdev);
 723         if (!dev->pdata)
 724                 return -ENODEV;
 725
 726         dev->base = devm_ioremap_resource(&pdev->dev, mem);
 727         if (IS_ERR(dev->base))
 728                 return PTR_ERR(dev->base);
 729
 730         dev->irq = platform_get_irq(pdev, 0);
 731         if (dev->irq < 0)
 732                 return dev->irq;
 733
 734         rc = devm_request_irq(&pdev->dev, dev->irq, atmel_twi_interrupt, 0,
 735                          dev_name(dev->dev), dev);
 736         if (rc) {
 737                 dev_err(dev->dev, "Cannot get irq %d: %d\n", dev->irq, rc);
 738                 return rc;
 739         }
 740
 741         platform_set_drvdata(pdev, dev);
 742
 743         dev->clk = devm_clk_get(dev->dev, NULL);
 744         if (IS_ERR(dev->clk)) {
 745                 dev_err(dev->dev, "no clock defined\n");
 746                 return -ENODEV;
 747         }
 748         clk_prepare_enable(dev->clk);
 749
 750         if (dev->dev->of_node) {
 751                 rc = at91_twi_configure_dma(dev, phy_addr);
 752                 if (rc == -EPROBE_DEFER)
 753                         return rc;
 754         }
 755
 756         rc = of_property_read_u32(dev->dev->of_node, "clock-frequency",
 757                         &bus_clk_rate);
 758         if (rc)
 759                 bus_clk_rate = DEFAULT_TWI_CLK_HZ;
 760
 761         at91_calc_twi_clock(dev, bus_clk_rate);
 762         at91_init_twi_bus(dev);
 763
 764         snprintf(dev->adapter.name, sizeof(dev->adapter.name), "AT91");
 765         i2c_set_adapdata(&dev->adapter, dev);
 766         dev->adapter.owner = THIS_MODULE;
 767         dev->adapter.class = I2C_CLASS_DEPRECATED;
 768         dev->adapter.algo = &at91_twi_algorithm;
 769         dev->adapter.quirks = &at91_twi_quirks;
 770         dev->adapter.dev.parent = dev->dev;
 771         dev->adapter.nr = pdev->id;
 772         dev->adapter.timeout = AT91_I2C_TIMEOUT;
 773         dev->adapter.dev.of_node = pdev->dev.of_node;
 774
 775         pm_runtime_set_autosuspend_delay(dev->dev, AUTOSUSPEND_TIMEOUT);
 776         pm_runtime_use_autosuspend(dev->dev);
 777         pm_runtime_set_active(dev->dev);
 778         pm_runtime_enable(dev->dev);
 779
 780         rc = i2c_add_numbered_adapter(&dev->adapter);
 781         if (rc) {
 782                 dev_err(dev->dev, "Adapter %s registration failed\n",
 783                         dev->adapter.name);
 784                 clk_disable_unprepare(dev->clk);
 785
 786                 pm_runtime_disable(dev->dev);
 787                 pm_runtime_set_suspended(dev->dev);
 788
 789                 return rc;
 790         }
 791
 792         dev_info(dev->dev, "AT91 i2c bus driver.\n");
 793         return 0;
 794 }
 795
 796 static int at91_twi_remove(struct platform_device *pdev)
 797 {
 798         struct at91_twi_dev *dev = platform_get_drvdata(pdev);
 799
 800         i2c_del_adapter(&dev->adapter);
 801         clk_disable_unprepare(dev->clk);
 802
 803         pm_runtime_disable(dev->dev);
 804         pm_runtime_set_suspended(dev->dev);
 805
 806         return 0;
 807 }
 808
 809 #ifdef CONFIG_PM
 810
 811 static int at91_twi_runtime_suspend(struct device *dev)
 812 {
 813         struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
 814
 815         clk_disable_unprepare(twi_dev->clk);
 816
 817         pinctrl_pm_select_sleep_state(dev);
 818
 819         return 0;
 820 }
 821
 822 static int at91_twi_runtime_resume(struct device *dev)
 823 {
 824         struct at91_twi_dev *twi_dev = dev_get_drvdata(dev);
 825
 826         pinctrl_pm_select_default_state(dev);
 827
 828         return clk_prepare_enable(twi_dev->clk);
 829 }
 830
 831 static int at91_twi_suspend_noirq(struct device *dev)
 832 {
 833         if (!pm_runtime_status_suspended(dev))
 834                 at91_twi_runtime_suspend(dev);
 835
 836         return 0;
 837 }
 838
 839 static int at91_twi_resume_noirq(struct device *dev)
 840 {
 841         int ret;
 842
 843         if (!pm_runtime_status_suspended(dev)) {
 844                 ret = at91_twi_runtime_resume(dev);
 845                 if (ret)
 846                         return ret;
 847         }
 848
 849         pm_runtime_mark_last_busy(dev);
 850         pm_request_autosuspend(dev);
 851
 852         return 0;
 853 }
 854
 855 static const struct dev_pm_ops at91_twi_pm = {
 856         .suspend_noirq  = at91_twi_suspend_noirq,
 857         .resume_noirq   = at91_twi_resume_noirq,
 858         .runtime_suspend        = at91_twi_runtime_suspend,
 859         .runtime_resume         = at91_twi_runtime_resume,
 860 };
 861
 862 #define at91_twi_pm_ops (&at91_twi_pm)
 863 #else
 864 #define at91_twi_pm_ops NULL
 865 #endif
 866
 867 static struct platform_driver at91_twi_driver = {
 868         .probe          = at91_twi_probe,
 869         .remove         = at91_twi_remove,
 870         .id_table       = at91_twi_devtypes,
 871         .driver         = {
 872                 .name   = "at91_i2c",
 873                 .of_match_table = of_match_ptr(atmel_twi_dt_ids),
 874                 .pm     = at91_twi_pm_ops,
 875         },
 876 };
 877
 878 static int __init at91_twi_init(void)
 879 {
 880         return platform_driver_register(&at91_twi_driver);
 881 }
 882
 883 static void __exit at91_twi_exit(void)
 884 {
 885         platform_driver_unregister(&at91_twi_driver);
 886 }
 887
 888 subsys_initcall(at91_twi_init);
 889 module_exit(at91_twi_exit);
 890
 891 MODULE_AUTHOR("Nikolaus Voss <n.voss@weinmann.de>");
 892 MODULE_DESCRIPTION("I2C (TWI) driver for Atmel AT91");
 893 MODULE_LICENSE("GPL");
 894 MODULE_ALIAS("platform:at91_i2c");