drivers/i2c/busses/i2c-tegra.c

   1 /*
   2  * drivers/i2c/busses/i2c-tegra.c
   3  *
   4  * Copyright (C) 2010 Google, Inc.
   5  * Author: Colin Cross <ccross@android.com>
   6  *
   7  * This software is licensed under the terms of the GNU General Public
   8  * License version 2, as published by the Free Software Foundation, and
   9  * may be copied, distributed, and modified under those terms.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14  * GNU General Public License for more details.
  15  *
  16  */
  17
  18 #include <linux/kernel.h>
  19 #include <linux/init.h>
  20 #include <linux/platform_device.h>
  21 #include <linux/clk.h>
  22 #include <linux/err.h>
  23 #include <linux/i2c.h>
  24 #include <linux/io.h>
  25 #include <linux/interrupt.h>
  26 #include <linux/delay.h>
  27 #include <linux/slab.h>
  28 #include <linux/i2c-tegra.h>
  29 #include <linux/of_i2c.h>
  30 #include <linux/module.h>
  31
  32 #include <asm/unaligned.h>
  33
  34 #include <mach/clk.h>
  35
  36 #define TEGRA_I2C_TIMEOUT (msecs_to_jiffies(1000))
  37 #define BYTES_PER_FIFO_WORD 4
  38
  39 #define I2C_CNFG                                0x000
  40 #define I2C_CNFG_DEBOUNCE_CNT_SHIFT             12
  41 #define I2C_CNFG_PACKET_MODE_EN                 (1<<10)
  42 #define I2C_CNFG_NEW_MASTER_FSM                 (1<<11)
  43 #define I2C_STATUS                              0x01C
  44 #define I2C_SL_CNFG                             0x020
  45 #define I2C_SL_CNFG_NACK                        (1<<1)
  46 #define I2C_SL_CNFG_NEWSL                       (1<<2)
  47 #define I2C_SL_ADDR1                            0x02c
  48 #define I2C_SL_ADDR2                            0x030
  49 #define I2C_TX_FIFO                             0x050
  50 #define I2C_RX_FIFO                             0x054
  51 #define I2C_PACKET_TRANSFER_STATUS              0x058
  52 #define I2C_FIFO_CONTROL                        0x05c
  53 #define I2C_FIFO_CONTROL_TX_FLUSH               (1<<1)
  54 #define I2C_FIFO_CONTROL_RX_FLUSH               (1<<0)
  55 #define I2C_FIFO_CONTROL_TX_TRIG_SHIFT          5
  56 #define I2C_FIFO_CONTROL_RX_TRIG_SHIFT          2
  57 #define I2C_FIFO_STATUS                         0x060
  58 #define I2C_FIFO_STATUS_TX_MASK                 0xF0
  59 #define I2C_FIFO_STATUS_TX_SHIFT                4
  60 #define I2C_FIFO_STATUS_RX_MASK                 0x0F
  61 #define I2C_FIFO_STATUS_RX_SHIFT                0
  62 #define I2C_INT_MASK                            0x064
  63 #define I2C_INT_STATUS                          0x068
  64 #define I2C_INT_PACKET_XFER_COMPLETE            (1<<7)
  65 #define I2C_INT_ALL_PACKETS_XFER_COMPLETE       (1<<6)
  66 #define I2C_INT_TX_FIFO_OVERFLOW                (1<<5)
  67 #define I2C_INT_RX_FIFO_UNDERFLOW               (1<<4)
  68 #define I2C_INT_NO_ACK                          (1<<3)
  69 #define I2C_INT_ARBITRATION_LOST                (1<<2)
  70 #define I2C_INT_TX_FIFO_DATA_REQ                (1<<1)
  71 #define I2C_INT_RX_FIFO_DATA_REQ                (1<<0)
  72 #define I2C_CLK_DIVISOR                         0x06c
  73
  74 #define DVC_CTRL_REG1                           0x000
  75 #define DVC_CTRL_REG1_INTR_EN                   (1<<10)
  76 #define DVC_CTRL_REG2                           0x004
  77 #define DVC_CTRL_REG3                           0x008
  78 #define DVC_CTRL_REG3_SW_PROG                   (1<<26)
  79 #define DVC_CTRL_REG3_I2C_DONE_INTR_EN          (1<<30)
  80 #define DVC_STATUS                              0x00c
  81 #define DVC_STATUS_I2C_DONE_INTR                (1<<30)
  82
  83 #define I2C_ERR_NONE                            0x00
  84 #define I2C_ERR_NO_ACK                          0x01
  85 #define I2C_ERR_ARBITRATION_LOST                0x02
  86 #define I2C_ERR_UNKNOWN_INTERRUPT               0x04
  87
  88 #define PACKET_HEADER0_HEADER_SIZE_SHIFT        28
  89 #define PACKET_HEADER0_PACKET_ID_SHIFT          16
  90 #define PACKET_HEADER0_CONT_ID_SHIFT            12
  91 #define PACKET_HEADER0_PROTOCOL_I2C             (1<<4)
  92
  93 #define I2C_HEADER_HIGHSPEED_MODE               (1<<22)
  94 #define I2C_HEADER_CONT_ON_NAK                  (1<<21)
  95 #define I2C_HEADER_SEND_START_BYTE              (1<<20)
  96 #define I2C_HEADER_READ                         (1<<19)
  97 #define I2C_HEADER_10BIT_ADDR                   (1<<18)
  98 #define I2C_HEADER_IE_ENABLE                    (1<<17)
  99 #define I2C_HEADER_REPEAT_START                 (1<<16)
 100 #define I2C_HEADER_MASTER_ADDR_SHIFT            12
 101 #define I2C_HEADER_SLAVE_ADDR_SHIFT             1
 102
 103 /**
 104  * struct tegra_i2c_dev - per device i2c context
 105  * @dev: device reference for power management
 106  * @adapter: core i2c layer adapter information
 107  * @clk: clock reference for i2c controller
 108  * @i2c_clk: clock reference for i2c bus
 109  * @iomem: memory resource for registers
 110  * @base: ioremapped registers cookie
 111  * @cont_id: i2c controller id, used for for packet header
 112  * @irq: irq number of transfer complete interrupt
 113  * @is_dvc: identifies the DVC i2c controller, has a different register layout
 114  * @msg_complete: transfer completion notifier
 115  * @msg_err: error code for completed message
 116  * @msg_buf: pointer to current message data
 117  * @msg_buf_remaining: size of unsent data in the message buffer
 118  * @msg_read: identifies read transfers
 119  * @bus_clk_rate: current i2c bus clock rate
 120  * @is_suspended: prevents i2c controller accesses after suspend is called
 121  */
 122 struct tegra_i2c_dev {
 123         struct device *dev;
 124         struct i2c_adapter adapter;
 125         struct clk *clk;
 126         struct clk *i2c_clk;
 127         struct resource *iomem;
 128         void __iomem *base;
 129         int cont_id;
 130         int irq;
 131         bool irq_disabled;
 132         int is_dvc;
 133         struct completion msg_complete;
 134         int msg_err;
 135         u8 *msg_buf;
 136         size_t msg_buf_remaining;
 137         int msg_read;
 138         unsigned long bus_clk_rate;
 139         bool is_suspended;
 140 };
 141
 142 static void dvc_writel(struct tegra_i2c_dev *i2c_dev, u32 val, unsigned long reg)
 143 {
 144         writel(val, i2c_dev->base + reg);
 145 }
 146
 147 static u32 dvc_readl(struct tegra_i2c_dev *i2c_dev, unsigned long reg)
 148 {
 149         return readl(i2c_dev->base + reg);
 150 }
 151
 152 /*
 153  * i2c_writel and i2c_readl will offset the register if necessary to talk
 154  * to the I2C block inside the DVC block
 155  */
 156 static unsigned long tegra_i2c_reg_addr(struct tegra_i2c_dev *i2c_dev,
 157         unsigned long reg)
 158 {
 159         if (i2c_dev->is_dvc)
 160                 reg += (reg >= I2C_TX_FIFO) ? 0x10 : 0x40;
 161         return reg;
 162 }
 163
 164 static void i2c_writel(struct tegra_i2c_dev *i2c_dev, u32 val,
 165         unsigned long reg)
 166 {
 167         writel(val, i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg));
 168 }
 169
 170 static u32 i2c_readl(struct tegra_i2c_dev *i2c_dev, unsigned long reg)
 171 {
 172         return readl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg));
 173 }
 174
 175 static void i2c_writesl(struct tegra_i2c_dev *i2c_dev, void *data,
 176         unsigned long reg, int len)
 177 {
 178         writesl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg), data, len);
 179 }
 180
 181 static void i2c_readsl(struct tegra_i2c_dev *i2c_dev, void *data,
 182         unsigned long reg, int len)
 183 {
 184         readsl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg), data, len);
 185 }
 186
 187 static void tegra_i2c_mask_irq(struct tegra_i2c_dev *i2c_dev, u32 mask)
 188 {
 189         u32 int_mask = i2c_readl(i2c_dev, I2C_INT_MASK);
 190         int_mask &= ~mask;
 191         i2c_writel(i2c_dev, int_mask, I2C_INT_MASK);
 192 }
 193
 194 static void tegra_i2c_unmask_irq(struct tegra_i2c_dev *i2c_dev, u32 mask)
 195 {
 196         u32 int_mask = i2c_readl(i2c_dev, I2C_INT_MASK);
 197         int_mask |= mask;
 198         i2c_writel(i2c_dev, int_mask, I2C_INT_MASK);
 199 }
 200
 201 static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev)
 202 {
 203         unsigned long timeout = jiffies + HZ;
 204         u32 val = i2c_readl(i2c_dev, I2C_FIFO_CONTROL);
 205         val |= I2C_FIFO_CONTROL_TX_FLUSH | I2C_FIFO_CONTROL_RX_FLUSH;
 206         i2c_writel(i2c_dev, val, I2C_FIFO_CONTROL);
 207
 208         while (i2c_readl(i2c_dev, I2C_FIFO_CONTROL) &
 209                 (I2C_FIFO_CONTROL_TX_FLUSH | I2C_FIFO_CONTROL_RX_FLUSH)) {
 210                 if (time_after(jiffies, timeout)) {
 211                         dev_warn(i2c_dev->dev, "timeout waiting for fifo flush\n");
 212                         return -ETIMEDOUT;
 213                 }
 214                 msleep(1);
 215         }
 216         return 0;
 217 }
 218
 219 static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev)
 220 {
 221         u32 val;
 222         int rx_fifo_avail;
 223         u8 *buf = i2c_dev->msg_buf;
 224         size_t buf_remaining = i2c_dev->msg_buf_remaining;
 225         int words_to_transfer;
 226
 227         val = i2c_readl(i2c_dev, I2C_FIFO_STATUS);
 228         rx_fifo_avail = (val & I2C_FIFO_STATUS_RX_MASK) >>
 229                 I2C_FIFO_STATUS_RX_SHIFT;
 230
 231         /* Rounds down to not include partial word at the end of buf */
 232         words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD;
 233         if (words_to_transfer > rx_fifo_avail)
 234                 words_to_transfer = rx_fifo_avail;
 235
 236         i2c_readsl(i2c_dev, buf, I2C_RX_FIFO, words_to_transfer);
 237
 238         buf += words_to_transfer * BYTES_PER_FIFO_WORD;
 239         buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD;
 240         rx_fifo_avail -= words_to_transfer;
 241
 242         /*
 243          * If there is a partial word at the end of buf, handle it manually to
 244          * prevent overwriting past the end of buf
 245          */
 246         if (rx_fifo_avail > 0 && buf_remaining > 0) {
 247                 BUG_ON(buf_remaining > 3);
 248                 val = i2c_readl(i2c_dev, I2C_RX_FIFO);
 249                 memcpy(buf, &val, buf_remaining);
 250                 buf_remaining = 0;
 251                 rx_fifo_avail--;
 252         }
 253
 254         BUG_ON(rx_fifo_avail > 0 && buf_remaining > 0);
 255         i2c_dev->msg_buf_remaining = buf_remaining;
 256         i2c_dev->msg_buf = buf;
 257         return 0;
 258 }
 259
 260 static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
 261 {
 262         u32 val;
 263         int tx_fifo_avail;
 264         u8 *buf = i2c_dev->msg_buf;
 265         size_t buf_remaining = i2c_dev->msg_buf_remaining;
 266         int words_to_transfer;
 267
 268         val = i2c_readl(i2c_dev, I2C_FIFO_STATUS);
 269         tx_fifo_avail = (val & I2C_FIFO_STATUS_TX_MASK) >>
 270                 I2C_FIFO_STATUS_TX_SHIFT;
 271
 272         /* Rounds down to not include partial word at the end of buf */
 273         words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD;
 274
 275         /* It's very common to have < 4 bytes, so optimize that case. */
 276         if (words_to_transfer) {
 277                 if (words_to_transfer > tx_fifo_avail)
 278                         words_to_transfer = tx_fifo_avail;
 279
 280                 /*
 281                  * Update state before writing to FIFO.  If this casues us
 282                  * to finish writing all bytes (AKA buf_remaining goes to 0) we
 283                  * have a potential for an interrupt (PACKET_XFER_COMPLETE is
 284                  * not maskable).  We need to make sure that the isr sees
 285                  * buf_remaining as 0 and doesn't call us back re-entrantly.
 286                  */
 287                 buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD;
 288                 tx_fifo_avail -= words_to_transfer;
 289                 i2c_dev->msg_buf_remaining = buf_remaining;
 290                 i2c_dev->msg_buf = buf +
 291                         words_to_transfer * BYTES_PER_FIFO_WORD;
 292                 barrier();
 293
 294                 i2c_writesl(i2c_dev, buf, I2C_TX_FIFO, words_to_transfer);
 295
 296                 buf += words_to_transfer * BYTES_PER_FIFO_WORD;
 297         }
 298
 299         /*
 300          * If there is a partial word at the end of buf, handle it manually to
 301          * prevent reading past the end of buf, which could cross a page
 302          * boundary and fault.
 303          */
 304         if (tx_fifo_avail > 0 && buf_remaining > 0) {
 305                 BUG_ON(buf_remaining > 3);
 306                 memcpy(&val, buf, buf_remaining);
 307
 308                 /* Again update before writing to FIFO to make sure isr sees. */
 309                 i2c_dev->msg_buf_remaining = 0;
 310                 i2c_dev->msg_buf = NULL;
 311                 barrier();
 312
 313                 i2c_writel(i2c_dev, val, I2C_TX_FIFO);
 314         }
 315
 316         return 0;
 317 }
 318
 319 /*
 320  * One of the Tegra I2C blocks is inside the DVC (Digital Voltage Controller)
 321  * block.  This block is identical to the rest of the I2C blocks, except that
 322  * it only supports master mode, it has registers moved around, and it needs
 323  * some extra init to get it into I2C mode.  The register moves are handled
 324  * by i2c_readl and i2c_writel
 325  */
 326 static void tegra_dvc_init(struct tegra_i2c_dev *i2c_dev)
 327 {
 328         u32 val = 0;
 329         val = dvc_readl(i2c_dev, DVC_CTRL_REG3);
 330         val |= DVC_CTRL_REG3_SW_PROG;
 331         val |= DVC_CTRL_REG3_I2C_DONE_INTR_EN;
 332         dvc_writel(i2c_dev, val, DVC_CTRL_REG3);
 333
 334         val = dvc_readl(i2c_dev, DVC_CTRL_REG1);
 335         val |= DVC_CTRL_REG1_INTR_EN;
 336         dvc_writel(i2c_dev, val, DVC_CTRL_REG1);
 337 }
 338
 339 static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
 340 {
 341         u32 val;
 342         int err = 0;
 343
 344         clk_prepare_enable(i2c_dev->clk);
 345
 346         tegra_periph_reset_assert(i2c_dev->clk);
 347         udelay(2);
 348         tegra_periph_reset_deassert(i2c_dev->clk);
 349
 350         if (i2c_dev->is_dvc)
 351                 tegra_dvc_init(i2c_dev);
 352
 353         val = I2C_CNFG_NEW_MASTER_FSM | I2C_CNFG_PACKET_MODE_EN |
 354                 (0x2 << I2C_CNFG_DEBOUNCE_CNT_SHIFT);
 355         i2c_writel(i2c_dev, val, I2C_CNFG);
 356         i2c_writel(i2c_dev, 0, I2C_INT_MASK);
 357         clk_set_rate(i2c_dev->clk, i2c_dev->bus_clk_rate * 8);
 358
 359         if (!i2c_dev->is_dvc) {
 360                 u32 sl_cfg = i2c_readl(i2c_dev, I2C_SL_CNFG);
 361                 sl_cfg |= I2C_SL_CNFG_NACK | I2C_SL_CNFG_NEWSL;
 362                 i2c_writel(i2c_dev, sl_cfg, I2C_SL_CNFG);
 363                 i2c_writel(i2c_dev, 0xfc, I2C_SL_ADDR1);
 364                 i2c_writel(i2c_dev, 0x00, I2C_SL_ADDR2);
 365
 366         }
 367
 368         val = 7 << I2C_FIFO_CONTROL_TX_TRIG_SHIFT |
 369                 0 << I2C_FIFO_CONTROL_RX_TRIG_SHIFT;
 370         i2c_writel(i2c_dev, val, I2C_FIFO_CONTROL);
 371
 372         if (tegra_i2c_flush_fifos(i2c_dev))
 373                 err = -ETIMEDOUT;
 374
 375         clk_disable_unprepare(i2c_dev->clk);
 376
 377         if (i2c_dev->irq_disabled) {
 378                 i2c_dev->irq_disabled = 0;
 379                 enable_irq(i2c_dev->irq);
 380         }
 381
 382         return err;
 383 }
 384
 385 static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
 386 {
 387         u32 status;
 388         const u32 status_err = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST;
 389         struct tegra_i2c_dev *i2c_dev = dev_id;
 390
 391         status = i2c_readl(i2c_dev, I2C_INT_STATUS);
 392
 393         if (status == 0) {
 394                 dev_warn(i2c_dev->dev, "irq status 0 %08x %08x %08x\n",
 395                          i2c_readl(i2c_dev, I2C_PACKET_TRANSFER_STATUS),
 396                          i2c_readl(i2c_dev, I2C_STATUS),
 397                          i2c_readl(i2c_dev, I2C_CNFG));
 398                 i2c_dev->msg_err |= I2C_ERR_UNKNOWN_INTERRUPT;
 399
 400                 if (!i2c_dev->irq_disabled) {
 401                         disable_irq_nosync(i2c_dev->irq);
 402                         i2c_dev->irq_disabled = 1;
 403                 }
 404                 goto err;
 405         }
 406
 407         if (unlikely(status & status_err)) {
 408                 if (status & I2C_INT_NO_ACK)
 409                         i2c_dev->msg_err |= I2C_ERR_NO_ACK;
 410                 if (status & I2C_INT_ARBITRATION_LOST)
 411                         i2c_dev->msg_err |= I2C_ERR_ARBITRATION_LOST;
 412                 goto err;
 413         }
 414
 415         if (i2c_dev->msg_read && (status & I2C_INT_RX_FIFO_DATA_REQ)) {
 416                 if (i2c_dev->msg_buf_remaining)
 417                         tegra_i2c_empty_rx_fifo(i2c_dev);
 418                 else
 419                         BUG();
 420         }
 421
 422         if (!i2c_dev->msg_read && (status & I2C_INT_TX_FIFO_DATA_REQ)) {
 423                 if (i2c_dev->msg_buf_remaining)
 424                         tegra_i2c_fill_tx_fifo(i2c_dev);
 425                 else
 426                         tegra_i2c_mask_irq(i2c_dev, I2C_INT_TX_FIFO_DATA_REQ);
 427         }
 428
 429         i2c_writel(i2c_dev, status, I2C_INT_STATUS);
 430         if (i2c_dev->is_dvc)
 431                 dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS);
 432
 433         if (status & I2C_INT_PACKET_XFER_COMPLETE) {
 434                 BUG_ON(i2c_dev->msg_buf_remaining);
 435                 complete(&i2c_dev->msg_complete);
 436         }
 437         return IRQ_HANDLED;
 438 err:
 439         /* An error occurred, mask all interrupts */
 440         tegra_i2c_mask_irq(i2c_dev, I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST |
 441                 I2C_INT_PACKET_XFER_COMPLETE | I2C_INT_TX_FIFO_DATA_REQ |
 442                 I2C_INT_RX_FIFO_DATA_REQ);
 443         i2c_writel(i2c_dev, status, I2C_INT_STATUS);
 444         if (i2c_dev->is_dvc)
 445                 dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS);
 446
 447         complete(&i2c_dev->msg_complete);
 448         return IRQ_HANDLED;
 449 }
 450
 451 static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 452         struct i2c_msg *msg, int stop)
 453 {
 454         u32 packet_header;
 455         u32 int_mask;
 456         int ret;
 457
 458         tegra_i2c_flush_fifos(i2c_dev);
 459
 460         if (msg->len == 0)
 461                 return -EINVAL;
 462
 463         i2c_dev->msg_buf = msg->buf;
 464         i2c_dev->msg_buf_remaining = msg->len;
 465         i2c_dev->msg_err = I2C_ERR_NONE;
 466         i2c_dev->msg_read = (msg->flags & I2C_M_RD);
 467         INIT_COMPLETION(i2c_dev->msg_complete);
 468
 469         packet_header = (0 << PACKET_HEADER0_HEADER_SIZE_SHIFT) |
 470                         PACKET_HEADER0_PROTOCOL_I2C |
 471                         (i2c_dev->cont_id << PACKET_HEADER0_CONT_ID_SHIFT) |
 472                         (1 << PACKET_HEADER0_PACKET_ID_SHIFT);
 473         i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
 474
 475         packet_header = msg->len - 1;
 476         i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
 477
 478         packet_header = I2C_HEADER_IE_ENABLE;
 479         if (!stop)
 480                 packet_header |= I2C_HEADER_REPEAT_START;
 481         if (msg->flags & I2C_M_TEN) {
 482                 packet_header |= msg->addr;
 483                 packet_header |= I2C_HEADER_10BIT_ADDR;
 484         } else {
 485                 packet_header |= msg->addr << I2C_HEADER_SLAVE_ADDR_SHIFT;
 486         }
 487         if (msg->flags & I2C_M_IGNORE_NAK)
 488                 packet_header |= I2C_HEADER_CONT_ON_NAK;
 489         if (msg->flags & I2C_M_RD)
 490                 packet_header |= I2C_HEADER_READ;
 491         i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
 492
 493         if (!(msg->flags & I2C_M_RD))
 494                 tegra_i2c_fill_tx_fifo(i2c_dev);
 495
 496         int_mask = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST;
 497         if (msg->flags & I2C_M_RD)
 498                 int_mask |= I2C_INT_RX_FIFO_DATA_REQ;
 499         else if (i2c_dev->msg_buf_remaining)
 500                 int_mask |= I2C_INT_TX_FIFO_DATA_REQ;
 501         tegra_i2c_unmask_irq(i2c_dev, int_mask);
 502         dev_dbg(i2c_dev->dev, "unmasked irq: %02x\n",
 503                 i2c_readl(i2c_dev, I2C_INT_MASK));
 504
 505         ret = wait_for_completion_timeout(&i2c_dev->msg_complete, TEGRA_I2C_TIMEOUT);
 506         tegra_i2c_mask_irq(i2c_dev, int_mask);
 507
 508         if (WARN_ON(ret == 0)) {
 509                 dev_err(i2c_dev->dev, "i2c transfer timed out\n");
 510
 511                 tegra_i2c_init(i2c_dev);
 512                 return -ETIMEDOUT;
 513         }
 514
 515         dev_dbg(i2c_dev->dev, "transfer complete: %d %d %d\n",
 516                 ret, completion_done(&i2c_dev->msg_complete), i2c_dev->msg_err);
 517
 518         if (likely(i2c_dev->msg_err == I2C_ERR_NONE))
 519                 return 0;
 520
 521         /*
 522          * NACK interrupt is generated before the I2C controller generates the
 523          * STOP condition on the bus. So wait for 2 clock periods before resetting
 524          * the controller so that STOP condition has been delivered properly.
 525          */
 526         if (i2c_dev->msg_err == I2C_ERR_NO_ACK)
 527                 udelay(DIV_ROUND_UP(2 * 1000000, i2c_dev->bus_clk_rate));
 528
 529         tegra_i2c_init(i2c_dev);
 530         if (i2c_dev->msg_err == I2C_ERR_NO_ACK) {
 531                 if (msg->flags & I2C_M_IGNORE_NAK)
 532                         return 0;
 533                 return -EREMOTEIO;
 534         }
 535
 536         return -EIO;
 537 }
 538
 539 static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
 540         int num)
 541 {
 542         struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
 543         int i;
 544         int ret = 0;
 545
 546         if (i2c_dev->is_suspended)
 547                 return -EBUSY;
 548
 549         clk_prepare_enable(i2c_dev->clk);
 550         for (i = 0; i < num; i++) {
 551                 int stop = (i == (num - 1)) ? 1  : 0;
 552                 ret = tegra_i2c_xfer_msg(i2c_dev, &msgs[i], stop);
 553                 if (ret)
 554                         break;
 555         }
 556         clk_disable_unprepare(i2c_dev->clk);
 557         return ret ?: i;
 558 }
 559
 560 static u32 tegra_i2c_func(struct i2c_adapter *adap)
 561 {
 562         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR;
 563 }
 564
 565 static const struct i2c_algorithm tegra_i2c_algo = {
 566         .master_xfer    = tegra_i2c_xfer,
 567         .functionality  = tegra_i2c_func,
 568 };
 569
 570 static int __devinit tegra_i2c_probe(struct platform_device *pdev)
 571 {
 572         struct tegra_i2c_dev *i2c_dev;
 573         struct tegra_i2c_platform_data *pdata = pdev->dev.platform_data;
 574         struct resource *res;
 575         struct resource *iomem;
 576         struct clk *clk;
 577         struct clk *i2c_clk;
 578         const unsigned int *prop;
 579         void __iomem *base;
 580         int irq;
 581         int ret = 0;
 582
 583         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 584         if (!res) {
 585                 dev_err(&pdev->dev, "no mem resource\n");
 586                 return -EINVAL;
 587         }
 588         iomem = request_mem_region(res->start, resource_size(res), pdev->name);
 589         if (!iomem) {
 590                 dev_err(&pdev->dev, "I2C region already claimed\n");
 591                 return -EBUSY;
 592         }
 593
 594         base = ioremap(iomem->start, resource_size(iomem));
 595         if (!base) {
 596                 dev_err(&pdev->dev, "Cannot ioremap I2C region\n");
 597                 return -ENOMEM;
 598         }
 599
 600         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 601         if (!res) {
 602                 dev_err(&pdev->dev, "no irq resource\n");
 603                 ret = -EINVAL;
 604                 goto err_iounmap;
 605         }
 606         irq = res->start;
 607
 608         clk = clk_get(&pdev->dev, NULL);
 609         if (IS_ERR(clk)) {
 610                 dev_err(&pdev->dev, "missing controller clock");
 611                 ret = PTR_ERR(clk);
 612                 goto err_release_region;
 613         }
 614
 615         i2c_clk = clk_get(&pdev->dev, "i2c");
 616         if (IS_ERR(i2c_clk)) {
 617                 dev_err(&pdev->dev, "missing bus clock");
 618                 ret = PTR_ERR(i2c_clk);
 619                 goto err_clk_put;
 620         }
 621
 622         i2c_dev = kzalloc(sizeof(struct tegra_i2c_dev), GFP_KERNEL);
 623         if (!i2c_dev) {
 624                 ret = -ENOMEM;
 625                 goto err_i2c_clk_put;
 626         }
 627
 628         i2c_dev->base = base;
 629         i2c_dev->clk = clk;
 630         i2c_dev->i2c_clk = i2c_clk;
 631         i2c_dev->iomem = iomem;
 632         i2c_dev->adapter.algo = &tegra_i2c_algo;
 633         i2c_dev->irq = irq;
 634         i2c_dev->cont_id = pdev->id;
 635         i2c_dev->dev = &pdev->dev;
 636
 637         i2c_dev->bus_clk_rate = 100000; /* default clock rate */
 638         if (pdata) {
 639                 i2c_dev->bus_clk_rate = pdata->bus_clk_rate;
 640
 641         } else if (i2c_dev->dev->of_node) {    /* if there is a device tree node ... */
 642                 prop = of_get_property(i2c_dev->dev->of_node,
 643                                 "clock-frequency", NULL);
 644                 if (prop)
 645                         i2c_dev->bus_clk_rate = be32_to_cpup(prop);
 646         }
 647
 648         if (pdev->dev.of_node)
 649                 i2c_dev->is_dvc = of_device_is_compatible(pdev->dev.of_node,
 650                                                 "nvidia,tegra20-i2c-dvc");
 651         else if (pdev->id == 3)
 652                 i2c_dev->is_dvc = 1;
 653         init_completion(&i2c_dev->msg_complete);
 654
 655         platform_set_drvdata(pdev, i2c_dev);
 656
 657         ret = tegra_i2c_init(i2c_dev);
 658         if (ret) {
 659                 dev_err(&pdev->dev, "Failed to initialize i2c controller");
 660                 goto err_free;
 661         }
 662
 663         ret = request_irq(i2c_dev->irq, tegra_i2c_isr, 0, pdev->name, i2c_dev);
 664         if (ret) {
 665                 dev_err(&pdev->dev, "Failed to request irq %i\n", i2c_dev->irq);
 666                 goto err_free;
 667         }
 668
 669         clk_prepare_enable(i2c_dev->i2c_clk);
 670
 671         i2c_set_adapdata(&i2c_dev->adapter, i2c_dev);
 672         i2c_dev->adapter.owner = THIS_MODULE;
 673         i2c_dev->adapter.class = I2C_CLASS_HWMON;
 674         strlcpy(i2c_dev->adapter.name, "Tegra I2C adapter",
 675                 sizeof(i2c_dev->adapter.name));
 676         i2c_dev->adapter.algo = &tegra_i2c_algo;
 677         i2c_dev->adapter.dev.parent = &pdev->dev;
 678         i2c_dev->adapter.nr = pdev->id;
 679         i2c_dev->adapter.dev.of_node = pdev->dev.of_node;
 680
 681         ret = i2c_add_numbered_adapter(&i2c_dev->adapter);
 682         if (ret) {
 683                 dev_err(&pdev->dev, "Failed to add I2C adapter\n");
 684                 goto err_free_irq;
 685         }
 686
 687         of_i2c_register_devices(&i2c_dev->adapter);
 688
 689         return 0;
 690 err_free_irq:
 691         free_irq(i2c_dev->irq, i2c_dev);
 692 err_free:
 693         kfree(i2c_dev);
 694 err_i2c_clk_put:
 695         clk_put(i2c_clk);
 696 err_clk_put:
 697         clk_put(clk);
 698 err_release_region:
 699         release_mem_region(iomem->start, resource_size(iomem));
 700 err_iounmap:
 701         iounmap(base);
 702         return ret;
 703 }
 704
 705 static int __devexit tegra_i2c_remove(struct platform_device *pdev)
 706 {
 707         struct tegra_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
 708         i2c_del_adapter(&i2c_dev->adapter);
 709         free_irq(i2c_dev->irq, i2c_dev);
 710         clk_put(i2c_dev->i2c_clk);
 711         clk_put(i2c_dev->clk);
 712         release_mem_region(i2c_dev->iomem->start,
 713                 resource_size(i2c_dev->iomem));
 714         iounmap(i2c_dev->base);
 715         kfree(i2c_dev);
 716         return 0;
 717 }
 718
 719 #ifdef CONFIG_PM
 720 static int tegra_i2c_suspend(struct platform_device *pdev, pm_message_t state)
 721 {
 722         struct tegra_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
 723
 724         i2c_lock_adapter(&i2c_dev->adapter);
 725         i2c_dev->is_suspended = true;
 726         i2c_unlock_adapter(&i2c_dev->adapter);
 727
 728         return 0;
 729 }
 730
 731 static int tegra_i2c_resume(struct platform_device *pdev)
 732 {
 733         struct tegra_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
 734         int ret;
 735
 736         i2c_lock_adapter(&i2c_dev->adapter);
 737
 738         ret = tegra_i2c_init(i2c_dev);
 739
 740         if (ret) {
 741                 i2c_unlock_adapter(&i2c_dev->adapter);
 742                 return ret;
 743         }
 744
 745         i2c_dev->is_suspended = false;
 746
 747         i2c_unlock_adapter(&i2c_dev->adapter);
 748
 749         return 0;
 750 }
 751 #endif
 752
 753 #if defined(CONFIG_OF)
 754 /* Match table for of_platform binding */
 755 static const struct of_device_id tegra_i2c_of_match[] __devinitconst = {
 756         { .compatible = "nvidia,tegra20-i2c", },
 757         { .compatible = "nvidia,tegra20-i2c-dvc", },
 758         {},
 759 };
 760 MODULE_DEVICE_TABLE(of, tegra_i2c_of_match);
 761 #else
 762 #define tegra_i2c_of_match NULL
 763 #endif
 764
 765 static struct platform_driver tegra_i2c_driver = {
 766         .probe   = tegra_i2c_probe,
 767         .remove  = __devexit_p(tegra_i2c_remove),
 768 #ifdef CONFIG_PM
 769         .suspend = tegra_i2c_suspend,
 770         .resume  = tegra_i2c_resume,
 771 #endif
 772         .driver  = {
 773                 .name  = "tegra-i2c",
 774                 .owner = THIS_MODULE,
 775                 .of_match_table = tegra_i2c_of_match,
 776         },
 777 };
 778
 779 static int __init tegra_i2c_init_driver(void)
 780 {
 781         return platform_driver_register(&tegra_i2c_driver);
 782 }
 783
 784 static void __exit tegra_i2c_exit_driver(void)
 785 {
 786         platform_driver_unregister(&tegra_i2c_driver);
 787 }
 788
 789 subsys_initcall(tegra_i2c_init_driver);
 790 module_exit(tegra_i2c_exit_driver);
 791
 792 MODULE_DESCRIPTION("nVidia Tegra2 I2C Bus Controller driver");
 793 MODULE_AUTHOR("Colin Cross");
 794 MODULE_LICENSE("GPL v2");