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
  30 #include <asm/unaligned.h>
  31
  32 #include <mach/clk.h>
  33
  34 #define TEGRA_I2C_TIMEOUT (msecs_to_jiffies(1000))
  35 #define BYTES_PER_FIFO_WORD 4
  36
  37 #define I2C_CNFG                                0x000
  38 #define I2C_CNFG_PACKET_MODE_EN                 (1<<10)
  39 #define I2C_CNFG_NEW_MASTER_FSM                 (1<<11)
  40 #define I2C_SL_CNFG                             0x020
  41 #define I2C_SL_CNFG_NEWSL                       (1<<2)
  42 #define I2C_SL_ADDR1                            0x02c
  43 #define I2C_TX_FIFO                             0x050
  44 #define I2C_RX_FIFO                             0x054
  45 #define I2C_PACKET_TRANSFER_STATUS              0x058
  46 #define I2C_FIFO_CONTROL                        0x05c
  47 #define I2C_FIFO_CONTROL_TX_FLUSH               (1<<1)
  48 #define I2C_FIFO_CONTROL_RX_FLUSH               (1<<0)
  49 #define I2C_FIFO_CONTROL_TX_TRIG_SHIFT          5
  50 #define I2C_FIFO_CONTROL_RX_TRIG_SHIFT          2
  51 #define I2C_FIFO_STATUS                         0x060
  52 #define I2C_FIFO_STATUS_TX_MASK                 0xF0
  53 #define I2C_FIFO_STATUS_TX_SHIFT                4
  54 #define I2C_FIFO_STATUS_RX_MASK                 0x0F
  55 #define I2C_FIFO_STATUS_RX_SHIFT                0
  56 #define I2C_INT_MASK                            0x064
  57 #define I2C_INT_STATUS                          0x068
  58 #define I2C_INT_PACKET_XFER_COMPLETE            (1<<7)
  59 #define I2C_INT_ALL_PACKETS_XFER_COMPLETE       (1<<6)
  60 #define I2C_INT_TX_FIFO_OVERFLOW                (1<<5)
  61 #define I2C_INT_RX_FIFO_UNDERFLOW               (1<<4)
  62 #define I2C_INT_NO_ACK                          (1<<3)
  63 #define I2C_INT_ARBITRATION_LOST                (1<<2)
  64 #define I2C_INT_TX_FIFO_DATA_REQ                (1<<1)
  65 #define I2C_INT_RX_FIFO_DATA_REQ                (1<<0)
  66 #define I2C_CLK_DIVISOR                         0x06c
  67
  68 #define DVC_CTRL_REG1                           0x000
  69 #define DVC_CTRL_REG1_INTR_EN                   (1<<10)
  70 #define DVC_CTRL_REG2                           0x004
  71 #define DVC_CTRL_REG3                           0x008
  72 #define DVC_CTRL_REG3_SW_PROG                   (1<<26)
  73 #define DVC_CTRL_REG3_I2C_DONE_INTR_EN          (1<<30)
  74 #define DVC_STATUS                              0x00c
  75 #define DVC_STATUS_I2C_DONE_INTR                (1<<30)
  76
  77 #define I2C_ERR_NONE                            0x00
  78 #define I2C_ERR_NO_ACK                          0x01
  79 #define I2C_ERR_ARBITRATION_LOST                0x02
  80
  81 #define PACKET_HEADER0_HEADER_SIZE_SHIFT        28
  82 #define PACKET_HEADER0_PACKET_ID_SHIFT          16
  83 #define PACKET_HEADER0_CONT_ID_SHIFT            12
  84 #define PACKET_HEADER0_PROTOCOL_I2C             (1<<4)
  85
  86 #define I2C_HEADER_HIGHSPEED_MODE               (1<<22)
  87 #define I2C_HEADER_CONT_ON_NAK                  (1<<21)
  88 #define I2C_HEADER_SEND_START_BYTE              (1<<20)
  89 #define I2C_HEADER_READ                         (1<<19)
  90 #define I2C_HEADER_10BIT_ADDR                   (1<<18)
  91 #define I2C_HEADER_IE_ENABLE                    (1<<17)
  92 #define I2C_HEADER_REPEAT_START                 (1<<16)
  93 #define I2C_HEADER_MASTER_ADDR_SHIFT            12
  94 #define I2C_HEADER_SLAVE_ADDR_SHIFT             1
  95
  96 /**
  97  * struct tegra_i2c_dev - per device i2c context
  98  * @dev: device reference for power management
  99  * @adapter: core i2c layer adapter information
 100  * @clk: clock reference for i2c controller
 101  * @i2c_clk: clock reference for i2c bus
 102  * @iomem: memory resource for registers
 103  * @base: ioremapped registers cookie
 104  * @cont_id: i2c controller id, used for for packet header
 105  * @irq: irq number of transfer complete interrupt
 106  * @is_dvc: identifies the DVC i2c controller, has a different register layout
 107  * @msg_complete: transfer completion notifier
 108  * @msg_err: error code for completed message
 109  * @msg_buf: pointer to current message data
 110  * @msg_buf_remaining: size of unsent data in the message buffer
 111  * @msg_read: identifies read transfers
 112  * @bus_clk_rate: current i2c bus clock rate
 113  * @is_suspended: prevents i2c controller accesses after suspend is called
 114  */
 115 struct tegra_i2c_dev {
 116         struct device *dev;
 117         struct i2c_adapter adapter;
 118         struct clk *clk;
 119         struct clk *i2c_clk;
 120         struct resource *iomem;
 121         void __iomem *base;
 122         int cont_id;
 123         int irq;
 124         int is_dvc;
 125         struct completion msg_complete;
 126         int msg_err;
 127         u8 *msg_buf;
 128         size_t msg_buf_remaining;
 129         int msg_read;
 130         unsigned long bus_clk_rate;
 131         bool is_suspended;
 132 };
 133
 134 static void dvc_writel(struct tegra_i2c_dev *i2c_dev, u32 val, unsigned long reg)
 135 {
 136         writel(val, i2c_dev->base + reg);
 137 }
 138
 139 static u32 dvc_readl(struct tegra_i2c_dev *i2c_dev, unsigned long reg)
 140 {
 141         return readl(i2c_dev->base + reg);
 142 }
 143
 144 /*
 145  * i2c_writel and i2c_readl will offset the register if necessary to talk
 146  * to the I2C block inside the DVC block
 147  */
 148 static unsigned long tegra_i2c_reg_addr(struct tegra_i2c_dev *i2c_dev,
 149         unsigned long reg)
 150 {
 151         if (i2c_dev->is_dvc)
 152                 reg += (reg >= I2C_TX_FIFO) ? 0x10 : 0x40;
 153         return reg;
 154 }
 155
 156 static void i2c_writel(struct tegra_i2c_dev *i2c_dev, u32 val,
 157         unsigned long reg)
 158 {
 159         writel(val, i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg));
 160 }
 161
 162 static u32 i2c_readl(struct tegra_i2c_dev *i2c_dev, unsigned long reg)
 163 {
 164         return readl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg));
 165 }
 166
 167 static void i2c_writesl(struct tegra_i2c_dev *i2c_dev, void *data,
 168         unsigned long reg, int len)
 169 {
 170         writesl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg), data, len);
 171 }
 172
 173 static void i2c_readsl(struct tegra_i2c_dev *i2c_dev, void *data,
 174         unsigned long reg, int len)
 175 {
 176         readsl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg), data, len);
 177 }
 178
 179 static void tegra_i2c_mask_irq(struct tegra_i2c_dev *i2c_dev, u32 mask)
 180 {
 181         u32 int_mask = i2c_readl(i2c_dev, I2C_INT_MASK);
 182         int_mask &= ~mask;
 183         i2c_writel(i2c_dev, int_mask, I2C_INT_MASK);
 184 }
 185
 186 static void tegra_i2c_unmask_irq(struct tegra_i2c_dev *i2c_dev, u32 mask)
 187 {
 188         u32 int_mask = i2c_readl(i2c_dev, I2C_INT_MASK);
 189         int_mask |= mask;
 190         i2c_writel(i2c_dev, int_mask, I2C_INT_MASK);
 191 }
 192
 193 static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev)
 194 {
 195         unsigned long timeout = jiffies + HZ;
 196         u32 val = i2c_readl(i2c_dev, I2C_FIFO_CONTROL);
 197         val |= I2C_FIFO_CONTROL_TX_FLUSH | I2C_FIFO_CONTROL_RX_FLUSH;
 198         i2c_writel(i2c_dev, val, I2C_FIFO_CONTROL);
 199
 200         while (i2c_readl(i2c_dev, I2C_FIFO_CONTROL) &
 201                 (I2C_FIFO_CONTROL_TX_FLUSH | I2C_FIFO_CONTROL_RX_FLUSH)) {
 202                 if (time_after(jiffies, timeout)) {
 203                         dev_warn(i2c_dev->dev, "timeout waiting for fifo flush\n");
 204                         return -ETIMEDOUT;
 205                 }
 206                 msleep(1);
 207         }
 208         return 0;
 209 }
 210
 211 static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev)
 212 {
 213         u32 val;
 214         int rx_fifo_avail;
 215         u8 *buf = i2c_dev->msg_buf;
 216         size_t buf_remaining = i2c_dev->msg_buf_remaining;
 217         int words_to_transfer;
 218
 219         val = i2c_readl(i2c_dev, I2C_FIFO_STATUS);
 220         rx_fifo_avail = (val & I2C_FIFO_STATUS_RX_MASK) >>
 221                 I2C_FIFO_STATUS_RX_SHIFT;
 222
 223         /* Rounds down to not include partial word at the end of buf */
 224         words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD;
 225         if (words_to_transfer > rx_fifo_avail)
 226                 words_to_transfer = rx_fifo_avail;
 227
 228         i2c_readsl(i2c_dev, buf, I2C_RX_FIFO, words_to_transfer);
 229
 230         buf += words_to_transfer * BYTES_PER_FIFO_WORD;
 231         buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD;
 232         rx_fifo_avail -= words_to_transfer;
 233
 234         /*
 235          * If there is a partial word at the end of buf, handle it manually to
 236          * prevent overwriting past the end of buf
 237          */
 238         if (rx_fifo_avail > 0 && buf_remaining > 0) {
 239                 BUG_ON(buf_remaining > 3);
 240                 val = i2c_readl(i2c_dev, I2C_RX_FIFO);
 241                 memcpy(buf, &val, buf_remaining);
 242                 buf_remaining = 0;
 243                 rx_fifo_avail--;
 244         }
 245
 246         BUG_ON(rx_fifo_avail > 0 && buf_remaining > 0);
 247         i2c_dev->msg_buf_remaining = buf_remaining;
 248         i2c_dev->msg_buf = buf;
 249         return 0;
 250 }
 251
 252 static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
 253 {
 254         u32 val;
 255         int tx_fifo_avail;
 256         u8 *buf = i2c_dev->msg_buf;
 257         size_t buf_remaining = i2c_dev->msg_buf_remaining;
 258         int words_to_transfer;
 259
 260         val = i2c_readl(i2c_dev, I2C_FIFO_STATUS);
 261         tx_fifo_avail = (val & I2C_FIFO_STATUS_TX_MASK) >>
 262                 I2C_FIFO_STATUS_TX_SHIFT;
 263
 264         /* Rounds down to not include partial word at the end of buf */
 265         words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD;
 266         if (words_to_transfer > tx_fifo_avail)
 267                 words_to_transfer = tx_fifo_avail;
 268
 269         i2c_writesl(i2c_dev, buf, I2C_TX_FIFO, words_to_transfer);
 270
 271         buf += words_to_transfer * BYTES_PER_FIFO_WORD;
 272         buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD;
 273         tx_fifo_avail -= words_to_transfer;
 274
 275         /*
 276          * If there is a partial word at the end of buf, handle it manually to
 277          * prevent reading past the end of buf, which could cross a page
 278          * boundary and fault.
 279          */
 280         if (tx_fifo_avail > 0 && buf_remaining > 0) {
 281                 BUG_ON(buf_remaining > 3);
 282                 memcpy(&val, buf, buf_remaining);
 283                 i2c_writel(i2c_dev, val, I2C_TX_FIFO);
 284                 buf_remaining = 0;
 285                 tx_fifo_avail--;
 286         }
 287
 288         BUG_ON(tx_fifo_avail > 0 && buf_remaining > 0);
 289         i2c_dev->msg_buf_remaining = buf_remaining;
 290         i2c_dev->msg_buf = buf;
 291         return 0;
 292 }
 293
 294 /*
 295  * One of the Tegra I2C blocks is inside the DVC (Digital Voltage Controller)
 296  * block.  This block is identical to the rest of the I2C blocks, except that
 297  * it only supports master mode, it has registers moved around, and it needs
 298  * some extra init to get it into I2C mode.  The register moves are handled
 299  * by i2c_readl and i2c_writel
 300  */
 301 static void tegra_dvc_init(struct tegra_i2c_dev *i2c_dev)
 302 {
 303         u32 val = 0;
 304         val = dvc_readl(i2c_dev, DVC_CTRL_REG3);
 305         val |= DVC_CTRL_REG3_SW_PROG;
 306         val |= DVC_CTRL_REG3_I2C_DONE_INTR_EN;
 307         dvc_writel(i2c_dev, val, DVC_CTRL_REG3);
 308
 309         val = dvc_readl(i2c_dev, DVC_CTRL_REG1);
 310         val |= DVC_CTRL_REG1_INTR_EN;
 311         dvc_writel(i2c_dev, val, DVC_CTRL_REG1);
 312 }
 313
 314 static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
 315 {
 316         u32 val;
 317         int err = 0;
 318
 319         clk_enable(i2c_dev->clk);
 320
 321         tegra_periph_reset_assert(i2c_dev->clk);
 322         udelay(2);
 323         tegra_periph_reset_deassert(i2c_dev->clk);
 324
 325         if (i2c_dev->is_dvc)
 326                 tegra_dvc_init(i2c_dev);
 327
 328         val = I2C_CNFG_NEW_MASTER_FSM | I2C_CNFG_PACKET_MODE_EN;
 329         i2c_writel(i2c_dev, val, I2C_CNFG);
 330         i2c_writel(i2c_dev, 0, I2C_INT_MASK);
 331         clk_set_rate(i2c_dev->clk, i2c_dev->bus_clk_rate * 8);
 332
 333         if (!i2c_dev->is_dvc) {
 334                 u32 sl_cfg = i2c_readl(i2c_dev, I2C_SL_CNFG);
 335                 i2c_writel(i2c_dev, sl_cfg | I2C_SL_CNFG_NEWSL, I2C_SL_CNFG);
 336         }
 337
 338         val = 7 << I2C_FIFO_CONTROL_TX_TRIG_SHIFT |
 339                 0 << I2C_FIFO_CONTROL_RX_TRIG_SHIFT;
 340         i2c_writel(i2c_dev, val, I2C_FIFO_CONTROL);
 341
 342         if (tegra_i2c_flush_fifos(i2c_dev))
 343                 err = -ETIMEDOUT;
 344
 345         clk_disable(i2c_dev->clk);
 346         return err;
 347 }
 348
 349 static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
 350 {
 351         u32 status;
 352         const u32 status_err = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST;
 353         struct tegra_i2c_dev *i2c_dev = dev_id;
 354
 355         status = i2c_readl(i2c_dev, I2C_INT_STATUS);
 356
 357         if (status == 0) {
 358                 dev_warn(i2c_dev->dev, "interrupt with no status\n");
 359                 return IRQ_NONE;
 360         }
 361
 362         if (unlikely(status & status_err)) {
 363                 if (status & I2C_INT_NO_ACK)
 364                         i2c_dev->msg_err |= I2C_ERR_NO_ACK;
 365                 if (status & I2C_INT_ARBITRATION_LOST)
 366                         i2c_dev->msg_err |= I2C_ERR_ARBITRATION_LOST;
 367                 complete(&i2c_dev->msg_complete);
 368                 goto err;
 369         }
 370
 371         if (i2c_dev->msg_read && (status & I2C_INT_RX_FIFO_DATA_REQ)) {
 372                 if (i2c_dev->msg_buf_remaining)
 373                         tegra_i2c_empty_rx_fifo(i2c_dev);
 374                 else
 375                         BUG();
 376         }
 377
 378         if (!i2c_dev->msg_read && (status & I2C_INT_TX_FIFO_DATA_REQ)) {
 379                 if (i2c_dev->msg_buf_remaining)
 380                         tegra_i2c_fill_tx_fifo(i2c_dev);
 381                 else
 382                         tegra_i2c_mask_irq(i2c_dev, I2C_INT_TX_FIFO_DATA_REQ);
 383         }
 384
 385         if ((status & I2C_INT_PACKET_XFER_COMPLETE) &&
 386                         !i2c_dev->msg_buf_remaining)
 387                 complete(&i2c_dev->msg_complete);
 388
 389         i2c_writel(i2c_dev, status, I2C_INT_STATUS);
 390         if (i2c_dev->is_dvc)
 391                 dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS);
 392         return IRQ_HANDLED;
 393 err:
 394         /* An error occurred, mask all interrupts */
 395         tegra_i2c_mask_irq(i2c_dev, I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST |
 396                 I2C_INT_PACKET_XFER_COMPLETE | I2C_INT_TX_FIFO_DATA_REQ |
 397                 I2C_INT_RX_FIFO_DATA_REQ);
 398         i2c_writel(i2c_dev, status, I2C_INT_STATUS);
 399         return IRQ_HANDLED;
 400 }
 401
 402 static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 403         struct i2c_msg *msg, int stop)
 404 {
 405         u32 packet_header;
 406         u32 int_mask;
 407         int ret;
 408
 409         tegra_i2c_flush_fifos(i2c_dev);
 410         i2c_writel(i2c_dev, 0xFF, I2C_INT_STATUS);
 411
 412         if (msg->len == 0)
 413                 return -EINVAL;
 414
 415         i2c_dev->msg_buf = msg->buf;
 416         i2c_dev->msg_buf_remaining = msg->len;
 417         i2c_dev->msg_err = I2C_ERR_NONE;
 418         i2c_dev->msg_read = (msg->flags & I2C_M_RD);
 419         INIT_COMPLETION(i2c_dev->msg_complete);
 420
 421         packet_header = (0 << PACKET_HEADER0_HEADER_SIZE_SHIFT) |
 422                         PACKET_HEADER0_PROTOCOL_I2C |
 423                         (i2c_dev->cont_id << PACKET_HEADER0_CONT_ID_SHIFT) |
 424                         (1 << PACKET_HEADER0_PACKET_ID_SHIFT);
 425         i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
 426
 427         packet_header = msg->len - 1;
 428         i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
 429
 430         packet_header = msg->addr << I2C_HEADER_SLAVE_ADDR_SHIFT;
 431         packet_header |= I2C_HEADER_IE_ENABLE;
 432         if (msg->flags & I2C_M_TEN)
 433                 packet_header |= I2C_HEADER_10BIT_ADDR;
 434         if (msg->flags & I2C_M_IGNORE_NAK)
 435                 packet_header |= I2C_HEADER_CONT_ON_NAK;
 436         if (msg->flags & I2C_M_NOSTART)
 437                 packet_header |= I2C_HEADER_REPEAT_START;
 438         if (msg->flags & I2C_M_RD)
 439                 packet_header |= I2C_HEADER_READ;
 440         i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
 441
 442         if (!(msg->flags & I2C_M_RD))
 443                 tegra_i2c_fill_tx_fifo(i2c_dev);
 444
 445         int_mask = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST;
 446         if (msg->flags & I2C_M_RD)
 447                 int_mask |= I2C_INT_RX_FIFO_DATA_REQ;
 448         else if (i2c_dev->msg_buf_remaining)
 449                 int_mask |= I2C_INT_TX_FIFO_DATA_REQ;
 450         tegra_i2c_unmask_irq(i2c_dev, int_mask);
 451         dev_dbg(i2c_dev->dev, "unmasked irq: %02x\n",
 452                 i2c_readl(i2c_dev, I2C_INT_MASK));
 453
 454         ret = wait_for_completion_timeout(&i2c_dev->msg_complete, TEGRA_I2C_TIMEOUT);
 455         tegra_i2c_mask_irq(i2c_dev, int_mask);
 456
 457         if (WARN_ON(ret == 0)) {
 458                 dev_err(i2c_dev->dev, "i2c transfer timed out\n");
 459
 460                 tegra_i2c_init(i2c_dev);
 461                 return -ETIMEDOUT;
 462         }
 463
 464         dev_dbg(i2c_dev->dev, "transfer complete: %d %d %d\n",
 465                 ret, completion_done(&i2c_dev->msg_complete), i2c_dev->msg_err);
 466
 467         if (likely(i2c_dev->msg_err == I2C_ERR_NONE))
 468                 return 0;
 469
 470         tegra_i2c_init(i2c_dev);
 471         if (i2c_dev->msg_err == I2C_ERR_NO_ACK) {
 472                 if (msg->flags & I2C_M_IGNORE_NAK)
 473                         return 0;
 474                 return -EREMOTEIO;
 475         }
 476
 477         return -EIO;
 478 }
 479
 480 static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
 481         int num)
 482 {
 483         struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
 484         int i;
 485         int ret = 0;
 486
 487         if (i2c_dev->is_suspended)
 488                 return -EBUSY;
 489
 490         clk_enable(i2c_dev->clk);
 491         for (i = 0; i < num; i++) {
 492                 int stop = (i == (num - 1)) ? 1  : 0;
 493                 ret = tegra_i2c_xfer_msg(i2c_dev, &msgs[i], stop);
 494                 if (ret)
 495                         break;
 496         }
 497         clk_disable(i2c_dev->clk);
 498         return ret ?: i;
 499 }
 500
 501 static u32 tegra_i2c_func(struct i2c_adapter *adap)
 502 {
 503         return I2C_FUNC_I2C;
 504 }
 505
 506 static const struct i2c_algorithm tegra_i2c_algo = {
 507         .master_xfer    = tegra_i2c_xfer,
 508         .functionality  = tegra_i2c_func,
 509 };
 510
 511 static int tegra_i2c_probe(struct platform_device *pdev)
 512 {
 513         struct tegra_i2c_dev *i2c_dev;
 514         struct tegra_i2c_platform_data *pdata = pdev->dev.platform_data;
 515         struct resource *res;
 516         struct resource *iomem;
 517         struct clk *clk;
 518         struct clk *i2c_clk;
 519         void *base;
 520         int irq;
 521         int ret = 0;
 522
 523         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 524         if (!res) {
 525                 dev_err(&pdev->dev, "no mem resource\n");
 526                 return -EINVAL;
 527         }
 528         iomem = request_mem_region(res->start, resource_size(res), pdev->name);
 529         if (!iomem) {
 530                 dev_err(&pdev->dev, "I2C region already claimed\n");
 531                 return -EBUSY;
 532         }
 533
 534         base = ioremap(iomem->start, resource_size(iomem));
 535         if (!base) {
 536                 dev_err(&pdev->dev, "Cannot ioremap I2C region\n");
 537                 return -ENOMEM;
 538         }
 539
 540         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 541         if (!res) {
 542                 dev_err(&pdev->dev, "no irq resource\n");
 543                 ret = -EINVAL;
 544                 goto err_iounmap;
 545         }
 546         irq = res->start;
 547
 548         clk = clk_get(&pdev->dev, NULL);
 549         if (IS_ERR(clk)) {
 550                 dev_err(&pdev->dev, "missing controller clock");
 551                 ret = PTR_ERR(clk);
 552                 goto err_release_region;
 553         }
 554
 555         i2c_clk = clk_get(&pdev->dev, "i2c");
 556         if (IS_ERR(i2c_clk)) {
 557                 dev_err(&pdev->dev, "missing bus clock");
 558                 ret = PTR_ERR(i2c_clk);
 559                 goto err_clk_put;
 560         }
 561
 562         i2c_dev = kzalloc(sizeof(struct tegra_i2c_dev), GFP_KERNEL);
 563         if (!i2c_dev) {
 564                 ret = -ENOMEM;
 565                 goto err_i2c_clk_put;
 566         }
 567
 568         i2c_dev->base = base;
 569         i2c_dev->clk = clk;
 570         i2c_dev->i2c_clk = i2c_clk;
 571         i2c_dev->iomem = iomem;
 572         i2c_dev->adapter.algo = &tegra_i2c_algo;
 573         i2c_dev->irq = irq;
 574         i2c_dev->cont_id = pdev->id;
 575         i2c_dev->dev = &pdev->dev;
 576         i2c_dev->bus_clk_rate = pdata ? pdata->bus_clk_rate : 100000;
 577
 578         if (pdev->id == 3)
 579                 i2c_dev->is_dvc = 1;
 580         init_completion(&i2c_dev->msg_complete);
 581
 582         platform_set_drvdata(pdev, i2c_dev);
 583
 584         ret = tegra_i2c_init(i2c_dev);
 585         if (ret) {
 586                 dev_err(&pdev->dev, "Failed to initialize i2c controller");
 587                 goto err_free;
 588         }
 589
 590         ret = request_irq(i2c_dev->irq, tegra_i2c_isr, 0, pdev->name, i2c_dev);
 591         if (ret) {
 592                 dev_err(&pdev->dev, "Failed to request irq %i\n", i2c_dev->irq);
 593                 goto err_free;
 594         }
 595
 596         clk_enable(i2c_dev->i2c_clk);
 597
 598         i2c_set_adapdata(&i2c_dev->adapter, i2c_dev);
 599         i2c_dev->adapter.owner = THIS_MODULE;
 600         i2c_dev->adapter.class = I2C_CLASS_HWMON;
 601         strlcpy(i2c_dev->adapter.name, "Tegra I2C adapter",
 602                 sizeof(i2c_dev->adapter.name));
 603         i2c_dev->adapter.algo = &tegra_i2c_algo;
 604         i2c_dev->adapter.dev.parent = &pdev->dev;
 605         i2c_dev->adapter.nr = pdev->id;
 606
 607         ret = i2c_add_numbered_adapter(&i2c_dev->adapter);
 608         if (ret) {
 609                 dev_err(&pdev->dev, "Failed to add I2C adapter\n");
 610                 goto err_free_irq;
 611         }
 612
 613         return 0;
 614 err_free_irq:
 615         free_irq(i2c_dev->irq, i2c_dev);
 616 err_free:
 617         kfree(i2c_dev);
 618 err_i2c_clk_put:
 619         clk_put(i2c_clk);
 620 err_clk_put:
 621         clk_put(clk);
 622 err_release_region:
 623         release_mem_region(iomem->start, resource_size(iomem));
 624 err_iounmap:
 625         iounmap(base);
 626         return ret;
 627 }
 628
 629 static int tegra_i2c_remove(struct platform_device *pdev)
 630 {
 631         struct tegra_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
 632         i2c_del_adapter(&i2c_dev->adapter);
 633         free_irq(i2c_dev->irq, i2c_dev);
 634         clk_put(i2c_dev->i2c_clk);
 635         clk_put(i2c_dev->clk);
 636         release_mem_region(i2c_dev->iomem->start,
 637                 resource_size(i2c_dev->iomem));
 638         iounmap(i2c_dev->base);
 639         kfree(i2c_dev);
 640         return 0;
 641 }
 642
 643 #ifdef CONFIG_PM
 644 static int tegra_i2c_suspend(struct platform_device *pdev, pm_message_t state)
 645 {
 646         struct tegra_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
 647
 648         i2c_lock_adapter(&i2c_dev->adapter);
 649         i2c_dev->is_suspended = true;
 650         i2c_unlock_adapter(&i2c_dev->adapter);
 651
 652         return 0;
 653 }
 654
 655 static int tegra_i2c_resume(struct platform_device *pdev)
 656 {
 657         struct tegra_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
 658         int ret;
 659
 660         i2c_lock_adapter(&i2c_dev->adapter);
 661
 662         ret = tegra_i2c_init(i2c_dev);
 663
 664         if (ret) {
 665                 i2c_unlock_adapter(&i2c_dev->adapter);
 666                 return ret;
 667         }
 668
 669         i2c_dev->is_suspended = false;
 670
 671         i2c_unlock_adapter(&i2c_dev->adapter);
 672
 673         return 0;
 674 }
 675 #endif
 676
 677 static struct platform_driver tegra_i2c_driver = {
 678         .probe   = tegra_i2c_probe,
 679         .remove  = tegra_i2c_remove,
 680 #ifdef CONFIG_PM
 681         .suspend = tegra_i2c_suspend,
 682         .resume  = tegra_i2c_resume,
 683 #endif
 684         .driver  = {
 685                 .name  = "tegra-i2c",
 686                 .owner = THIS_MODULE,
 687         },
 688 };
 689
 690 static int __init tegra_i2c_init_driver(void)
 691 {
 692         return platform_driver_register(&tegra_i2c_driver);
 693 }
 694
 695 static void __exit tegra_i2c_exit_driver(void)
 696 {
 697         platform_driver_unregister(&tegra_i2c_driver);
 698 }
 699
 700 subsys_initcall(tegra_i2c_init_driver);
 701 module_exit(tegra_i2c_exit_driver);
 702
 703 MODULE_DESCRIPTION("nVidia Tegra2 I2C Bus Controller driver");
 704 MODULE_AUTHOR("Colin Cross");
 705 MODULE_LICENSE("GPL v2");