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/of_device.h>
  29 #include <linux/module.h>
  30 #include <linux/reset.h>
  31
  32 #include <asm/unaligned.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_DEBOUNCE_CNT_SHIFT             12
  39 #define I2C_CNFG_PACKET_MODE_EN                 (1<<10)
  40 #define I2C_CNFG_NEW_MASTER_FSM                 (1<<11)
  41 #define I2C_STATUS                              0x01C
  42 #define I2C_SL_CNFG                             0x020
  43 #define I2C_SL_CNFG_NACK                        (1<<1)
  44 #define I2C_SL_CNFG_NEWSL                       (1<<2)
  45 #define I2C_SL_ADDR1                            0x02c
  46 #define I2C_SL_ADDR2                            0x030
  47 #define I2C_TX_FIFO                             0x050
  48 #define I2C_RX_FIFO                             0x054
  49 #define I2C_PACKET_TRANSFER_STATUS              0x058
  50 #define I2C_FIFO_CONTROL                        0x05c
  51 #define I2C_FIFO_CONTROL_TX_FLUSH               (1<<1)
  52 #define I2C_FIFO_CONTROL_RX_FLUSH               (1<<0)
  53 #define I2C_FIFO_CONTROL_TX_TRIG_SHIFT          5
  54 #define I2C_FIFO_CONTROL_RX_TRIG_SHIFT          2
  55 #define I2C_FIFO_STATUS                         0x060
  56 #define I2C_FIFO_STATUS_TX_MASK                 0xF0
  57 #define I2C_FIFO_STATUS_TX_SHIFT                4
  58 #define I2C_FIFO_STATUS_RX_MASK                 0x0F
  59 #define I2C_FIFO_STATUS_RX_SHIFT                0
  60 #define I2C_INT_MASK                            0x064
  61 #define I2C_INT_STATUS                          0x068
  62 #define I2C_INT_PACKET_XFER_COMPLETE            (1<<7)
  63 #define I2C_INT_ALL_PACKETS_XFER_COMPLETE       (1<<6)
  64 #define I2C_INT_TX_FIFO_OVERFLOW                (1<<5)
  65 #define I2C_INT_RX_FIFO_UNDERFLOW               (1<<4)
  66 #define I2C_INT_NO_ACK                          (1<<3)
  67 #define I2C_INT_ARBITRATION_LOST                (1<<2)
  68 #define I2C_INT_TX_FIFO_DATA_REQ                (1<<1)
  69 #define I2C_INT_RX_FIFO_DATA_REQ                (1<<0)
  70 #define I2C_CLK_DIVISOR                         0x06c
  71 #define I2C_CLK_DIVISOR_STD_FAST_MODE_SHIFT     16
  72 #define I2C_CLK_MULTIPLIER_STD_FAST_MODE        8
  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_CONTINUE_XFER                (1<<15)
 101 #define I2C_HEADER_MASTER_ADDR_SHIFT            12
 102 #define I2C_HEADER_SLAVE_ADDR_SHIFT             1
 103 /*
 104  * msg_end_type: The bus control which need to be send at end of transfer.
 105  * @MSG_END_STOP: Send stop pulse at end of transfer.
 106  * @MSG_END_REPEAT_START: Send repeat start at end of transfer.
 107  * @MSG_END_CONTINUE: The following on message is coming and so do not send
 108  *              stop or repeat start.
 109  */
 110 enum msg_end_type {
 111         MSG_END_STOP,
 112         MSG_END_REPEAT_START,
 113         MSG_END_CONTINUE,
 114 };
 115
 116 /**
 117  * struct tegra_i2c_hw_feature : Different HW support on Tegra
 118  * @has_continue_xfer_support: Continue transfer supports.
 119  * @has_per_pkt_xfer_complete_irq: Has enable/disable capability for transfer
 120  *              complete interrupt per packet basis.
 121  * @has_single_clk_source: The i2c controller has single clock source. Tegra30
 122  *              and earlier Socs has two clock sources i.e. div-clk and
 123  *              fast-clk.
 124  * @clk_divisor_hs_mode: Clock divisor in HS mode.
 125  * @clk_divisor_std_fast_mode: Clock divisor in standard/fast mode. It is
 126  *              applicable if there is no fast clock source i.e. single clock
 127  *              source.
 128  */
 129
 130 struct tegra_i2c_hw_feature {
 131         bool has_continue_xfer_support;
 132         bool has_per_pkt_xfer_complete_irq;
 133         bool has_single_clk_source;
 134         int clk_divisor_hs_mode;
 135         int clk_divisor_std_fast_mode;
 136 };
 137
 138 /**
 139  * struct tegra_i2c_dev - per device i2c context
 140  * @dev: device reference for power management
 141  * @hw: Tegra i2c hw feature.
 142  * @adapter: core i2c layer adapter information
 143  * @div_clk: clock reference for div clock of i2c controller.
 144  * @fast_clk: clock reference for fast clock of i2c controller.
 145  * @base: ioremapped registers cookie
 146  * @cont_id: i2c controller id, used for for packet header
 147  * @irq: irq number of transfer complete interrupt
 148  * @is_dvc: identifies the DVC i2c controller, has a different register layout
 149  * @msg_complete: transfer completion notifier
 150  * @msg_err: error code for completed message
 151  * @msg_buf: pointer to current message data
 152  * @msg_buf_remaining: size of unsent data in the message buffer
 153  * @msg_read: identifies read transfers
 154  * @bus_clk_rate: current i2c bus clock rate
 155  * @is_suspended: prevents i2c controller accesses after suspend is called
 156  */
 157 struct tegra_i2c_dev {
 158         struct device *dev;
 159         const struct tegra_i2c_hw_feature *hw;
 160         struct i2c_adapter adapter;
 161         struct clk *div_clk;
 162         struct clk *fast_clk;
 163         struct reset_control *rst;
 164         void __iomem *base;
 165         int cont_id;
 166         int irq;
 167         bool irq_disabled;
 168         int is_dvc;
 169         struct completion msg_complete;
 170         int msg_err;
 171         u8 *msg_buf;
 172         size_t msg_buf_remaining;
 173         int msg_read;
 174         u32 bus_clk_rate;
 175         bool is_suspended;
 176 };
 177
 178 static void dvc_writel(struct tegra_i2c_dev *i2c_dev, u32 val, unsigned long reg)
 179 {
 180         writel(val, i2c_dev->base + reg);
 181 }
 182
 183 static u32 dvc_readl(struct tegra_i2c_dev *i2c_dev, unsigned long reg)
 184 {
 185         return readl(i2c_dev->base + reg);
 186 }
 187
 188 /*
 189  * i2c_writel and i2c_readl will offset the register if necessary to talk
 190  * to the I2C block inside the DVC block
 191  */
 192 static unsigned long tegra_i2c_reg_addr(struct tegra_i2c_dev *i2c_dev,
 193         unsigned long reg)
 194 {
 195         if (i2c_dev->is_dvc)
 196                 reg += (reg >= I2C_TX_FIFO) ? 0x10 : 0x40;
 197         return reg;
 198 }
 199
 200 static void i2c_writel(struct tegra_i2c_dev *i2c_dev, u32 val,
 201         unsigned long reg)
 202 {
 203         writel(val, i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg));
 204
 205         /* Read back register to make sure that register writes completed */
 206         if (reg != I2C_TX_FIFO)
 207                 readl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg));
 208 }
 209
 210 static u32 i2c_readl(struct tegra_i2c_dev *i2c_dev, unsigned long reg)
 211 {
 212         return readl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg));
 213 }
 214
 215 static void i2c_writesl(struct tegra_i2c_dev *i2c_dev, void *data,
 216         unsigned long reg, int len)
 217 {
 218         writesl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg), data, len);
 219 }
 220
 221 static void i2c_readsl(struct tegra_i2c_dev *i2c_dev, void *data,
 222         unsigned long reg, int len)
 223 {
 224         readsl(i2c_dev->base + tegra_i2c_reg_addr(i2c_dev, reg), data, len);
 225 }
 226
 227 static void tegra_i2c_mask_irq(struct tegra_i2c_dev *i2c_dev, u32 mask)
 228 {
 229         u32 int_mask = i2c_readl(i2c_dev, I2C_INT_MASK);
 230         int_mask &= ~mask;
 231         i2c_writel(i2c_dev, int_mask, I2C_INT_MASK);
 232 }
 233
 234 static void tegra_i2c_unmask_irq(struct tegra_i2c_dev *i2c_dev, u32 mask)
 235 {
 236         u32 int_mask = i2c_readl(i2c_dev, I2C_INT_MASK);
 237         int_mask |= mask;
 238         i2c_writel(i2c_dev, int_mask, I2C_INT_MASK);
 239 }
 240
 241 static int tegra_i2c_flush_fifos(struct tegra_i2c_dev *i2c_dev)
 242 {
 243         unsigned long timeout = jiffies + HZ;
 244         u32 val = i2c_readl(i2c_dev, I2C_FIFO_CONTROL);
 245         val |= I2C_FIFO_CONTROL_TX_FLUSH | I2C_FIFO_CONTROL_RX_FLUSH;
 246         i2c_writel(i2c_dev, val, I2C_FIFO_CONTROL);
 247
 248         while (i2c_readl(i2c_dev, I2C_FIFO_CONTROL) &
 249                 (I2C_FIFO_CONTROL_TX_FLUSH | I2C_FIFO_CONTROL_RX_FLUSH)) {
 250                 if (time_after(jiffies, timeout)) {
 251                         dev_warn(i2c_dev->dev, "timeout waiting for fifo flush\n");
 252                         return -ETIMEDOUT;
 253                 }
 254                 msleep(1);
 255         }
 256         return 0;
 257 }
 258
 259 static int tegra_i2c_empty_rx_fifo(struct tegra_i2c_dev *i2c_dev)
 260 {
 261         u32 val;
 262         int rx_fifo_avail;
 263         u8 *buf = i2c_dev->msg_buf;
 264         size_t buf_remaining = i2c_dev->msg_buf_remaining;
 265         int words_to_transfer;
 266
 267         val = i2c_readl(i2c_dev, I2C_FIFO_STATUS);
 268         rx_fifo_avail = (val & I2C_FIFO_STATUS_RX_MASK) >>
 269                 I2C_FIFO_STATUS_RX_SHIFT;
 270
 271         /* Rounds down to not include partial word at the end of buf */
 272         words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD;
 273         if (words_to_transfer > rx_fifo_avail)
 274                 words_to_transfer = rx_fifo_avail;
 275
 276         i2c_readsl(i2c_dev, buf, I2C_RX_FIFO, words_to_transfer);
 277
 278         buf += words_to_transfer * BYTES_PER_FIFO_WORD;
 279         buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD;
 280         rx_fifo_avail -= words_to_transfer;
 281
 282         /*
 283          * If there is a partial word at the end of buf, handle it manually to
 284          * prevent overwriting past the end of buf
 285          */
 286         if (rx_fifo_avail > 0 && buf_remaining > 0) {
 287                 BUG_ON(buf_remaining > 3);
 288                 val = i2c_readl(i2c_dev, I2C_RX_FIFO);
 289                 val = cpu_to_le32(val);
 290                 memcpy(buf, &val, buf_remaining);
 291                 buf_remaining = 0;
 292                 rx_fifo_avail--;
 293         }
 294
 295         BUG_ON(rx_fifo_avail > 0 && buf_remaining > 0);
 296         i2c_dev->msg_buf_remaining = buf_remaining;
 297         i2c_dev->msg_buf = buf;
 298         return 0;
 299 }
 300
 301 static int tegra_i2c_fill_tx_fifo(struct tegra_i2c_dev *i2c_dev)
 302 {
 303         u32 val;
 304         int tx_fifo_avail;
 305         u8 *buf = i2c_dev->msg_buf;
 306         size_t buf_remaining = i2c_dev->msg_buf_remaining;
 307         int words_to_transfer;
 308
 309         val = i2c_readl(i2c_dev, I2C_FIFO_STATUS);
 310         tx_fifo_avail = (val & I2C_FIFO_STATUS_TX_MASK) >>
 311                 I2C_FIFO_STATUS_TX_SHIFT;
 312
 313         /* Rounds down to not include partial word at the end of buf */
 314         words_to_transfer = buf_remaining / BYTES_PER_FIFO_WORD;
 315
 316         /* It's very common to have < 4 bytes, so optimize that case. */
 317         if (words_to_transfer) {
 318                 if (words_to_transfer > tx_fifo_avail)
 319                         words_to_transfer = tx_fifo_avail;
 320
 321                 /*
 322                  * Update state before writing to FIFO.  If this casues us
 323                  * to finish writing all bytes (AKA buf_remaining goes to 0) we
 324                  * have a potential for an interrupt (PACKET_XFER_COMPLETE is
 325                  * not maskable).  We need to make sure that the isr sees
 326                  * buf_remaining as 0 and doesn't call us back re-entrantly.
 327                  */
 328                 buf_remaining -= words_to_transfer * BYTES_PER_FIFO_WORD;
 329                 tx_fifo_avail -= words_to_transfer;
 330                 i2c_dev->msg_buf_remaining = buf_remaining;
 331                 i2c_dev->msg_buf = buf +
 332                         words_to_transfer * BYTES_PER_FIFO_WORD;
 333                 barrier();
 334
 335                 i2c_writesl(i2c_dev, buf, I2C_TX_FIFO, words_to_transfer);
 336
 337                 buf += words_to_transfer * BYTES_PER_FIFO_WORD;
 338         }
 339
 340         /*
 341          * If there is a partial word at the end of buf, handle it manually to
 342          * prevent reading past the end of buf, which could cross a page
 343          * boundary and fault.
 344          */
 345         if (tx_fifo_avail > 0 && buf_remaining > 0) {
 346                 BUG_ON(buf_remaining > 3);
 347                 memcpy(&val, buf, buf_remaining);
 348                 val = le32_to_cpu(val);
 349
 350                 /* Again update before writing to FIFO to make sure isr sees. */
 351                 i2c_dev->msg_buf_remaining = 0;
 352                 i2c_dev->msg_buf = NULL;
 353                 barrier();
 354
 355                 i2c_writel(i2c_dev, val, I2C_TX_FIFO);
 356         }
 357
 358         return 0;
 359 }
 360
 361 /*
 362  * One of the Tegra I2C blocks is inside the DVC (Digital Voltage Controller)
 363  * block.  This block is identical to the rest of the I2C blocks, except that
 364  * it only supports master mode, it has registers moved around, and it needs
 365  * some extra init to get it into I2C mode.  The register moves are handled
 366  * by i2c_readl and i2c_writel
 367  */
 368 static void tegra_dvc_init(struct tegra_i2c_dev *i2c_dev)
 369 {
 370         u32 val = 0;
 371         val = dvc_readl(i2c_dev, DVC_CTRL_REG3);
 372         val |= DVC_CTRL_REG3_SW_PROG;
 373         val |= DVC_CTRL_REG3_I2C_DONE_INTR_EN;
 374         dvc_writel(i2c_dev, val, DVC_CTRL_REG3);
 375
 376         val = dvc_readl(i2c_dev, DVC_CTRL_REG1);
 377         val |= DVC_CTRL_REG1_INTR_EN;
 378         dvc_writel(i2c_dev, val, DVC_CTRL_REG1);
 379 }
 380
 381 static inline int tegra_i2c_clock_enable(struct tegra_i2c_dev *i2c_dev)
 382 {
 383         int ret;
 384         if (!i2c_dev->hw->has_single_clk_source) {
 385                 ret = clk_enable(i2c_dev->fast_clk);
 386                 if (ret < 0) {
 387                         dev_err(i2c_dev->dev,
 388                                 "Enabling fast clk failed, err %d\n", ret);
 389                         return ret;
 390                 }
 391         }
 392         ret = clk_enable(i2c_dev->div_clk);
 393         if (ret < 0) {
 394                 dev_err(i2c_dev->dev,
 395                         "Enabling div clk failed, err %d\n", ret);
 396                 clk_disable(i2c_dev->fast_clk);
 397         }
 398         return ret;
 399 }
 400
 401 static inline void tegra_i2c_clock_disable(struct tegra_i2c_dev *i2c_dev)
 402 {
 403         clk_disable(i2c_dev->div_clk);
 404         if (!i2c_dev->hw->has_single_clk_source)
 405                 clk_disable(i2c_dev->fast_clk);
 406 }
 407
 408 static int tegra_i2c_init(struct tegra_i2c_dev *i2c_dev)
 409 {
 410         u32 val;
 411         int err = 0;
 412         u32 clk_divisor;
 413
 414         err = tegra_i2c_clock_enable(i2c_dev);
 415         if (err < 0) {
 416                 dev_err(i2c_dev->dev, "Clock enable failed %d\n", err);
 417                 return err;
 418         }
 419
 420         reset_control_assert(i2c_dev->rst);
 421         udelay(2);
 422         reset_control_deassert(i2c_dev->rst);
 423
 424         if (i2c_dev->is_dvc)
 425                 tegra_dvc_init(i2c_dev);
 426
 427         val = I2C_CNFG_NEW_MASTER_FSM | I2C_CNFG_PACKET_MODE_EN |
 428                 (0x2 << I2C_CNFG_DEBOUNCE_CNT_SHIFT);
 429         i2c_writel(i2c_dev, val, I2C_CNFG);
 430         i2c_writel(i2c_dev, 0, I2C_INT_MASK);
 431
 432         /* Make sure clock divisor programmed correctly */
 433         clk_divisor = i2c_dev->hw->clk_divisor_hs_mode;
 434         clk_divisor |= i2c_dev->hw->clk_divisor_std_fast_mode <<
 435                                         I2C_CLK_DIVISOR_STD_FAST_MODE_SHIFT;
 436         i2c_writel(i2c_dev, clk_divisor, I2C_CLK_DIVISOR);
 437
 438         if (!i2c_dev->is_dvc) {
 439                 u32 sl_cfg = i2c_readl(i2c_dev, I2C_SL_CNFG);
 440                 sl_cfg |= I2C_SL_CNFG_NACK | I2C_SL_CNFG_NEWSL;
 441                 i2c_writel(i2c_dev, sl_cfg, I2C_SL_CNFG);
 442                 i2c_writel(i2c_dev, 0xfc, I2C_SL_ADDR1);
 443                 i2c_writel(i2c_dev, 0x00, I2C_SL_ADDR2);
 444
 445         }
 446
 447         val = 7 << I2C_FIFO_CONTROL_TX_TRIG_SHIFT |
 448                 0 << I2C_FIFO_CONTROL_RX_TRIG_SHIFT;
 449         i2c_writel(i2c_dev, val, I2C_FIFO_CONTROL);
 450
 451         if (tegra_i2c_flush_fifos(i2c_dev))
 452                 err = -ETIMEDOUT;
 453
 454         tegra_i2c_clock_disable(i2c_dev);
 455
 456         if (i2c_dev->irq_disabled) {
 457                 i2c_dev->irq_disabled = 0;
 458                 enable_irq(i2c_dev->irq);
 459         }
 460
 461         return err;
 462 }
 463
 464 static irqreturn_t tegra_i2c_isr(int irq, void *dev_id)
 465 {
 466         u32 status;
 467         const u32 status_err = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST;
 468         struct tegra_i2c_dev *i2c_dev = dev_id;
 469
 470         status = i2c_readl(i2c_dev, I2C_INT_STATUS);
 471
 472         if (status == 0) {
 473                 dev_warn(i2c_dev->dev, "irq status 0 %08x %08x %08x\n",
 474                          i2c_readl(i2c_dev, I2C_PACKET_TRANSFER_STATUS),
 475                          i2c_readl(i2c_dev, I2C_STATUS),
 476                          i2c_readl(i2c_dev, I2C_CNFG));
 477                 i2c_dev->msg_err |= I2C_ERR_UNKNOWN_INTERRUPT;
 478
 479                 if (!i2c_dev->irq_disabled) {
 480                         disable_irq_nosync(i2c_dev->irq);
 481                         i2c_dev->irq_disabled = 1;
 482                 }
 483                 goto err;
 484         }
 485
 486         if (unlikely(status & status_err)) {
 487                 if (status & I2C_INT_NO_ACK)
 488                         i2c_dev->msg_err |= I2C_ERR_NO_ACK;
 489                 if (status & I2C_INT_ARBITRATION_LOST)
 490                         i2c_dev->msg_err |= I2C_ERR_ARBITRATION_LOST;
 491                 goto err;
 492         }
 493
 494         if (i2c_dev->msg_read && (status & I2C_INT_RX_FIFO_DATA_REQ)) {
 495                 if (i2c_dev->msg_buf_remaining)
 496                         tegra_i2c_empty_rx_fifo(i2c_dev);
 497                 else
 498                         BUG();
 499         }
 500
 501         if (!i2c_dev->msg_read && (status & I2C_INT_TX_FIFO_DATA_REQ)) {
 502                 if (i2c_dev->msg_buf_remaining)
 503                         tegra_i2c_fill_tx_fifo(i2c_dev);
 504                 else
 505                         tegra_i2c_mask_irq(i2c_dev, I2C_INT_TX_FIFO_DATA_REQ);
 506         }
 507
 508         i2c_writel(i2c_dev, status, I2C_INT_STATUS);
 509         if (i2c_dev->is_dvc)
 510                 dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS);
 511
 512         if (status & I2C_INT_PACKET_XFER_COMPLETE) {
 513                 BUG_ON(i2c_dev->msg_buf_remaining);
 514                 complete(&i2c_dev->msg_complete);
 515         }
 516         return IRQ_HANDLED;
 517 err:
 518         /* An error occurred, mask all interrupts */
 519         tegra_i2c_mask_irq(i2c_dev, I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST |
 520                 I2C_INT_PACKET_XFER_COMPLETE | I2C_INT_TX_FIFO_DATA_REQ |
 521                 I2C_INT_RX_FIFO_DATA_REQ);
 522         i2c_writel(i2c_dev, status, I2C_INT_STATUS);
 523         if (i2c_dev->is_dvc)
 524                 dvc_writel(i2c_dev, DVC_STATUS_I2C_DONE_INTR, DVC_STATUS);
 525
 526         complete(&i2c_dev->msg_complete);
 527         return IRQ_HANDLED;
 528 }
 529
 530 static int tegra_i2c_xfer_msg(struct tegra_i2c_dev *i2c_dev,
 531         struct i2c_msg *msg, enum msg_end_type end_state)
 532 {
 533         u32 packet_header;
 534         u32 int_mask;
 535         unsigned long time_left;
 536
 537         tegra_i2c_flush_fifos(i2c_dev);
 538
 539         if (msg->len == 0)
 540                 return -EINVAL;
 541
 542         i2c_dev->msg_buf = msg->buf;
 543         i2c_dev->msg_buf_remaining = msg->len;
 544         i2c_dev->msg_err = I2C_ERR_NONE;
 545         i2c_dev->msg_read = (msg->flags & I2C_M_RD);
 546         reinit_completion(&i2c_dev->msg_complete);
 547
 548         packet_header = (0 << PACKET_HEADER0_HEADER_SIZE_SHIFT) |
 549                         PACKET_HEADER0_PROTOCOL_I2C |
 550                         (i2c_dev->cont_id << PACKET_HEADER0_CONT_ID_SHIFT) |
 551                         (1 << PACKET_HEADER0_PACKET_ID_SHIFT);
 552         i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
 553
 554         packet_header = msg->len - 1;
 555         i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
 556
 557         packet_header = I2C_HEADER_IE_ENABLE;
 558         if (end_state == MSG_END_CONTINUE)
 559                 packet_header |= I2C_HEADER_CONTINUE_XFER;
 560         else if (end_state == MSG_END_REPEAT_START)
 561                 packet_header |= I2C_HEADER_REPEAT_START;
 562         if (msg->flags & I2C_M_TEN) {
 563                 packet_header |= msg->addr;
 564                 packet_header |= I2C_HEADER_10BIT_ADDR;
 565         } else {
 566                 packet_header |= msg->addr << I2C_HEADER_SLAVE_ADDR_SHIFT;
 567         }
 568         if (msg->flags & I2C_M_IGNORE_NAK)
 569                 packet_header |= I2C_HEADER_CONT_ON_NAK;
 570         if (msg->flags & I2C_M_RD)
 571                 packet_header |= I2C_HEADER_READ;
 572         i2c_writel(i2c_dev, packet_header, I2C_TX_FIFO);
 573
 574         if (!(msg->flags & I2C_M_RD))
 575                 tegra_i2c_fill_tx_fifo(i2c_dev);
 576
 577         int_mask = I2C_INT_NO_ACK | I2C_INT_ARBITRATION_LOST;
 578         if (i2c_dev->hw->has_per_pkt_xfer_complete_irq)
 579                 int_mask |= I2C_INT_PACKET_XFER_COMPLETE;
 580         if (msg->flags & I2C_M_RD)
 581                 int_mask |= I2C_INT_RX_FIFO_DATA_REQ;
 582         else if (i2c_dev->msg_buf_remaining)
 583                 int_mask |= I2C_INT_TX_FIFO_DATA_REQ;
 584         tegra_i2c_unmask_irq(i2c_dev, int_mask);
 585         dev_dbg(i2c_dev->dev, "unmasked irq: %02x\n",
 586                 i2c_readl(i2c_dev, I2C_INT_MASK));
 587
 588         time_left = wait_for_completion_timeout(&i2c_dev->msg_complete,
 589                                                 TEGRA_I2C_TIMEOUT);
 590         tegra_i2c_mask_irq(i2c_dev, int_mask);
 591
 592         if (time_left == 0) {
 593                 dev_err(i2c_dev->dev, "i2c transfer timed out\n");
 594
 595                 tegra_i2c_init(i2c_dev);
 596                 return -ETIMEDOUT;
 597         }
 598
 599         dev_dbg(i2c_dev->dev, "transfer complete: %lu %d %d\n",
 600                 time_left, completion_done(&i2c_dev->msg_complete),
 601                 i2c_dev->msg_err);
 602
 603         if (likely(i2c_dev->msg_err == I2C_ERR_NONE))
 604                 return 0;
 605
 606         /*
 607          * NACK interrupt is generated before the I2C controller generates the
 608          * STOP condition on the bus. So wait for 2 clock periods before resetting
 609          * the controller so that STOP condition has been delivered properly.
 610          */
 611         if (i2c_dev->msg_err == I2C_ERR_NO_ACK)
 612                 udelay(DIV_ROUND_UP(2 * 1000000, i2c_dev->bus_clk_rate));
 613
 614         tegra_i2c_init(i2c_dev);
 615         if (i2c_dev->msg_err == I2C_ERR_NO_ACK) {
 616                 if (msg->flags & I2C_M_IGNORE_NAK)
 617                         return 0;
 618                 return -EREMOTEIO;
 619         }
 620
 621         return -EIO;
 622 }
 623
 624 static int tegra_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[],
 625         int num)
 626 {
 627         struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
 628         int i;
 629         int ret = 0;
 630
 631         if (i2c_dev->is_suspended)
 632                 return -EBUSY;
 633
 634         ret = tegra_i2c_clock_enable(i2c_dev);
 635         if (ret < 0) {
 636                 dev_err(i2c_dev->dev, "Clock enable failed %d\n", ret);
 637                 return ret;
 638         }
 639
 640         for (i = 0; i < num; i++) {
 641                 enum msg_end_type end_type = MSG_END_STOP;
 642                 if (i < (num - 1)) {
 643                         if (msgs[i + 1].flags & I2C_M_NOSTART)
 644                                 end_type = MSG_END_CONTINUE;
 645                         else
 646                                 end_type = MSG_END_REPEAT_START;
 647                 }
 648                 ret = tegra_i2c_xfer_msg(i2c_dev, &msgs[i], end_type);
 649                 if (ret)
 650                         break;
 651         }
 652         tegra_i2c_clock_disable(i2c_dev);
 653         return ret ?: i;
 654 }
 655
 656 static u32 tegra_i2c_func(struct i2c_adapter *adap)
 657 {
 658         struct tegra_i2c_dev *i2c_dev = i2c_get_adapdata(adap);
 659         u32 ret = I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK) |
 660                   I2C_FUNC_10BIT_ADDR | I2C_FUNC_PROTOCOL_MANGLING;
 661
 662         if (i2c_dev->hw->has_continue_xfer_support)
 663                 ret |= I2C_FUNC_NOSTART;
 664         return ret;
 665 }
 666
 667 static const struct i2c_algorithm tegra_i2c_algo = {
 668         .master_xfer    = tegra_i2c_xfer,
 669         .functionality  = tegra_i2c_func,
 670 };
 671
 672 static const struct tegra_i2c_hw_feature tegra20_i2c_hw = {
 673         .has_continue_xfer_support = false,
 674         .has_per_pkt_xfer_complete_irq = false,
 675         .has_single_clk_source = false,
 676         .clk_divisor_hs_mode = 3,
 677         .clk_divisor_std_fast_mode = 0,
 678 };
 679
 680 static const struct tegra_i2c_hw_feature tegra30_i2c_hw = {
 681         .has_continue_xfer_support = true,
 682         .has_per_pkt_xfer_complete_irq = false,
 683         .has_single_clk_source = false,
 684         .clk_divisor_hs_mode = 3,
 685         .clk_divisor_std_fast_mode = 0,
 686 };
 687
 688 static const struct tegra_i2c_hw_feature tegra114_i2c_hw = {
 689         .has_continue_xfer_support = true,
 690         .has_per_pkt_xfer_complete_irq = true,
 691         .has_single_clk_source = true,
 692         .clk_divisor_hs_mode = 1,
 693         .clk_divisor_std_fast_mode = 0x19,
 694 };
 695
 696 /* Match table for of_platform binding */
 697 static const struct of_device_id tegra_i2c_of_match[] = {
 698         { .compatible = "nvidia,tegra114-i2c", .data = &tegra114_i2c_hw, },
 699         { .compatible = "nvidia,tegra30-i2c", .data = &tegra30_i2c_hw, },
 700         { .compatible = "nvidia,tegra20-i2c", .data = &tegra20_i2c_hw, },
 701         { .compatible = "nvidia,tegra20-i2c-dvc", .data = &tegra20_i2c_hw, },
 702         {},
 703 };
 704 MODULE_DEVICE_TABLE(of, tegra_i2c_of_match);
 705
 706 static int tegra_i2c_probe(struct platform_device *pdev)
 707 {
 708         struct tegra_i2c_dev *i2c_dev;
 709         struct resource *res;
 710         struct clk *div_clk;
 711         struct clk *fast_clk;
 712         void __iomem *base;
 713         int irq;
 714         int ret = 0;
 715         int clk_multiplier = I2C_CLK_MULTIPLIER_STD_FAST_MODE;
 716
 717         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 718         base = devm_ioremap_resource(&pdev->dev, res);
 719         if (IS_ERR(base))
 720                 return PTR_ERR(base);
 721
 722         res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 723         if (!res) {
 724                 dev_err(&pdev->dev, "no irq resource\n");
 725                 return -EINVAL;
 726         }
 727         irq = res->start;
 728
 729         div_clk = devm_clk_get(&pdev->dev, "div-clk");
 730         if (IS_ERR(div_clk)) {
 731                 dev_err(&pdev->dev, "missing controller clock");
 732                 return PTR_ERR(div_clk);
 733         }
 734
 735         i2c_dev = devm_kzalloc(&pdev->dev, sizeof(*i2c_dev), GFP_KERNEL);
 736         if (!i2c_dev)
 737                 return -ENOMEM;
 738
 739         i2c_dev->base = base;
 740         i2c_dev->div_clk = div_clk;
 741         i2c_dev->adapter.algo = &tegra_i2c_algo;
 742         i2c_dev->irq = irq;
 743         i2c_dev->cont_id = pdev->id;
 744         i2c_dev->dev = &pdev->dev;
 745
 746         i2c_dev->rst = devm_reset_control_get(&pdev->dev, "i2c");
 747         if (IS_ERR(i2c_dev->rst)) {
 748                 dev_err(&pdev->dev, "missing controller reset");
 749                 return PTR_ERR(i2c_dev->rst);
 750         }
 751
 752         ret = of_property_read_u32(i2c_dev->dev->of_node, "clock-frequency",
 753                                         &i2c_dev->bus_clk_rate);
 754         if (ret)
 755                 i2c_dev->bus_clk_rate = 100000; /* default clock rate */
 756
 757         i2c_dev->hw = &tegra20_i2c_hw;
 758
 759         if (pdev->dev.of_node) {
 760                 const struct of_device_id *match;
 761                 match = of_match_device(tegra_i2c_of_match, &pdev->dev);
 762                 i2c_dev->hw = match->data;
 763                 i2c_dev->is_dvc = of_device_is_compatible(pdev->dev.of_node,
 764                                                 "nvidia,tegra20-i2c-dvc");
 765         } else if (pdev->id == 3) {
 766                 i2c_dev->is_dvc = 1;
 767         }
 768         init_completion(&i2c_dev->msg_complete);
 769
 770         if (!i2c_dev->hw->has_single_clk_source) {
 771                 fast_clk = devm_clk_get(&pdev->dev, "fast-clk");
 772                 if (IS_ERR(fast_clk)) {
 773                         dev_err(&pdev->dev, "missing fast clock");
 774                         return PTR_ERR(fast_clk);
 775                 }
 776                 i2c_dev->fast_clk = fast_clk;
 777         }
 778
 779         platform_set_drvdata(pdev, i2c_dev);
 780
 781         if (!i2c_dev->hw->has_single_clk_source) {
 782                 ret = clk_prepare(i2c_dev->fast_clk);
 783                 if (ret < 0) {
 784                         dev_err(i2c_dev->dev, "Clock prepare failed %d\n", ret);
 785                         return ret;
 786                 }
 787         }
 788
 789         clk_multiplier *= (i2c_dev->hw->clk_divisor_std_fast_mode + 1);
 790         ret = clk_set_rate(i2c_dev->div_clk,
 791                            i2c_dev->bus_clk_rate * clk_multiplier);
 792         if (ret) {
 793                 dev_err(i2c_dev->dev, "Clock rate change failed %d\n", ret);
 794                 goto unprepare_fast_clk;
 795         }
 796
 797         ret = clk_prepare(i2c_dev->div_clk);
 798         if (ret < 0) {
 799                 dev_err(i2c_dev->dev, "Clock prepare failed %d\n", ret);
 800                 goto unprepare_fast_clk;
 801         }
 802
 803         ret = tegra_i2c_init(i2c_dev);
 804         if (ret) {
 805                 dev_err(&pdev->dev, "Failed to initialize i2c controller");
 806                 goto unprepare_div_clk;
 807         }
 808
 809         ret = devm_request_irq(&pdev->dev, i2c_dev->irq,
 810                         tegra_i2c_isr, 0, dev_name(&pdev->dev), i2c_dev);
 811         if (ret) {
 812                 dev_err(&pdev->dev, "Failed to request irq %i\n", i2c_dev->irq);
 813                 goto unprepare_div_clk;
 814         }
 815
 816         i2c_set_adapdata(&i2c_dev->adapter, i2c_dev);
 817         i2c_dev->adapter.owner = THIS_MODULE;
 818         i2c_dev->adapter.class = I2C_CLASS_DEPRECATED;
 819         strlcpy(i2c_dev->adapter.name, "Tegra I2C adapter",
 820                 sizeof(i2c_dev->adapter.name));
 821         i2c_dev->adapter.algo = &tegra_i2c_algo;
 822         i2c_dev->adapter.dev.parent = &pdev->dev;
 823         i2c_dev->adapter.nr = pdev->id;
 824         i2c_dev->adapter.dev.of_node = pdev->dev.of_node;
 825
 826         ret = i2c_add_numbered_adapter(&i2c_dev->adapter);
 827         if (ret) {
 828                 dev_err(&pdev->dev, "Failed to add I2C adapter\n");
 829                 goto unprepare_div_clk;
 830         }
 831
 832         return 0;
 833
 834 unprepare_div_clk:
 835         clk_unprepare(i2c_dev->div_clk);
 836
 837 unprepare_fast_clk:
 838         if (!i2c_dev->hw->has_single_clk_source)
 839                 clk_unprepare(i2c_dev->fast_clk);
 840
 841         return ret;
 842 }
 843
 844 static int tegra_i2c_remove(struct platform_device *pdev)
 845 {
 846         struct tegra_i2c_dev *i2c_dev = platform_get_drvdata(pdev);
 847         i2c_del_adapter(&i2c_dev->adapter);
 848
 849         clk_unprepare(i2c_dev->div_clk);
 850         if (!i2c_dev->hw->has_single_clk_source)
 851                 clk_unprepare(i2c_dev->fast_clk);
 852
 853         return 0;
 854 }
 855
 856 #ifdef CONFIG_PM_SLEEP
 857 static int tegra_i2c_suspend(struct device *dev)
 858 {
 859         struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev);
 860
 861         i2c_lock_adapter(&i2c_dev->adapter);
 862         i2c_dev->is_suspended = true;
 863         i2c_unlock_adapter(&i2c_dev->adapter);
 864
 865         return 0;
 866 }
 867
 868 static int tegra_i2c_resume(struct device *dev)
 869 {
 870         struct tegra_i2c_dev *i2c_dev = dev_get_drvdata(dev);
 871         int ret;
 872
 873         i2c_lock_adapter(&i2c_dev->adapter);
 874
 875         ret = tegra_i2c_init(i2c_dev);
 876
 877         if (ret) {
 878                 i2c_unlock_adapter(&i2c_dev->adapter);
 879                 return ret;
 880         }
 881
 882         i2c_dev->is_suspended = false;
 883
 884         i2c_unlock_adapter(&i2c_dev->adapter);
 885
 886         return 0;
 887 }
 888
 889 static SIMPLE_DEV_PM_OPS(tegra_i2c_pm, tegra_i2c_suspend, tegra_i2c_resume);
 890 #define TEGRA_I2C_PM    (&tegra_i2c_pm)
 891 #else
 892 #define TEGRA_I2C_PM    NULL
 893 #endif
 894
 895 static struct platform_driver tegra_i2c_driver = {
 896         .probe   = tegra_i2c_probe,
 897         .remove  = tegra_i2c_remove,
 898         .driver  = {
 899                 .name  = "tegra-i2c",
 900                 .of_match_table = tegra_i2c_of_match,
 901                 .pm    = TEGRA_I2C_PM,
 902         },
 903 };
 904
 905 static int __init tegra_i2c_init_driver(void)
 906 {
 907         return platform_driver_register(&tegra_i2c_driver);
 908 }
 909
 910 static void __exit tegra_i2c_exit_driver(void)
 911 {
 912         platform_driver_unregister(&tegra_i2c_driver);
 913 }
 914
 915 subsys_initcall(tegra_i2c_init_driver);
 916 module_exit(tegra_i2c_exit_driver);
 917
 918 MODULE_DESCRIPTION("nVidia Tegra2 I2C Bus Controller driver");
 919 MODULE_AUTHOR("Colin Cross");
 920 MODULE_LICENSE("GPL v2");