drivers/i2c/busses/i2c-aspeed.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  *  Aspeed 24XX/25XX I2C Controller.
   4  *
   5  *  Copyright (C) 2012-2017 ASPEED Technology Inc.
   6  *  Copyright 2017 IBM Corporation
   7  *  Copyright 2017 Google, Inc.
   8  */
   9
  10 #include <linux/clk.h>
  11 #include <linux/completion.h>
  12 #include <linux/err.h>
  13 #include <linux/errno.h>
  14 #include <linux/i2c.h>
  15 #include <linux/init.h>
  16 #include <linux/interrupt.h>
  17 #include <linux/io.h>
  18 #include <linux/irq.h>
  19 #include <linux/kernel.h>
  20 #include <linux/module.h>
  21 #include <linux/of_address.h>
  22 #include <linux/of_irq.h>
  23 #include <linux/of_platform.h>
  24 #include <linux/platform_device.h>
  25 #include <linux/reset.h>
  26 #include <linux/slab.h>
  27
  28 /* I2C Register */
  29 #define ASPEED_I2C_FUN_CTRL_REG                         0x00
  30 #define ASPEED_I2C_AC_TIMING_REG1                       0x04
  31 #define ASPEED_I2C_AC_TIMING_REG2                       0x08
  32 #define ASPEED_I2C_INTR_CTRL_REG                        0x0c
  33 #define ASPEED_I2C_INTR_STS_REG                         0x10
  34 #define ASPEED_I2C_CMD_REG                              0x14
  35 #define ASPEED_I2C_DEV_ADDR_REG                         0x18
  36 #define ASPEED_I2C_BYTE_BUF_REG                         0x20
  37
  38 /* Global Register Definition */
  39 /* 0x00 : I2C Interrupt Status Register  */
  40 /* 0x08 : I2C Interrupt Target Assignment  */
  41
  42 /* Device Register Definition */
  43 /* 0x00 : I2CD Function Control Register  */
  44 #define ASPEED_I2CD_MULTI_MASTER_DIS                    BIT(15)
  45 #define ASPEED_I2CD_SDA_DRIVE_1T_EN                     BIT(8)
  46 #define ASPEED_I2CD_M_SDA_DRIVE_1T_EN                   BIT(7)
  47 #define ASPEED_I2CD_M_HIGH_SPEED_EN                     BIT(6)
  48 #define ASPEED_I2CD_SLAVE_EN                            BIT(1)
  49 #define ASPEED_I2CD_MASTER_EN                           BIT(0)
  50
  51 /* 0x04 : I2CD Clock and AC Timing Control Register #1 */
  52 #define ASPEED_I2CD_TIME_TBUF_MASK                      GENMASK(31, 28)
  53 #define ASPEED_I2CD_TIME_THDSTA_MASK                    GENMASK(27, 24)
  54 #define ASPEED_I2CD_TIME_TACST_MASK                     GENMASK(23, 20)
  55 #define ASPEED_I2CD_TIME_SCL_HIGH_SHIFT                 16
  56 #define ASPEED_I2CD_TIME_SCL_HIGH_MASK                  GENMASK(19, 16)
  57 #define ASPEED_I2CD_TIME_SCL_LOW_SHIFT                  12
  58 #define ASPEED_I2CD_TIME_SCL_LOW_MASK                   GENMASK(15, 12)
  59 #define ASPEED_I2CD_TIME_BASE_DIVISOR_MASK              GENMASK(3, 0)
  60 #define ASPEED_I2CD_TIME_SCL_REG_MAX                    GENMASK(3, 0)
  61 /* 0x08 : I2CD Clock and AC Timing Control Register #2 */
  62 #define ASPEED_NO_TIMEOUT_CTRL                          0
  63
  64 /* 0x0c : I2CD Interrupt Control Register &
  65  * 0x10 : I2CD Interrupt Status Register
  66  *
  67  * These share bit definitions, so use the same values for the enable &
  68  * status bits.
  69  */
  70 #define ASPEED_I2CD_INTR_RECV_MASK                      0xf000ffff
  71 #define ASPEED_I2CD_INTR_SDA_DL_TIMEOUT                 BIT(14)
  72 #define ASPEED_I2CD_INTR_BUS_RECOVER_DONE               BIT(13)
  73 #define ASPEED_I2CD_INTR_SLAVE_MATCH                    BIT(7)
  74 #define ASPEED_I2CD_INTR_SCL_TIMEOUT                    BIT(6)
  75 #define ASPEED_I2CD_INTR_ABNORMAL                       BIT(5)
  76 #define ASPEED_I2CD_INTR_NORMAL_STOP                    BIT(4)
  77 #define ASPEED_I2CD_INTR_ARBIT_LOSS                     BIT(3)
  78 #define ASPEED_I2CD_INTR_RX_DONE                        BIT(2)
  79 #define ASPEED_I2CD_INTR_TX_NAK                         BIT(1)
  80 #define ASPEED_I2CD_INTR_TX_ACK                         BIT(0)
  81 #define ASPEED_I2CD_INTR_MASTER_ERRORS                                         \
  82                 (ASPEED_I2CD_INTR_SDA_DL_TIMEOUT |                             \
  83                  ASPEED_I2CD_INTR_SCL_TIMEOUT |                                \
  84                  ASPEED_I2CD_INTR_ABNORMAL |                                   \
  85                  ASPEED_I2CD_INTR_ARBIT_LOSS)
  86 #define ASPEED_I2CD_INTR_ALL                                                   \
  87                 (ASPEED_I2CD_INTR_SDA_DL_TIMEOUT |                             \
  88                  ASPEED_I2CD_INTR_BUS_RECOVER_DONE |                           \
  89                  ASPEED_I2CD_INTR_SCL_TIMEOUT |                                \
  90                  ASPEED_I2CD_INTR_ABNORMAL |                                   \
  91                  ASPEED_I2CD_INTR_NORMAL_STOP |                                \
  92                  ASPEED_I2CD_INTR_ARBIT_LOSS |                                 \
  93                  ASPEED_I2CD_INTR_RX_DONE |                                    \
  94                  ASPEED_I2CD_INTR_TX_NAK |                                     \
  95                  ASPEED_I2CD_INTR_TX_ACK)
  96
  97 /* 0x14 : I2CD Command/Status Register   */
  98 #define ASPEED_I2CD_SCL_LINE_STS                        BIT(18)
  99 #define ASPEED_I2CD_SDA_LINE_STS                        BIT(17)
 100 #define ASPEED_I2CD_BUS_BUSY_STS                        BIT(16)
 101 #define ASPEED_I2CD_BUS_RECOVER_CMD                     BIT(11)
 102
 103 /* Command Bit */
 104 #define ASPEED_I2CD_M_STOP_CMD                          BIT(5)
 105 #define ASPEED_I2CD_M_S_RX_CMD_LAST                     BIT(4)
 106 #define ASPEED_I2CD_M_RX_CMD                            BIT(3)
 107 #define ASPEED_I2CD_S_TX_CMD                            BIT(2)
 108 #define ASPEED_I2CD_M_TX_CMD                            BIT(1)
 109 #define ASPEED_I2CD_M_START_CMD                         BIT(0)
 110 #define ASPEED_I2CD_MASTER_CMDS_MASK                                           \
 111                 (ASPEED_I2CD_M_STOP_CMD |                                      \
 112                  ASPEED_I2CD_M_S_RX_CMD_LAST |                                 \
 113                  ASPEED_I2CD_M_RX_CMD |                                        \
 114                  ASPEED_I2CD_M_TX_CMD |                                        \
 115                  ASPEED_I2CD_M_START_CMD)
 116
 117 /* 0x18 : I2CD Slave Device Address Register   */
 118 #define ASPEED_I2CD_DEV_ADDR_MASK                       GENMASK(6, 0)
 119
 120 enum aspeed_i2c_master_state {
 121         ASPEED_I2C_MASTER_INACTIVE,
 122         ASPEED_I2C_MASTER_PENDING,
 123         ASPEED_I2C_MASTER_START,
 124         ASPEED_I2C_MASTER_TX_FIRST,
 125         ASPEED_I2C_MASTER_TX,
 126         ASPEED_I2C_MASTER_RX_FIRST,
 127         ASPEED_I2C_MASTER_RX,
 128         ASPEED_I2C_MASTER_STOP,
 129 };
 130
 131 enum aspeed_i2c_slave_state {
 132         ASPEED_I2C_SLAVE_INACTIVE,
 133         ASPEED_I2C_SLAVE_START,
 134         ASPEED_I2C_SLAVE_READ_REQUESTED,
 135         ASPEED_I2C_SLAVE_READ_PROCESSED,
 136         ASPEED_I2C_SLAVE_WRITE_REQUESTED,
 137         ASPEED_I2C_SLAVE_WRITE_RECEIVED,
 138         ASPEED_I2C_SLAVE_STOP,
 139 };
 140
 141 struct aspeed_i2c_bus {
 142         struct i2c_adapter              adap;
 143         struct device                   *dev;
 144         void __iomem                    *base;
 145         struct reset_control            *rst;
 146         /* Synchronizes I/O mem access to base. */
 147         spinlock_t                      lock;
 148         struct completion               cmd_complete;
 149         u32                             (*get_clk_reg_val)(struct device *dev,
 150                                                            u32 divisor);
 151         unsigned long                   parent_clk_frequency;
 152         u32                             bus_frequency;
 153         /* Transaction state. */
 154         enum aspeed_i2c_master_state    master_state;
 155         struct i2c_msg                  *msgs;
 156         size_t                          buf_index;
 157         size_t                          msgs_index;
 158         size_t                          msgs_count;
 159         bool                            send_stop;
 160         int                             cmd_err;
 161         /* Protected only by i2c_lock_bus */
 162         int                             master_xfer_result;
 163         /* Multi-master */
 164         bool                            multi_master;
 165 #if IS_ENABLED(CONFIG_I2C_SLAVE)
 166         struct i2c_client               *slave;
 167         enum aspeed_i2c_slave_state     slave_state;
 168 #endif /* CONFIG_I2C_SLAVE */
 169 };
 170
 171 static int aspeed_i2c_reset(struct aspeed_i2c_bus *bus);
 172
 173 static int aspeed_i2c_recover_bus(struct aspeed_i2c_bus *bus)
 174 {
 175         unsigned long time_left, flags;
 176         int ret = 0;
 177         u32 command;
 178
 179         spin_lock_irqsave(&bus->lock, flags);
 180         command = readl(bus->base + ASPEED_I2C_CMD_REG);
 181
 182         if (command & ASPEED_I2CD_SDA_LINE_STS) {
 183                 /* Bus is idle: no recovery needed. */
 184                 if (command & ASPEED_I2CD_SCL_LINE_STS)
 185                         goto out;
 186                 dev_dbg(bus->dev, "SCL hung (state %x), attempting recovery\n",
 187                         command);
 188
 189                 reinit_completion(&bus->cmd_complete);
 190                 writel(ASPEED_I2CD_M_STOP_CMD, bus->base + ASPEED_I2C_CMD_REG);
 191                 spin_unlock_irqrestore(&bus->lock, flags);
 192
 193                 time_left = wait_for_completion_timeout(
 194                                 &bus->cmd_complete, bus->adap.timeout);
 195
 196                 spin_lock_irqsave(&bus->lock, flags);
 197                 if (time_left == 0)
 198                         goto reset_out;
 199                 else if (bus->cmd_err)
 200                         goto reset_out;
 201                 /* Recovery failed. */
 202                 else if (!(readl(bus->base + ASPEED_I2C_CMD_REG) &
 203                            ASPEED_I2CD_SCL_LINE_STS))
 204                         goto reset_out;
 205         /* Bus error. */
 206         } else {
 207                 dev_dbg(bus->dev, "SDA hung (state %x), attempting recovery\n",
 208                         command);
 209
 210                 reinit_completion(&bus->cmd_complete);
 211                 /* Writes 1 to 8 SCL clock cycles until SDA is released. */
 212                 writel(ASPEED_I2CD_BUS_RECOVER_CMD,
 213                        bus->base + ASPEED_I2C_CMD_REG);
 214                 spin_unlock_irqrestore(&bus->lock, flags);
 215
 216                 time_left = wait_for_completion_timeout(
 217                                 &bus->cmd_complete, bus->adap.timeout);
 218
 219                 spin_lock_irqsave(&bus->lock, flags);
 220                 if (time_left == 0)
 221                         goto reset_out;
 222                 else if (bus->cmd_err)
 223                         goto reset_out;
 224                 /* Recovery failed. */
 225                 else if (!(readl(bus->base + ASPEED_I2C_CMD_REG) &
 226                            ASPEED_I2CD_SDA_LINE_STS))
 227                         goto reset_out;
 228         }
 229
 230 out:
 231         spin_unlock_irqrestore(&bus->lock, flags);
 232
 233         return ret;
 234
 235 reset_out:
 236         spin_unlock_irqrestore(&bus->lock, flags);
 237
 238         return aspeed_i2c_reset(bus);
 239 }
 240
 241 #if IS_ENABLED(CONFIG_I2C_SLAVE)
 242 static u32 aspeed_i2c_slave_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
 243 {
 244         u32 command, irq_handled = 0;
 245         struct i2c_client *slave = bus->slave;
 246         u8 value;
 247
 248         if (!slave)
 249                 return 0;
 250
 251         command = readl(bus->base + ASPEED_I2C_CMD_REG);
 252
 253         /* Slave was requested, restart state machine. */
 254         if (irq_status & ASPEED_I2CD_INTR_SLAVE_MATCH) {
 255                 irq_handled |= ASPEED_I2CD_INTR_SLAVE_MATCH;
 256                 bus->slave_state = ASPEED_I2C_SLAVE_START;
 257         }
 258
 259         /* Slave is not currently active, irq was for someone else. */
 260         if (bus->slave_state == ASPEED_I2C_SLAVE_INACTIVE)
 261                 return irq_handled;
 262
 263         dev_dbg(bus->dev, "slave irq status 0x%08x, cmd 0x%08x\n",
 264                 irq_status, command);
 265
 266         /* Slave was sent something. */
 267         if (irq_status & ASPEED_I2CD_INTR_RX_DONE) {
 268                 value = readl(bus->base + ASPEED_I2C_BYTE_BUF_REG) >> 8;
 269                 /* Handle address frame. */
 270                 if (bus->slave_state == ASPEED_I2C_SLAVE_START) {
 271                         if (value & 0x1)
 272                                 bus->slave_state =
 273                                                 ASPEED_I2C_SLAVE_READ_REQUESTED;
 274                         else
 275                                 bus->slave_state =
 276                                                 ASPEED_I2C_SLAVE_WRITE_REQUESTED;
 277                 }
 278                 irq_handled |= ASPEED_I2CD_INTR_RX_DONE;
 279         }
 280
 281         /* Slave was asked to stop. */
 282         if (irq_status & ASPEED_I2CD_INTR_NORMAL_STOP) {
 283                 irq_handled |= ASPEED_I2CD_INTR_NORMAL_STOP;
 284                 bus->slave_state = ASPEED_I2C_SLAVE_STOP;
 285         }
 286         if (irq_status & ASPEED_I2CD_INTR_TX_NAK &&
 287             bus->slave_state == ASPEED_I2C_SLAVE_READ_PROCESSED) {
 288                 irq_handled |= ASPEED_I2CD_INTR_TX_NAK;
 289                 bus->slave_state = ASPEED_I2C_SLAVE_STOP;
 290         }
 291
 292         switch (bus->slave_state) {
 293         case ASPEED_I2C_SLAVE_READ_REQUESTED:
 294                 if (unlikely(irq_status & ASPEED_I2CD_INTR_TX_ACK))
 295                         dev_err(bus->dev, "Unexpected ACK on read request.\n");
 296                 bus->slave_state = ASPEED_I2C_SLAVE_READ_PROCESSED;
 297                 i2c_slave_event(slave, I2C_SLAVE_READ_REQUESTED, &value);
 298                 writel(value, bus->base + ASPEED_I2C_BYTE_BUF_REG);
 299                 writel(ASPEED_I2CD_S_TX_CMD, bus->base + ASPEED_I2C_CMD_REG);
 300                 break;
 301         case ASPEED_I2C_SLAVE_READ_PROCESSED:
 302                 if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_ACK))) {
 303                         dev_err(bus->dev,
 304                                 "Expected ACK after processed read.\n");
 305                         break;
 306                 }
 307                 irq_handled |= ASPEED_I2CD_INTR_TX_ACK;
 308                 i2c_slave_event(slave, I2C_SLAVE_READ_PROCESSED, &value);
 309                 writel(value, bus->base + ASPEED_I2C_BYTE_BUF_REG);
 310                 writel(ASPEED_I2CD_S_TX_CMD, bus->base + ASPEED_I2C_CMD_REG);
 311                 break;
 312         case ASPEED_I2C_SLAVE_WRITE_REQUESTED:
 313                 bus->slave_state = ASPEED_I2C_SLAVE_WRITE_RECEIVED;
 314                 i2c_slave_event(slave, I2C_SLAVE_WRITE_REQUESTED, &value);
 315                 break;
 316         case ASPEED_I2C_SLAVE_WRITE_RECEIVED:
 317                 i2c_slave_event(slave, I2C_SLAVE_WRITE_RECEIVED, &value);
 318                 break;
 319         case ASPEED_I2C_SLAVE_STOP:
 320                 i2c_slave_event(slave, I2C_SLAVE_STOP, &value);
 321                 bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;
 322                 break;
 323         case ASPEED_I2C_SLAVE_START:
 324                 /* Slave was just started. Waiting for the next event. */;
 325                 break;
 326         default:
 327                 dev_err(bus->dev, "unknown slave_state: %d\n",
 328                         bus->slave_state);
 329                 bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;
 330                 break;
 331         }
 332
 333         return irq_handled;
 334 }
 335 #endif /* CONFIG_I2C_SLAVE */
 336
 337 /* precondition: bus.lock has been acquired. */
 338 static void aspeed_i2c_do_start(struct aspeed_i2c_bus *bus)
 339 {
 340         u32 command = ASPEED_I2CD_M_START_CMD | ASPEED_I2CD_M_TX_CMD;
 341         struct i2c_msg *msg = &bus->msgs[bus->msgs_index];
 342         u8 slave_addr = i2c_8bit_addr_from_msg(msg);
 343
 344 #if IS_ENABLED(CONFIG_I2C_SLAVE)
 345         /*
 346          * If it's requested in the middle of a slave session, set the master
 347          * state to 'pending' then H/W will continue handling this master
 348          * command when the bus comes back to the idle state.
 349          */
 350         if (bus->slave_state != ASPEED_I2C_SLAVE_INACTIVE) {
 351                 bus->master_state = ASPEED_I2C_MASTER_PENDING;
 352                 return;
 353         }
 354 #endif /* CONFIG_I2C_SLAVE */
 355
 356         bus->master_state = ASPEED_I2C_MASTER_START;
 357         bus->buf_index = 0;
 358
 359         if (msg->flags & I2C_M_RD) {
 360                 command |= ASPEED_I2CD_M_RX_CMD;
 361                 /* Need to let the hardware know to NACK after RX. */
 362                 if (msg->len == 1 && !(msg->flags & I2C_M_RECV_LEN))
 363                         command |= ASPEED_I2CD_M_S_RX_CMD_LAST;
 364         }
 365
 366         writel(slave_addr, bus->base + ASPEED_I2C_BYTE_BUF_REG);
 367         writel(command, bus->base + ASPEED_I2C_CMD_REG);
 368 }
 369
 370 /* precondition: bus.lock has been acquired. */
 371 static void aspeed_i2c_do_stop(struct aspeed_i2c_bus *bus)
 372 {
 373         bus->master_state = ASPEED_I2C_MASTER_STOP;
 374         writel(ASPEED_I2CD_M_STOP_CMD, bus->base + ASPEED_I2C_CMD_REG);
 375 }
 376
 377 /* precondition: bus.lock has been acquired. */
 378 static void aspeed_i2c_next_msg_or_stop(struct aspeed_i2c_bus *bus)
 379 {
 380         if (bus->msgs_index + 1 < bus->msgs_count) {
 381                 bus->msgs_index++;
 382                 aspeed_i2c_do_start(bus);
 383         } else {
 384                 aspeed_i2c_do_stop(bus);
 385         }
 386 }
 387
 388 static int aspeed_i2c_is_irq_error(u32 irq_status)
 389 {
 390         if (irq_status & ASPEED_I2CD_INTR_ARBIT_LOSS)
 391                 return -EAGAIN;
 392         if (irq_status & (ASPEED_I2CD_INTR_SDA_DL_TIMEOUT |
 393                           ASPEED_I2CD_INTR_SCL_TIMEOUT))
 394                 return -EBUSY;
 395         if (irq_status & (ASPEED_I2CD_INTR_ABNORMAL))
 396                 return -EPROTO;
 397
 398         return 0;
 399 }
 400
 401 static u32 aspeed_i2c_master_irq(struct aspeed_i2c_bus *bus, u32 irq_status)
 402 {
 403         u32 irq_handled = 0, command = 0;
 404         struct i2c_msg *msg;
 405         u8 recv_byte;
 406         int ret;
 407
 408         if (irq_status & ASPEED_I2CD_INTR_BUS_RECOVER_DONE) {
 409                 bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
 410                 irq_handled |= ASPEED_I2CD_INTR_BUS_RECOVER_DONE;
 411                 goto out_complete;
 412         }
 413
 414         /*
 415          * We encountered an interrupt that reports an error: the hardware
 416          * should clear the command queue effectively taking us back to the
 417          * INACTIVE state.
 418          */
 419         ret = aspeed_i2c_is_irq_error(irq_status);
 420         if (ret) {
 421                 dev_dbg(bus->dev, "received error interrupt: 0x%08x\n",
 422                         irq_status);
 423                 irq_handled |= (irq_status & ASPEED_I2CD_INTR_MASTER_ERRORS);
 424                 if (bus->master_state != ASPEED_I2C_MASTER_INACTIVE) {
 425                         bus->cmd_err = ret;
 426                         bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
 427                         goto out_complete;
 428                 }
 429         }
 430
 431         /* Master is not currently active, irq was for someone else. */
 432         if (bus->master_state == ASPEED_I2C_MASTER_INACTIVE ||
 433             bus->master_state == ASPEED_I2C_MASTER_PENDING)
 434                 goto out_no_complete;
 435
 436         /* We are in an invalid state; reset bus to a known state. */
 437         if (!bus->msgs) {
 438                 dev_err(bus->dev, "bus in unknown state. irq_status: 0x%x\n",
 439                         irq_status);
 440                 bus->cmd_err = -EIO;
 441                 if (bus->master_state != ASPEED_I2C_MASTER_STOP &&
 442                     bus->master_state != ASPEED_I2C_MASTER_INACTIVE)
 443                         aspeed_i2c_do_stop(bus);
 444                 goto out_no_complete;
 445         }
 446         msg = &bus->msgs[bus->msgs_index];
 447
 448         /*
 449          * START is a special case because we still have to handle a subsequent
 450          * TX or RX immediately after we handle it, so we handle it here and
 451          * then update the state and handle the new state below.
 452          */
 453         if (bus->master_state == ASPEED_I2C_MASTER_START) {
 454 #if IS_ENABLED(CONFIG_I2C_SLAVE)
 455                 /*
 456                  * If a peer master starts a xfer immediately after it queues a
 457                  * master command, clear the queued master command and change
 458                  * its state to 'pending'. To simplify handling of pending
 459                  * cases, it uses S/W solution instead of H/W command queue
 460                  * handling.
 461                  */
 462                 if (unlikely(irq_status & ASPEED_I2CD_INTR_SLAVE_MATCH)) {
 463                         writel(readl(bus->base + ASPEED_I2C_CMD_REG) &
 464                                 ~ASPEED_I2CD_MASTER_CMDS_MASK,
 465                                bus->base + ASPEED_I2C_CMD_REG);
 466                         bus->master_state = ASPEED_I2C_MASTER_PENDING;
 467                         dev_dbg(bus->dev,
 468                                 "master goes pending due to a slave start\n");
 469                         goto out_no_complete;
 470                 }
 471 #endif /* CONFIG_I2C_SLAVE */
 472                 if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_ACK))) {
 473                         if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_NAK))) {
 474                                 bus->cmd_err = -ENXIO;
 475                                 bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
 476                                 goto out_complete;
 477                         }
 478                         pr_devel("no slave present at %02x\n", msg->addr);
 479                         irq_handled |= ASPEED_I2CD_INTR_TX_NAK;
 480                         bus->cmd_err = -ENXIO;
 481                         aspeed_i2c_do_stop(bus);
 482                         goto out_no_complete;
 483                 }
 484                 irq_handled |= ASPEED_I2CD_INTR_TX_ACK;
 485                 if (msg->len == 0) { /* SMBUS_QUICK */
 486                         aspeed_i2c_do_stop(bus);
 487                         goto out_no_complete;
 488                 }
 489                 if (msg->flags & I2C_M_RD)
 490                         bus->master_state = ASPEED_I2C_MASTER_RX_FIRST;
 491                 else
 492                         bus->master_state = ASPEED_I2C_MASTER_TX_FIRST;
 493         }
 494
 495         switch (bus->master_state) {
 496         case ASPEED_I2C_MASTER_TX:
 497                 if (unlikely(irq_status & ASPEED_I2CD_INTR_TX_NAK)) {
 498                         dev_dbg(bus->dev, "slave NACKed TX\n");
 499                         irq_handled |= ASPEED_I2CD_INTR_TX_NAK;
 500                         goto error_and_stop;
 501                 } else if (unlikely(!(irq_status & ASPEED_I2CD_INTR_TX_ACK))) {
 502                         dev_err(bus->dev, "slave failed to ACK TX\n");
 503                         goto error_and_stop;
 504                 }
 505                 irq_handled |= ASPEED_I2CD_INTR_TX_ACK;
 506                 fallthrough;
 507         case ASPEED_I2C_MASTER_TX_FIRST:
 508                 if (bus->buf_index < msg->len) {
 509                         bus->master_state = ASPEED_I2C_MASTER_TX;
 510                         writel(msg->buf[bus->buf_index++],
 511                                bus->base + ASPEED_I2C_BYTE_BUF_REG);
 512                         writel(ASPEED_I2CD_M_TX_CMD,
 513                                bus->base + ASPEED_I2C_CMD_REG);
 514                 } else {
 515                         aspeed_i2c_next_msg_or_stop(bus);
 516                 }
 517                 goto out_no_complete;
 518         case ASPEED_I2C_MASTER_RX_FIRST:
 519                 /* RX may not have completed yet (only address cycle) */
 520                 if (!(irq_status & ASPEED_I2CD_INTR_RX_DONE))
 521                         goto out_no_complete;
 522                 fallthrough;
 523         case ASPEED_I2C_MASTER_RX:
 524                 if (unlikely(!(irq_status & ASPEED_I2CD_INTR_RX_DONE))) {
 525                         dev_err(bus->dev, "master failed to RX\n");
 526                         goto error_and_stop;
 527                 }
 528                 irq_handled |= ASPEED_I2CD_INTR_RX_DONE;
 529
 530                 recv_byte = readl(bus->base + ASPEED_I2C_BYTE_BUF_REG) >> 8;
 531                 msg->buf[bus->buf_index++] = recv_byte;
 532
 533                 if (msg->flags & I2C_M_RECV_LEN) {
 534                         if (unlikely(recv_byte > I2C_SMBUS_BLOCK_MAX)) {
 535                                 bus->cmd_err = -EPROTO;
 536                                 aspeed_i2c_do_stop(bus);
 537                                 goto out_no_complete;
 538                         }
 539                         msg->len = recv_byte +
 540                                         ((msg->flags & I2C_CLIENT_PEC) ? 2 : 1);
 541                         msg->flags &= ~I2C_M_RECV_LEN;
 542                 }
 543
 544                 if (bus->buf_index < msg->len) {
 545                         bus->master_state = ASPEED_I2C_MASTER_RX;
 546                         command = ASPEED_I2CD_M_RX_CMD;
 547                         if (bus->buf_index + 1 == msg->len)
 548                                 command |= ASPEED_I2CD_M_S_RX_CMD_LAST;
 549                         writel(command, bus->base + ASPEED_I2C_CMD_REG);
 550                 } else {
 551                         aspeed_i2c_next_msg_or_stop(bus);
 552                 }
 553                 goto out_no_complete;
 554         case ASPEED_I2C_MASTER_STOP:
 555                 if (unlikely(!(irq_status & ASPEED_I2CD_INTR_NORMAL_STOP))) {
 556                         dev_err(bus->dev,
 557                                 "master failed to STOP. irq_status:0x%x\n",
 558                                 irq_status);
 559                         bus->cmd_err = -EIO;
 560                         /* Do not STOP as we have already tried. */
 561                 } else {
 562                         irq_handled |= ASPEED_I2CD_INTR_NORMAL_STOP;
 563                 }
 564
 565                 bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
 566                 goto out_complete;
 567         case ASPEED_I2C_MASTER_INACTIVE:
 568                 dev_err(bus->dev,
 569                         "master received interrupt 0x%08x, but is inactive\n",
 570                         irq_status);
 571                 bus->cmd_err = -EIO;
 572                 /* Do not STOP as we should be inactive. */
 573                 goto out_complete;
 574         default:
 575                 WARN(1, "unknown master state\n");
 576                 bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
 577                 bus->cmd_err = -EINVAL;
 578                 goto out_complete;
 579         }
 580 error_and_stop:
 581         bus->cmd_err = -EIO;
 582         aspeed_i2c_do_stop(bus);
 583         goto out_no_complete;
 584 out_complete:
 585         bus->msgs = NULL;
 586         if (bus->cmd_err)
 587                 bus->master_xfer_result = bus->cmd_err;
 588         else
 589                 bus->master_xfer_result = bus->msgs_index + 1;
 590         complete(&bus->cmd_complete);
 591 out_no_complete:
 592         return irq_handled;
 593 }
 594
 595 static irqreturn_t aspeed_i2c_bus_irq(int irq, void *dev_id)
 596 {
 597         struct aspeed_i2c_bus *bus = dev_id;
 598         u32 irq_received, irq_remaining, irq_handled;
 599
 600         spin_lock(&bus->lock);
 601         irq_received = readl(bus->base + ASPEED_I2C_INTR_STS_REG);
 602         /* Ack all interrupts except for Rx done */
 603         writel(irq_received & ~ASPEED_I2CD_INTR_RX_DONE,
 604                bus->base + ASPEED_I2C_INTR_STS_REG);
 605         readl(bus->base + ASPEED_I2C_INTR_STS_REG);
 606         irq_received &= ASPEED_I2CD_INTR_RECV_MASK;
 607         irq_remaining = irq_received;
 608
 609 #if IS_ENABLED(CONFIG_I2C_SLAVE)
 610         /*
 611          * In most cases, interrupt bits will be set one by one, although
 612          * multiple interrupt bits could be set at the same time. It's also
 613          * possible that master interrupt bits could be set along with slave
 614          * interrupt bits. Each case needs to be handled using corresponding
 615          * handlers depending on the current state.
 616          */
 617         if (bus->master_state != ASPEED_I2C_MASTER_INACTIVE &&
 618             bus->master_state != ASPEED_I2C_MASTER_PENDING) {
 619                 irq_handled = aspeed_i2c_master_irq(bus, irq_remaining);
 620                 irq_remaining &= ~irq_handled;
 621                 if (irq_remaining)
 622                         irq_handled |= aspeed_i2c_slave_irq(bus, irq_remaining);
 623         } else {
 624                 irq_handled = aspeed_i2c_slave_irq(bus, irq_remaining);
 625                 irq_remaining &= ~irq_handled;
 626                 if (irq_remaining)
 627                         irq_handled |= aspeed_i2c_master_irq(bus,
 628                                                              irq_remaining);
 629         }
 630
 631         /*
 632          * Start a pending master command at here if a slave operation is
 633          * completed.
 634          */
 635         if (bus->master_state == ASPEED_I2C_MASTER_PENDING &&
 636             bus->slave_state == ASPEED_I2C_SLAVE_INACTIVE)
 637                 aspeed_i2c_do_start(bus);
 638 #else
 639         irq_handled = aspeed_i2c_master_irq(bus, irq_remaining);
 640 #endif /* CONFIG_I2C_SLAVE */
 641
 642         irq_remaining &= ~irq_handled;
 643         if (irq_remaining)
 644                 dev_err(bus->dev,
 645                         "irq handled != irq. expected 0x%08x, but was 0x%08x\n",
 646                         irq_received, irq_handled);
 647
 648         /* Ack Rx done */
 649         if (irq_received & ASPEED_I2CD_INTR_RX_DONE) {
 650                 writel(ASPEED_I2CD_INTR_RX_DONE,
 651                        bus->base + ASPEED_I2C_INTR_STS_REG);
 652                 readl(bus->base + ASPEED_I2C_INTR_STS_REG);
 653         }
 654         spin_unlock(&bus->lock);
 655         return irq_remaining ? IRQ_NONE : IRQ_HANDLED;
 656 }
 657
 658 static int aspeed_i2c_master_xfer(struct i2c_adapter *adap,
 659                                   struct i2c_msg *msgs, int num)
 660 {
 661         struct aspeed_i2c_bus *bus = i2c_get_adapdata(adap);
 662         unsigned long time_left, flags;
 663
 664         spin_lock_irqsave(&bus->lock, flags);
 665         bus->cmd_err = 0;
 666
 667         /* If bus is busy in a single master environment, attempt recovery. */
 668         if (!bus->multi_master &&
 669             (readl(bus->base + ASPEED_I2C_CMD_REG) &
 670              ASPEED_I2CD_BUS_BUSY_STS)) {
 671                 int ret;
 672
 673                 spin_unlock_irqrestore(&bus->lock, flags);
 674                 ret = aspeed_i2c_recover_bus(bus);
 675                 if (ret)
 676                         return ret;
 677                 spin_lock_irqsave(&bus->lock, flags);
 678         }
 679
 680         bus->cmd_err = 0;
 681         bus->msgs = msgs;
 682         bus->msgs_index = 0;
 683         bus->msgs_count = num;
 684
 685         reinit_completion(&bus->cmd_complete);
 686         aspeed_i2c_do_start(bus);
 687         spin_unlock_irqrestore(&bus->lock, flags);
 688
 689         time_left = wait_for_completion_timeout(&bus->cmd_complete,
 690                                                 bus->adap.timeout);
 691
 692         if (time_left == 0) {
 693                 /*
 694                  * If timed out and bus is still busy in a multi master
 695                  * environment, attempt recovery at here.
 696                  */
 697                 if (bus->multi_master &&
 698                     (readl(bus->base + ASPEED_I2C_CMD_REG) &
 699                      ASPEED_I2CD_BUS_BUSY_STS))
 700                         aspeed_i2c_recover_bus(bus);
 701
 702                 /*
 703                  * If timed out and the state is still pending, drop the pending
 704                  * master command.
 705                  */
 706                 spin_lock_irqsave(&bus->lock, flags);
 707                 if (bus->master_state == ASPEED_I2C_MASTER_PENDING)
 708                         bus->master_state = ASPEED_I2C_MASTER_INACTIVE;
 709                 spin_unlock_irqrestore(&bus->lock, flags);
 710
 711                 return -ETIMEDOUT;
 712         }
 713
 714         return bus->master_xfer_result;
 715 }
 716
 717 static u32 aspeed_i2c_functionality(struct i2c_adapter *adap)
 718 {
 719         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA;
 720 }
 721
 722 #if IS_ENABLED(CONFIG_I2C_SLAVE)
 723 /* precondition: bus.lock has been acquired. */
 724 static void __aspeed_i2c_reg_slave(struct aspeed_i2c_bus *bus, u16 slave_addr)
 725 {
 726         u32 addr_reg_val, func_ctrl_reg_val;
 727
 728         /*
 729          * Set slave addr.  Reserved bits can all safely be written with zeros
 730          * on all of ast2[456]00, so zero everything else to ensure we only
 731          * enable a single slave address (ast2500 has two, ast2600 has three,
 732          * the enable bits for which are also in this register) so that we don't
 733          * end up with additional phantom devices responding on the bus.
 734          */
 735         addr_reg_val = slave_addr & ASPEED_I2CD_DEV_ADDR_MASK;
 736         writel(addr_reg_val, bus->base + ASPEED_I2C_DEV_ADDR_REG);
 737
 738         /* Turn on slave mode. */
 739         func_ctrl_reg_val = readl(bus->base + ASPEED_I2C_FUN_CTRL_REG);
 740         func_ctrl_reg_val |= ASPEED_I2CD_SLAVE_EN;
 741         writel(func_ctrl_reg_val, bus->base + ASPEED_I2C_FUN_CTRL_REG);
 742 }
 743
 744 static int aspeed_i2c_reg_slave(struct i2c_client *client)
 745 {
 746         struct aspeed_i2c_bus *bus = i2c_get_adapdata(client->adapter);
 747         unsigned long flags;
 748
 749         spin_lock_irqsave(&bus->lock, flags);
 750         if (bus->slave) {
 751                 spin_unlock_irqrestore(&bus->lock, flags);
 752                 return -EINVAL;
 753         }
 754
 755         __aspeed_i2c_reg_slave(bus, client->addr);
 756
 757         bus->slave = client;
 758         bus->slave_state = ASPEED_I2C_SLAVE_INACTIVE;
 759         spin_unlock_irqrestore(&bus->lock, flags);
 760
 761         return 0;
 762 }
 763
 764 static int aspeed_i2c_unreg_slave(struct i2c_client *client)
 765 {
 766         struct aspeed_i2c_bus *bus = i2c_get_adapdata(client->adapter);
 767         u32 func_ctrl_reg_val;
 768         unsigned long flags;
 769
 770         spin_lock_irqsave(&bus->lock, flags);
 771         if (!bus->slave) {
 772                 spin_unlock_irqrestore(&bus->lock, flags);
 773                 return -EINVAL;
 774         }
 775
 776         /* Turn off slave mode. */
 777         func_ctrl_reg_val = readl(bus->base + ASPEED_I2C_FUN_CTRL_REG);
 778         func_ctrl_reg_val &= ~ASPEED_I2CD_SLAVE_EN;
 779         writel(func_ctrl_reg_val, bus->base + ASPEED_I2C_FUN_CTRL_REG);
 780
 781         bus->slave = NULL;
 782         spin_unlock_irqrestore(&bus->lock, flags);
 783
 784         return 0;
 785 }
 786 #endif /* CONFIG_I2C_SLAVE */
 787
 788 static const struct i2c_algorithm aspeed_i2c_algo = {
 789         .master_xfer    = aspeed_i2c_master_xfer,
 790         .functionality  = aspeed_i2c_functionality,
 791 #if IS_ENABLED(CONFIG_I2C_SLAVE)
 792         .reg_slave      = aspeed_i2c_reg_slave,
 793         .unreg_slave    = aspeed_i2c_unreg_slave,
 794 #endif /* CONFIG_I2C_SLAVE */
 795 };
 796
 797 static u32 aspeed_i2c_get_clk_reg_val(struct device *dev,
 798                                       u32 clk_high_low_mask,
 799                                       u32 divisor)
 800 {
 801         u32 base_clk_divisor, clk_high_low_max, clk_high, clk_low, tmp;
 802
 803         /*
 804          * SCL_high and SCL_low represent a value 1 greater than what is stored
 805          * since a zero divider is meaningless. Thus, the max value each can
 806          * store is every bit set + 1. Since SCL_high and SCL_low are added
 807          * together (see below), the max value of both is the max value of one
 808          * them times two.
 809          */
 810         clk_high_low_max = (clk_high_low_mask + 1) * 2;
 811
 812         /*
 813          * The actual clock frequency of SCL is:
 814          *      SCL_freq = APB_freq / (base_freq * (SCL_high + SCL_low))
 815          *               = APB_freq / divisor
 816          * where base_freq is a programmable clock divider; its value is
 817          *      base_freq = 1 << base_clk_divisor
 818          * SCL_high is the number of base_freq clock cycles that SCL stays high
 819          * and SCL_low is the number of base_freq clock cycles that SCL stays
 820          * low for a period of SCL.
 821          * The actual register has a minimum SCL_high and SCL_low minimum of 1;
 822          * thus, they start counting at zero. So
 823          *      SCL_high = clk_high + 1
 824          *      SCL_low  = clk_low + 1
 825          * Thus,
 826          *      SCL_freq = APB_freq /
 827          *              ((1 << base_clk_divisor) * (clk_high + 1 + clk_low + 1))
 828          * The documentation recommends clk_high >= clk_high_max / 2 and
 829          * clk_low >= clk_low_max / 2 - 1 when possible; this last constraint
 830          * gives us the following solution:
 831          */
 832         base_clk_divisor = divisor > clk_high_low_max ?
 833                         ilog2((divisor - 1) / clk_high_low_max) + 1 : 0;
 834
 835         if (base_clk_divisor > ASPEED_I2CD_TIME_BASE_DIVISOR_MASK) {
 836                 base_clk_divisor = ASPEED_I2CD_TIME_BASE_DIVISOR_MASK;
 837                 clk_low = clk_high_low_mask;
 838                 clk_high = clk_high_low_mask;
 839                 dev_err(dev,
 840                         "clamping clock divider: divider requested, %u, is greater than largest possible divider, %u.\n",
 841                         divisor, (1 << base_clk_divisor) * clk_high_low_max);
 842         } else {
 843                 tmp = (divisor + (1 << base_clk_divisor) - 1)
 844                                 >> base_clk_divisor;
 845                 clk_low = tmp / 2;
 846                 clk_high = tmp - clk_low;
 847
 848                 if (clk_high)
 849                         clk_high--;
 850
 851                 if (clk_low)
 852                         clk_low--;
 853         }
 854
 855
 856         return ((clk_high << ASPEED_I2CD_TIME_SCL_HIGH_SHIFT)
 857                 & ASPEED_I2CD_TIME_SCL_HIGH_MASK)
 858                         | ((clk_low << ASPEED_I2CD_TIME_SCL_LOW_SHIFT)
 859                            & ASPEED_I2CD_TIME_SCL_LOW_MASK)
 860                         | (base_clk_divisor
 861                            & ASPEED_I2CD_TIME_BASE_DIVISOR_MASK);
 862 }
 863
 864 static u32 aspeed_i2c_24xx_get_clk_reg_val(struct device *dev, u32 divisor)
 865 {
 866         /*
 867          * clk_high and clk_low are each 3 bits wide, so each can hold a max
 868          * value of 8 giving a clk_high_low_max of 16.
 869          */
 870         return aspeed_i2c_get_clk_reg_val(dev, GENMASK(2, 0), divisor);
 871 }
 872
 873 static u32 aspeed_i2c_25xx_get_clk_reg_val(struct device *dev, u32 divisor)
 874 {
 875         /*
 876          * clk_high and clk_low are each 4 bits wide, so each can hold a max
 877          * value of 16 giving a clk_high_low_max of 32.
 878          */
 879         return aspeed_i2c_get_clk_reg_val(dev, GENMASK(3, 0), divisor);
 880 }
 881
 882 /* precondition: bus.lock has been acquired. */
 883 static int aspeed_i2c_init_clk(struct aspeed_i2c_bus *bus)
 884 {
 885         u32 divisor, clk_reg_val;
 886
 887         divisor = DIV_ROUND_UP(bus->parent_clk_frequency, bus->bus_frequency);
 888         clk_reg_val = readl(bus->base + ASPEED_I2C_AC_TIMING_REG1);
 889         clk_reg_val &= (ASPEED_I2CD_TIME_TBUF_MASK |
 890                         ASPEED_I2CD_TIME_THDSTA_MASK |
 891                         ASPEED_I2CD_TIME_TACST_MASK);
 892         clk_reg_val |= bus->get_clk_reg_val(bus->dev, divisor);
 893         writel(clk_reg_val, bus->base + ASPEED_I2C_AC_TIMING_REG1);
 894         writel(ASPEED_NO_TIMEOUT_CTRL, bus->base + ASPEED_I2C_AC_TIMING_REG2);
 895
 896         return 0;
 897 }
 898
 899 /* precondition: bus.lock has been acquired. */
 900 static int aspeed_i2c_init(struct aspeed_i2c_bus *bus,
 901                              struct platform_device *pdev)
 902 {
 903         u32 fun_ctrl_reg = ASPEED_I2CD_MASTER_EN;
 904         int ret;
 905
 906         /* Disable everything. */
 907         writel(0, bus->base + ASPEED_I2C_FUN_CTRL_REG);
 908
 909         ret = aspeed_i2c_init_clk(bus);
 910         if (ret < 0)
 911                 return ret;
 912
 913         if (of_property_read_bool(pdev->dev.of_node, "multi-master"))
 914                 bus->multi_master = true;
 915         else
 916                 fun_ctrl_reg |= ASPEED_I2CD_MULTI_MASTER_DIS;
 917
 918         /* Enable Master Mode */
 919         writel(readl(bus->base + ASPEED_I2C_FUN_CTRL_REG) | fun_ctrl_reg,
 920                bus->base + ASPEED_I2C_FUN_CTRL_REG);
 921
 922 #if IS_ENABLED(CONFIG_I2C_SLAVE)
 923         /* If slave has already been registered, re-enable it. */
 924         if (bus->slave)
 925                 __aspeed_i2c_reg_slave(bus, bus->slave->addr);
 926 #endif /* CONFIG_I2C_SLAVE */
 927
 928         /* Set interrupt generation of I2C controller */
 929         writel(ASPEED_I2CD_INTR_ALL, bus->base + ASPEED_I2C_INTR_CTRL_REG);
 930
 931         return 0;
 932 }
 933
 934 static int aspeed_i2c_reset(struct aspeed_i2c_bus *bus)
 935 {
 936         struct platform_device *pdev = to_platform_device(bus->dev);
 937         unsigned long flags;
 938         int ret;
 939
 940         spin_lock_irqsave(&bus->lock, flags);
 941
 942         /* Disable and ack all interrupts. */
 943         writel(0, bus->base + ASPEED_I2C_INTR_CTRL_REG);
 944         writel(0xffffffff, bus->base + ASPEED_I2C_INTR_STS_REG);
 945
 946         ret = aspeed_i2c_init(bus, pdev);
 947
 948         spin_unlock_irqrestore(&bus->lock, flags);
 949
 950         return ret;
 951 }
 952
 953 static const struct of_device_id aspeed_i2c_bus_of_table[] = {
 954         {
 955                 .compatible = "aspeed,ast2400-i2c-bus",
 956                 .data = aspeed_i2c_24xx_get_clk_reg_val,
 957         },
 958         {
 959                 .compatible = "aspeed,ast2500-i2c-bus",
 960                 .data = aspeed_i2c_25xx_get_clk_reg_val,
 961         },
 962         {
 963                 .compatible = "aspeed,ast2600-i2c-bus",
 964                 .data = aspeed_i2c_25xx_get_clk_reg_val,
 965         },
 966         { },
 967 };
 968 MODULE_DEVICE_TABLE(of, aspeed_i2c_bus_of_table);
 969
 970 static int aspeed_i2c_probe_bus(struct platform_device *pdev)
 971 {
 972         const struct of_device_id *match;
 973         struct aspeed_i2c_bus *bus;
 974         struct clk *parent_clk;
 975         struct resource *res;
 976         int irq, ret;
 977
 978         bus = devm_kzalloc(&pdev->dev, sizeof(*bus), GFP_KERNEL);
 979         if (!bus)
 980                 return -ENOMEM;
 981
 982         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 983         bus->base = devm_ioremap_resource(&pdev->dev, res);
 984         if (IS_ERR(bus->base))
 985                 return PTR_ERR(bus->base);
 986
 987         parent_clk = devm_clk_get(&pdev->dev, NULL);
 988         if (IS_ERR(parent_clk))
 989                 return PTR_ERR(parent_clk);
 990         bus->parent_clk_frequency = clk_get_rate(parent_clk);
 991         /* We just need the clock rate, we don't actually use the clk object. */
 992         devm_clk_put(&pdev->dev, parent_clk);
 993
 994         bus->rst = devm_reset_control_get_shared(&pdev->dev, NULL);
 995         if (IS_ERR(bus->rst)) {
 996                 dev_err(&pdev->dev,
 997                         "missing or invalid reset controller device tree entry\n");
 998                 return PTR_ERR(bus->rst);
 999         }
1000         reset_control_deassert(bus->rst);
1001
1002         ret = of_property_read_u32(pdev->dev.of_node,
1003                                    "bus-frequency", &bus->bus_frequency);
1004         if (ret < 0) {
1005                 dev_err(&pdev->dev,
1006                         "Could not read bus-frequency property\n");
1007                 bus->bus_frequency = I2C_MAX_STANDARD_MODE_FREQ;
1008         }
1009
1010         match = of_match_node(aspeed_i2c_bus_of_table, pdev->dev.of_node);
1011         if (!match)
1012                 bus->get_clk_reg_val = aspeed_i2c_24xx_get_clk_reg_val;
1013         else
1014                 bus->get_clk_reg_val = (u32 (*)(struct device *, u32))
1015                                 match->data;
1016
1017         /* Initialize the I2C adapter */
1018         spin_lock_init(&bus->lock);
1019         init_completion(&bus->cmd_complete);
1020         bus->adap.owner = THIS_MODULE;
1021         bus->adap.retries = 0;
1022         bus->adap.algo = &aspeed_i2c_algo;
1023         bus->adap.dev.parent = &pdev->dev;
1024         bus->adap.dev.of_node = pdev->dev.of_node;
1025         strscpy(bus->adap.name, pdev->name, sizeof(bus->adap.name));
1026         i2c_set_adapdata(&bus->adap, bus);
1027
1028         bus->dev = &pdev->dev;
1029
1030         /* Clean up any left over interrupt state. */
1031         writel(0, bus->base + ASPEED_I2C_INTR_CTRL_REG);
1032         writel(0xffffffff, bus->base + ASPEED_I2C_INTR_STS_REG);
1033         /*
1034          * bus.lock does not need to be held because the interrupt handler has
1035          * not been enabled yet.
1036          */
1037         ret = aspeed_i2c_init(bus, pdev);
1038         if (ret < 0)
1039                 return ret;
1040
1041         irq = irq_of_parse_and_map(pdev->dev.of_node, 0);
1042         ret = devm_request_irq(&pdev->dev, irq, aspeed_i2c_bus_irq,
1043                                0, dev_name(&pdev->dev), bus);
1044         if (ret < 0)
1045                 return ret;
1046
1047         ret = i2c_add_adapter(&bus->adap);
1048         if (ret < 0)
1049                 return ret;
1050
1051         platform_set_drvdata(pdev, bus);
1052
1053         dev_info(bus->dev, "i2c bus %d registered, irq %d\n",
1054                  bus->adap.nr, irq);
1055
1056         return 0;
1057 }
1058
1059 static int aspeed_i2c_remove_bus(struct platform_device *pdev)
1060 {
1061         struct aspeed_i2c_bus *bus = platform_get_drvdata(pdev);
1062         unsigned long flags;
1063
1064         spin_lock_irqsave(&bus->lock, flags);
1065
1066         /* Disable everything. */
1067         writel(0, bus->base + ASPEED_I2C_FUN_CTRL_REG);
1068         writel(0, bus->base + ASPEED_I2C_INTR_CTRL_REG);
1069
1070         spin_unlock_irqrestore(&bus->lock, flags);
1071
1072         reset_control_assert(bus->rst);
1073
1074         i2c_del_adapter(&bus->adap);
1075
1076         return 0;
1077 }
1078
1079 static struct platform_driver aspeed_i2c_bus_driver = {
1080         .probe          = aspeed_i2c_probe_bus,
1081         .remove         = aspeed_i2c_remove_bus,
1082         .driver         = {
1083                 .name           = "aspeed-i2c-bus",
1084                 .of_match_table = aspeed_i2c_bus_of_table,
1085         },
1086 };
1087 module_platform_driver(aspeed_i2c_bus_driver);
1088
1089 MODULE_AUTHOR("Brendan Higgins <brendanhiggins@google.com>");
1090 MODULE_DESCRIPTION("Aspeed I2C Bus Driver");
1091 MODULE_LICENSE("GPL v2");