LXR linux/drivers/i2c/busses/i2c-axxia.c

   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * This driver implements I2C master functionality using the LSI API2C
   4 * controller.
   5 *
   6 * NOTE: The controller has a limitation in that it can only do transfers of
   7 * maximum 255 bytes at a time. If a larger transfer is attempted, error code
   8 * (-EINVAL) is returned.
   9 */
  10#include <linux/clk.h>
  11#include <linux/clkdev.h>
  12#include <linux/delay.h>
  13#include <linux/err.h>
  14#include <linux/i2c.h>
  15#include <linux/init.h>
  16#include <linux/interrupt.h>
  17#include <linux/module.h>
  18#include <linux/io.h>
  19#include <linux/kernel.h>
  20#include <linux/platform_device.h>
  21
  22#define SCL_WAIT_TIMEOUT_NS 25000000
  23#define I2C_XFER_TIMEOUT    (msecs_to_jiffies(250))
  24#define I2C_STOP_TIMEOUT    (msecs_to_jiffies(100))
  25#define FIFO_SIZE           8
  26#define SEQ_LEN             2
  27
  28#define GLOBAL_CONTROL          0x00
  29#define   GLOBAL_MST_EN         BIT(0)
  30#define   GLOBAL_SLV_EN         BIT(1)
  31#define   GLOBAL_IBML_EN        BIT(2)
  32#define INTERRUPT_STATUS        0x04
  33#define INTERRUPT_ENABLE        0x08
  34#define   INT_SLV               BIT(1)
  35#define   INT_MST               BIT(0)
  36#define WAIT_TIMER_CONTROL      0x0c
  37#define   WT_EN                 BIT(15)
  38#define   WT_VALUE(_x)          ((_x) & 0x7fff)
  39#define IBML_TIMEOUT            0x10
  40#define IBML_LOW_MEXT           0x14
  41#define IBML_LOW_SEXT           0x18
  42#define TIMER_CLOCK_DIV         0x1c
  43#define I2C_BUS_MONITOR         0x20
  44#define   BM_SDAC               BIT(3)
  45#define   BM_SCLC               BIT(2)
  46#define   BM_SDAS               BIT(1)
  47#define   BM_SCLS               BIT(0)
  48#define SOFT_RESET              0x24
  49#define MST_COMMAND             0x28
  50#define   CMD_BUSY              (1<<3)
  51#define   CMD_MANUAL            (0x00 | CMD_BUSY)
  52#define   CMD_AUTO              (0x01 | CMD_BUSY)
  53#define   CMD_SEQUENCE          (0x02 | CMD_BUSY)
  54#define MST_RX_XFER             0x2c
  55#define MST_TX_XFER             0x30
  56#define MST_ADDR_1              0x34
  57#define MST_ADDR_2              0x38
  58#define MST_DATA                0x3c
  59#define MST_TX_FIFO             0x40
  60#define MST_RX_FIFO             0x44
  61#define MST_INT_ENABLE          0x48
  62#define MST_INT_STATUS          0x4c
  63#define   MST_STATUS_RFL        (1 << 13) /* RX FIFO serivce */
  64#define   MST_STATUS_TFL        (1 << 12) /* TX FIFO service */
  65#define   MST_STATUS_SNS        (1 << 11) /* Manual mode done */
  66#define   MST_STATUS_SS         (1 << 10) /* Automatic mode done */
  67#define   MST_STATUS_SCC        (1 << 9)  /* Stop complete */
  68#define   MST_STATUS_IP         (1 << 8)  /* Invalid parameter */
  69#define   MST_STATUS_TSS        (1 << 7)  /* Timeout */
  70#define   MST_STATUS_AL         (1 << 6)  /* Arbitration lost */
  71#define   MST_STATUS_ND         (1 << 5)  /* NAK on data phase */
  72#define   MST_STATUS_NA         (1 << 4)  /* NAK on address phase */
  73#define   MST_STATUS_NAK        (MST_STATUS_NA | \
  74                                 MST_STATUS_ND)
  75#define   MST_STATUS_ERR        (MST_STATUS_NAK | \
  76                                 MST_STATUS_AL  | \
  77                                 MST_STATUS_IP)
  78#define MST_TX_BYTES_XFRD       0x50
  79#define MST_RX_BYTES_XFRD       0x54
  80#define SLV_ADDR_DEC_CTL        0x58
  81#define   SLV_ADDR_DEC_GCE      BIT(0)  /* ACK to General Call Address from own master (loopback) */
  82#define   SLV_ADDR_DEC_OGCE     BIT(1)  /* ACK to General Call Address from external masters */
  83#define   SLV_ADDR_DEC_SA1E     BIT(2)  /* ACK to addr_1 enabled */
  84#define   SLV_ADDR_DEC_SA1M     BIT(3)  /* 10-bit addressing for addr_1 enabled */
  85#define   SLV_ADDR_DEC_SA2E     BIT(4)  /* ACK to addr_2 enabled */
  86#define   SLV_ADDR_DEC_SA2M     BIT(5)  /* 10-bit addressing for addr_2 enabled */
  87#define SLV_ADDR_1              0x5c
  88#define SLV_ADDR_2              0x60
  89#define SLV_RX_CTL              0x64
  90#define   SLV_RX_ACSA1          BIT(0)  /* Generate ACK for writes to addr_1 */
  91#define   SLV_RX_ACSA2          BIT(1)  /* Generate ACK for writes to addr_2 */
  92#define   SLV_RX_ACGCA          BIT(2)  /* ACK data phase transfers to General Call Address */
  93#define SLV_DATA                0x68
  94#define SLV_RX_FIFO             0x6c
  95#define   SLV_FIFO_DV1          BIT(0)  /* Data Valid for addr_1 */
  96#define   SLV_FIFO_DV2          BIT(1)  /* Data Valid for addr_2 */
  97#define   SLV_FIFO_AS           BIT(2)  /* (N)ACK Sent */
  98#define   SLV_FIFO_TNAK         BIT(3)  /* Timeout NACK */
  99#define   SLV_FIFO_STRC         BIT(4)  /* First byte after start condition received */
 100#define   SLV_FIFO_RSC          BIT(5)  /* Repeated Start Condition */
 101#define   SLV_FIFO_STPC         BIT(6)  /* Stop Condition */
 102#define   SLV_FIFO_DV           (SLV_FIFO_DV1 | SLV_FIFO_DV2)
 103#define SLV_INT_ENABLE          0x70
 104#define SLV_INT_STATUS          0x74
 105#define   SLV_STATUS_RFH        BIT(0)  /* FIFO service */
 106#define   SLV_STATUS_WTC        BIT(1)  /* Write transfer complete */
 107#define   SLV_STATUS_SRS1       BIT(2)  /* Slave read from addr 1 */
 108#define   SLV_STATUS_SRRS1      BIT(3)  /* Repeated start from addr 1 */
 109#define   SLV_STATUS_SRND1      BIT(4)  /* Read request not following start condition */
 110#define   SLV_STATUS_SRC1       BIT(5)  /* Read canceled */
 111#define   SLV_STATUS_SRAT1      BIT(6)  /* Slave Read timed out */
 112#define   SLV_STATUS_SRDRE1     BIT(7)  /* Data written after timed out */
 113#define SLV_READ_DUMMY          0x78
 114#define SCL_HIGH_PERIOD         0x80
 115#define SCL_LOW_PERIOD          0x84
 116#define SPIKE_FLTR_LEN          0x88
 117#define SDA_SETUP_TIME          0x8c
 118#define SDA_HOLD_TIME           0x90
 119
 120/**
 121 * axxia_i2c_dev - I2C device context
 122 * @base: pointer to register struct
 123 * @msg: pointer to current message
 124 * @msg_r: pointer to current read message (sequence transfer)
 125 * @msg_xfrd: number of bytes transferred in tx_fifo
 126 * @msg_xfrd_r: number of bytes transferred in rx_fifo
 127 * @msg_err: error code for completed message
 128 * @msg_complete: xfer completion object
 129 * @dev: device reference
 130 * @adapter: core i2c abstraction
 131 * @i2c_clk: clock reference for i2c input clock
 132 * @bus_clk_rate: current i2c bus clock rate
 133 * @last: a flag indicating is this is last message in transfer
 134 */
 135struct axxia_i2c_dev {
 136        void __iomem *base;
 137        struct i2c_msg *msg;
 138        struct i2c_msg *msg_r;
 139        size_t msg_xfrd;
 140        size_t msg_xfrd_r;
 141        int msg_err;
 142        struct completion msg_complete;
 143        struct device *dev;
 144        struct i2c_adapter adapter;
 145        struct clk *i2c_clk;
 146        u32 bus_clk_rate;
 147        bool last;
 148        struct i2c_client *slave;
 149        int irq;
 150};
 151
 152static void i2c_int_disable(struct axxia_i2c_dev *idev, u32 mask)
 153{
 154        u32 int_en;
 155
 156        int_en = readl(idev->base + MST_INT_ENABLE);
 157        writel(int_en & ~mask, idev->base + MST_INT_ENABLE);
 158}
 159
 160static void i2c_int_enable(struct axxia_i2c_dev *idev, u32 mask)
 161{
 162        u32 int_en;
 163
 164        int_en = readl(idev->base + MST_INT_ENABLE);
 165        writel(int_en | mask, idev->base + MST_INT_ENABLE);
 166}
 167
 168/**
 169 * ns_to_clk - Convert time (ns) to clock cycles for the given clock frequency.
 170 */
 171static u32 ns_to_clk(u64 ns, u32 clk_mhz)
 172{
 173        return div_u64(ns * clk_mhz, 1000);
 174}
 175
 176static int axxia_i2c_init(struct axxia_i2c_dev *idev)
 177{
 178        u32 divisor = clk_get_rate(idev->i2c_clk) / idev->bus_clk_rate;
 179        u32 clk_mhz = clk_get_rate(idev->i2c_clk) / 1000000;
 180        u32 t_setup;
 181        u32 t_high, t_low;
 182        u32 tmo_clk;
 183        u32 prescale;
 184        unsigned long timeout;
 185
 186        dev_dbg(idev->dev, "rate=%uHz per_clk=%uMHz -> ratio=1:%u\n",
 187                idev->bus_clk_rate, clk_mhz, divisor);
 188
 189        /* Reset controller */
 190        writel(0x01, idev->base + SOFT_RESET);
 191        timeout = jiffies + msecs_to_jiffies(100);
 192        while (readl(idev->base + SOFT_RESET) & 1) {
 193                if (time_after(jiffies, timeout)) {
 194                        dev_warn(idev->dev, "Soft reset failed\n");
 195                        break;
 196                }
 197        }
 198
 199        /* Enable Master Mode */
 200        writel(0x1, idev->base + GLOBAL_CONTROL);
 201
 202        if (idev->bus_clk_rate <= I2C_MAX_STANDARD_MODE_FREQ) {
 203                /* Standard mode SCL 50/50, tSU:DAT = 250 ns */
 204                t_high = divisor * 1 / 2;
 205                t_low = divisor * 1 / 2;
 206                t_setup = ns_to_clk(250, clk_mhz);
 207        } else {
 208                /* Fast mode SCL 33/66, tSU:DAT = 100 ns */
 209                t_high = divisor * 1 / 3;
 210                t_low = divisor * 2 / 3;
 211                t_setup = ns_to_clk(100, clk_mhz);
 212        }
 213
 214        /* SCL High Time */
 215        writel(t_high, idev->base + SCL_HIGH_PERIOD);
 216        /* SCL Low Time */
 217        writel(t_low, idev->base + SCL_LOW_PERIOD);
 218        /* SDA Setup Time */
 219        writel(t_setup, idev->base + SDA_SETUP_TIME);
 220        /* SDA Hold Time, 300ns */
 221        writel(ns_to_clk(300, clk_mhz), idev->base + SDA_HOLD_TIME);
 222        /* Filter <50ns spikes */
 223        writel(ns_to_clk(50, clk_mhz), idev->base + SPIKE_FLTR_LEN);
 224
 225        /* Configure Time-Out Registers */
 226        tmo_clk = ns_to_clk(SCL_WAIT_TIMEOUT_NS, clk_mhz);
 227
 228        /* Find prescaler value that makes tmo_clk fit in 15-bits counter. */
 229        for (prescale = 0; prescale < 15; ++prescale) {
 230                if (tmo_clk <= 0x7fff)
 231                        break;
 232                tmo_clk >>= 1;
 233        }
 234        if (tmo_clk > 0x7fff)
 235                tmo_clk = 0x7fff;
 236
 237        /* Prescale divider (log2) */
 238        writel(prescale, idev->base + TIMER_CLOCK_DIV);
 239        /* Timeout in divided clocks */
 240        writel(WT_EN | WT_VALUE(tmo_clk), idev->base + WAIT_TIMER_CONTROL);
 241
 242        /* Mask all master interrupt bits */
 243        i2c_int_disable(idev, ~0);
 244
 245        /* Interrupt enable */
 246        writel(0x01, idev->base + INTERRUPT_ENABLE);
 247
 248        return 0;
 249}
 250
 251static int i2c_m_rd(const struct i2c_msg *msg)
 252{
 253        return (msg->flags & I2C_M_RD) != 0;
 254}
 255
 256static int i2c_m_ten(const struct i2c_msg *msg)
 257{
 258        return (msg->flags & I2C_M_TEN) != 0;
 259}
 260
 261static int i2c_m_recv_len(const struct i2c_msg *msg)
 262{
 263        return (msg->flags & I2C_M_RECV_LEN) != 0;
 264}
 265
 266/**
 267 * axxia_i2c_empty_rx_fifo - Fetch data from RX FIFO and update SMBus block
 268 * transfer length if this is the first byte of such a transfer.
 269 */
 270static int axxia_i2c_empty_rx_fifo(struct axxia_i2c_dev *idev)
 271{
 272        struct i2c_msg *msg = idev->msg_r;
 273        size_t rx_fifo_avail = readl(idev->base + MST_RX_FIFO);
 274        int bytes_to_transfer = min(rx_fifo_avail, msg->len - idev->msg_xfrd_r);
 275
 276        while (bytes_to_transfer-- > 0) {
 277                int c = readl(idev->base + MST_DATA);
 278
 279                if (idev->msg_xfrd_r == 0 && i2c_m_recv_len(msg)) {
 280                        /*
 281                         * Check length byte for SMBus block read
 282                         */
 283                        if (c <= 0 || c > I2C_SMBUS_BLOCK_MAX) {
 284                                idev->msg_err = -EPROTO;
 285                                i2c_int_disable(idev, ~MST_STATUS_TSS);
 286                                complete(&idev->msg_complete);
 287                                break;
 288                        }
 289                        msg->len = 1 + c;
 290                        writel(msg->len, idev->base + MST_RX_XFER);
 291                }
 292                msg->buf[idev->msg_xfrd_r++] = c;
 293        }
 294
 295        return 0;
 296}
 297
 298/**
 299 * axxia_i2c_fill_tx_fifo - Fill TX FIFO from current message buffer.
 300 * @return: Number of bytes left to transfer.
 301 */
 302static int axxia_i2c_fill_tx_fifo(struct axxia_i2c_dev *idev)
 303{
 304        struct i2c_msg *msg = idev->msg;
 305        size_t tx_fifo_avail = FIFO_SIZE - readl(idev->base + MST_TX_FIFO);
 306        int bytes_to_transfer = min(tx_fifo_avail, msg->len - idev->msg_xfrd);
 307        int ret = msg->len - idev->msg_xfrd - bytes_to_transfer;
 308
 309        while (bytes_to_transfer-- > 0)
 310                writel(msg->buf[idev->msg_xfrd++], idev->base + MST_DATA);
 311
 312        return ret;
 313}
 314
 315static void axxia_i2c_slv_fifo_event(struct axxia_i2c_dev *idev)
 316{
 317        u32 fifo_status = readl(idev->base + SLV_RX_FIFO);
 318        u8 val;
 319
 320        dev_dbg(idev->dev, "slave irq fifo_status=0x%x\n", fifo_status);
 321
 322        if (fifo_status & SLV_FIFO_DV1) {
 323                if (fifo_status & SLV_FIFO_STRC)
 324                        i2c_slave_event(idev->slave,
 325                                        I2C_SLAVE_WRITE_REQUESTED, &val);
 326
 327                val = readl(idev->base + SLV_DATA);
 328                i2c_slave_event(idev->slave, I2C_SLAVE_WRITE_RECEIVED, &val);
 329        }
 330        if (fifo_status & SLV_FIFO_STPC) {
 331                readl(idev->base + SLV_DATA); /* dummy read */
 332                i2c_slave_event(idev->slave, I2C_SLAVE_STOP, &val);
 333        }
 334        if (fifo_status & SLV_FIFO_RSC)
 335                readl(idev->base + SLV_DATA); /* dummy read */
 336}
 337
 338static irqreturn_t axxia_i2c_slv_isr(struct axxia_i2c_dev *idev)
 339{
 340        u32 status = readl(idev->base + SLV_INT_STATUS);
 341        u8 val;
 342
 343        dev_dbg(idev->dev, "slave irq status=0x%x\n", status);
 344
 345        if (status & SLV_STATUS_RFH)
 346                axxia_i2c_slv_fifo_event(idev);
 347        if (status & SLV_STATUS_SRS1) {
 348                i2c_slave_event(idev->slave, I2C_SLAVE_READ_REQUESTED, &val);
 349                writel(val, idev->base + SLV_DATA);
 350        }
 351        if (status & SLV_STATUS_SRND1) {
 352                i2c_slave_event(idev->slave, I2C_SLAVE_READ_PROCESSED, &val);
 353                writel(val, idev->base + SLV_DATA);
 354        }
 355        if (status & SLV_STATUS_SRC1)
 356                i2c_slave_event(idev->slave, I2C_SLAVE_STOP, &val);
 357
 358        writel(INT_SLV, idev->base + INTERRUPT_STATUS);
 359        return IRQ_HANDLED;
 360}
 361
 362static irqreturn_t axxia_i2c_isr(int irq, void *_dev)
 363{
 364        struct axxia_i2c_dev *idev = _dev;
 365        irqreturn_t ret = IRQ_NONE;
 366        u32 status;
 367
 368        status = readl(idev->base + INTERRUPT_STATUS);
 369
 370        if (status & INT_SLV)
 371                ret = axxia_i2c_slv_isr(idev);
 372        if (!(status & INT_MST))
 373                return ret;
 374
 375        /* Read interrupt status bits */
 376        status = readl(idev->base + MST_INT_STATUS);
 377
 378        if (!idev->msg) {
 379                dev_warn(idev->dev, "unexpected interrupt\n");
 380                goto out;
 381        }
 382
 383        /* RX FIFO needs service? */
 384        if (i2c_m_rd(idev->msg_r) && (status & MST_STATUS_RFL))
 385                axxia_i2c_empty_rx_fifo(idev);
 386
 387        /* TX FIFO needs service? */
 388        if (!i2c_m_rd(idev->msg) && (status & MST_STATUS_TFL)) {
 389                if (axxia_i2c_fill_tx_fifo(idev) == 0)
 390                        i2c_int_disable(idev, MST_STATUS_TFL);
 391        }
 392
 393        if (unlikely(status & MST_STATUS_ERR)) {
 394                /* Transfer error */
 395                i2c_int_disable(idev, ~0);
 396                if (status & MST_STATUS_AL)
 397                        idev->msg_err = -EAGAIN;
 398                else if (status & MST_STATUS_NAK)
 399                        idev->msg_err = -ENXIO;
 400                else
 401                        idev->msg_err = -EIO;
 402                dev_dbg(idev->dev, "error %#x, addr=%#x rx=%u/%u tx=%u/%u\n",
 403                        status,
 404                        idev->msg->addr,
 405                        readl(idev->base + MST_RX_BYTES_XFRD),
 406                        readl(idev->base + MST_RX_XFER),
 407                        readl(idev->base + MST_TX_BYTES_XFRD),
 408                        readl(idev->base + MST_TX_XFER));
 409                complete(&idev->msg_complete);
 410        } else if (status & MST_STATUS_SCC) {
 411                /* Stop completed */
 412                i2c_int_disable(idev, ~MST_STATUS_TSS);
 413                complete(&idev->msg_complete);
 414        } else if (status & (MST_STATUS_SNS | MST_STATUS_SS)) {
 415                /* Transfer done */
 416                int mask = idev->last ? ~0 : ~MST_STATUS_TSS;
 417
 418                i2c_int_disable(idev, mask);
 419                if (i2c_m_rd(idev->msg_r) && idev->msg_xfrd_r < idev->msg_r->len)
 420                        axxia_i2c_empty_rx_fifo(idev);
 421                complete(&idev->msg_complete);
 422        } else if (status & MST_STATUS_TSS) {
 423                /* Transfer timeout */
 424                idev->msg_err = -ETIMEDOUT;
 425                i2c_int_disable(idev, ~MST_STATUS_TSS);
 426                complete(&idev->msg_complete);
 427        }
 428
 429out:
 430        /* Clear interrupt */
 431        writel(INT_MST, idev->base + INTERRUPT_STATUS);
 432
 433        return IRQ_HANDLED;
 434}
 435
 436static void axxia_i2c_set_addr(struct axxia_i2c_dev *idev, struct i2c_msg *msg)
 437{
 438        u32 addr_1, addr_2;
 439
 440        if (i2c_m_ten(msg)) {
 441                /* 10-bit address
 442                 *   addr_1: 5'b11110 | addr[9:8] | (R/nW)
 443                 *   addr_2: addr[7:0]
 444                 */
 445                addr_1 = 0xF0 | ((msg->addr >> 7) & 0x06);
 446                if (i2c_m_rd(msg))
 447                        addr_1 |= 1;    /* Set the R/nW bit of the address */
 448                addr_2 = msg->addr & 0xFF;
 449        } else {
 450                /* 7-bit address
 451                 *   addr_1: addr[6:0] | (R/nW)
 452                 *   addr_2: dont care
 453                 */
 454                addr_1 = i2c_8bit_addr_from_msg(msg);
 455                addr_2 = 0;
 456        }
 457
 458        writel(addr_1, idev->base + MST_ADDR_1);
 459        writel(addr_2, idev->base + MST_ADDR_2);
 460}
 461
 462/* The NAK interrupt will be sent _before_ issuing STOP command
 463 * so the controller might still be busy processing it. No
 464 * interrupt will be sent at the end so we have to poll for it
 465 */
 466static int axxia_i2c_handle_seq_nak(struct axxia_i2c_dev *idev)
 467{
 468        unsigned long timeout = jiffies + I2C_XFER_TIMEOUT;
 469
 470        do {
 471                if ((readl(idev->base + MST_COMMAND) & CMD_BUSY) == 0)
 472                        return 0;
 473                usleep_range(1, 100);
 474        } while (time_before(jiffies, timeout));
 475
 476        return -ETIMEDOUT;
 477}
 478
 479static int axxia_i2c_xfer_seq(struct axxia_i2c_dev *idev, struct i2c_msg msgs[])
 480{
 481        u32 int_mask = MST_STATUS_ERR | MST_STATUS_SS | MST_STATUS_RFL;
 482        u32 rlen = i2c_m_recv_len(&msgs[1]) ? I2C_SMBUS_BLOCK_MAX : msgs[1].len;
 483        unsigned long time_left;
 484
 485        axxia_i2c_set_addr(idev, &msgs[0]);
 486
 487        writel(msgs[0].len, idev->base + MST_TX_XFER);
 488        writel(rlen, idev->base + MST_RX_XFER);
 489
 490        idev->msg = &msgs[0];
 491        idev->msg_r = &msgs[1];
 492        idev->msg_xfrd = 0;
 493        idev->msg_xfrd_r = 0;
 494        idev->last = true;
 495        axxia_i2c_fill_tx_fifo(idev);
 496
 497        writel(CMD_SEQUENCE, idev->base + MST_COMMAND);
 498
 499        reinit_completion(&idev->msg_complete);
 500        i2c_int_enable(idev, int_mask);
 501
 502        time_left = wait_for_completion_timeout(&idev->msg_complete,
 503                                                I2C_XFER_TIMEOUT);
 504
 505        if (idev->msg_err == -ENXIO) {
 506                if (axxia_i2c_handle_seq_nak(idev))
 507                        axxia_i2c_init(idev);
 508        } else if (readl(idev->base + MST_COMMAND) & CMD_BUSY) {
 509                dev_warn(idev->dev, "busy after xfer\n");
 510        }
 511
 512        if (time_left == 0) {
 513                idev->msg_err = -ETIMEDOUT;
 514                i2c_recover_bus(&idev->adapter);
 515                axxia_i2c_init(idev);
 516        }
 517
 518        if (unlikely(idev->msg_err) && idev->msg_err != -ENXIO)
 519                axxia_i2c_init(idev);
 520
 521        return idev->msg_err;
 522}
 523
 524static int axxia_i2c_xfer_msg(struct axxia_i2c_dev *idev, struct i2c_msg *msg,
 525                              bool last)
 526{
 527        u32 int_mask = MST_STATUS_ERR;
 528        u32 rx_xfer, tx_xfer;
 529        unsigned long time_left;
 530        unsigned int wt_value;
 531
 532        idev->msg = msg;
 533        idev->msg_r = msg;
 534        idev->msg_xfrd = 0;
 535        idev->msg_xfrd_r = 0;
 536        idev->last = last;
 537        reinit_completion(&idev->msg_complete);
 538
 539        axxia_i2c_set_addr(idev, msg);
 540
 541        if (i2c_m_rd(msg)) {
 542                /* I2C read transfer */
 543                rx_xfer = i2c_m_recv_len(msg) ? I2C_SMBUS_BLOCK_MAX : msg->len;
 544                tx_xfer = 0;
 545        } else {
 546                /* I2C write transfer */
 547                rx_xfer = 0;
 548                tx_xfer = msg->len;
 549        }
 550
 551        writel(rx_xfer, idev->base + MST_RX_XFER);
 552        writel(tx_xfer, idev->base + MST_TX_XFER);
 553
 554        if (i2c_m_rd(msg))
 555                int_mask |= MST_STATUS_RFL;
 556        else if (axxia_i2c_fill_tx_fifo(idev) != 0)
 557                int_mask |= MST_STATUS_TFL;
 558
 559        wt_value = WT_VALUE(readl(idev->base + WAIT_TIMER_CONTROL));
 560        /* Disable wait timer temporarly */
 561        writel(wt_value, idev->base + WAIT_TIMER_CONTROL);
 562        /* Check if timeout error happened */
 563        if (idev->msg_err)
 564                goto out;
 565
 566        if (!last) {
 567                writel(CMD_MANUAL, idev->base + MST_COMMAND);
 568                int_mask |= MST_STATUS_SNS;
 569        } else {
 570                writel(CMD_AUTO, idev->base + MST_COMMAND);
 571                int_mask |= MST_STATUS_SS;
 572        }
 573
 574        writel(WT_EN | wt_value, idev->base + WAIT_TIMER_CONTROL);
 575
 576        i2c_int_enable(idev, int_mask);
 577
 578        time_left = wait_for_completion_timeout(&idev->msg_complete,
 579                                              I2C_XFER_TIMEOUT);
 580
 581        i2c_int_disable(idev, int_mask);
 582
 583        if (readl(idev->base + MST_COMMAND) & CMD_BUSY)
 584                dev_warn(idev->dev, "busy after xfer\n");
 585
 586        if (time_left == 0) {
 587                idev->msg_err = -ETIMEDOUT;
 588                i2c_recover_bus(&idev->adapter);
 589                axxia_i2c_init(idev);
 590        }
 591
 592out:
 593        if (unlikely(idev->msg_err) && idev->msg_err != -ENXIO &&
 594                        idev->msg_err != -ETIMEDOUT)
 595                axxia_i2c_init(idev);
 596
 597        return idev->msg_err;
 598}
 599
 600/* This function checks if the msgs[] array contains messages compatible with
 601 * Sequence mode of operation. This mode assumes there will be exactly one
 602 * write of non-zero length followed by exactly one read of non-zero length,
 603 * both targeted at the same client device.
 604 */
 605static bool axxia_i2c_sequence_ok(struct i2c_msg msgs[], int num)
 606{
 607        return num == SEQ_LEN && !i2c_m_rd(&msgs[0]) && i2c_m_rd(&msgs[1]) &&
 608               msgs[0].len > 0 && msgs[0].len <= FIFO_SIZE &&
 609               msgs[1].len > 0 && msgs[0].addr == msgs[1].addr;
 610}
 611
 612static int
 613axxia_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg msgs[], int num)
 614{
 615        struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
 616        int i;
 617        int ret = 0;
 618
 619        idev->msg_err = 0;
 620
 621        if (axxia_i2c_sequence_ok(msgs, num)) {
 622                ret = axxia_i2c_xfer_seq(idev, msgs);
 623                return ret ? : SEQ_LEN;
 624        }
 625
 626        i2c_int_enable(idev, MST_STATUS_TSS);
 627
 628        for (i = 0; ret == 0 && i < num; ++i)
 629                ret = axxia_i2c_xfer_msg(idev, &msgs[i], i == (num - 1));
 630
 631        return ret ? : i;
 632}
 633
 634static int axxia_i2c_get_scl(struct i2c_adapter *adap)
 635{
 636        struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
 637
 638        return !!(readl(idev->base + I2C_BUS_MONITOR) & BM_SCLS);
 639}
 640
 641static void axxia_i2c_set_scl(struct i2c_adapter *adap, int val)
 642{
 643        struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
 644        u32 tmp;
 645
 646        /* Preserve SDA Control */
 647        tmp = readl(idev->base + I2C_BUS_MONITOR) & BM_SDAC;
 648        if (!val)
 649                tmp |= BM_SCLC;
 650        writel(tmp, idev->base + I2C_BUS_MONITOR);
 651}
 652
 653static int axxia_i2c_get_sda(struct i2c_adapter *adap)
 654{
 655        struct axxia_i2c_dev *idev = i2c_get_adapdata(adap);
 656
 657        return !!(readl(idev->base + I2C_BUS_MONITOR) & BM_SDAS);
 658}
 659
 660static struct i2c_bus_recovery_info axxia_i2c_recovery_info = {
 661        .recover_bus = i2c_generic_scl_recovery,
 662        .get_scl = axxia_i2c_get_scl,
 663        .set_scl = axxia_i2c_set_scl,
 664        .get_sda = axxia_i2c_get_sda,
 665};
 666
 667static u32 axxia_i2c_func(struct i2c_adapter *adap)
 668{
 669        u32 caps = (I2C_FUNC_I2C | I2C_FUNC_10BIT_ADDR |
 670                    I2C_FUNC_SMBUS_EMUL | I2C_FUNC_SMBUS_BLOCK_DATA);
 671        return caps;
 672}
 673
 674static int axxia_i2c_reg_slave(struct i2c_client *slave)
 675{
 676        struct axxia_i2c_dev *idev = i2c_get_adapdata(slave->adapter);
 677        u32 slv_int_mask = SLV_STATUS_RFH;
 678        u32 dec_ctl;
 679
 680        if (idev->slave)
 681                return -EBUSY;
 682
 683        idev->slave = slave;
 684
 685        /* Enable slave mode as well */
 686        writel(GLOBAL_MST_EN | GLOBAL_SLV_EN, idev->base + GLOBAL_CONTROL);
 687        writel(INT_MST | INT_SLV, idev->base + INTERRUPT_ENABLE);
 688
 689        /* Set slave address */
 690        dec_ctl = SLV_ADDR_DEC_SA1E;
 691        if (slave->flags & I2C_CLIENT_TEN)
 692                dec_ctl |= SLV_ADDR_DEC_SA1M;
 693
 694        writel(SLV_RX_ACSA1, idev->base + SLV_RX_CTL);
 695        writel(dec_ctl, idev->base + SLV_ADDR_DEC_CTL);
 696        writel(slave->addr, idev->base + SLV_ADDR_1);
 697
 698        /* Enable interrupts */
 699        slv_int_mask |= SLV_STATUS_SRS1 | SLV_STATUS_SRRS1 | SLV_STATUS_SRND1;
 700        slv_int_mask |= SLV_STATUS_SRC1;
 701        writel(slv_int_mask, idev->base + SLV_INT_ENABLE);
 702
 703        return 0;
 704}
 705
 706static int axxia_i2c_unreg_slave(struct i2c_client *slave)
 707{
 708        struct axxia_i2c_dev *idev = i2c_get_adapdata(slave->adapter);
 709
 710        /* Disable slave mode */
 711        writel(GLOBAL_MST_EN, idev->base + GLOBAL_CONTROL);
 712        writel(INT_MST, idev->base + INTERRUPT_ENABLE);
 713
 714        synchronize_irq(idev->irq);
 715
 716        idev->slave = NULL;
 717
 718        return 0;
 719}
 720
 721static const struct i2c_algorithm axxia_i2c_algo = {
 722        .master_xfer = axxia_i2c_xfer,
 723        .functionality = axxia_i2c_func,
 724        .reg_slave = axxia_i2c_reg_slave,
 725        .unreg_slave = axxia_i2c_unreg_slave,
 726};
 727
 728static const struct i2c_adapter_quirks axxia_i2c_quirks = {
 729        .max_read_len = 255,
 730        .max_write_len = 255,
 731};
 732
 733static int axxia_i2c_probe(struct platform_device *pdev)
 734{
 735        struct device_node *np = pdev->dev.of_node;
 736        struct axxia_i2c_dev *idev = NULL;
 737        void __iomem *base;
 738        int ret = 0;
 739
 740        idev = devm_kzalloc(&pdev->dev, sizeof(*idev), GFP_KERNEL);
 741        if (!idev)
 742                return -ENOMEM;
 743
 744        base = devm_platform_ioremap_resource(pdev, 0);
 745        if (IS_ERR(base))
 746                return PTR_ERR(base);
 747
 748        idev->irq = platform_get_irq(pdev, 0);
 749        if (idev->irq < 0)
 750                return idev->irq;
 751
 752        idev->i2c_clk = devm_clk_get(&pdev->dev, "i2c");
 753        if (IS_ERR(idev->i2c_clk)) {
 754                dev_err(&pdev->dev, "missing clock\n");
 755                return PTR_ERR(idev->i2c_clk);
 756        }
 757
 758        idev->base = base;
 759        idev->dev = &pdev->dev;
 760        init_completion(&idev->msg_complete);
 761
 762        of_property_read_u32(np, "clock-frequency", &idev->bus_clk_rate);
 763        if (idev->bus_clk_rate == 0)
 764                idev->bus_clk_rate = I2C_MAX_STANDARD_MODE_FREQ;        /* default clock rate */
 765
 766        ret = clk_prepare_enable(idev->i2c_clk);
 767        if (ret) {
 768                dev_err(&pdev->dev, "failed to enable clock\n");
 769                return ret;
 770        }
 771
 772        ret = axxia_i2c_init(idev);
 773        if (ret) {
 774                dev_err(&pdev->dev, "failed to initialize\n");
 775                goto error_disable_clk;
 776        }
 777
 778        ret = devm_request_irq(&pdev->dev, idev->irq, axxia_i2c_isr, 0,
 779                               pdev->name, idev);
 780        if (ret) {
 781                dev_err(&pdev->dev, "failed to claim IRQ%d\n", idev->irq);
 782                goto error_disable_clk;
 783        }
 784
 785        i2c_set_adapdata(&idev->adapter, idev);
 786        strlcpy(idev->adapter.name, pdev->name, sizeof(idev->adapter.name));
 787        idev->adapter.owner = THIS_MODULE;
 788        idev->adapter.algo = &axxia_i2c_algo;
 789        idev->adapter.bus_recovery_info = &axxia_i2c_recovery_info;
 790        idev->adapter.quirks = &axxia_i2c_quirks;
 791        idev->adapter.dev.parent = &pdev->dev;
 792        idev->adapter.dev.of_node = pdev->dev.of_node;
 793
 794        platform_set_drvdata(pdev, idev);
 795
 796        ret = i2c_add_adapter(&idev->adapter);
 797        if (ret)
 798                goto error_disable_clk;
 799
 800        return 0;
 801
 802error_disable_clk:
 803        clk_disable_unprepare(idev->i2c_clk);
 804        return ret;
 805}
 806
 807static int axxia_i2c_remove(struct platform_device *pdev)
 808{
 809        struct axxia_i2c_dev *idev = platform_get_drvdata(pdev);
 810
 811        clk_disable_unprepare(idev->i2c_clk);
 812        i2c_del_adapter(&idev->adapter);
 813
 814        return 0;
 815}
 816
 817/* Match table for of_platform binding */
 818static const struct of_device_id axxia_i2c_of_match[] = {
 819        { .compatible = "lsi,api2c", },
 820        {},
 821};
 822
 823MODULE_DEVICE_TABLE(of, axxia_i2c_of_match);
 824
 825static struct platform_driver axxia_i2c_driver = {
 826        .probe = axxia_i2c_probe,
 827        .remove = axxia_i2c_remove,
 828        .driver = {
 829                .name = "axxia-i2c",
 830                .of_match_table = axxia_i2c_of_match,
 831        },
 832};
 833
 834module_platform_driver(axxia_i2c_driver);
 835
 836MODULE_DESCRIPTION("Axxia I2C Bus driver");
 837MODULE_AUTHOR("Anders Berg <anders.berg@lsi.com>");
 838MODULE_LICENSE("GPL v2");
 839