drivers/i2c/busses/i2c-imx.c

   1 /*
   2  *      Copyright (C) 2002 Motorola GSG-China
   3  *
   4  *      This program is free software; you can redistribute it and/or
   5  *      modify it under the terms of the GNU General Public License
   6  *      as published by the Free Software Foundation; either version 2
   7  *      of the License, or (at your option) any later version.
   8  *
   9  *      This program is distributed in the hope that it will be useful,
  10  *      but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  *      MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  *      GNU General Public License for more details.
  13  *
  14  *      You should have received a copy of the GNU General Public License
  15  *      along with this program; if not, write to the Free Software
  16  *      Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307,
  17  *      USA.
  18  *
  19  * Author:
  20  *      Darius Augulis, Teltonika Inc.
  21  *
  22  * Desc.:
  23  *      Implementation of I2C Adapter/Algorithm Driver
  24  *      for I2C Bus integrated in Freescale i.MX/MXC processors
  25  *
  26  *      Derived from Motorola GSG China I2C example driver
  27  *
  28  *      Copyright (C) 2005 Torsten Koschorrek <koschorrek at synertronixx.de
  29  *      Copyright (C) 2005 Matthias Blaschke <blaschke at synertronixx.de
  30  *      Copyright (C) 2007 RightHand Technologies, Inc.
  31  *      Copyright (C) 2008 Darius Augulis <darius.augulis at teltonika.lt>
  32  *
  33  *      Copyright 2013 Freescale Semiconductor, Inc.
  34  *
  35  */
  36
  37 /** Includes *******************************************************************
  38 *******************************************************************************/
  39
  40 #include <linux/init.h>
  41 #include <linux/kernel.h>
  42 #include <linux/module.h>
  43 #include <linux/errno.h>
  44 #include <linux/err.h>
  45 #include <linux/interrupt.h>
  46 #include <linux/delay.h>
  47 #include <linux/i2c.h>
  48 #include <linux/io.h>
  49 #include <linux/sched.h>
  50 #include <linux/platform_device.h>
  51 #include <linux/clk.h>
  52 #include <linux/slab.h>
  53 #include <linux/of.h>
  54 #include <linux/of_device.h>
  55 #include <linux/platform_data/i2c-imx.h>
  56
  57 /** Defines ********************************************************************
  58 *******************************************************************************/
  59
  60 /* This will be the driver name the kernel reports */
  61 #define DRIVER_NAME "imx-i2c"
  62
  63 /* Default value */
  64 #define IMX_I2C_BIT_RATE        100000  /* 100kHz */
  65
  66 /* IMX I2C registers:
  67  * the I2C register offset is different between SoCs,
  68  * to provid support for all these chips, split the
  69  * register offset into a fixed base address and a
  70  * variable shift value, then the full register offset
  71  * will be calculated by
  72  * reg_off = ( reg_base_addr << reg_shift)
  73  */
  74 #define IMX_I2C_IADR    0x00    /* i2c slave address */
  75 #define IMX_I2C_IFDR    0x01    /* i2c frequency divider */
  76 #define IMX_I2C_I2CR    0x02    /* i2c control */
  77 #define IMX_I2C_I2SR    0x03    /* i2c status */
  78 #define IMX_I2C_I2DR    0x04    /* i2c transfer data */
  79
  80 #define IMX_I2C_REGSHIFT        2
  81 #define VF610_I2C_REGSHIFT      0
  82
  83 /* Bits of IMX I2C registers */
  84 #define I2SR_RXAK       0x01
  85 #define I2SR_IIF        0x02
  86 #define I2SR_SRW        0x04
  87 #define I2SR_IAL        0x10
  88 #define I2SR_IBB        0x20
  89 #define I2SR_IAAS       0x40
  90 #define I2SR_ICF        0x80
  91 #define I2CR_RSTA       0x04
  92 #define I2CR_TXAK       0x08
  93 #define I2CR_MTX        0x10
  94 #define I2CR_MSTA       0x20
  95 #define I2CR_IIEN       0x40
  96 #define I2CR_IEN        0x80
  97
  98 /* register bits different operating codes definition:
  99  * 1) I2SR: Interrupt flags clear operation differ between SoCs:
 100  * - write zero to clear(w0c) INT flag on i.MX,
 101  * - but write one to clear(w1c) INT flag on Vybrid.
 102  * 2) I2CR: I2C module enable operation also differ between SoCs:
 103  * - set I2CR_IEN bit enable the module on i.MX,
 104  * - but clear I2CR_IEN bit enable the module on Vybrid.
 105  */
 106 #define I2SR_CLR_OPCODE_W0C     0x0
 107 #define I2SR_CLR_OPCODE_W1C     (I2SR_IAL | I2SR_IIF)
 108 #define I2CR_IEN_OPCODE_0       0x0
 109 #define I2CR_IEN_OPCODE_1       I2CR_IEN
 110
 111 /** Variables ******************************************************************
 112 *******************************************************************************/
 113
 114 /*
 115  * sorted list of clock divider, register value pairs
 116  * taken from table 26-5, p.26-9, Freescale i.MX
 117  * Integrated Portable System Processor Reference Manual
 118  * Document Number: MC9328MXLRM, Rev. 5.1, 06/2007
 119  *
 120  * Duplicated divider values removed from list
 121  */
 122 struct imx_i2c_clk_pair {
 123         u16     div;
 124         u16     val;
 125 };
 126
 127 static struct imx_i2c_clk_pair imx_i2c_clk_div[] = {
 128         { 22,   0x20 }, { 24,   0x21 }, { 26,   0x22 }, { 28,   0x23 },
 129         { 30,   0x00 }, { 32,   0x24 }, { 36,   0x25 }, { 40,   0x26 },
 130         { 42,   0x03 }, { 44,   0x27 }, { 48,   0x28 }, { 52,   0x05 },
 131         { 56,   0x29 }, { 60,   0x06 }, { 64,   0x2A }, { 72,   0x2B },
 132         { 80,   0x2C }, { 88,   0x09 }, { 96,   0x2D }, { 104,  0x0A },
 133         { 112,  0x2E }, { 128,  0x2F }, { 144,  0x0C }, { 160,  0x30 },
 134         { 192,  0x31 }, { 224,  0x32 }, { 240,  0x0F }, { 256,  0x33 },
 135         { 288,  0x10 }, { 320,  0x34 }, { 384,  0x35 }, { 448,  0x36 },
 136         { 480,  0x13 }, { 512,  0x37 }, { 576,  0x14 }, { 640,  0x38 },
 137         { 768,  0x39 }, { 896,  0x3A }, { 960,  0x17 }, { 1024, 0x3B },
 138         { 1152, 0x18 }, { 1280, 0x3C }, { 1536, 0x3D }, { 1792, 0x3E },
 139         { 1920, 0x1B }, { 2048, 0x3F }, { 2304, 0x1C }, { 2560, 0x1D },
 140         { 3072, 0x1E }, { 3840, 0x1F }
 141 };
 142
 143 /* Vybrid VF610 clock divider, register value pairs */
 144 static struct imx_i2c_clk_pair vf610_i2c_clk_div[] = {
 145         { 20,   0x00 }, { 22,   0x01 }, { 24,   0x02 }, { 26,   0x03 },
 146         { 28,   0x04 }, { 30,   0x05 }, { 32,   0x09 }, { 34,   0x06 },
 147         { 36,   0x0A }, { 40,   0x07 }, { 44,   0x0C }, { 48,   0x0D },
 148         { 52,   0x43 }, { 56,   0x0E }, { 60,   0x45 }, { 64,   0x12 },
 149         { 68,   0x0F }, { 72,   0x13 }, { 80,   0x14 }, { 88,   0x15 },
 150         { 96,   0x19 }, { 104,  0x16 }, { 112,  0x1A }, { 128,  0x17 },
 151         { 136,  0x4F }, { 144,  0x1C }, { 160,  0x1D }, { 176,  0x55 },
 152         { 192,  0x1E }, { 208,  0x56 }, { 224,  0x22 }, { 228,  0x24 },
 153         { 240,  0x1F }, { 256,  0x23 }, { 288,  0x5C }, { 320,  0x25 },
 154         { 384,  0x26 }, { 448,  0x2A }, { 480,  0x27 }, { 512,  0x2B },
 155         { 576,  0x2C }, { 640,  0x2D }, { 768,  0x31 }, { 896,  0x32 },
 156         { 960,  0x2F }, { 1024, 0x33 }, { 1152, 0x34 }, { 1280, 0x35 },
 157         { 1536, 0x36 }, { 1792, 0x3A }, { 1920, 0x37 }, { 2048, 0x3B },
 158         { 2304, 0x3C }, { 2560, 0x3D }, { 3072, 0x3E }, { 3584, 0x7A },
 159         { 3840, 0x3F }, { 4096, 0x7B }, { 5120, 0x7D }, { 6144, 0x7E },
 160 };
 161
 162 enum imx_i2c_type {
 163         IMX1_I2C,
 164         IMX21_I2C,
 165         VF610_I2C,
 166 };
 167
 168 struct imx_i2c_hwdata {
 169         enum imx_i2c_type       devtype;
 170         unsigned                regshift;
 171         struct imx_i2c_clk_pair *clk_div;
 172         unsigned                ndivs;
 173         unsigned                i2sr_clr_opcode;
 174         unsigned                i2cr_ien_opcode;
 175 };
 176
 177 struct imx_i2c_struct {
 178         struct i2c_adapter      adapter;
 179         struct clk              *clk;
 180         void __iomem            *base;
 181         wait_queue_head_t       queue;
 182         unsigned long           i2csr;
 183         unsigned int            disable_delay;
 184         int                     stopped;
 185         unsigned int            ifdr; /* IMX_I2C_IFDR */
 186         unsigned int            cur_clk;
 187         unsigned int            bitrate;
 188         const struct imx_i2c_hwdata     *hwdata;
 189 };
 190
 191 static const struct imx_i2c_hwdata imx1_i2c_hwdata  = {
 192         .devtype                = IMX1_I2C,
 193         .regshift               = IMX_I2C_REGSHIFT,
 194         .clk_div                = imx_i2c_clk_div,
 195         .ndivs                  = ARRAY_SIZE(imx_i2c_clk_div),
 196         .i2sr_clr_opcode        = I2SR_CLR_OPCODE_W0C,
 197         .i2cr_ien_opcode        = I2CR_IEN_OPCODE_1,
 198
 199 };
 200
 201 static const struct imx_i2c_hwdata imx21_i2c_hwdata  = {
 202         .devtype                = IMX21_I2C,
 203         .regshift               = IMX_I2C_REGSHIFT,
 204         .clk_div                = imx_i2c_clk_div,
 205         .ndivs                  = ARRAY_SIZE(imx_i2c_clk_div),
 206         .i2sr_clr_opcode        = I2SR_CLR_OPCODE_W0C,
 207         .i2cr_ien_opcode        = I2CR_IEN_OPCODE_1,
 208
 209 };
 210
 211 static struct imx_i2c_hwdata vf610_i2c_hwdata = {
 212         .devtype                = VF610_I2C,
 213         .regshift               = VF610_I2C_REGSHIFT,
 214         .clk_div                = vf610_i2c_clk_div,
 215         .ndivs                  = ARRAY_SIZE(vf610_i2c_clk_div),
 216         .i2sr_clr_opcode        = I2SR_CLR_OPCODE_W1C,
 217         .i2cr_ien_opcode        = I2CR_IEN_OPCODE_0,
 218
 219 };
 220
 221 static struct platform_device_id imx_i2c_devtype[] = {
 222         {
 223                 .name = "imx1-i2c",
 224                 .driver_data = (kernel_ulong_t)&imx1_i2c_hwdata,
 225         }, {
 226                 .name = "imx21-i2c",
 227                 .driver_data = (kernel_ulong_t)&imx21_i2c_hwdata,
 228         }, {
 229                 /* sentinel */
 230         }
 231 };
 232 MODULE_DEVICE_TABLE(platform, imx_i2c_devtype);
 233
 234 static const struct of_device_id i2c_imx_dt_ids[] = {
 235         { .compatible = "fsl,imx1-i2c", .data = &imx1_i2c_hwdata, },
 236         { .compatible = "fsl,imx21-i2c", .data = &imx21_i2c_hwdata, },
 237         { .compatible = "fsl,vf610-i2c", .data = &vf610_i2c_hwdata, },
 238         { /* sentinel */ }
 239 };
 240 MODULE_DEVICE_TABLE(of, i2c_imx_dt_ids);
 241
 242 static inline int is_imx1_i2c(struct imx_i2c_struct *i2c_imx)
 243 {
 244         return i2c_imx->hwdata->devtype == IMX1_I2C;
 245 }
 246
 247 static inline void imx_i2c_write_reg(unsigned int val,
 248                 struct imx_i2c_struct *i2c_imx, unsigned int reg)
 249 {
 250         writeb(val, i2c_imx->base + (reg << i2c_imx->hwdata->regshift));
 251 }
 252
 253 static inline unsigned char imx_i2c_read_reg(struct imx_i2c_struct *i2c_imx,
 254                 unsigned int reg)
 255 {
 256         return readb(i2c_imx->base + (reg << i2c_imx->hwdata->regshift));
 257 }
 258
 259 /** Functions for IMX I2C adapter driver ***************************************
 260 *******************************************************************************/
 261
 262 static int i2c_imx_bus_busy(struct imx_i2c_struct *i2c_imx, int for_busy)
 263 {
 264         unsigned long orig_jiffies = jiffies;
 265         unsigned int temp;
 266
 267         dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
 268
 269         while (1) {
 270                 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
 271                 if (for_busy && (temp & I2SR_IBB))
 272                         break;
 273                 if (!for_busy && !(temp & I2SR_IBB))
 274                         break;
 275                 if (time_after(jiffies, orig_jiffies + msecs_to_jiffies(500))) {
 276                         dev_dbg(&i2c_imx->adapter.dev,
 277                                 "<%s> I2C bus is busy\n", __func__);
 278                         return -ETIMEDOUT;
 279                 }
 280                 schedule();
 281         }
 282
 283         return 0;
 284 }
 285
 286 static int i2c_imx_trx_complete(struct imx_i2c_struct *i2c_imx)
 287 {
 288         wait_event_timeout(i2c_imx->queue, i2c_imx->i2csr & I2SR_IIF, HZ / 10);
 289
 290         if (unlikely(!(i2c_imx->i2csr & I2SR_IIF))) {
 291                 dev_dbg(&i2c_imx->adapter.dev, "<%s> Timeout\n", __func__);
 292                 return -ETIMEDOUT;
 293         }
 294         dev_dbg(&i2c_imx->adapter.dev, "<%s> TRX complete\n", __func__);
 295         i2c_imx->i2csr = 0;
 296         return 0;
 297 }
 298
 299 static int i2c_imx_acked(struct imx_i2c_struct *i2c_imx)
 300 {
 301         if (imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR) & I2SR_RXAK) {
 302                 dev_dbg(&i2c_imx->adapter.dev, "<%s> No ACK\n", __func__);
 303                 return -EIO;  /* No ACK */
 304         }
 305
 306         dev_dbg(&i2c_imx->adapter.dev, "<%s> ACK received\n", __func__);
 307         return 0;
 308 }
 309
 310 static void i2c_imx_set_clk(struct imx_i2c_struct *i2c_imx)
 311 {
 312         struct imx_i2c_clk_pair *i2c_clk_div = i2c_imx->hwdata->clk_div;
 313         unsigned int i2c_clk_rate;
 314         unsigned int div;
 315         int i;
 316
 317         /* Divider value calculation */
 318         i2c_clk_rate = clk_get_rate(i2c_imx->clk);
 319         if (i2c_imx->cur_clk == i2c_clk_rate)
 320                 return;
 321         else
 322                 i2c_imx->cur_clk = i2c_clk_rate;
 323
 324         div = (i2c_clk_rate + i2c_imx->bitrate - 1) / i2c_imx->bitrate;
 325         if (div < i2c_clk_div[0].div)
 326                 i = 0;
 327         else if (div > i2c_clk_div[i2c_imx->hwdata->ndivs - 1].div)
 328                 i = i2c_imx->hwdata->ndivs - 1;
 329         else
 330                 for (i = 0; i2c_clk_div[i].div < div; i++);
 331
 332         /* Store divider value */
 333         i2c_imx->ifdr = i2c_clk_div[i].val;
 334
 335         /*
 336          * There dummy delay is calculated.
 337          * It should be about one I2C clock period long.
 338          * This delay is used in I2C bus disable function
 339          * to fix chip hardware bug.
 340          */
 341         i2c_imx->disable_delay = (500000U * i2c_clk_div[i].div
 342                 + (i2c_clk_rate / 2) - 1) / (i2c_clk_rate / 2);
 343
 344 #ifdef CONFIG_I2C_DEBUG_BUS
 345         dev_dbg(&i2c_imx->adapter.dev, "I2C_CLK=%d, REQ DIV=%d\n",
 346                 i2c_clk_rate, div);
 347         dev_dbg(&i2c_imx->adapter.dev, "IFDR[IC]=0x%x, REAL DIV=%d\n",
 348                 i2c_clk_div[i].val, i2c_clk_div[i].div);
 349 #endif
 350 }
 351
 352 static int i2c_imx_start(struct imx_i2c_struct *i2c_imx)
 353 {
 354         unsigned int temp = 0;
 355         int result;
 356
 357         dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
 358
 359         i2c_imx_set_clk(i2c_imx);
 360
 361         result = clk_prepare_enable(i2c_imx->clk);
 362         if (result)
 363                 return result;
 364         imx_i2c_write_reg(i2c_imx->ifdr, i2c_imx, IMX_I2C_IFDR);
 365         /* Enable I2C controller */
 366         imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR);
 367         imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode, i2c_imx, IMX_I2C_I2CR);
 368
 369         /* Wait controller to be stable */
 370         udelay(50);
 371
 372         /* Start I2C transaction */
 373         temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
 374         temp |= I2CR_MSTA;
 375         imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
 376         result = i2c_imx_bus_busy(i2c_imx, 1);
 377         if (result)
 378                 return result;
 379         i2c_imx->stopped = 0;
 380
 381         temp |= I2CR_IIEN | I2CR_MTX | I2CR_TXAK;
 382         imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
 383         return result;
 384 }
 385
 386 static void i2c_imx_stop(struct imx_i2c_struct *i2c_imx)
 387 {
 388         unsigned int temp = 0;
 389
 390         if (!i2c_imx->stopped) {
 391                 /* Stop I2C transaction */
 392                 dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
 393                 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
 394                 temp &= ~(I2CR_MSTA | I2CR_MTX);
 395                 imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
 396         }
 397         if (is_imx1_i2c(i2c_imx)) {
 398                 /*
 399                  * This delay caused by an i.MXL hardware bug.
 400                  * If no (or too short) delay, no "STOP" bit will be generated.
 401                  */
 402                 udelay(i2c_imx->disable_delay);
 403         }
 404
 405         if (!i2c_imx->stopped) {
 406                 i2c_imx_bus_busy(i2c_imx, 0);
 407                 i2c_imx->stopped = 1;
 408         }
 409
 410         /* Disable I2C controller */
 411         temp = i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN,
 412         imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
 413         clk_disable_unprepare(i2c_imx->clk);
 414 }
 415
 416 static irqreturn_t i2c_imx_isr(int irq, void *dev_id)
 417 {
 418         struct imx_i2c_struct *i2c_imx = dev_id;
 419         unsigned int temp;
 420
 421         temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
 422         if (temp & I2SR_IIF) {
 423                 /* save status register */
 424                 i2c_imx->i2csr = temp;
 425                 temp &= ~I2SR_IIF;
 426                 temp |= (i2c_imx->hwdata->i2sr_clr_opcode & I2SR_IIF);
 427                 imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2SR);
 428                 wake_up(&i2c_imx->queue);
 429                 return IRQ_HANDLED;
 430         }
 431
 432         return IRQ_NONE;
 433 }
 434
 435 static int i2c_imx_write(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs)
 436 {
 437         int i, result;
 438
 439         dev_dbg(&i2c_imx->adapter.dev, "<%s> write slave address: addr=0x%x\n",
 440                 __func__, msgs->addr << 1);
 441
 442         /* write slave address */
 443         imx_i2c_write_reg(msgs->addr << 1, i2c_imx, IMX_I2C_I2DR);
 444         result = i2c_imx_trx_complete(i2c_imx);
 445         if (result)
 446                 return result;
 447         result = i2c_imx_acked(i2c_imx);
 448         if (result)
 449                 return result;
 450         dev_dbg(&i2c_imx->adapter.dev, "<%s> write data\n", __func__);
 451
 452         /* write data */
 453         for (i = 0; i < msgs->len; i++) {
 454                 dev_dbg(&i2c_imx->adapter.dev,
 455                         "<%s> write byte: B%d=0x%X\n",
 456                         __func__, i, msgs->buf[i]);
 457                 imx_i2c_write_reg(msgs->buf[i], i2c_imx, IMX_I2C_I2DR);
 458                 result = i2c_imx_trx_complete(i2c_imx);
 459                 if (result)
 460                         return result;
 461                 result = i2c_imx_acked(i2c_imx);
 462                 if (result)
 463                         return result;
 464         }
 465         return 0;
 466 }
 467
 468 static int i2c_imx_read(struct imx_i2c_struct *i2c_imx, struct i2c_msg *msgs, bool is_lastmsg)
 469 {
 470         int i, result;
 471         unsigned int temp;
 472         int block_data = msgs->flags & I2C_M_RECV_LEN;
 473
 474         dev_dbg(&i2c_imx->adapter.dev,
 475                 "<%s> write slave address: addr=0x%x\n",
 476                 __func__, (msgs->addr << 1) | 0x01);
 477
 478         /* write slave address */
 479         imx_i2c_write_reg((msgs->addr << 1) | 0x01, i2c_imx, IMX_I2C_I2DR);
 480         result = i2c_imx_trx_complete(i2c_imx);
 481         if (result)
 482                 return result;
 483         result = i2c_imx_acked(i2c_imx);
 484         if (result)
 485                 return result;
 486
 487         dev_dbg(&i2c_imx->adapter.dev, "<%s> setup bus\n", __func__);
 488
 489         /* setup bus to read data */
 490         temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
 491         temp &= ~I2CR_MTX;
 492
 493         /*
 494          * Reset the I2CR_TXAK flag initially for SMBus block read since the
 495          * length is unknown
 496          */
 497         if ((msgs->len - 1) || block_data)
 498                 temp &= ~I2CR_TXAK;
 499         imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
 500         imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR); /* dummy read */
 501
 502         dev_dbg(&i2c_imx->adapter.dev, "<%s> read data\n", __func__);
 503
 504         /* read data */
 505         for (i = 0; i < msgs->len; i++) {
 506                 u8 len = 0;
 507                 result = i2c_imx_trx_complete(i2c_imx);
 508                 if (result)
 509                         return result;
 510                 /*
 511                  * First byte is the length of remaining packet
 512                  * in the SMBus block data read. Add it to
 513                  * msgs->len.
 514                  */
 515                 if ((!i) && block_data) {
 516                         len = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
 517                         if ((len == 0) || (len > I2C_SMBUS_BLOCK_MAX))
 518                                 return -EPROTO;
 519                         dev_dbg(&i2c_imx->adapter.dev,
 520                                 "<%s> read length: 0x%X\n",
 521                                 __func__, len);
 522                         msgs->len += len;
 523                 }
 524                 if (i == (msgs->len - 1)) {
 525                         if (is_lastmsg) {
 526                                 /*
 527                                  * It must generate STOP before read I2DR to prevent
 528                                  * controller from generating another clock cycle
 529                                  */
 530                                 dev_dbg(&i2c_imx->adapter.dev,
 531                                         "<%s> clear MSTA\n", __func__);
 532                                 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
 533                                 temp &= ~(I2CR_MSTA | I2CR_MTX);
 534                                 imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
 535                                 i2c_imx_bus_busy(i2c_imx, 0);
 536                                 i2c_imx->stopped = 1;
 537                         } else {
 538                                 /*
 539                                  * For i2c master receiver repeat restart operation like:
 540                                  * read -> repeat MSTA -> read/write
 541                                  * The controller must set MTX before read the last byte in
 542                                  * the first read operation, otherwise the first read cost
 543                                  * one extra clock cycle.
 544                                  */
 545                                 temp = readb(i2c_imx->base + IMX_I2C_I2CR);
 546                                 temp |= I2CR_MTX;
 547                                 writeb(temp, i2c_imx->base + IMX_I2C_I2CR);
 548                         }
 549                 } else if (i == (msgs->len - 2)) {
 550                         dev_dbg(&i2c_imx->adapter.dev,
 551                                 "<%s> set TXAK\n", __func__);
 552                         temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
 553                         temp |= I2CR_TXAK;
 554                         imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
 555                 }
 556                 if ((!i) && block_data)
 557                         msgs->buf[0] = len;
 558                 else
 559                         msgs->buf[i] =  imx_i2c_read_reg(i2c_imx, IMX_I2C_I2DR);
 560                 dev_dbg(&i2c_imx->adapter.dev,
 561                         "<%s> read byte: B%d=0x%X\n",
 562                         __func__, i, msgs->buf[i]);
 563         }
 564         return 0;
 565 }
 566
 567 static int i2c_imx_xfer(struct i2c_adapter *adapter,
 568                                                 struct i2c_msg *msgs, int num)
 569 {
 570         unsigned int i, temp;
 571         int result;
 572         bool is_lastmsg = false;
 573         struct imx_i2c_struct *i2c_imx = i2c_get_adapdata(adapter);
 574
 575         dev_dbg(&i2c_imx->adapter.dev, "<%s>\n", __func__);
 576
 577         /* Start I2C transfer */
 578         result = i2c_imx_start(i2c_imx);
 579         if (result)
 580                 goto fail0;
 581
 582         /* read/write data */
 583         for (i = 0; i < num; i++) {
 584                 if (i == num - 1)
 585                         is_lastmsg = true;
 586
 587                 if (i) {
 588                         dev_dbg(&i2c_imx->adapter.dev,
 589                                 "<%s> repeated start\n", __func__);
 590                         temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
 591                         temp |= I2CR_RSTA;
 592                         imx_i2c_write_reg(temp, i2c_imx, IMX_I2C_I2CR);
 593                         result =  i2c_imx_bus_busy(i2c_imx, 1);
 594                         if (result)
 595                                 goto fail0;
 596                 }
 597                 dev_dbg(&i2c_imx->adapter.dev,
 598                         "<%s> transfer message: %d\n", __func__, i);
 599                 /* write/read data */
 600 #ifdef CONFIG_I2C_DEBUG_BUS
 601                 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2CR);
 602                 dev_dbg(&i2c_imx->adapter.dev, "<%s> CONTROL: IEN=%d, IIEN=%d, "
 603                         "MSTA=%d, MTX=%d, TXAK=%d, RSTA=%d\n", __func__,
 604                         (temp & I2CR_IEN ? 1 : 0), (temp & I2CR_IIEN ? 1 : 0),
 605                         (temp & I2CR_MSTA ? 1 : 0), (temp & I2CR_MTX ? 1 : 0),
 606                         (temp & I2CR_TXAK ? 1 : 0), (temp & I2CR_RSTA ? 1 : 0));
 607                 temp = imx_i2c_read_reg(i2c_imx, IMX_I2C_I2SR);
 608                 dev_dbg(&i2c_imx->adapter.dev,
 609                         "<%s> STATUS: ICF=%d, IAAS=%d, IBB=%d, "
 610                         "IAL=%d, SRW=%d, IIF=%d, RXAK=%d\n", __func__,
 611                         (temp & I2SR_ICF ? 1 : 0), (temp & I2SR_IAAS ? 1 : 0),
 612                         (temp & I2SR_IBB ? 1 : 0), (temp & I2SR_IAL ? 1 : 0),
 613                         (temp & I2SR_SRW ? 1 : 0), (temp & I2SR_IIF ? 1 : 0),
 614                         (temp & I2SR_RXAK ? 1 : 0));
 615 #endif
 616                 if (msgs[i].flags & I2C_M_RD)
 617                         result = i2c_imx_read(i2c_imx, &msgs[i], is_lastmsg);
 618                 else
 619                         result = i2c_imx_write(i2c_imx, &msgs[i]);
 620                 if (result)
 621                         goto fail0;
 622         }
 623
 624 fail0:
 625         /* Stop I2C transfer */
 626         i2c_imx_stop(i2c_imx);
 627
 628         dev_dbg(&i2c_imx->adapter.dev, "<%s> exit with: %s: %d\n", __func__,
 629                 (result < 0) ? "error" : "success msg",
 630                         (result < 0) ? result : num);
 631         return (result < 0) ? result : num;
 632 }
 633
 634 static u32 i2c_imx_func(struct i2c_adapter *adapter)
 635 {
 636         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL
 637                 | I2C_FUNC_SMBUS_READ_BLOCK_DATA;
 638 }
 639
 640 static struct i2c_algorithm i2c_imx_algo = {
 641         .master_xfer    = i2c_imx_xfer,
 642         .functionality  = i2c_imx_func,
 643 };
 644
 645 static int i2c_imx_probe(struct platform_device *pdev)
 646 {
 647         const struct of_device_id *of_id = of_match_device(i2c_imx_dt_ids,
 648                                                            &pdev->dev);
 649         struct imx_i2c_struct *i2c_imx;
 650         struct resource *res;
 651         struct imxi2c_platform_data *pdata = dev_get_platdata(&pdev->dev);
 652         void __iomem *base;
 653         int irq, ret;
 654
 655         dev_dbg(&pdev->dev, "<%s>\n", __func__);
 656
 657         irq = platform_get_irq(pdev, 0);
 658         if (irq < 0) {
 659                 dev_err(&pdev->dev, "can't get irq number\n");
 660                 return irq;
 661         }
 662
 663         res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 664         base = devm_ioremap_resource(&pdev->dev, res);
 665         if (IS_ERR(base))
 666                 return PTR_ERR(base);
 667
 668         i2c_imx = devm_kzalloc(&pdev->dev, sizeof(struct imx_i2c_struct),
 669                                 GFP_KERNEL);
 670         if (!i2c_imx)
 671                 return -ENOMEM;
 672
 673         if (of_id)
 674                 i2c_imx->hwdata = of_id->data;
 675         else
 676                 i2c_imx->hwdata = (struct imx_i2c_hwdata *)
 677                                 platform_get_device_id(pdev)->driver_data;
 678
 679         /* Setup i2c_imx driver structure */
 680         strlcpy(i2c_imx->adapter.name, pdev->name, sizeof(i2c_imx->adapter.name));
 681         i2c_imx->adapter.owner          = THIS_MODULE;
 682         i2c_imx->adapter.algo           = &i2c_imx_algo;
 683         i2c_imx->adapter.dev.parent     = &pdev->dev;
 684         i2c_imx->adapter.nr             = pdev->id;
 685         i2c_imx->adapter.dev.of_node    = pdev->dev.of_node;
 686         i2c_imx->base                   = base;
 687
 688         /* Get I2C clock */
 689         i2c_imx->clk = devm_clk_get(&pdev->dev, NULL);
 690         if (IS_ERR(i2c_imx->clk)) {
 691                 dev_err(&pdev->dev, "can't get I2C clock\n");
 692                 return PTR_ERR(i2c_imx->clk);
 693         }
 694
 695         ret = clk_prepare_enable(i2c_imx->clk);
 696         if (ret) {
 697                 dev_err(&pdev->dev, "can't enable I2C clock\n");
 698                 return ret;
 699         }
 700         /* Request IRQ */
 701         ret = devm_request_irq(&pdev->dev, irq, i2c_imx_isr, 0,
 702                                 pdev->name, i2c_imx);
 703         if (ret) {
 704                 dev_err(&pdev->dev, "can't claim irq %d\n", irq);
 705                 return ret;
 706         }
 707
 708         /* Init queue */
 709         init_waitqueue_head(&i2c_imx->queue);
 710
 711         /* Set up adapter data */
 712         i2c_set_adapdata(&i2c_imx->adapter, i2c_imx);
 713
 714         /* Set up clock divider */
 715         i2c_imx->bitrate = IMX_I2C_BIT_RATE;
 716         ret = of_property_read_u32(pdev->dev.of_node,
 717                                    "clock-frequency", &i2c_imx->bitrate);
 718         if (ret < 0 && pdata && pdata->bitrate)
 719                 i2c_imx->bitrate = pdata->bitrate;
 720
 721         /* Set up chip registers to defaults */
 722         imx_i2c_write_reg(i2c_imx->hwdata->i2cr_ien_opcode ^ I2CR_IEN,
 723                         i2c_imx, IMX_I2C_I2CR);
 724         imx_i2c_write_reg(i2c_imx->hwdata->i2sr_clr_opcode, i2c_imx, IMX_I2C_I2SR);
 725
 726         /* Add I2C adapter */
 727         ret = i2c_add_numbered_adapter(&i2c_imx->adapter);
 728         if (ret < 0) {
 729                 dev_err(&pdev->dev, "registration failed\n");
 730                 return ret;
 731         }
 732
 733         /* Set up platform driver data */
 734         platform_set_drvdata(pdev, i2c_imx);
 735         clk_disable_unprepare(i2c_imx->clk);
 736
 737         dev_dbg(&i2c_imx->adapter.dev, "claimed irq %d\n", irq);
 738         dev_dbg(&i2c_imx->adapter.dev, "device resources from 0x%x to 0x%x\n",
 739                 res->start, res->end);
 740         dev_dbg(&i2c_imx->adapter.dev, "allocated %d bytes at 0x%x\n",
 741                 resource_size(res), res->start);
 742         dev_dbg(&i2c_imx->adapter.dev, "adapter name: \"%s\"\n",
 743                 i2c_imx->adapter.name);
 744         dev_info(&i2c_imx->adapter.dev, "IMX I2C adapter registered\n");
 745
 746         return 0;   /* Return OK */
 747 }
 748
 749 static int i2c_imx_remove(struct platform_device *pdev)
 750 {
 751         struct imx_i2c_struct *i2c_imx = platform_get_drvdata(pdev);
 752
 753         /* remove adapter */
 754         dev_dbg(&i2c_imx->adapter.dev, "adapter removed\n");
 755         i2c_del_adapter(&i2c_imx->adapter);
 756
 757         /* setup chip registers to defaults */
 758         imx_i2c_write_reg(0, i2c_imx, IMX_I2C_IADR);
 759         imx_i2c_write_reg(0, i2c_imx, IMX_I2C_IFDR);
 760         imx_i2c_write_reg(0, i2c_imx, IMX_I2C_I2CR);
 761         imx_i2c_write_reg(0, i2c_imx, IMX_I2C_I2SR);
 762
 763         return 0;
 764 }
 765
 766 static struct platform_driver i2c_imx_driver = {
 767         .probe = i2c_imx_probe,
 768         .remove = i2c_imx_remove,
 769         .driver = {
 770                 .name   = DRIVER_NAME,
 771                 .owner  = THIS_MODULE,
 772                 .of_match_table = i2c_imx_dt_ids,
 773         },
 774         .id_table       = imx_i2c_devtype,
 775 };
 776
 777 static int __init i2c_adap_imx_init(void)
 778 {
 779         return platform_driver_register(&i2c_imx_driver);
 780 }
 781 subsys_initcall(i2c_adap_imx_init);
 782
 783 static void __exit i2c_adap_imx_exit(void)
 784 {
 785         platform_driver_unregister(&i2c_imx_driver);
 786 }
 787 module_exit(i2c_adap_imx_exit);
 788
 789 MODULE_LICENSE("GPL");
 790 MODULE_AUTHOR("Darius Augulis");
 791 MODULE_DESCRIPTION("I2C adapter driver for IMX I2C bus");
 792 MODULE_ALIAS("platform:" DRIVER_NAME);