arch/mips/mti-sead3/sead3-pic32-i2c-drv.c

   1 /*
   2  * This file is subject to the terms and conditions of the GNU General Public
   3  * License.  See the file "COPYING" in the main directory of this archive
   4  * for more details.
   5  *
   6  * Copyright (C) 2012 MIPS Technologies, Inc.  All rights reserved.
   7  */
   8 #include <linux/delay.h>
   9 #include <linux/kernel.h>
  10 #include <linux/module.h>
  11 #include <linux/spinlock.h>
  12 #include <linux/platform_device.h>
  13 #include <linux/init.h>
  14 #include <linux/errno.h>
  15 #include <linux/i2c.h>
  16 #include <linux/slab.h>
  17
  18 #define PIC32_I2CxCON           0x0000
  19 #define PIC32_I2CxCONCLR        0x0004
  20 #define PIC32_I2CxCONSET        0x0008
  21 #define PIC32_I2CxCONINV        0x000C
  22 #define  I2CCON_ON              (1<<15)
  23 #define  I2CCON_FRZ             (1<<14)
  24 #define  I2CCON_SIDL            (1<<13)
  25 #define  I2CCON_SCLREL          (1<<12)
  26 #define  I2CCON_STRICT          (1<<11)
  27 #define  I2CCON_A10M            (1<<10)
  28 #define  I2CCON_DISSLW          (1<<9)
  29 #define  I2CCON_SMEN            (1<<8)
  30 #define  I2CCON_GCEN            (1<<7)
  31 #define  I2CCON_STREN           (1<<6)
  32 #define  I2CCON_ACKDT           (1<<5)
  33 #define  I2CCON_ACKEN           (1<<4)
  34 #define  I2CCON_RCEN            (1<<3)
  35 #define  I2CCON_PEN             (1<<2)
  36 #define  I2CCON_RSEN            (1<<1)
  37 #define  I2CCON_SEN             (1<<0)
  38
  39 #define PIC32_I2CxSTAT          0x0010
  40 #define PIC32_I2CxSTATCLR       0x0014
  41 #define PIC32_I2CxSTATSET       0x0018
  42 #define PIC32_I2CxSTATINV       0x001C
  43 #define  I2CSTAT_ACKSTAT        (1<<15)
  44 #define  I2CSTAT_TRSTAT         (1<<14)
  45 #define  I2CSTAT_BCL            (1<<10)
  46 #define  I2CSTAT_GCSTAT         (1<<9)
  47 #define  I2CSTAT_ADD10          (1<<8)
  48 #define  I2CSTAT_IWCOL          (1<<7)
  49 #define  I2CSTAT_I2COV          (1<<6)
  50 #define  I2CSTAT_DA             (1<<5)
  51 #define  I2CSTAT_P              (1<<4)
  52 #define  I2CSTAT_S              (1<<3)
  53 #define  I2CSTAT_RW             (1<<2)
  54 #define  I2CSTAT_RBF            (1<<1)
  55 #define  I2CSTAT_TBF            (1<<0)
  56
  57 #define PIC32_I2CxADD           0x0020
  58 #define PIC32_I2CxADDCLR        0x0024
  59 #define PIC32_I2CxADDSET        0x0028
  60 #define PIC32_I2CxADDINV        0x002C
  61 #define PIC32_I2CxMSK           0x0030
  62 #define PIC32_I2CxMSKCLR        0x0034
  63 #define PIC32_I2CxMSKSET        0x0038
  64 #define PIC32_I2CxMSKINV        0x003C
  65 #define PIC32_I2CxBRG           0x0040
  66 #define PIC32_I2CxBRGCLR        0x0044
  67 #define PIC32_I2CxBRGSET        0x0048
  68 #define PIC32_I2CxBRGINV        0x004C
  69 #define PIC32_I2CxTRN           0x0050
  70 #define PIC32_I2CxTRNCLR        0x0054
  71 #define PIC32_I2CxTRNSET        0x0058
  72 #define PIC32_I2CxTRNINV        0x005C
  73 #define PIC32_I2CxRCV           0x0060
  74
  75 struct i2c_platform_data {
  76         u32     base;
  77         struct i2c_adapter adap;
  78         u32     xfer_timeout;
  79         u32     ack_timeout;
  80         u32     ctl_timeout;
  81 };
  82
  83 extern u32 pic32_bus_readl(u32 reg);
  84 extern void pic32_bus_writel(u32 val, u32 reg);
  85
  86 static inline void
  87 StartI2C(struct i2c_platform_data *adap)
  88 {
  89         pr_debug("StartI2C\n");
  90         pic32_bus_writel(I2CCON_SEN, adap->base + PIC32_I2CxCONSET);
  91 }
  92
  93 static inline void
  94 StopI2C(struct i2c_platform_data *adap)
  95 {
  96         pr_debug("StopI2C\n");
  97         pic32_bus_writel(I2CCON_PEN, adap->base + PIC32_I2CxCONSET);
  98 }
  99
 100 static inline void
 101 AckI2C(struct i2c_platform_data *adap)
 102 {
 103         pr_debug("AckI2C\n");
 104         pic32_bus_writel(I2CCON_ACKDT, adap->base + PIC32_I2CxCONCLR);
 105         pic32_bus_writel(I2CCON_ACKEN, adap->base + PIC32_I2CxCONSET);
 106 }
 107
 108 static inline void
 109 NotAckI2C(struct i2c_platform_data *adap)
 110 {
 111         pr_debug("NakI2C\n");
 112         pic32_bus_writel(I2CCON_ACKDT, adap->base + PIC32_I2CxCONSET);
 113         pic32_bus_writel(I2CCON_ACKEN, adap->base + PIC32_I2CxCONSET);
 114 }
 115
 116 static inline int
 117 IdleI2C(struct i2c_platform_data *adap)
 118 {
 119         int i;
 120
 121         pr_debug("IdleI2C\n");
 122         for (i = 0; i < adap->ctl_timeout; i++) {
 123                 if (((pic32_bus_readl(adap->base + PIC32_I2CxCON) &
 124                      (I2CCON_ACKEN | I2CCON_RCEN | I2CCON_PEN | I2CCON_RSEN |
 125                       I2CCON_SEN)) == 0) &&
 126                     ((pic32_bus_readl(adap->base + PIC32_I2CxSTAT) &
 127                      (I2CSTAT_TRSTAT)) == 0))
 128                         return 0;
 129                 udelay(1);
 130         }
 131         return -ETIMEDOUT;
 132 }
 133
 134 static inline u32
 135 MasterWriteI2C(struct i2c_platform_data *adap, u32 byte)
 136 {
 137         pr_debug("MasterWriteI2C\n");
 138
 139         pic32_bus_writel(byte, adap->base + PIC32_I2CxTRN);
 140
 141         return pic32_bus_readl(adap->base + PIC32_I2CxSTAT) & I2CSTAT_IWCOL;
 142 }
 143
 144 static inline u32
 145 MasterReadI2C(struct i2c_platform_data *adap)
 146 {
 147         pr_debug("MasterReadI2C\n");
 148
 149         pic32_bus_writel(I2CCON_RCEN, adap->base + PIC32_I2CxCONSET);
 150
 151         while (pic32_bus_readl(adap->base + PIC32_I2CxCON) & I2CCON_RCEN)
 152                 ;
 153
 154         pic32_bus_writel(I2CSTAT_I2COV, adap->base + PIC32_I2CxSTATCLR);
 155
 156         return pic32_bus_readl(adap->base + PIC32_I2CxRCV);
 157 }
 158
 159 static int
 160 do_address(struct i2c_platform_data *adap, unsigned int addr, int rd)
 161 {
 162         pr_debug("doaddress\n");
 163
 164         IdleI2C(adap);
 165         StartI2C(adap);
 166         IdleI2C(adap);
 167
 168         addr <<= 1;
 169         if (rd)
 170                 addr |= 1;
 171
 172         if (MasterWriteI2C(adap, addr))
 173                 return -EIO;
 174         IdleI2C(adap);
 175         if (pic32_bus_readl(adap->base + PIC32_I2CxSTAT) & I2CSTAT_ACKSTAT)
 176                 return -EIO;
 177         return 0;
 178 }
 179
 180 static int
 181 i2c_read(struct i2c_platform_data *adap, unsigned char *buf,
 182                     unsigned int len)
 183 {
 184         int     i;
 185         u32     data;
 186
 187         pr_debug("i2c_read\n");
 188
 189         i = 0;
 190         while (i < len) {
 191                 data = MasterReadI2C(adap);
 192                 buf[i++] = data;
 193                 if (i < len)
 194                         AckI2C(adap);
 195                 else
 196                         NotAckI2C(adap);
 197         }
 198
 199         StopI2C(adap);
 200         IdleI2C(adap);
 201         return 0;
 202 }
 203
 204 static int
 205 i2c_write(struct i2c_platform_data *adap, unsigned char *buf,
 206                      unsigned int len)
 207 {
 208         int     i;
 209         u32     data;
 210
 211         pr_debug("i2c_write\n");
 212
 213         i = 0;
 214         while (i < len) {
 215                 data = buf[i];
 216                 if (MasterWriteI2C(adap, data))
 217                         return -EIO;
 218                 IdleI2C(adap);
 219                 if (pic32_bus_readl(adap->base + PIC32_I2CxSTAT) &
 220                     I2CSTAT_ACKSTAT)
 221                         return -EIO;
 222                 i++;
 223         }
 224
 225         StopI2C(adap);
 226         IdleI2C(adap);
 227         return 0;
 228 }
 229
 230 static int
 231 platform_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num)
 232 {
 233         struct i2c_platform_data *adap = i2c_adap->algo_data;
 234         struct i2c_msg *p;
 235         int i, err = 0;
 236
 237         pr_debug("platform_xfer\n");
 238         for (i = 0; i < num; i++) {
 239 #define __BUFSIZE 80
 240                 int ii;
 241                 static char buf[__BUFSIZE];
 242                 char *b = buf;
 243
 244                 p = &msgs[i];
 245                 b += sprintf(buf, " [%d bytes]", p->len);
 246                 if ((p->flags & I2C_M_RD) == 0) {
 247                         for (ii = 0; ii < p->len; ii++) {
 248                                 if (b < &buf[__BUFSIZE-4]) {
 249                                         b += sprintf(b, " %02x", p->buf[ii]);
 250                                 } else {
 251                                         strcat(b, "...");
 252                                         break;
 253                                 }
 254                         }
 255                 }
 256                 pr_debug("xfer%d: DevAddr: %04x Op:%s Data:%s\n", i, p->addr,
 257                          (p->flags & I2C_M_RD) ? "Rd" : "Wr", buf);
 258         }
 259
 260
 261         for (i = 0; !err && i < num; i++) {
 262                 p = &msgs[i];
 263                 err = do_address(adap, p->addr, p->flags & I2C_M_RD);
 264                 if (err || !p->len)
 265                         continue;
 266                 if (p->flags & I2C_M_RD)
 267                         err = i2c_read(adap, p->buf, p->len);
 268                 else
 269                         err = i2c_write(adap, p->buf, p->len);
 270         }
 271
 272         /* Return the number of messages processed, or the error code. */
 273         if (err == 0)
 274                 err = num;
 275
 276         return err;
 277 }
 278
 279 static u32
 280 platform_func(struct i2c_adapter *adap)
 281 {
 282         pr_debug("platform_algo\n");
 283         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 284 }
 285
 286 static const struct i2c_algorithm platform_algo = {
 287         .master_xfer    = platform_xfer,
 288         .functionality  = platform_func,
 289 };
 290
 291 static void i2c_platform_setup(struct i2c_platform_data *priv)
 292 {
 293         pr_debug("i2c_platform_setup\n");
 294
 295         pic32_bus_writel(500, priv->base + PIC32_I2CxBRG);
 296         pic32_bus_writel(I2CCON_ON, priv->base + PIC32_I2CxCONCLR);
 297         pic32_bus_writel(I2CCON_ON, priv->base + PIC32_I2CxCONSET);
 298         pic32_bus_writel((I2CSTAT_BCL | I2CSTAT_IWCOL),
 299                 (priv->base + PIC32_I2CxSTATCLR));
 300 }
 301
 302 static void i2c_platform_disable(struct i2c_platform_data *priv)
 303 {
 304         pr_debug("i2c_platform_disable\n");
 305 }
 306
 307 static int i2c_platform_probe(struct platform_device *pdev)
 308 {
 309         struct i2c_platform_data *priv;
 310         struct resource *r;
 311         int ret;
 312
 313         pr_debug("i2c_platform_probe\n");
 314         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 315         if (!r) {
 316                 ret = -ENODEV;
 317                 goto out;
 318         }
 319
 320         priv = kzalloc(sizeof(struct i2c_platform_data), GFP_KERNEL);
 321         if (!priv) {
 322                 ret = -ENOMEM;
 323                 goto out;
 324         }
 325
 326         /* FIXME: need to allocate resource in PIC32 space */
 327 #if 0
 328         priv->base = bus_request_region(r->start, resource_size(r),
 329                                           pdev->name);
 330 #else
 331         priv->base = r->start;
 332 #endif
 333         if (!priv->base) {
 334                 ret = -EBUSY;
 335                 goto out_mem;
 336         }
 337
 338         priv->xfer_timeout = 200;
 339         priv->ack_timeout = 200;
 340         priv->ctl_timeout = 200;
 341
 342         priv->adap.nr = pdev->id;
 343         priv->adap.algo = &platform_algo;
 344         priv->adap.algo_data = priv;
 345         priv->adap.dev.parent = &pdev->dev;
 346         strlcpy(priv->adap.name, "PIC32 I2C", sizeof(priv->adap.name));
 347
 348         i2c_platform_setup(priv);
 349
 350         ret = i2c_add_numbered_adapter(&priv->adap);
 351         if (ret == 0) {
 352                 platform_set_drvdata(pdev, priv);
 353                 return 0;
 354         }
 355
 356         i2c_platform_disable(priv);
 357
 358 out_mem:
 359         kfree(priv);
 360 out:
 361         return ret;
 362 }
 363
 364 static int i2c_platform_remove(struct platform_device *pdev)
 365 {
 366         struct i2c_platform_data *priv = platform_get_drvdata(pdev);
 367
 368         pr_debug("i2c_platform_remove\n");
 369         platform_set_drvdata(pdev, NULL);
 370         i2c_del_adapter(&priv->adap);
 371         i2c_platform_disable(priv);
 372         kfree(priv);
 373         return 0;
 374 }
 375
 376 #ifdef CONFIG_PM
 377 static int
 378 i2c_platform_suspend(struct platform_device *pdev, pm_message_t state)
 379 {
 380         struct i2c_platform_data *priv = platform_get_drvdata(pdev);
 381
 382         dev_dbg(&pdev->dev, "i2c_platform_disable\n");
 383         i2c_platform_disable(priv);
 384
 385         return 0;
 386 }
 387
 388 static int
 389 i2c_platform_resume(struct platform_device *pdev)
 390 {
 391         struct i2c_platform_data *priv = platform_get_drvdata(pdev);
 392
 393         dev_dbg(&pdev->dev, "i2c_platform_setup\n");
 394         i2c_platform_setup(priv);
 395
 396         return 0;
 397 }
 398 #else
 399 #define i2c_platform_suspend    NULL
 400 #define i2c_platform_resume     NULL
 401 #endif
 402
 403 static struct platform_driver i2c_platform_driver = {
 404         .driver = {
 405                 .name   = "i2c_pic32",
 406                 .owner  = THIS_MODULE,
 407         },
 408         .probe          = i2c_platform_probe,
 409         .remove         = i2c_platform_remove,
 410         .suspend        = i2c_platform_suspend,
 411         .resume         = i2c_platform_resume,
 412 };
 413
 414 static int __init
 415 i2c_platform_init(void)
 416 {
 417         pr_debug("i2c_platform_init\n");
 418         return platform_driver_register(&i2c_platform_driver);
 419 }
 420
 421 static void __exit
 422 i2c_platform_exit(void)
 423 {
 424         pr_debug("i2c_platform_exit\n");
 425         platform_driver_unregister(&i2c_platform_driver);
 426 }
 427
 428 MODULE_AUTHOR("Chris Dearman, MIPS Technologies INC.");
 429 MODULE_DESCRIPTION("PIC32 I2C driver");
 430 MODULE_LICENSE("GPL");
 431
 432 module_init(i2c_platform_init);
 433 module_exit(i2c_platform_exit);