arch/mips/mti-sead3/sead3-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/init.h>
   9 #include <linux/module.h>
  10 #include <linux/slab.h>
  11 #include <linux/delay.h>
  12 #include <linux/i2c.h>
  13 #include <linux/platform_device.h>
  14
  15 #define PIC32_I2CxCON           0x0000
  16 #define  PIC32_I2CCON_ON        (1<<15)
  17 #define  PIC32_I2CCON_ACKDT     (1<<5)
  18 #define  PIC32_I2CCON_ACKEN     (1<<4)
  19 #define  PIC32_I2CCON_RCEN      (1<<3)
  20 #define  PIC32_I2CCON_PEN       (1<<2)
  21 #define  PIC32_I2CCON_RSEN      (1<<1)
  22 #define  PIC32_I2CCON_SEN       (1<<0)
  23 #define PIC32_I2CxCONCLR        0x0004
  24 #define PIC32_I2CxCONSET        0x0008
  25 #define PIC32_I2CxSTAT          0x0010
  26 #define PIC32_I2CxSTATCLR       0x0014
  27 #define  PIC32_I2CSTAT_ACKSTAT  (1<<15)
  28 #define  PIC32_I2CSTAT_TRSTAT   (1<<14)
  29 #define  PIC32_I2CSTAT_BCL      (1<<10)
  30 #define  PIC32_I2CSTAT_IWCOL    (1<<7)
  31 #define  PIC32_I2CSTAT_I2COV    (1<<6)
  32 #define PIC32_I2CxBRG           0x0040
  33 #define PIC32_I2CxTRN           0x0050
  34 #define PIC32_I2CxRCV           0x0060
  35
  36 static DEFINE_SPINLOCK(pic32_bus_lock);
  37
  38 static void __iomem *bus_xfer   = (void __iomem *)0xbf000600;
  39 static void __iomem *bus_status = (void __iomem *)0xbf000060;
  40
  41 #define DELAY() udelay(100)
  42
  43 static inline unsigned int ioready(void)
  44 {
  45         return readl(bus_status) & 1;
  46 }
  47
  48 static inline void wait_ioready(void)
  49 {
  50         do { } while (!ioready());
  51 }
  52
  53 static inline void wait_ioclear(void)
  54 {
  55         do { } while (ioready());
  56 }
  57
  58 static inline void check_ioclear(void)
  59 {
  60         if (ioready()) {
  61                 do {
  62                         (void) readl(bus_xfer);
  63                         DELAY();
  64                 } while (ioready());
  65         }
  66 }
  67
  68 static u32 pic32_bus_readl(u32 reg)
  69 {
  70         unsigned long flags;
  71         u32 status, val;
  72
  73         spin_lock_irqsave(&pic32_bus_lock, flags);
  74
  75         check_ioclear();
  76         writel((0x01 << 24) | (reg & 0x00ffffff), bus_xfer);
  77         DELAY();
  78         wait_ioready();
  79         status = readl(bus_xfer);
  80         DELAY();
  81         val = readl(bus_xfer);
  82         wait_ioclear();
  83
  84         spin_unlock_irqrestore(&pic32_bus_lock, flags);
  85
  86         return val;
  87 }
  88
  89 static void pic32_bus_writel(u32 val, u32 reg)
  90 {
  91         unsigned long flags;
  92         u32 status;
  93
  94         spin_lock_irqsave(&pic32_bus_lock, flags);
  95
  96         check_ioclear();
  97         writel((0x10 << 24) | (reg & 0x00ffffff), bus_xfer);
  98         DELAY();
  99         writel(val, bus_xfer);
 100         DELAY();
 101         wait_ioready();
 102         status = readl(bus_xfer);
 103         wait_ioclear();
 104
 105         spin_unlock_irqrestore(&pic32_bus_lock, flags);
 106 }
 107
 108 struct pic32_i2c_platform_data {
 109         u32     base;
 110         struct i2c_adapter adap;
 111         u32     xfer_timeout;
 112         u32     ack_timeout;
 113         u32     ctl_timeout;
 114 };
 115
 116 static inline void pic32_i2c_start(struct pic32_i2c_platform_data *adap)
 117 {
 118         pic32_bus_writel(PIC32_I2CCON_SEN, adap->base + PIC32_I2CxCONSET);
 119 }
 120
 121 static inline void pic32_i2c_stop(struct pic32_i2c_platform_data *adap)
 122 {
 123         pic32_bus_writel(PIC32_I2CCON_PEN, adap->base + PIC32_I2CxCONSET);
 124 }
 125
 126 static inline void pic32_i2c_ack(struct pic32_i2c_platform_data *adap)
 127 {
 128         pic32_bus_writel(PIC32_I2CCON_ACKDT, adap->base + PIC32_I2CxCONCLR);
 129         pic32_bus_writel(PIC32_I2CCON_ACKEN, adap->base + PIC32_I2CxCONSET);
 130 }
 131
 132 static inline void pic32_i2c_nack(struct pic32_i2c_platform_data *adap)
 133 {
 134         pic32_bus_writel(PIC32_I2CCON_ACKDT, adap->base + PIC32_I2CxCONSET);
 135         pic32_bus_writel(PIC32_I2CCON_ACKEN, adap->base + PIC32_I2CxCONSET);
 136 }
 137
 138 static inline int pic32_i2c_idle(struct pic32_i2c_platform_data *adap)
 139 {
 140         int i;
 141
 142         for (i = 0; i < adap->ctl_timeout; i++) {
 143                 if (((pic32_bus_readl(adap->base + PIC32_I2CxCON) &
 144                       (PIC32_I2CCON_ACKEN | PIC32_I2CCON_RCEN |
 145                        PIC32_I2CCON_PEN | PIC32_I2CCON_RSEN |
 146                        PIC32_I2CCON_SEN)) == 0) &&
 147                     ((pic32_bus_readl(adap->base + PIC32_I2CxSTAT) &
 148                       (PIC32_I2CSTAT_TRSTAT)) == 0))
 149                         return 0;
 150                 udelay(1);
 151         }
 152         return -ETIMEDOUT;
 153 }
 154
 155 static inline u32 pic32_i2c_master_write(struct pic32_i2c_platform_data *adap,
 156                 u32 byte)
 157 {
 158         pic32_bus_writel(byte, adap->base + PIC32_I2CxTRN);
 159         return pic32_bus_readl(adap->base + PIC32_I2CxSTAT) &
 160                         PIC32_I2CSTAT_IWCOL;
 161 }
 162
 163 static inline u32 pic32_i2c_master_read(struct pic32_i2c_platform_data *adap)
 164 {
 165         pic32_bus_writel(PIC32_I2CCON_RCEN, adap->base + PIC32_I2CxCONSET);
 166         while (pic32_bus_readl(adap->base + PIC32_I2CxCON) & PIC32_I2CCON_RCEN)
 167                 ;
 168         pic32_bus_writel(PIC32_I2CSTAT_I2COV, adap->base + PIC32_I2CxSTATCLR);
 169         return pic32_bus_readl(adap->base + PIC32_I2CxRCV);
 170 }
 171
 172 static int pic32_i2c_address(struct pic32_i2c_platform_data *adap,
 173                 unsigned int addr, int rd)
 174 {
 175         pic32_i2c_idle(adap);
 176         pic32_i2c_start(adap);
 177         pic32_i2c_idle(adap);
 178
 179         addr <<= 1;
 180         if (rd)
 181                 addr |= 1;
 182
 183         if (pic32_i2c_master_write(adap, addr))
 184                 return -EIO;
 185         pic32_i2c_idle(adap);
 186         if (pic32_bus_readl(adap->base + PIC32_I2CxSTAT) &
 187                         PIC32_I2CSTAT_ACKSTAT)
 188                 return -EIO;
 189         return 0;
 190 }
 191
 192 static int sead3_i2c_read(struct pic32_i2c_platform_data *adap,
 193                 unsigned char *buf, unsigned int len)
 194 {
 195         u32 data;
 196         int i;
 197
 198         i = 0;
 199         while (i < len) {
 200                 data = pic32_i2c_master_read(adap);
 201                 buf[i++] = data;
 202                 if (i < len)
 203                         pic32_i2c_ack(adap);
 204                 else
 205                         pic32_i2c_nack(adap);
 206         }
 207
 208         pic32_i2c_stop(adap);
 209         pic32_i2c_idle(adap);
 210         return 0;
 211 }
 212
 213 static int sead3_i2c_write(struct pic32_i2c_platform_data *adap,
 214                 unsigned char *buf, unsigned int len)
 215 {
 216         int i;
 217         u32 data;
 218
 219         i = 0;
 220         while (i < len) {
 221                 data = buf[i];
 222                 if (pic32_i2c_master_write(adap, data))
 223                         return -EIO;
 224                 pic32_i2c_idle(adap);
 225                 if (pic32_bus_readl(adap->base + PIC32_I2CxSTAT) &
 226                                         PIC32_I2CSTAT_ACKSTAT)
 227                         return -EIO;
 228                 i++;
 229         }
 230
 231         pic32_i2c_stop(adap);
 232         pic32_i2c_idle(adap);
 233         return 0;
 234 }
 235
 236 static int sead3_pic32_platform_xfer(struct i2c_adapter *i2c_adap,
 237                 struct i2c_msg *msgs, int num)
 238 {
 239         struct pic32_i2c_platform_data *adap = i2c_adap->algo_data;
 240         struct i2c_msg *p;
 241         int i, err = 0;
 242
 243         for (i = 0; i < num; i++) {
 244 #define __BUFSIZE 80
 245                 int ii;
 246                 static char buf[__BUFSIZE];
 247                 char *b = buf;
 248
 249                 p = &msgs[i];
 250                 b += sprintf(buf, " [%d bytes]", p->len);
 251                 if ((p->flags & I2C_M_RD) == 0) {
 252                         for (ii = 0; ii < p->len; ii++) {
 253                                 if (b < &buf[__BUFSIZE-4]) {
 254                                         b += sprintf(b, " %02x", p->buf[ii]);
 255                                 } else {
 256                                         strcat(b, "...");
 257                                         break;
 258                                 }
 259                         }
 260                 }
 261         }
 262
 263         for (i = 0; !err && i < num; i++) {
 264                 p = &msgs[i];
 265                 err = pic32_i2c_address(adap, p->addr, p->flags & I2C_M_RD);
 266                 if (err || !p->len)
 267                         continue;
 268                 if (p->flags & I2C_M_RD)
 269                         err = sead3_i2c_read(adap, p->buf, p->len);
 270                 else
 271                         err = sead3_i2c_write(adap, p->buf, p->len);
 272         }
 273
 274         /* Return the number of messages processed, or the error code. */
 275         if (err == 0)
 276                 err = num;
 277
 278         return err;
 279 }
 280
 281 static u32 sead3_pic32_platform_func(struct i2c_adapter *adap)
 282 {
 283         return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
 284 }
 285
 286 static const struct i2c_algorithm sead3_platform_algo = {
 287         .master_xfer    = sead3_pic32_platform_xfer,
 288         .functionality  = sead3_pic32_platform_func,
 289 };
 290
 291 static void sead3_i2c_platform_setup(struct pic32_i2c_platform_data *priv)
 292 {
 293         pic32_bus_writel(500, priv->base + PIC32_I2CxBRG);
 294         pic32_bus_writel(PIC32_I2CCON_ON, priv->base + PIC32_I2CxCONCLR);
 295         pic32_bus_writel(PIC32_I2CCON_ON, priv->base + PIC32_I2CxCONSET);
 296         pic32_bus_writel(PIC32_I2CSTAT_BCL | PIC32_I2CSTAT_IWCOL,
 297                 priv->base + PIC32_I2CxSTATCLR);
 298 }
 299
 300 static int sead3_i2c_platform_probe(struct platform_device *pdev)
 301 {
 302         struct pic32_i2c_platform_data *priv;
 303         struct resource *r;
 304         int ret;
 305
 306         r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 307         if (!r) {
 308                 ret = -ENODEV;
 309                 goto out;
 310         }
 311
 312         priv = kzalloc(sizeof(struct pic32_i2c_platform_data), GFP_KERNEL);
 313         if (!priv) {
 314                 ret = -ENOMEM;
 315                 goto out;
 316         }
 317
 318         priv->base = r->start;
 319         if (!priv->base) {
 320                 ret = -EBUSY;
 321                 goto out_mem;
 322         }
 323
 324         priv->xfer_timeout = 200;
 325         priv->ack_timeout = 200;
 326         priv->ctl_timeout = 200;
 327
 328         priv->adap.nr = pdev->id;
 329         priv->adap.algo = &sead3_platform_algo;
 330         priv->adap.algo_data = priv;
 331         priv->adap.dev.parent = &pdev->dev;
 332         strlcpy(priv->adap.name, "SEAD3 PIC32", sizeof(priv->adap.name));
 333
 334         sead3_i2c_platform_setup(priv);
 335
 336         ret = i2c_add_numbered_adapter(&priv->adap);
 337         if (ret == 0) {
 338                 platform_set_drvdata(pdev, priv);
 339                 return 0;
 340         }
 341
 342 out_mem:
 343         kfree(priv);
 344 out:
 345         return ret;
 346 }
 347
 348 static int sead3_i2c_platform_remove(struct platform_device *pdev)
 349 {
 350         struct pic32_i2c_platform_data *priv = platform_get_drvdata(pdev);
 351
 352         platform_set_drvdata(pdev, NULL);
 353         i2c_del_adapter(&priv->adap);
 354         kfree(priv);
 355         return 0;
 356 }
 357
 358 #ifdef CONFIG_PM
 359 static int sead3_i2c_platform_suspend(struct platform_device *pdev,
 360                 pm_message_t state)
 361 {
 362         dev_dbg(&pdev->dev, "i2c_platform_disable\n");
 363         return 0;
 364 }
 365
 366 static int sead3_i2c_platform_resume(struct platform_device *pdev)
 367 {
 368         struct pic32_i2c_platform_data *priv = platform_get_drvdata(pdev);
 369
 370         dev_dbg(&pdev->dev, "sead3_i2c_platform_setup\n");
 371         sead3_i2c_platform_setup(priv);
 372
 373         return 0;
 374 }
 375 #else
 376 #define sead3_i2c_platform_suspend      NULL
 377 #define sead3_i2c_platform_resume       NULL
 378 #endif
 379
 380 static struct platform_driver sead3_i2c_platform_driver = {
 381         .driver = {
 382                 .name   = "sead3-i2c",
 383                 .owner  = THIS_MODULE,
 384         },
 385         .probe          = sead3_i2c_platform_probe,
 386         .remove         = sead3_i2c_platform_remove,
 387         .suspend        = sead3_i2c_platform_suspend,
 388         .resume         = sead3_i2c_platform_resume,
 389 };
 390
 391 static int __init sead3_i2c_platform_init(void)
 392 {
 393         return platform_driver_register(&sead3_i2c_platform_driver);
 394 }
 395 module_init(sead3_i2c_platform_init);
 396
 397 static void __exit sead3_i2c_platform_exit(void)
 398 {
 399         platform_driver_unregister(&sead3_i2c_platform_driver);
 400 }
 401 module_exit(sead3_i2c_platform_exit);
 402
 403 MODULE_AUTHOR("Chris Dearman, MIPS Technologies INC.");
 404 MODULE_DESCRIPTION("SEAD3 PIC32 I2C driver");
 405 MODULE_LICENSE("GPL");