1 /* 2 * i2c-au1550.c: SMBus (i2c) adapter for Alchemy PSC interface 3 * Copyright (C) 2004 Embedded Edge, LLC <dan@embeddededge.com> 4 * 5 * 2.6 port by Matt Porter <mporter@kernel.crashing.org> 6 * 7 * The documentation describes this as an SMBus controller, but it doesn't 8 * understand any of the SMBus protocol in hardware. It's really an I2C 9 * controller that could emulate most of the SMBus in software. 10 * 11 * This is just a skeleton adapter to use with the Au1550 PSC 12 * algorithm. It was developed for the Pb1550, but will work with 13 * any Au1550 board that has a similar PSC configuration. 14 * 15 * This program is free software; you can redistribute it and/or 16 * modify it under the terms of the GNU General Public License 17 * as published by the Free Software Foundation; either version 2 18 * of the License, or (at your option) any later version. 19 * 20 * This program is distributed in the hope that it will be useful, 21 * but WITHOUT ANY WARRANTY; without even the implied warranty of 22 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 23 * GNU General Public License for more details. 24 * 25 * You should have received a copy of the GNU General Public License 26 * along with this program; if not, write to the Free Software 27 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. 28 */ 29 30 #include <linux/delay.h> 31 #include <linux/kernel.h> 32 #include <linux/module.h> 33 #include <linux/platform_device.h> 34 #include <linux/init.h> 35 #include <linux/errno.h> 36 #include <linux/i2c.h> 37 #include <linux/slab.h> 38 39 #include <asm/mach-au1x00/au1xxx.h> 40 #include <asm/mach-au1x00/au1xxx_psc.h> 41 42 struct i2c_au1550_data { 43 u32 psc_base; 44 int xfer_timeout; 45 int ack_timeout; 46 struct i2c_adapter adap; 47 struct resource *ioarea; 48 }; 49 50 static int 51 wait_xfer_done(struct i2c_au1550_data *adap) 52 { 53 u32 stat; 54 int i; 55 volatile psc_smb_t *sp; 56 57 sp = (volatile psc_smb_t *)(adap->psc_base); 58 59 /* Wait for Tx Buffer Empty 60 */ 61 for (i = 0; i < adap->xfer_timeout; i++) { 62 stat = sp->psc_smbstat; 63 au_sync(); 64 if ((stat & PSC_SMBSTAT_TE) != 0) 65 return 0; 66 67 udelay(1); 68 } 69 70 return -ETIMEDOUT; 71 } 72 73 static int 74 wait_ack(struct i2c_au1550_data *adap) 75 { 76 u32 stat; 77 volatile psc_smb_t *sp; 78 79 if (wait_xfer_done(adap)) 80 return -ETIMEDOUT; 81 82 sp = (volatile psc_smb_t *)(adap->psc_base); 83 84 stat = sp->psc_smbevnt; 85 au_sync(); 86 87 if ((stat & (PSC_SMBEVNT_DN | PSC_SMBEVNT_AN | PSC_SMBEVNT_AL)) != 0) 88 return -ETIMEDOUT; 89 90 return 0; 91 } 92 93 static int 94 wait_master_done(struct i2c_au1550_data *adap) 95 { 96 u32 stat; 97 int i; 98 volatile psc_smb_t *sp; 99 100 sp = (volatile psc_smb_t *)(adap->psc_base); 101 102 /* Wait for Master Done. 103 */ 104 for (i = 0; i < adap->xfer_timeout; i++) { 105 stat = sp->psc_smbevnt; 106 au_sync(); 107 if ((stat & PSC_SMBEVNT_MD) != 0) 108 return 0; 109 udelay(1); 110 } 111 112 return -ETIMEDOUT; 113 } 114 115 static int 116 do_address(struct i2c_au1550_data *adap, unsigned int addr, int rd, int q) 117 { 118 volatile psc_smb_t *sp; 119 u32 stat; 120 121 sp = (volatile psc_smb_t *)(adap->psc_base); 122 123 /* Reset the FIFOs, clear events. 124 */ 125 stat = sp->psc_smbstat; 126 sp->psc_smbevnt = PSC_SMBEVNT_ALLCLR; 127 au_sync(); 128 129 if (!(stat & PSC_SMBSTAT_TE) || !(stat & PSC_SMBSTAT_RE)) { 130 sp->psc_smbpcr = PSC_SMBPCR_DC; 131 au_sync(); 132 do { 133 stat = sp->psc_smbpcr; 134 au_sync(); 135 } while ((stat & PSC_SMBPCR_DC) != 0); 136 udelay(50); 137 } 138 139 /* Write out the i2c chip address and specify operation 140 */ 141 addr <<= 1; 142 if (rd) 143 addr |= 1; 144 145 /* zero-byte xfers stop immediately */ 146 if (q) 147 addr |= PSC_SMBTXRX_STP; 148 149 /* Put byte into fifo, start up master. 150 */ 151 sp->psc_smbtxrx = addr; 152 au_sync(); 153 sp->psc_smbpcr = PSC_SMBPCR_MS; 154 au_sync(); 155 if (wait_ack(adap)) 156 return -EIO; 157 return (q) ? wait_master_done(adap) : 0; 158 } 159 160 static u32 161 wait_for_rx_byte(struct i2c_au1550_data *adap, u32 *ret_data) 162 { 163 int j; 164 u32 data, stat; 165 volatile psc_smb_t *sp; 166 167 if (wait_xfer_done(adap)) 168 return -EIO; 169 170 sp = (volatile psc_smb_t *)(adap->psc_base); 171 172 j = adap->xfer_timeout * 100; 173 do { 174 j--; 175 if (j <= 0) 176 return -EIO; 177 178 stat = sp->psc_smbstat; 179 au_sync(); 180 if ((stat & PSC_SMBSTAT_RE) == 0) 181 j = 0; 182 else 183 udelay(1); 184 } while (j > 0); 185 data = sp->psc_smbtxrx; 186 au_sync(); 187 *ret_data = data; 188 189 return 0; 190 } 191 192 static int 193 i2c_read(struct i2c_au1550_data *adap, unsigned char *buf, 194 unsigned int len) 195 { 196 int i; 197 u32 data; 198 volatile psc_smb_t *sp; 199 200 if (len == 0) 201 return 0; 202 203 /* A read is performed by stuffing the transmit fifo with 204 * zero bytes for timing, waiting for bytes to appear in the 205 * receive fifo, then reading the bytes. 206 */ 207 208 sp = (volatile psc_smb_t *)(adap->psc_base); 209 210 i = 0; 211 while (i < (len-1)) { 212 sp->psc_smbtxrx = 0; 213 au_sync(); 214 if (wait_for_rx_byte(adap, &data)) 215 return -EIO; 216 217 buf[i] = data; 218 i++; 219 } 220 221 /* The last byte has to indicate transfer done. 222 */ 223 sp->psc_smbtxrx = PSC_SMBTXRX_STP; 224 au_sync(); 225 if (wait_master_done(adap)) 226 return -EIO; 227 228 data = sp->psc_smbtxrx; 229 au_sync(); 230 buf[i] = data; 231 return 0; 232 } 233 234 static int 235 i2c_write(struct i2c_au1550_data *adap, unsigned char *buf, 236 unsigned int len) 237 { 238 int i; 239 u32 data; 240 volatile psc_smb_t *sp; 241 242 if (len == 0) 243 return 0; 244 245 sp = (volatile psc_smb_t *)(adap->psc_base); 246 247 i = 0; 248 while (i < (len-1)) { 249 data = buf[i]; 250 sp->psc_smbtxrx = data; 251 au_sync(); 252 if (wait_ack(adap)) 253 return -EIO; 254 i++; 255 } 256 257 /* The last byte has to indicate transfer done. 258 */ 259 data = buf[i]; 260 data |= PSC_SMBTXRX_STP; 261 sp->psc_smbtxrx = data; 262 au_sync(); 263 if (wait_master_done(adap)) 264 return -EIO; 265 return 0; 266 } 267 268 static int 269 au1550_xfer(struct i2c_adapter *i2c_adap, struct i2c_msg *msgs, int num) 270 { 271 struct i2c_au1550_data *adap = i2c_adap->algo_data; 272 volatile psc_smb_t *sp = (volatile psc_smb_t *)adap->psc_base; 273 struct i2c_msg *p; 274 int i, err = 0; 275 276 sp->psc_ctrl = PSC_CTRL_ENABLE; 277 au_sync(); 278 279 for (i = 0; !err && i < num; i++) { 280 p = &msgs[i]; 281 err = do_address(adap, p->addr, p->flags & I2C_M_RD, 282 (p->len == 0)); 283 if (err || !p->len) 284 continue; 285 if (p->flags & I2C_M_RD) 286 err = i2c_read(adap, p->buf, p->len); 287 else 288 err = i2c_write(adap, p->buf, p->len); 289 } 290 291 /* Return the number of messages processed, or the error code. 292 */ 293 if (err == 0) 294 err = num; 295 296 sp->psc_ctrl = PSC_CTRL_SUSPEND; 297 au_sync(); 298 299 return err; 300 } 301 302 static u32 303 au1550_func(struct i2c_adapter *adap) 304 { 305 return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; 306 } 307 308 static const struct i2c_algorithm au1550_algo = { 309 .master_xfer = au1550_xfer, 310 .functionality = au1550_func, 311 }; 312 313 static void i2c_au1550_setup(struct i2c_au1550_data *priv) 314 { 315 volatile psc_smb_t *sp = (volatile psc_smb_t *)priv->psc_base; 316 u32 stat; 317 318 sp->psc_ctrl = PSC_CTRL_DISABLE; 319 au_sync(); 320 sp->psc_sel = PSC_SEL_PS_SMBUSMODE; 321 sp->psc_smbcfg = 0; 322 au_sync(); 323 sp->psc_ctrl = PSC_CTRL_ENABLE; 324 au_sync(); 325 do { 326 stat = sp->psc_smbstat; 327 au_sync(); 328 } while ((stat & PSC_SMBSTAT_SR) == 0); 329 330 sp->psc_smbcfg = (PSC_SMBCFG_RT_FIFO8 | PSC_SMBCFG_TT_FIFO8 | 331 PSC_SMBCFG_DD_DISABLE); 332 333 /* Divide by 8 to get a 6.25 MHz clock. The later protocol 334 * timings are based on this clock. 335 */ 336 sp->psc_smbcfg |= PSC_SMBCFG_SET_DIV(PSC_SMBCFG_DIV8); 337 sp->psc_smbmsk = PSC_SMBMSK_ALLMASK; 338 au_sync(); 339 340 /* Set the protocol timer values. See Table 71 in the 341 * Au1550 Data Book for standard timing values. 342 */ 343 sp->psc_smbtmr = PSC_SMBTMR_SET_TH(0) | PSC_SMBTMR_SET_PS(15) | \ 344 PSC_SMBTMR_SET_PU(15) | PSC_SMBTMR_SET_SH(15) | \ 345 PSC_SMBTMR_SET_SU(15) | PSC_SMBTMR_SET_CL(15) | \ 346 PSC_SMBTMR_SET_CH(15); 347 au_sync(); 348 349 sp->psc_smbcfg |= PSC_SMBCFG_DE_ENABLE; 350 do { 351 stat = sp->psc_smbstat; 352 au_sync(); 353 } while ((stat & PSC_SMBSTAT_SR) == 0); 354 355 sp->psc_ctrl = PSC_CTRL_SUSPEND; 356 au_sync(); 357 } 358 359 static void i2c_au1550_disable(struct i2c_au1550_data *priv) 360 { 361 volatile psc_smb_t *sp = (volatile psc_smb_t *)priv->psc_base; 362 363 sp->psc_smbcfg = 0; 364 sp->psc_ctrl = PSC_CTRL_DISABLE; 365 au_sync(); 366 } 367 368 /* 369 * registering functions to load algorithms at runtime 370 * Prior to calling us, the 50MHz clock frequency and routing 371 * must have been set up for the PSC indicated by the adapter. 372 */ 373 static int __devinit 374 i2c_au1550_probe(struct platform_device *pdev) 375 { 376 struct i2c_au1550_data *priv; 377 struct resource *r; 378 int ret; 379 380 r = platform_get_resource(pdev, IORESOURCE_MEM, 0); 381 if (!r) { 382 ret = -ENODEV; 383 goto out; 384 } 385 386 priv = kzalloc(sizeof(struct i2c_au1550_data), GFP_KERNEL); 387 if (!priv) { 388 ret = -ENOMEM; 389 goto out; 390 } 391 392 priv->ioarea = request_mem_region(r->start, resource_size(r), 393 pdev->name); 394 if (!priv->ioarea) { 395 ret = -EBUSY; 396 goto out_mem; 397 } 398 399 priv->psc_base = CKSEG1ADDR(r->start); 400 priv->xfer_timeout = 200; 401 priv->ack_timeout = 200; 402 403 priv->adap.nr = pdev->id; 404 priv->adap.algo = &au1550_algo; 405 priv->adap.algo_data = priv; 406 priv->adap.dev.parent = &pdev->dev; 407 strlcpy(priv->adap.name, "Au1xxx PSC I2C", sizeof(priv->adap.name)); 408 409 /* Now, set up the PSC for SMBus PIO mode. 410 */ 411 i2c_au1550_setup(priv); 412 413 ret = i2c_add_numbered_adapter(&priv->adap); 414 if (ret == 0) { 415 platform_set_drvdata(pdev, priv); 416 return 0; 417 } 418 419 i2c_au1550_disable(priv); 420 421 release_resource(priv->ioarea); 422 kfree(priv->ioarea); 423 out_mem: 424 kfree(priv); 425 out: 426 return ret; 427 } 428 429 static int __devexit 430 i2c_au1550_remove(struct platform_device *pdev) 431 { 432 struct i2c_au1550_data *priv = platform_get_drvdata(pdev); 433 434 platform_set_drvdata(pdev, NULL); 435 i2c_del_adapter(&priv->adap); 436 i2c_au1550_disable(priv); 437 release_resource(priv->ioarea); 438 kfree(priv->ioarea); 439 kfree(priv); 440 return 0; 441 } 442 443 #ifdef CONFIG_PM 444 static int 445 i2c_au1550_suspend(struct platform_device *pdev, pm_message_t state) 446 { 447 struct i2c_au1550_data *priv = platform_get_drvdata(pdev); 448 449 i2c_au1550_disable(priv); 450 451 return 0; 452 } 453 454 static int 455 i2c_au1550_resume(struct platform_device *pdev) 456 { 457 struct i2c_au1550_data *priv = platform_get_drvdata(pdev); 458 459 i2c_au1550_setup(priv); 460 461 return 0; 462 } 463 #else 464 #define i2c_au1550_suspend NULL 465 #define i2c_au1550_resume NULL 466 #endif 467 468 static struct platform_driver au1xpsc_smbus_driver = { 469 .driver = { 470 .name = "au1xpsc_smbus", 471 .owner = THIS_MODULE, 472 }, 473 .probe = i2c_au1550_probe, 474 .remove = __devexit_p(i2c_au1550_remove), 475 .suspend = i2c_au1550_suspend, 476 .resume = i2c_au1550_resume, 477 }; 478 479 static int __init 480 i2c_au1550_init(void) 481 { 482 return platform_driver_register(&au1xpsc_smbus_driver); 483 } 484 485 static void __exit 486 i2c_au1550_exit(void) 487 { 488 platform_driver_unregister(&au1xpsc_smbus_driver); 489 } 490 491 MODULE_AUTHOR("Dan Malek, Embedded Edge, LLC."); 492 MODULE_DESCRIPTION("SMBus adapter Alchemy pb1550"); 493 MODULE_LICENSE("GPL"); 494 MODULE_ALIAS("platform:au1xpsc_smbus"); 495 496 module_init (i2c_au1550_init); 497 module_exit (i2c_au1550_exit); 498