1 /* bbc_i2c.c: I2C low-level driver for BBC device on UltraSPARC-III 2 * platforms. 3 * 4 * Copyright (C) 2001, 2008 David S. Miller (davem@davemloft.net) 5 */ 6 7 #include <linux/module.h> 8 #include <linux/kernel.h> 9 #include <linux/types.h> 10 #include <linux/slab.h> 11 #include <linux/sched.h> 12 #include <linux/wait.h> 13 #include <linux/delay.h> 14 #include <linux/init.h> 15 #include <linux/interrupt.h> 16 #include <linux/of.h> 17 #include <linux/of_device.h> 18 #include <asm/bbc.h> 19 #include <asm/io.h> 20 21 #include "bbc_i2c.h" 22 23 /* Convert this driver to use i2c bus layer someday... */ 24 #define I2C_PCF_PIN 0x80 25 #define I2C_PCF_ESO 0x40 26 #define I2C_PCF_ES1 0x20 27 #define I2C_PCF_ES2 0x10 28 #define I2C_PCF_ENI 0x08 29 #define I2C_PCF_STA 0x04 30 #define I2C_PCF_STO 0x02 31 #define I2C_PCF_ACK 0x01 32 33 #define I2C_PCF_START (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_ENI | I2C_PCF_STA | I2C_PCF_ACK) 34 #define I2C_PCF_STOP (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_STO | I2C_PCF_ACK) 35 #define I2C_PCF_REPSTART ( I2C_PCF_ESO | I2C_PCF_STA | I2C_PCF_ACK) 36 #define I2C_PCF_IDLE (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_ACK) 37 38 #define I2C_PCF_INI 0x40 /* 1 if not initialized */ 39 #define I2C_PCF_STS 0x20 40 #define I2C_PCF_BER 0x10 41 #define I2C_PCF_AD0 0x08 42 #define I2C_PCF_LRB 0x08 43 #define I2C_PCF_AAS 0x04 44 #define I2C_PCF_LAB 0x02 45 #define I2C_PCF_BB 0x01 46 47 /* The BBC devices have two I2C controllers. The first I2C controller 48 * connects mainly to configuration proms (NVRAM, cpu configuration, 49 * dimm types, etc.). Whereas the second I2C controller connects to 50 * environmental control devices such as fans and temperature sensors. 51 * The second controller also connects to the smartcard reader, if present. 52 */ 53 54 static void set_device_claimage(struct bbc_i2c_bus *bp, struct of_device *op, int val) 55 { 56 int i; 57 58 for (i = 0; i < NUM_CHILDREN; i++) { 59 if (bp->devs[i].device == op) { 60 bp->devs[i].client_claimed = val; 61 return; 62 } 63 } 64 } 65 66 #define claim_device(BP,ECHILD) set_device_claimage(BP,ECHILD,1) 67 #define release_device(BP,ECHILD) set_device_claimage(BP,ECHILD,0) 68 69 struct of_device *bbc_i2c_getdev(struct bbc_i2c_bus *bp, int index) 70 { 71 struct of_device *op = NULL; 72 int curidx = 0, i; 73 74 for (i = 0; i < NUM_CHILDREN; i++) { 75 if (!(op = bp->devs[i].device)) 76 break; 77 if (curidx == index) 78 goto out; 79 op = NULL; 80 curidx++; 81 } 82 83 out: 84 if (curidx == index) 85 return op; 86 return NULL; 87 } 88 89 struct bbc_i2c_client *bbc_i2c_attach(struct bbc_i2c_bus *bp, struct of_device *op) 90 { 91 struct bbc_i2c_client *client; 92 const u32 *reg; 93 94 client = kzalloc(sizeof(*client), GFP_KERNEL); 95 if (!client) 96 return NULL; 97 client->bp = bp; 98 client->op = op; 99 100 reg = of_get_property(op->node, "reg", NULL); 101 if (!reg) { 102 kfree(client); 103 return NULL; 104 } 105 106 client->bus = reg[0]; 107 client->address = reg[1]; 108 109 claim_device(bp, op); 110 111 return client; 112 } 113 114 void bbc_i2c_detach(struct bbc_i2c_client *client) 115 { 116 struct bbc_i2c_bus *bp = client->bp; 117 struct of_device *op = client->op; 118 119 release_device(bp, op); 120 kfree(client); 121 } 122 123 static int wait_for_pin(struct bbc_i2c_bus *bp, u8 *status) 124 { 125 DECLARE_WAITQUEUE(wait, current); 126 int limit = 32; 127 int ret = 1; 128 129 bp->waiting = 1; 130 add_wait_queue(&bp->wq, &wait); 131 while (limit-- > 0) { 132 long val; 133 134 val = wait_event_interruptible_timeout( 135 bp->wq, 136 (((*status = readb(bp->i2c_control_regs + 0)) 137 & I2C_PCF_PIN) == 0), 138 msecs_to_jiffies(250)); 139 if (val > 0) { 140 ret = 0; 141 break; 142 } 143 } 144 remove_wait_queue(&bp->wq, &wait); 145 bp->waiting = 0; 146 147 return ret; 148 } 149 150 int bbc_i2c_writeb(struct bbc_i2c_client *client, unsigned char val, int off) 151 { 152 struct bbc_i2c_bus *bp = client->bp; 153 int address = client->address; 154 u8 status; 155 int ret = -1; 156 157 if (bp->i2c_bussel_reg != NULL) 158 writeb(client->bus, bp->i2c_bussel_reg); 159 160 writeb(address, bp->i2c_control_regs + 0x1); 161 writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0); 162 if (wait_for_pin(bp, &status)) 163 goto out; 164 165 writeb(off, bp->i2c_control_regs + 0x1); 166 if (wait_for_pin(bp, &status) || 167 (status & I2C_PCF_LRB) != 0) 168 goto out; 169 170 writeb(val, bp->i2c_control_regs + 0x1); 171 if (wait_for_pin(bp, &status)) 172 goto out; 173 174 ret = 0; 175 176 out: 177 writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0); 178 return ret; 179 } 180 181 int bbc_i2c_readb(struct bbc_i2c_client *client, unsigned char *byte, int off) 182 { 183 struct bbc_i2c_bus *bp = client->bp; 184 unsigned char address = client->address, status; 185 int ret = -1; 186 187 if (bp->i2c_bussel_reg != NULL) 188 writeb(client->bus, bp->i2c_bussel_reg); 189 190 writeb(address, bp->i2c_control_regs + 0x1); 191 writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0); 192 if (wait_for_pin(bp, &status)) 193 goto out; 194 195 writeb(off, bp->i2c_control_regs + 0x1); 196 if (wait_for_pin(bp, &status) || 197 (status & I2C_PCF_LRB) != 0) 198 goto out; 199 200 writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0); 201 202 address |= 0x1; /* READ */ 203 204 writeb(address, bp->i2c_control_regs + 0x1); 205 writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0); 206 if (wait_for_pin(bp, &status)) 207 goto out; 208 209 /* Set PIN back to one so the device sends the first 210 * byte. 211 */ 212 (void) readb(bp->i2c_control_regs + 0x1); 213 if (wait_for_pin(bp, &status)) 214 goto out; 215 216 writeb(I2C_PCF_ESO | I2C_PCF_ENI, bp->i2c_control_regs + 0x0); 217 *byte = readb(bp->i2c_control_regs + 0x1); 218 if (wait_for_pin(bp, &status)) 219 goto out; 220 221 ret = 0; 222 223 out: 224 writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0); 225 (void) readb(bp->i2c_control_regs + 0x1); 226 227 return ret; 228 } 229 230 int bbc_i2c_write_buf(struct bbc_i2c_client *client, 231 char *buf, int len, int off) 232 { 233 int ret = 0; 234 235 while (len > 0) { 236 int err = bbc_i2c_writeb(client, *buf, off); 237 238 if (err < 0) { 239 ret = err; 240 break; 241 } 242 243 len--; 244 buf++; 245 off++; 246 } 247 return ret; 248 } 249 250 int bbc_i2c_read_buf(struct bbc_i2c_client *client, 251 char *buf, int len, int off) 252 { 253 int ret = 0; 254 255 while (len > 0) { 256 int err = bbc_i2c_readb(client, buf, off); 257 if (err < 0) { 258 ret = err; 259 break; 260 } 261 len--; 262 buf++; 263 off++; 264 } 265 266 return ret; 267 } 268 269 EXPORT_SYMBOL(bbc_i2c_getdev); 270 EXPORT_SYMBOL(bbc_i2c_attach); 271 EXPORT_SYMBOL(bbc_i2c_detach); 272 EXPORT_SYMBOL(bbc_i2c_writeb); 273 EXPORT_SYMBOL(bbc_i2c_readb); 274 EXPORT_SYMBOL(bbc_i2c_write_buf); 275 EXPORT_SYMBOL(bbc_i2c_read_buf); 276 277 static irqreturn_t bbc_i2c_interrupt(int irq, void *dev_id) 278 { 279 struct bbc_i2c_bus *bp = dev_id; 280 281 /* PIN going from set to clear is the only event which 282 * makes the i2c assert an interrupt. 283 */ 284 if (bp->waiting && 285 !(readb(bp->i2c_control_regs + 0x0) & I2C_PCF_PIN)) 286 wake_up_interruptible(&bp->wq); 287 288 return IRQ_HANDLED; 289 } 290 291 static void __init reset_one_i2c(struct bbc_i2c_bus *bp) 292 { 293 writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0); 294 writeb(bp->own, bp->i2c_control_regs + 0x1); 295 writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0); 296 writeb(bp->clock, bp->i2c_control_regs + 0x1); 297 writeb(I2C_PCF_IDLE, bp->i2c_control_regs + 0x0); 298 } 299 300 static struct bbc_i2c_bus * __init attach_one_i2c(struct of_device *op, int index) 301 { 302 struct bbc_i2c_bus *bp; 303 struct device_node *dp; 304 int entry; 305 306 bp = kzalloc(sizeof(*bp), GFP_KERNEL); 307 if (!bp) 308 return NULL; 309 310 bp->i2c_control_regs = of_ioremap(&op->resource[0], 0, 0x2, "bbc_i2c_regs"); 311 if (!bp->i2c_control_regs) 312 goto fail; 313 314 bp->i2c_bussel_reg = of_ioremap(&op->resource[1], 0, 0x1, "bbc_i2c_bussel"); 315 if (!bp->i2c_bussel_reg) 316 goto fail; 317 318 bp->waiting = 0; 319 init_waitqueue_head(&bp->wq); 320 if (request_irq(op->irqs[0], bbc_i2c_interrupt, 321 IRQF_SHARED, "bbc_i2c", bp)) 322 goto fail; 323 324 bp->index = index; 325 bp->op = op; 326 327 spin_lock_init(&bp->lock); 328 329 entry = 0; 330 for (dp = op->node->child; 331 dp && entry < 8; 332 dp = dp->sibling, entry++) { 333 struct of_device *child_op; 334 335 child_op = of_find_device_by_node(dp); 336 bp->devs[entry].device = child_op; 337 bp->devs[entry].client_claimed = 0; 338 } 339 340 writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0); 341 bp->own = readb(bp->i2c_control_regs + 0x01); 342 writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0); 343 bp->clock = readb(bp->i2c_control_regs + 0x01); 344 345 printk(KERN_INFO "i2c-%d: Regs at %p, %d devices, own %02x, clock %02x.\n", 346 bp->index, bp->i2c_control_regs, entry, bp->own, bp->clock); 347 348 reset_one_i2c(bp); 349 350 return bp; 351 352 fail: 353 if (bp->i2c_bussel_reg) 354 of_iounmap(&op->resource[1], bp->i2c_bussel_reg, 1); 355 if (bp->i2c_control_regs) 356 of_iounmap(&op->resource[0], bp->i2c_control_regs, 2); 357 kfree(bp); 358 return NULL; 359 } 360 361 extern int bbc_envctrl_init(struct bbc_i2c_bus *bp); 362 extern void bbc_envctrl_cleanup(struct bbc_i2c_bus *bp); 363 364 static int __devinit bbc_i2c_probe(struct of_device *op, 365 const struct of_device_id *match) 366 { 367 struct bbc_i2c_bus *bp; 368 int err, index = 0; 369 370 bp = attach_one_i2c(op, index); 371 if (!bp) 372 return -EINVAL; 373 374 err = bbc_envctrl_init(bp); 375 if (err) { 376 free_irq(op->irqs[0], bp); 377 if (bp->i2c_bussel_reg) 378 of_iounmap(&op->resource[0], bp->i2c_bussel_reg, 1); 379 if (bp->i2c_control_regs) 380 of_iounmap(&op->resource[1], bp->i2c_control_regs, 2); 381 kfree(bp); 382 } else { 383 dev_set_drvdata(&op->dev, bp); 384 } 385 386 return err; 387 } 388 389 static int __devexit bbc_i2c_remove(struct of_device *op) 390 { 391 struct bbc_i2c_bus *bp = dev_get_drvdata(&op->dev); 392 393 bbc_envctrl_cleanup(bp); 394 395 free_irq(op->irqs[0], bp); 396 397 if (bp->i2c_bussel_reg) 398 of_iounmap(&op->resource[0], bp->i2c_bussel_reg, 1); 399 if (bp->i2c_control_regs) 400 of_iounmap(&op->resource[1], bp->i2c_control_regs, 2); 401 402 kfree(bp); 403 404 return 0; 405 } 406 407 static const struct of_device_id bbc_i2c_match[] = { 408 { 409 .name = "i2c", 410 .compatible = "SUNW,bbc-i2c", 411 }, 412 {}, 413 }; 414 MODULE_DEVICE_TABLE(of, bbc_i2c_match); 415 416 static struct of_platform_driver bbc_i2c_driver = { 417 .name = "bbc_i2c", 418 .match_table = bbc_i2c_match, 419 .probe = bbc_i2c_probe, 420 .remove = __devexit_p(bbc_i2c_remove), 421 }; 422 423 static int __init bbc_i2c_init(void) 424 { 425 return of_register_driver(&bbc_i2c_driver, &of_bus_type); 426 } 427 428 static void __exit bbc_i2c_exit(void) 429 { 430 of_unregister_driver(&bbc_i2c_driver); 431 } 432 433 module_init(bbc_i2c_init); 434 module_exit(bbc_i2c_exit); 435 436 MODULE_LICENSE("GPL"); 437