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