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 platform_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 platform_device *bbc_i2c_getdev(struct bbc_i2c_bus *bp, int index) 70 { 71 struct platform_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 platform_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->dev.of_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 platform_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 ret = bbc_i2c_writeb(client, *buf, off); 237 if (ret < 0) 238 break; 239 len--; 240 buf++; 241 off++; 242 } 243 return ret; 244 } 245 246 int bbc_i2c_read_buf(struct bbc_i2c_client *client, 247 char *buf, int len, int off) 248 { 249 int ret = 0; 250 251 while (len > 0) { 252 ret = bbc_i2c_readb(client, buf, off); 253 if (ret < 0) 254 break; 255 len--; 256 buf++; 257 off++; 258 } 259 260 return ret; 261 } 262 263 EXPORT_SYMBOL(bbc_i2c_getdev); 264 EXPORT_SYMBOL(bbc_i2c_attach); 265 EXPORT_SYMBOL(bbc_i2c_detach); 266 EXPORT_SYMBOL(bbc_i2c_writeb); 267 EXPORT_SYMBOL(bbc_i2c_readb); 268 EXPORT_SYMBOL(bbc_i2c_write_buf); 269 EXPORT_SYMBOL(bbc_i2c_read_buf); 270 271 static irqreturn_t bbc_i2c_interrupt(int irq, void *dev_id) 272 { 273 struct bbc_i2c_bus *bp = dev_id; 274 275 /* PIN going from set to clear is the only event which 276 * makes the i2c assert an interrupt. 277 */ 278 if (bp->waiting && 279 !(readb(bp->i2c_control_regs + 0x0) & I2C_PCF_PIN)) 280 wake_up_interruptible(&bp->wq); 281 282 return IRQ_HANDLED; 283 } 284 285 static void reset_one_i2c(struct bbc_i2c_bus *bp) 286 { 287 writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0); 288 writeb(bp->own, bp->i2c_control_regs + 0x1); 289 writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0); 290 writeb(bp->clock, bp->i2c_control_regs + 0x1); 291 writeb(I2C_PCF_IDLE, bp->i2c_control_regs + 0x0); 292 } 293 294 static struct bbc_i2c_bus * attach_one_i2c(struct platform_device *op, int index) 295 { 296 struct bbc_i2c_bus *bp; 297 struct device_node *dp; 298 int entry; 299 300 bp = kzalloc(sizeof(*bp), GFP_KERNEL); 301 if (!bp) 302 return NULL; 303 304 bp->i2c_control_regs = of_ioremap(&op->resource[0], 0, 0x2, "bbc_i2c_regs"); 305 if (!bp->i2c_control_regs) 306 goto fail; 307 308 bp->i2c_bussel_reg = of_ioremap(&op->resource[1], 0, 0x1, "bbc_i2c_bussel"); 309 if (!bp->i2c_bussel_reg) 310 goto fail; 311 312 bp->waiting = 0; 313 init_waitqueue_head(&bp->wq); 314 if (request_irq(op->archdata.irqs[0], bbc_i2c_interrupt, 315 IRQF_SHARED, "bbc_i2c", bp)) 316 goto fail; 317 318 bp->index = index; 319 bp->op = op; 320 321 spin_lock_init(&bp->lock); 322 323 entry = 0; 324 for (dp = op->dev.of_node->child; 325 dp && entry < 8; 326 dp = dp->sibling, entry++) { 327 struct platform_device *child_op; 328 329 child_op = of_find_device_by_node(dp); 330 bp->devs[entry].device = child_op; 331 bp->devs[entry].client_claimed = 0; 332 } 333 334 writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0); 335 bp->own = readb(bp->i2c_control_regs + 0x01); 336 writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0); 337 bp->clock = readb(bp->i2c_control_regs + 0x01); 338 339 printk(KERN_INFO "i2c-%d: Regs at %p, %d devices, own %02x, clock %02x.\n", 340 bp->index, bp->i2c_control_regs, entry, bp->own, bp->clock); 341 342 reset_one_i2c(bp); 343 344 return bp; 345 346 fail: 347 if (bp->i2c_bussel_reg) 348 of_iounmap(&op->resource[1], bp->i2c_bussel_reg, 1); 349 if (bp->i2c_control_regs) 350 of_iounmap(&op->resource[0], bp->i2c_control_regs, 2); 351 kfree(bp); 352 return NULL; 353 } 354 355 extern int bbc_envctrl_init(struct bbc_i2c_bus *bp); 356 extern void bbc_envctrl_cleanup(struct bbc_i2c_bus *bp); 357 358 static int bbc_i2c_probe(struct platform_device *op) 359 { 360 struct bbc_i2c_bus *bp; 361 int err, index = 0; 362 363 bp = attach_one_i2c(op, index); 364 if (!bp) 365 return -EINVAL; 366 367 err = bbc_envctrl_init(bp); 368 if (err) { 369 free_irq(op->archdata.irqs[0], bp); 370 if (bp->i2c_bussel_reg) 371 of_iounmap(&op->resource[0], bp->i2c_bussel_reg, 1); 372 if (bp->i2c_control_regs) 373 of_iounmap(&op->resource[1], bp->i2c_control_regs, 2); 374 kfree(bp); 375 } else { 376 dev_set_drvdata(&op->dev, bp); 377 } 378 379 return err; 380 } 381 382 static int bbc_i2c_remove(struct platform_device *op) 383 { 384 struct bbc_i2c_bus *bp = dev_get_drvdata(&op->dev); 385 386 bbc_envctrl_cleanup(bp); 387 388 free_irq(op->archdata.irqs[0], bp); 389 390 if (bp->i2c_bussel_reg) 391 of_iounmap(&op->resource[0], bp->i2c_bussel_reg, 1); 392 if (bp->i2c_control_regs) 393 of_iounmap(&op->resource[1], bp->i2c_control_regs, 2); 394 395 kfree(bp); 396 397 return 0; 398 } 399 400 static const struct of_device_id bbc_i2c_match[] = { 401 { 402 .name = "i2c", 403 .compatible = "SUNW,bbc-i2c", 404 }, 405 {}, 406 }; 407 MODULE_DEVICE_TABLE(of, bbc_i2c_match); 408 409 static struct platform_driver bbc_i2c_driver = { 410 .driver = { 411 .name = "bbc_i2c", 412 .owner = THIS_MODULE, 413 .of_match_table = bbc_i2c_match, 414 }, 415 .probe = bbc_i2c_probe, 416 .remove = bbc_i2c_remove, 417 }; 418 419 module_platform_driver(bbc_i2c_driver); 420 421 MODULE_LICENSE("GPL"); 422