drivers/sbus/char/bbc_i2c.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /* bbc_i2c.c: I2C low-level driver for BBC device on UltraSPARC-III
   3  *            platforms.
   4  *
   5  * Copyright (C) 2001, 2008 David S. Miller ([email protected])
   6  */
   7
   8 #include <linux/module.h>
   9 #include <linux/kernel.h>
  10 #include <linux/types.h>
  11 #include <linux/slab.h>
  12 #include <linux/sched.h>
  13 #include <linux/wait.h>
  14 #include <linux/delay.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/of.h>
  17 #include <linux/of_platform.h>
  18 #include <linux/platform_device.h>
  19 #include <asm/bbc.h>
  20 #include <asm/io.h>
  21
  22 #include "bbc_i2c.h"
  23
  24 /* Convert this driver to use i2c bus layer someday... */
  25 #define I2C_PCF_PIN     0x80
  26 #define I2C_PCF_ESO     0x40
  27 #define I2C_PCF_ES1     0x20
  28 #define I2C_PCF_ES2     0x10
  29 #define I2C_PCF_ENI     0x08
  30 #define I2C_PCF_STA     0x04
  31 #define I2C_PCF_STO     0x02
  32 #define I2C_PCF_ACK     0x01
  33
  34 #define I2C_PCF_START    (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_ENI | I2C_PCF_STA | I2C_PCF_ACK)
  35 #define I2C_PCF_STOP     (I2C_PCF_PIN | I2C_PCF_ESO | I2C_PCF_STO | I2C_PCF_ACK)
  36 #define I2C_PCF_REPSTART (              I2C_PCF_ESO | I2C_PCF_STA | I2C_PCF_ACK)
  37 #define I2C_PCF_IDLE     (I2C_PCF_PIN | I2C_PCF_ESO               | I2C_PCF_ACK)
  38
  39 #define I2C_PCF_INI 0x40   /* 1 if not initialized */
  40 #define I2C_PCF_STS 0x20
  41 #define I2C_PCF_BER 0x10
  42 #define I2C_PCF_AD0 0x08
  43 #define I2C_PCF_LRB 0x08
  44 #define I2C_PCF_AAS 0x04
  45 #define I2C_PCF_LAB 0x02
  46 #define I2C_PCF_BB  0x01
  47
  48 /* The BBC devices have two I2C controllers.  The first I2C controller
  49  * connects mainly to configuration proms (NVRAM, cpu configuration,
  50  * dimm types, etc.).  Whereas the second I2C controller connects to
  51  * environmental control devices such as fans and temperature sensors.
  52  * The second controller also connects to the smartcard reader, if present.
  53  */
  54
  55 static void set_device_claimage(struct bbc_i2c_bus *bp, struct platform_device *op, int val)
  56 {
  57         int i;
  58
  59         for (i = 0; i < NUM_CHILDREN; i++) {
  60                 if (bp->devs[i].device == op) {
  61                         bp->devs[i].client_claimed = val;
  62                         return;
  63                 }
  64         }
  65 }
  66
  67 #define claim_device(BP,ECHILD)         set_device_claimage(BP,ECHILD,1)
  68 #define release_device(BP,ECHILD)       set_device_claimage(BP,ECHILD,0)
  69
  70 struct platform_device *bbc_i2c_getdev(struct bbc_i2c_bus *bp, int index)
  71 {
  72         struct platform_device *op = NULL;
  73         int curidx = 0, i;
  74
  75         for (i = 0; i < NUM_CHILDREN; i++) {
  76                 if (!(op = bp->devs[i].device))
  77                         break;
  78                 if (curidx == index)
  79                         goto out;
  80                 op = NULL;
  81                 curidx++;
  82         }
  83
  84 out:
  85         if (curidx == index)
  86                 return op;
  87         return NULL;
  88 }
  89
  90 struct bbc_i2c_client *bbc_i2c_attach(struct bbc_i2c_bus *bp, struct platform_device *op)
  91 {
  92         struct bbc_i2c_client *client;
  93         const u32 *reg;
  94
  95         client = kzalloc(sizeof(*client), GFP_KERNEL);
  96         if (!client)
  97                 return NULL;
  98         client->bp = bp;
  99         client->op = op;
 100
 101         reg = of_get_property(op->dev.of_node, "reg", NULL);
 102         if (!reg) {
 103                 kfree(client);
 104                 return NULL;
 105         }
 106
 107         client->bus = reg[0];
 108         client->address = reg[1];
 109
 110         claim_device(bp, op);
 111
 112         return client;
 113 }
 114
 115 void bbc_i2c_detach(struct bbc_i2c_client *client)
 116 {
 117         struct bbc_i2c_bus *bp = client->bp;
 118         struct platform_device *op = client->op;
 119
 120         release_device(bp, op);
 121         kfree(client);
 122 }
 123
 124 static int wait_for_pin(struct bbc_i2c_bus *bp, u8 *status)
 125 {
 126         DECLARE_WAITQUEUE(wait, current);
 127         int limit = 32;
 128         int ret = 1;
 129
 130         bp->waiting = 1;
 131         add_wait_queue(&bp->wq, &wait);
 132         while (limit-- > 0) {
 133                 long val;
 134
 135                 val = wait_event_interruptible_timeout(
 136                                 bp->wq,
 137                                 (((*status = readb(bp->i2c_control_regs + 0))
 138                                   & I2C_PCF_PIN) == 0),
 139                                 msecs_to_jiffies(250));
 140                 if (val > 0) {
 141                         ret = 0;
 142                         break;
 143                 }
 144         }
 145         remove_wait_queue(&bp->wq, &wait);
 146         bp->waiting = 0;
 147
 148         return ret;
 149 }
 150
 151 int bbc_i2c_writeb(struct bbc_i2c_client *client, unsigned char val, int off)
 152 {
 153         struct bbc_i2c_bus *bp = client->bp;
 154         int address = client->address;
 155         u8 status;
 156         int ret = -1;
 157
 158         if (bp->i2c_bussel_reg != NULL)
 159                 writeb(client->bus, bp->i2c_bussel_reg);
 160
 161         writeb(address, bp->i2c_control_regs + 0x1);
 162         writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
 163         if (wait_for_pin(bp, &status))
 164                 goto out;
 165
 166         writeb(off, bp->i2c_control_regs + 0x1);
 167         if (wait_for_pin(bp, &status) ||
 168             (status & I2C_PCF_LRB) != 0)
 169                 goto out;
 170
 171         writeb(val, bp->i2c_control_regs + 0x1);
 172         if (wait_for_pin(bp, &status))
 173                 goto out;
 174
 175         ret = 0;
 176
 177 out:
 178         writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
 179         return ret;
 180 }
 181
 182 int bbc_i2c_readb(struct bbc_i2c_client *client, unsigned char *byte, int off)
 183 {
 184         struct bbc_i2c_bus *bp = client->bp;
 185         unsigned char address = client->address, status;
 186         int ret = -1;
 187
 188         if (bp->i2c_bussel_reg != NULL)
 189                 writeb(client->bus, bp->i2c_bussel_reg);
 190
 191         writeb(address, bp->i2c_control_regs + 0x1);
 192         writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
 193         if (wait_for_pin(bp, &status))
 194                 goto out;
 195
 196         writeb(off, bp->i2c_control_regs + 0x1);
 197         if (wait_for_pin(bp, &status) ||
 198             (status & I2C_PCF_LRB) != 0)
 199                 goto out;
 200
 201         writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
 202
 203         address |= 0x1; /* READ */
 204
 205         writeb(address, bp->i2c_control_regs + 0x1);
 206         writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
 207         if (wait_for_pin(bp, &status))
 208                 goto out;
 209
 210         /* Set PIN back to one so the device sends the first
 211          * byte.
 212          */
 213         (void) readb(bp->i2c_control_regs + 0x1);
 214         if (wait_for_pin(bp, &status))
 215                 goto out;
 216
 217         writeb(I2C_PCF_ESO | I2C_PCF_ENI, bp->i2c_control_regs + 0x0);
 218         *byte = readb(bp->i2c_control_regs + 0x1);
 219         if (wait_for_pin(bp, &status))
 220                 goto out;
 221
 222         ret = 0;
 223
 224 out:
 225         writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
 226         (void) readb(bp->i2c_control_regs + 0x1);
 227
 228         return ret;
 229 }
 230
 231 int bbc_i2c_write_buf(struct bbc_i2c_client *client,
 232                       char *buf, int len, int off)
 233 {
 234         int ret = 0;
 235
 236         while (len > 0) {
 237                 ret = bbc_i2c_writeb(client, *buf, off);
 238                 if (ret < 0)
 239                         break;
 240                 len--;
 241                 buf++;
 242                 off++;
 243         }
 244         return ret;
 245 }
 246
 247 int bbc_i2c_read_buf(struct bbc_i2c_client *client,
 248                      char *buf, int len, int off)
 249 {
 250         int ret = 0;
 251
 252         while (len > 0) {
 253                 ret = bbc_i2c_readb(client, buf, off);
 254                 if (ret < 0)
 255                         break;
 256                 len--;
 257                 buf++;
 258                 off++;
 259         }
 260
 261         return ret;
 262 }
 263
 264 EXPORT_SYMBOL(bbc_i2c_getdev);
 265 EXPORT_SYMBOL(bbc_i2c_attach);
 266 EXPORT_SYMBOL(bbc_i2c_detach);
 267 EXPORT_SYMBOL(bbc_i2c_writeb);
 268 EXPORT_SYMBOL(bbc_i2c_readb);
 269 EXPORT_SYMBOL(bbc_i2c_write_buf);
 270 EXPORT_SYMBOL(bbc_i2c_read_buf);
 271
 272 static irqreturn_t bbc_i2c_interrupt(int irq, void *dev_id)
 273 {
 274         struct bbc_i2c_bus *bp = dev_id;
 275
 276         /* PIN going from set to clear is the only event which
 277          * makes the i2c assert an interrupt.
 278          */
 279         if (bp->waiting &&
 280             !(readb(bp->i2c_control_regs + 0x0) & I2C_PCF_PIN))
 281                 wake_up_interruptible(&bp->wq);
 282
 283         return IRQ_HANDLED;
 284 }
 285
 286 static void reset_one_i2c(struct bbc_i2c_bus *bp)
 287 {
 288         writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0);
 289         writeb(bp->own, bp->i2c_control_regs + 0x1);
 290         writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0);
 291         writeb(bp->clock, bp->i2c_control_regs + 0x1);
 292         writeb(I2C_PCF_IDLE, bp->i2c_control_regs + 0x0);
 293 }
 294
 295 static struct bbc_i2c_bus * attach_one_i2c(struct platform_device *op, int index)
 296 {
 297         struct bbc_i2c_bus *bp;
 298         struct device_node *dp;
 299         int entry;
 300
 301         bp = kzalloc(sizeof(*bp), GFP_KERNEL);
 302         if (!bp)
 303                 return NULL;
 304
 305         INIT_LIST_HEAD(&bp->temps);
 306         INIT_LIST_HEAD(&bp->fans);
 307
 308         bp->i2c_control_regs = of_ioremap(&op->resource[0], 0, 0x2, "bbc_i2c_regs");
 309         if (!bp->i2c_control_regs)
 310                 goto fail;
 311
 312         if (op->num_resources == 2) {
 313                 bp->i2c_bussel_reg = of_ioremap(&op->resource[1], 0, 0x1, "bbc_i2c_bussel");
 314                 if (!bp->i2c_bussel_reg)
 315                         goto fail;
 316         }
 317
 318         bp->waiting = 0;
 319         init_waitqueue_head(&bp->wq);
 320         if (request_irq(op->archdata.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->dev.of_node->child;
 331              dp && entry < 8;
 332              dp = dp->sibling, entry++) {
 333                 struct platform_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 static int bbc_i2c_probe(struct platform_device *op)
 362 {
 363         struct bbc_i2c_bus *bp;
 364         int err, index = 0;
 365
 366         bp = attach_one_i2c(op, index);
 367         if (!bp)
 368                 return -EINVAL;
 369
 370         err = bbc_envctrl_init(bp);
 371         if (err) {
 372                 free_irq(op->archdata.irqs[0], bp);
 373                 if (bp->i2c_bussel_reg)
 374                         of_iounmap(&op->resource[0], bp->i2c_bussel_reg, 1);
 375                 if (bp->i2c_control_regs)
 376                         of_iounmap(&op->resource[1], bp->i2c_control_regs, 2);
 377                 kfree(bp);
 378         } else {
 379                 dev_set_drvdata(&op->dev, bp);
 380         }
 381
 382         return err;
 383 }
 384
 385 static void bbc_i2c_remove(struct platform_device *op)
 386 {
 387         struct bbc_i2c_bus *bp = dev_get_drvdata(&op->dev);
 388
 389         bbc_envctrl_cleanup(bp);
 390
 391         free_irq(op->archdata.irqs[0], bp);
 392
 393         if (bp->i2c_bussel_reg)
 394                 of_iounmap(&op->resource[0], bp->i2c_bussel_reg, 1);
 395         if (bp->i2c_control_regs)
 396                 of_iounmap(&op->resource[1], bp->i2c_control_regs, 2);
 397
 398         kfree(bp);
 399 }
 400
 401 static const struct of_device_id bbc_i2c_match[] = {
 402         {
 403                 .name = "i2c",
 404                 .compatible = "SUNW,bbc-i2c",
 405         },
 406         {},
 407 };
 408 MODULE_DEVICE_TABLE(of, bbc_i2c_match);
 409
 410 static struct platform_driver bbc_i2c_driver = {
 411         .driver = {
 412                 .name = "bbc_i2c",
 413                 .of_match_table = bbc_i2c_match,
 414         },
 415         .probe          = bbc_i2c_probe,
 416         .remove_new     = bbc_i2c_remove,
 417 };
 418
 419 module_platform_driver(bbc_i2c_driver);
 420
 421 MODULE_DESCRIPTION("UltraSPARC-III bootbus i2c controller driver");
 422 MODULE_LICENSE("GPL");