f08e169ba1b51a150372753672741df102818591
[linux-2.6.git] / drivers / sbus / char / bbc_i2c.c
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                 unsigned 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");