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Linus Torvalds1da177e2005-04-16 15:20:36 -07001/* $Id: bbc_i2c.c,v 1.2 2001/04/02 09:59:08 davem Exp $
2 * bbc_i2c.c: I2C low-level driver for BBC device on UltraSPARC-III
3 * platforms.
4 *
5 * Copyright (C) 2001 David S. Miller (davem@redhat.com)
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/init.h>
16#include <linux/interrupt.h>
17#include <asm/oplib.h>
18#include <asm/ebus.h>
19#include <asm/spitfire.h>
20#include <asm/bbc.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#define NUM_CHILDREN 8
56struct bbc_i2c_bus {
57 struct bbc_i2c_bus *next;
58 int index;
59 spinlock_t lock;
60 void __iomem *i2c_bussel_reg;
61 void __iomem *i2c_control_regs;
62 unsigned char own, clock;
63
64 wait_queue_head_t wq;
65 volatile int waiting;
66
67 struct linux_ebus_device *bus_edev;
68 struct {
69 struct linux_ebus_child *device;
70 int client_claimed;
71 } devs[NUM_CHILDREN];
72};
73
74static struct bbc_i2c_bus *all_bbc_i2c;
75
76struct bbc_i2c_client {
77 struct bbc_i2c_bus *bp;
78 struct linux_ebus_child *echild;
79 int bus;
80 int address;
81};
82
83static int find_device(struct bbc_i2c_bus *bp, struct linux_ebus_child *echild)
84{
85 int i;
86
87 for (i = 0; i < NUM_CHILDREN; i++) {
88 if (bp->devs[i].device == echild) {
89 if (bp->devs[i].client_claimed)
90 return 0;
91 return 1;
92 }
93 }
94 return 0;
95}
96
97static void set_device_claimage(struct bbc_i2c_bus *bp, struct linux_ebus_child *echild, int val)
98{
99 int i;
100
101 for (i = 0; i < NUM_CHILDREN; i++) {
102 if (bp->devs[i].device == echild) {
103 bp->devs[i].client_claimed = val;
104 return;
105 }
106 }
107}
108
109#define claim_device(BP,ECHILD) set_device_claimage(BP,ECHILD,1)
110#define release_device(BP,ECHILD) set_device_claimage(BP,ECHILD,0)
111
112static struct bbc_i2c_bus *find_bus_for_device(struct linux_ebus_child *echild)
113{
114 struct bbc_i2c_bus *bp = all_bbc_i2c;
115
116 while (bp != NULL) {
117 if (find_device(bp, echild) != 0)
118 break;
119 bp = bp->next;
120 }
121
122 return bp;
123}
124
125struct linux_ebus_child *bbc_i2c_getdev(int index)
126{
127 struct bbc_i2c_bus *bp = all_bbc_i2c;
128 struct linux_ebus_child *echild = NULL;
129 int curidx = 0;
130
131 while (bp != NULL) {
132 struct bbc_i2c_bus *next = bp->next;
133 int i;
134
135 for (i = 0; i < NUM_CHILDREN; i++) {
136 if (!(echild = bp->devs[i].device))
137 break;
138 if (curidx == index)
139 goto out;
140 echild = NULL;
141 curidx++;
142 }
143 bp = next;
144 }
145out:
146 if (curidx == index)
147 return echild;
148 return NULL;
149}
150
151struct bbc_i2c_client *bbc_i2c_attach(struct linux_ebus_child *echild)
152{
153 struct bbc_i2c_bus *bp = find_bus_for_device(echild);
154 struct bbc_i2c_client *client;
155
156 if (!bp)
157 return NULL;
158 client = kmalloc(sizeof(*client), GFP_KERNEL);
159 if (!client)
160 return NULL;
161 memset(client, 0, sizeof(*client));
162 client->bp = bp;
163 client->echild = echild;
164 client->bus = echild->resource[0].start;
165 client->address = echild->resource[1].start;
166
167 claim_device(bp, echild);
168
169 return client;
170}
171
172void bbc_i2c_detach(struct bbc_i2c_client *client)
173{
174 struct bbc_i2c_bus *bp = client->bp;
175 struct linux_ebus_child *echild = client->echild;
176
177 release_device(bp, echild);
178 kfree(client);
179}
180
181static int wait_for_pin(struct bbc_i2c_bus *bp, u8 *status)
182{
183 DECLARE_WAITQUEUE(wait, current);
184 int limit = 32;
185 int ret = 1;
186
187 bp->waiting = 1;
188 add_wait_queue(&bp->wq, &wait);
189 while (limit-- > 0) {
190 u8 val;
191
192 set_current_state(TASK_INTERRUPTIBLE);
193 *status = val = readb(bp->i2c_control_regs + 0);
194 if ((val & I2C_PCF_PIN) == 0) {
195 ret = 0;
196 break;
197 }
198 msleep_interruptible(250);
199 }
200 remove_wait_queue(&bp->wq, &wait);
201 bp->waiting = 0;
202 current->state = TASK_RUNNING;
203
204 return ret;
205}
206
207int bbc_i2c_writeb(struct bbc_i2c_client *client, unsigned char val, int off)
208{
209 struct bbc_i2c_bus *bp = client->bp;
210 int address = client->address;
211 u8 status;
212 int ret = -1;
213
214 if (bp->i2c_bussel_reg != NULL)
215 writeb(client->bus, bp->i2c_bussel_reg);
216
217 writeb(address, bp->i2c_control_regs + 0x1);
218 writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
219 if (wait_for_pin(bp, &status))
220 goto out;
221
222 writeb(off, bp->i2c_control_regs + 0x1);
223 if (wait_for_pin(bp, &status) ||
224 (status & I2C_PCF_LRB) != 0)
225 goto out;
226
227 writeb(val, bp->i2c_control_regs + 0x1);
228 if (wait_for_pin(bp, &status))
229 goto out;
230
231 ret = 0;
232
233out:
234 writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
235 return ret;
236}
237
238int bbc_i2c_readb(struct bbc_i2c_client *client, unsigned char *byte, int off)
239{
240 struct bbc_i2c_bus *bp = client->bp;
241 unsigned char address = client->address, status;
242 int ret = -1;
243
244 if (bp->i2c_bussel_reg != NULL)
245 writeb(client->bus, bp->i2c_bussel_reg);
246
247 writeb(address, bp->i2c_control_regs + 0x1);
248 writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
249 if (wait_for_pin(bp, &status))
250 goto out;
251
252 writeb(off, bp->i2c_control_regs + 0x1);
253 if (wait_for_pin(bp, &status) ||
254 (status & I2C_PCF_LRB) != 0)
255 goto out;
256
257 writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
258
259 address |= 0x1; /* READ */
260
261 writeb(address, bp->i2c_control_regs + 0x1);
262 writeb(I2C_PCF_START, bp->i2c_control_regs + 0x0);
263 if (wait_for_pin(bp, &status))
264 goto out;
265
266 /* Set PIN back to one so the device sends the first
267 * byte.
268 */
269 (void) readb(bp->i2c_control_regs + 0x1);
270 if (wait_for_pin(bp, &status))
271 goto out;
272
273 writeb(I2C_PCF_ESO | I2C_PCF_ENI, bp->i2c_control_regs + 0x0);
274 *byte = readb(bp->i2c_control_regs + 0x1);
275 if (wait_for_pin(bp, &status))
276 goto out;
277
278 ret = 0;
279
280out:
281 writeb(I2C_PCF_STOP, bp->i2c_control_regs + 0x0);
282 (void) readb(bp->i2c_control_regs + 0x1);
283
284 return ret;
285}
286
287int bbc_i2c_write_buf(struct bbc_i2c_client *client,
288 char *buf, int len, int off)
289{
290 int ret = 0;
291
292 while (len > 0) {
293 int err = bbc_i2c_writeb(client, *buf, off);
294
295 if (err < 0) {
296 ret = err;
297 break;
298 }
299
300 len--;
301 buf++;
302 off++;
303 }
304 return ret;
305}
306
307int bbc_i2c_read_buf(struct bbc_i2c_client *client,
308 char *buf, int len, int off)
309{
310 int ret = 0;
311
312 while (len > 0) {
313 int err = bbc_i2c_readb(client, buf, off);
314 if (err < 0) {
315 ret = err;
316 break;
317 }
318 len--;
319 buf++;
320 off++;
321 }
322
323 return ret;
324}
325
326EXPORT_SYMBOL(bbc_i2c_getdev);
327EXPORT_SYMBOL(bbc_i2c_attach);
328EXPORT_SYMBOL(bbc_i2c_detach);
329EXPORT_SYMBOL(bbc_i2c_writeb);
330EXPORT_SYMBOL(bbc_i2c_readb);
331EXPORT_SYMBOL(bbc_i2c_write_buf);
332EXPORT_SYMBOL(bbc_i2c_read_buf);
333
334static irqreturn_t bbc_i2c_interrupt(int irq, void *dev_id, struct pt_regs *regs)
335{
336 struct bbc_i2c_bus *bp = dev_id;
337
338 /* PIN going from set to clear is the only event which
339 * makes the i2c assert an interrupt.
340 */
341 if (bp->waiting &&
342 !(readb(bp->i2c_control_regs + 0x0) & I2C_PCF_PIN))
343 wake_up(&bp->wq);
344
345 return IRQ_HANDLED;
346}
347
348static void __init reset_one_i2c(struct bbc_i2c_bus *bp)
349{
350 writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0);
351 writeb(bp->own, bp->i2c_control_regs + 0x1);
352 writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0);
353 writeb(bp->clock, bp->i2c_control_regs + 0x1);
354 writeb(I2C_PCF_IDLE, bp->i2c_control_regs + 0x0);
355}
356
357static int __init attach_one_i2c(struct linux_ebus_device *edev, int index)
358{
359 struct bbc_i2c_bus *bp = kmalloc(sizeof(*bp), GFP_KERNEL);
360 struct linux_ebus_child *echild;
361 int entry;
362
363 if (!bp)
364 return -ENOMEM;
365 memset(bp, 0, sizeof(*bp));
366
367 bp->i2c_control_regs = ioremap(edev->resource[0].start, 0x2);
368 if (!bp->i2c_control_regs)
369 goto fail;
370
371 if (edev->num_addrs == 2) {
372 bp->i2c_bussel_reg = ioremap(edev->resource[1].start, 0x1);
373 if (!bp->i2c_bussel_reg)
374 goto fail;
375 }
376
377 bp->waiting = 0;
378 init_waitqueue_head(&bp->wq);
379 if (request_irq(edev->irqs[0], bbc_i2c_interrupt,
380 SA_SHIRQ, "bbc_i2c", bp))
381 goto fail;
382
383 bp->index = index;
384 bp->bus_edev = edev;
385
386 spin_lock_init(&bp->lock);
387 bp->next = all_bbc_i2c;
388 all_bbc_i2c = bp;
389
390 entry = 0;
391 for (echild = edev->children;
392 echild && entry < 8;
393 echild = echild->next, entry++) {
394 bp->devs[entry].device = echild;
395 bp->devs[entry].client_claimed = 0;
396 }
397
398 writeb(I2C_PCF_PIN, bp->i2c_control_regs + 0x0);
399 bp->own = readb(bp->i2c_control_regs + 0x01);
400 writeb(I2C_PCF_PIN | I2C_PCF_ES1, bp->i2c_control_regs + 0x0);
401 bp->clock = readb(bp->i2c_control_regs + 0x01);
402
403 printk(KERN_INFO "i2c-%d: Regs at %p, %d devices, own %02x, clock %02x.\n",
404 bp->index, bp->i2c_control_regs, entry, bp->own, bp->clock);
405
406 reset_one_i2c(bp);
407
408 return 0;
409
410fail:
411 if (bp->i2c_bussel_reg)
412 iounmap(bp->i2c_bussel_reg);
413 if (bp->i2c_control_regs)
414 iounmap(bp->i2c_control_regs);
415 kfree(bp);
416 return -EINVAL;
417}
418
419static int __init bbc_present(void)
420{
421 struct linux_ebus *ebus = NULL;
422 struct linux_ebus_device *edev = NULL;
423
424 for_each_ebus(ebus) {
425 for_each_ebusdev(edev, ebus) {
426 if (!strcmp(edev->prom_name, "bbc"))
427 return 1;
428 }
429 }
430 return 0;
431}
432
433extern int bbc_envctrl_init(void);
434extern void bbc_envctrl_cleanup(void);
435static void bbc_i2c_cleanup(void);
436
437static int __init bbc_i2c_init(void)
438{
439 struct linux_ebus *ebus = NULL;
440 struct linux_ebus_device *edev = NULL;
441 int err, index = 0;
442
443 if (tlb_type != cheetah || !bbc_present())
444 return -ENODEV;
445
446 for_each_ebus(ebus) {
447 for_each_ebusdev(edev, ebus) {
448 if (!strcmp(edev->prom_name, "i2c")) {
449 if (!attach_one_i2c(edev, index))
450 index++;
451 }
452 }
453 }
454
455 if (!index)
456 return -ENODEV;
457
458 err = bbc_envctrl_init();
459 if (err)
460 bbc_i2c_cleanup();
461 return err;
462}
463
464static void bbc_i2c_cleanup(void)
465{
466 struct bbc_i2c_bus *bp = all_bbc_i2c;
467
468 bbc_envctrl_cleanup();
469
470 while (bp != NULL) {
471 struct bbc_i2c_bus *next = bp->next;
472
473 free_irq(bp->bus_edev->irqs[0], bp);
474
475 if (bp->i2c_bussel_reg)
476 iounmap(bp->i2c_bussel_reg);
477 if (bp->i2c_control_regs)
478 iounmap(bp->i2c_control_regs);
479
480 kfree(bp);
481
482 bp = next;
483 }
484 all_bbc_i2c = NULL;
485}
486
487module_init(bbc_i2c_init);
488module_exit(bbc_i2c_cleanup);