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
set_device_claimage(struct bbc_i2c_bus * bp,struct platform_device * op,int val)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
bbc_i2c_getdev(struct bbc_i2c_bus * bp,int index)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
bbc_i2c_attach(struct bbc_i2c_bus * bp,struct platform_device * op)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
bbc_i2c_detach(struct bbc_i2c_client * client)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
wait_for_pin(struct bbc_i2c_bus * bp,u8 * status)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
bbc_i2c_writeb(struct bbc_i2c_client * client,unsigned char val,int off)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
bbc_i2c_readb(struct bbc_i2c_client * client,unsigned char * byte,int off)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
bbc_i2c_write_buf(struct bbc_i2c_client * client,char * buf,int len,int off)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
bbc_i2c_read_buf(struct bbc_i2c_client * client,char * buf,int len,int off)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
bbc_i2c_interrupt(int irq,void * dev_id)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
reset_one_i2c(struct bbc_i2c_bus * bp)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
attach_one_i2c(struct platform_device * op,int index)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
bbc_i2c_probe(struct platform_device * op)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
bbc_i2c_remove(struct platform_device * op)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