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da672773 MD |
1 | /* |
2 | * SuperH Mobile I2C Controller | |
3 | * | |
4 | * Copyright (C) 2008 Magnus Damm | |
5 | * | |
6 | * Portions of the code based on out-of-tree driver i2c-sh7343.c | |
7 | * Copyright (c) 2006 Carlos Munoz <carlos@kenati.com> | |
8 | * | |
9 | * This program is free software; you can redistribute it and/or modify | |
10 | * it under the terms of the GNU General Public License as published by | |
11 | * the Free Software Foundation; either version 2 of the License | |
12 | * | |
13 | * This program is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
16 | * GNU General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU General Public License | |
19 | * along with this program; if not, write to the Free Software | |
20 | * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA | |
21 | */ | |
22 | ||
23 | #include <linux/kernel.h> | |
24 | #include <linux/module.h> | |
25 | #include <linux/init.h> | |
26 | #include <linux/delay.h> | |
27 | #include <linux/platform_device.h> | |
28 | #include <linux/interrupt.h> | |
29 | #include <linux/i2c.h> | |
30 | #include <linux/err.h> | |
31 | #include <linux/clk.h> | |
32 | #include <linux/io.h> | |
33 | ||
34 | enum sh_mobile_i2c_op { | |
35 | OP_START = 0, | |
36 | OP_TX_ONLY, | |
37 | OP_TX_STOP, | |
38 | OP_TX_TO_RX, | |
39 | OP_RX_ONLY, | |
40 | OP_RX_STOP, | |
41 | }; | |
42 | ||
43 | struct sh_mobile_i2c_data { | |
44 | struct device *dev; | |
45 | void __iomem *reg; | |
46 | struct i2c_adapter adap; | |
47 | ||
48 | struct clk *clk; | |
49 | u_int8_t iccl; | |
50 | u_int8_t icch; | |
51 | ||
52 | spinlock_t lock; | |
53 | wait_queue_head_t wait; | |
54 | struct i2c_msg *msg; | |
55 | int pos; | |
56 | int sr; | |
57 | }; | |
58 | ||
59 | #define NORMAL_SPEED 100000 /* FAST_SPEED 400000 */ | |
60 | ||
61 | /* Register offsets */ | |
62 | #define ICDR(pd) (pd->reg + 0x00) | |
63 | #define ICCR(pd) (pd->reg + 0x04) | |
64 | #define ICSR(pd) (pd->reg + 0x08) | |
65 | #define ICIC(pd) (pd->reg + 0x0c) | |
66 | #define ICCL(pd) (pd->reg + 0x10) | |
67 | #define ICCH(pd) (pd->reg + 0x14) | |
68 | ||
69 | /* Register bits */ | |
70 | #define ICCR_ICE 0x80 | |
71 | #define ICCR_RACK 0x40 | |
72 | #define ICCR_TRS 0x10 | |
73 | #define ICCR_BBSY 0x04 | |
74 | #define ICCR_SCP 0x01 | |
75 | ||
76 | #define ICSR_SCLM 0x80 | |
77 | #define ICSR_SDAM 0x40 | |
78 | #define SW_DONE 0x20 | |
79 | #define ICSR_BUSY 0x10 | |
80 | #define ICSR_AL 0x08 | |
81 | #define ICSR_TACK 0x04 | |
82 | #define ICSR_WAIT 0x02 | |
83 | #define ICSR_DTE 0x01 | |
84 | ||
85 | #define ICIC_ALE 0x08 | |
86 | #define ICIC_TACKE 0x04 | |
87 | #define ICIC_WAITE 0x02 | |
88 | #define ICIC_DTEE 0x01 | |
89 | ||
90 | static void activate_ch(struct sh_mobile_i2c_data *pd) | |
91 | { | |
92 | /* Make sure the clock is enabled */ | |
93 | clk_enable(pd->clk); | |
94 | ||
95 | /* Enable channel and configure rx ack */ | |
96 | iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd)); | |
97 | ||
98 | /* Mask all interrupts */ | |
99 | iowrite8(0, ICIC(pd)); | |
100 | ||
101 | /* Set the clock */ | |
102 | iowrite8(pd->iccl, ICCL(pd)); | |
103 | iowrite8(pd->icch, ICCH(pd)); | |
104 | } | |
105 | ||
106 | static void deactivate_ch(struct sh_mobile_i2c_data *pd) | |
107 | { | |
108 | /* Clear/disable interrupts */ | |
109 | iowrite8(0, ICSR(pd)); | |
110 | iowrite8(0, ICIC(pd)); | |
111 | ||
112 | /* Disable channel */ | |
113 | iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd)); | |
114 | ||
115 | /* Disable clock */ | |
116 | clk_disable(pd->clk); | |
117 | } | |
118 | ||
119 | static unsigned char i2c_op(struct sh_mobile_i2c_data *pd, | |
120 | enum sh_mobile_i2c_op op, unsigned char data) | |
121 | { | |
122 | unsigned char ret = 0; | |
123 | unsigned long flags; | |
124 | ||
125 | dev_dbg(pd->dev, "op %d, data in 0x%02x\n", op, data); | |
126 | ||
127 | spin_lock_irqsave(&pd->lock, flags); | |
128 | ||
129 | switch (op) { | |
130 | case OP_START: | |
131 | iowrite8(0x94, ICCR(pd)); | |
132 | break; | |
133 | case OP_TX_ONLY: | |
134 | iowrite8(data, ICDR(pd)); | |
135 | break; | |
136 | case OP_TX_STOP: | |
137 | iowrite8(data, ICDR(pd)); | |
138 | iowrite8(0x90, ICCR(pd)); | |
139 | iowrite8(ICIC_ALE | ICIC_TACKE, ICIC(pd)); | |
140 | break; | |
141 | case OP_TX_TO_RX: | |
142 | iowrite8(data, ICDR(pd)); | |
143 | iowrite8(0x81, ICCR(pd)); | |
144 | break; | |
145 | case OP_RX_ONLY: | |
146 | ret = ioread8(ICDR(pd)); | |
147 | break; | |
148 | case OP_RX_STOP: | |
149 | ret = ioread8(ICDR(pd)); | |
150 | iowrite8(0xc0, ICCR(pd)); | |
151 | break; | |
152 | } | |
153 | ||
154 | spin_unlock_irqrestore(&pd->lock, flags); | |
155 | ||
156 | dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret); | |
157 | return ret; | |
158 | } | |
159 | ||
160 | static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id) | |
161 | { | |
162 | struct platform_device *dev = dev_id; | |
163 | struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev); | |
164 | struct i2c_msg *msg = pd->msg; | |
165 | unsigned char data, sr; | |
166 | int wakeup = 0; | |
167 | ||
168 | sr = ioread8(ICSR(pd)); | |
169 | pd->sr |= sr; | |
170 | ||
171 | dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr, | |
172 | (msg->flags & I2C_M_RD) ? "read" : "write", | |
173 | pd->pos, msg->len); | |
174 | ||
175 | if (sr & (ICSR_AL | ICSR_TACK)) { | |
176 | iowrite8(0, ICIC(pd)); /* disable interrupts */ | |
177 | wakeup = 1; | |
178 | goto do_wakeup; | |
179 | } | |
180 | ||
181 | if (pd->pos == msg->len) { | |
182 | i2c_op(pd, OP_RX_ONLY, 0); | |
183 | wakeup = 1; | |
184 | goto do_wakeup; | |
185 | } | |
186 | ||
187 | if (pd->pos == -1) { | |
188 | data = (msg->addr & 0x7f) << 1; | |
189 | data |= (msg->flags & I2C_M_RD) ? 1 : 0; | |
190 | } else | |
191 | data = msg->buf[pd->pos]; | |
192 | ||
193 | if ((pd->pos == -1) || !(msg->flags & I2C_M_RD)) { | |
194 | if (msg->flags & I2C_M_RD) | |
195 | i2c_op(pd, OP_TX_TO_RX, data); | |
196 | else if (pd->pos == (msg->len - 1)) { | |
197 | i2c_op(pd, OP_TX_STOP, data); | |
198 | wakeup = 1; | |
199 | } else | |
200 | i2c_op(pd, OP_TX_ONLY, data); | |
201 | } else { | |
202 | if (pd->pos == (msg->len - 1)) | |
203 | data = i2c_op(pd, OP_RX_STOP, 0); | |
204 | else | |
205 | data = i2c_op(pd, OP_RX_ONLY, 0); | |
206 | ||
207 | msg->buf[pd->pos] = data; | |
208 | } | |
209 | pd->pos++; | |
210 | ||
211 | do_wakeup: | |
212 | if (wakeup) { | |
213 | pd->sr |= SW_DONE; | |
214 | wake_up(&pd->wait); | |
215 | } | |
216 | ||
217 | return IRQ_HANDLED; | |
218 | } | |
219 | ||
220 | static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg) | |
221 | { | |
222 | /* Initialize channel registers */ | |
223 | iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd)); | |
224 | ||
225 | /* Enable channel and configure rx ack */ | |
226 | iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd)); | |
227 | ||
228 | /* Set the clock */ | |
229 | iowrite8(pd->iccl, ICCL(pd)); | |
230 | iowrite8(pd->icch, ICCH(pd)); | |
231 | ||
232 | pd->msg = usr_msg; | |
233 | pd->pos = -1; | |
234 | pd->sr = 0; | |
235 | ||
236 | /* Enable all interrupts except wait */ | |
237 | iowrite8(ioread8(ICIC(pd)) | ICIC_ALE | ICIC_TACKE | ICIC_DTEE, | |
238 | ICIC(pd)); | |
239 | return 0; | |
240 | } | |
241 | ||
242 | static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter, | |
243 | struct i2c_msg *msgs, | |
244 | int num) | |
245 | { | |
246 | struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter); | |
247 | struct i2c_msg *msg; | |
248 | int err = 0; | |
249 | u_int8_t val; | |
250 | int i, k, retry_count; | |
251 | ||
252 | activate_ch(pd); | |
253 | ||
254 | /* Process all messages */ | |
255 | for (i = 0; i < num; i++) { | |
256 | msg = &msgs[i]; | |
257 | ||
258 | err = start_ch(pd, msg); | |
259 | if (err) | |
260 | break; | |
261 | ||
262 | i2c_op(pd, OP_START, 0); | |
263 | ||
264 | /* The interrupt handler takes care of the rest... */ | |
265 | k = wait_event_timeout(pd->wait, | |
266 | pd->sr & (ICSR_TACK | SW_DONE), | |
267 | 5 * HZ); | |
268 | if (!k) | |
269 | dev_err(pd->dev, "Transfer request timed out\n"); | |
270 | ||
271 | retry_count = 10; | |
272 | again: | |
273 | val = ioread8(ICSR(pd)); | |
274 | ||
275 | dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr); | |
276 | ||
277 | if ((val | pd->sr) & (ICSR_TACK | ICSR_AL)) { | |
278 | err = -EIO; | |
279 | break; | |
280 | } | |
281 | ||
282 | /* the interrupt handler may wake us up before the | |
283 | * transfer is finished, so poll the hardware | |
284 | * until we're done. | |
285 | */ | |
286 | ||
287 | if (!(!(val & ICSR_BUSY) && (val & ICSR_SCLM) && | |
288 | (val & ICSR_SDAM))) { | |
289 | msleep(1); | |
290 | if (retry_count--) | |
291 | goto again; | |
292 | ||
293 | err = -EIO; | |
294 | dev_err(pd->dev, "Polling timed out\n"); | |
295 | break; | |
296 | } | |
297 | } | |
298 | ||
299 | deactivate_ch(pd); | |
300 | ||
301 | if (!err) | |
302 | err = num; | |
303 | return err; | |
304 | } | |
305 | ||
306 | static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter) | |
307 | { | |
308 | return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL; | |
309 | } | |
310 | ||
311 | static struct i2c_algorithm sh_mobile_i2c_algorithm = { | |
312 | .functionality = sh_mobile_i2c_func, | |
313 | .master_xfer = sh_mobile_i2c_xfer, | |
314 | }; | |
315 | ||
316 | static void sh_mobile_i2c_setup_channel(struct platform_device *dev) | |
317 | { | |
318 | struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev); | |
319 | unsigned long peripheral_clk = clk_get_rate(pd->clk); | |
320 | u_int32_t num; | |
321 | u_int32_t denom; | |
322 | u_int32_t tmp; | |
323 | ||
324 | spin_lock_init(&pd->lock); | |
325 | init_waitqueue_head(&pd->wait); | |
326 | ||
327 | /* Calculate the value for iccl. From the data sheet: | |
328 | * iccl = (p clock / transfer rate) * (L / (L + H)) | |
329 | * where L and H are the SCL low/high ratio (5/4 in this case). | |
330 | * We also round off the result. | |
331 | */ | |
332 | num = peripheral_clk * 5; | |
333 | denom = NORMAL_SPEED * 9; | |
334 | tmp = num * 10 / denom; | |
335 | if (tmp % 10 >= 5) | |
336 | pd->iccl = (u_int8_t)((num/denom) + 1); | |
337 | else | |
338 | pd->iccl = (u_int8_t)(num/denom); | |
339 | ||
340 | /* Calculate the value for icch. From the data sheet: | |
341 | icch = (p clock / transfer rate) * (H / (L + H)) */ | |
342 | num = peripheral_clk * 4; | |
343 | tmp = num * 10 / denom; | |
344 | if (tmp % 10 >= 5) | |
345 | pd->icch = (u_int8_t)((num/denom) + 1); | |
346 | else | |
347 | pd->icch = (u_int8_t)(num/denom); | |
348 | } | |
349 | ||
350 | static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, int hook) | |
351 | { | |
352 | struct resource *res; | |
353 | int ret = -ENXIO; | |
354 | int q, m; | |
355 | int k = 0; | |
356 | int n = 0; | |
357 | ||
358 | while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) { | |
359 | for (n = res->start; hook && n <= res->end; n++) { | |
360 | if (request_irq(n, sh_mobile_i2c_isr, IRQF_DISABLED, | |
361 | dev->dev.bus_id, dev)) | |
362 | goto rollback; | |
363 | } | |
364 | k++; | |
365 | } | |
366 | ||
367 | if (hook) | |
368 | return k > 0 ? 0 : -ENOENT; | |
369 | ||
370 | k--; | |
371 | ret = 0; | |
372 | ||
373 | rollback: | |
374 | for (q = k; k >= 0; k--) { | |
375 | for (m = n; m >= res->start; m--) | |
376 | free_irq(m, dev); | |
377 | ||
378 | res = platform_get_resource(dev, IORESOURCE_IRQ, k - 1); | |
379 | m = res->end; | |
380 | } | |
381 | ||
382 | return ret; | |
383 | } | |
384 | ||
385 | static int sh_mobile_i2c_probe(struct platform_device *dev) | |
386 | { | |
387 | struct sh_mobile_i2c_data *pd; | |
388 | struct i2c_adapter *adap; | |
389 | struct resource *res; | |
390 | int size; | |
391 | int ret; | |
392 | ||
393 | pd = kzalloc(sizeof(struct sh_mobile_i2c_data), GFP_KERNEL); | |
394 | if (pd == NULL) { | |
395 | dev_err(&dev->dev, "cannot allocate private data\n"); | |
396 | return -ENOMEM; | |
397 | } | |
398 | ||
399 | pd->clk = clk_get(&dev->dev, "peripheral_clk"); | |
400 | if (IS_ERR(pd->clk)) { | |
401 | dev_err(&dev->dev, "cannot get peripheral clock\n"); | |
402 | ret = PTR_ERR(pd->clk); | |
403 | goto err; | |
404 | } | |
405 | ||
406 | ret = sh_mobile_i2c_hook_irqs(dev, 1); | |
407 | if (ret) { | |
408 | dev_err(&dev->dev, "cannot request IRQ\n"); | |
409 | goto err_clk; | |
410 | } | |
411 | ||
412 | pd->dev = &dev->dev; | |
413 | platform_set_drvdata(dev, pd); | |
414 | ||
415 | res = platform_get_resource(dev, IORESOURCE_MEM, 0); | |
416 | if (res == NULL) { | |
417 | dev_err(&dev->dev, "cannot find IO resource\n"); | |
418 | ret = -ENOENT; | |
419 | goto err_irq; | |
420 | } | |
421 | ||
422 | size = (res->end - res->start) + 1; | |
423 | ||
424 | pd->reg = ioremap(res->start, size); | |
425 | if (pd->reg == NULL) { | |
426 | dev_err(&dev->dev, "cannot map IO\n"); | |
427 | ret = -ENXIO; | |
428 | goto err_irq; | |
429 | } | |
430 | ||
431 | /* setup the private data */ | |
432 | adap = &pd->adap; | |
433 | i2c_set_adapdata(adap, pd); | |
434 | ||
435 | adap->owner = THIS_MODULE; | |
436 | adap->algo = &sh_mobile_i2c_algorithm; | |
437 | adap->dev.parent = &dev->dev; | |
438 | adap->retries = 5; | |
439 | adap->nr = dev->id; | |
440 | ||
441 | strlcpy(adap->name, dev->name, sizeof(adap->name)); | |
442 | ||
443 | sh_mobile_i2c_setup_channel(dev); | |
444 | ||
445 | ret = i2c_add_numbered_adapter(adap); | |
446 | if (ret < 0) { | |
447 | dev_err(&dev->dev, "cannot add numbered adapter\n"); | |
448 | goto err_all; | |
449 | } | |
450 | ||
451 | return 0; | |
452 | ||
453 | err_all: | |
454 | iounmap(pd->reg); | |
455 | err_irq: | |
456 | sh_mobile_i2c_hook_irqs(dev, 0); | |
457 | err_clk: | |
458 | clk_put(pd->clk); | |
459 | err: | |
460 | kfree(pd); | |
461 | return ret; | |
462 | } | |
463 | ||
464 | static int sh_mobile_i2c_remove(struct platform_device *dev) | |
465 | { | |
466 | struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev); | |
467 | ||
468 | i2c_del_adapter(&pd->adap); | |
469 | iounmap(pd->reg); | |
470 | sh_mobile_i2c_hook_irqs(dev, 0); | |
471 | clk_put(pd->clk); | |
472 | kfree(pd); | |
473 | return 0; | |
474 | } | |
475 | ||
476 | static struct platform_driver sh_mobile_i2c_driver = { | |
477 | .driver = { | |
478 | .name = "i2c-sh_mobile", | |
479 | .owner = THIS_MODULE, | |
480 | }, | |
481 | .probe = sh_mobile_i2c_probe, | |
482 | .remove = sh_mobile_i2c_remove, | |
483 | }; | |
484 | ||
485 | static int __init sh_mobile_i2c_adap_init(void) | |
486 | { | |
487 | return platform_driver_register(&sh_mobile_i2c_driver); | |
488 | } | |
489 | ||
490 | static void __exit sh_mobile_i2c_adap_exit(void) | |
491 | { | |
492 | platform_driver_unregister(&sh_mobile_i2c_driver); | |
493 | } | |
494 | ||
495 | module_init(sh_mobile_i2c_adap_init); | |
496 | module_exit(sh_mobile_i2c_adap_exit); | |
497 | ||
498 | MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver"); | |
499 | MODULE_AUTHOR("Magnus Damm"); | |
500 | MODULE_LICENSE("GPL v2"); |