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1 | // SPDX-License-Identifier: GPL-2.0-or-later | |
2 | /* | |
3 | * drivers/i2c/busses/i2c-ibm_iic.c | |
4 | * | |
5 | * Support for the IIC peripheral on IBM PPC 4xx | |
6 | * | |
7 | * Copyright (c) 2003, 2004 Zultys Technologies. | |
8 | * Eugene Surovegin <eugene.surovegin@zultys.com> or <ebs@ebshome.net> | |
9 | * | |
10 | * Copyright (c) 2008 PIKA Technologies | |
11 | * Sean MacLennan <smaclennan@pikatech.com> | |
12 | * | |
13 | * Based on original work by | |
14 | * Ian DaSilva <idasilva@mvista.com> | |
15 | * Armin Kuster <akuster@mvista.com> | |
16 | * Matt Porter <mporter@mvista.com> | |
17 | * | |
18 | * Copyright 2000-2003 MontaVista Software Inc. | |
19 | * | |
20 | * Original driver version was highly leveraged from i2c-elektor.c | |
21 | * | |
22 | * Copyright 1995-97 Simon G. Vogl | |
23 | * 1998-99 Hans Berglund | |
24 | * | |
25 | * With some changes from Kyösti Mälkki <kmalkki@cc.hut.fi> | |
26 | * and even Frodo Looijaard <frodol@dds.nl> | |
27 | */ | |
28 | ||
29 | #include <linux/module.h> | |
30 | #include <linux/kernel.h> | |
31 | #include <linux/ioport.h> | |
32 | #include <linux/delay.h> | |
33 | #include <linux/slab.h> | |
34 | #include <linux/interrupt.h> | |
35 | #include <linux/sched/signal.h> | |
36 | ||
37 | #include <asm/irq.h> | |
38 | #include <linux/io.h> | |
39 | #include <linux/i2c.h> | |
40 | #include <linux/of_address.h> | |
41 | #include <linux/of_irq.h> | |
42 | #include <linux/of_platform.h> | |
43 | ||
44 | #include "i2c-ibm_iic.h" | |
45 | ||
46 | #define DRIVER_VERSION "2.2" | |
47 | ||
48 | MODULE_DESCRIPTION("IBM IIC driver v" DRIVER_VERSION); | |
49 | MODULE_LICENSE("GPL"); | |
50 | ||
51 | static bool iic_force_poll; | |
52 | module_param(iic_force_poll, bool, 0); | |
53 | MODULE_PARM_DESC(iic_force_poll, "Force polling mode"); | |
54 | ||
55 | static bool iic_force_fast; | |
56 | module_param(iic_force_fast, bool, 0); | |
57 | MODULE_PARM_DESC(iic_force_fast, "Force fast mode (400 kHz)"); | |
58 | ||
59 | #define DBG_LEVEL 0 | |
60 | ||
61 | #ifdef DBG | |
62 | #undef DBG | |
63 | #endif | |
64 | ||
65 | #ifdef DBG2 | |
66 | #undef DBG2 | |
67 | #endif | |
68 | ||
69 | #if DBG_LEVEL > 0 | |
70 | # define DBG(f,x...) printk(KERN_DEBUG "ibm-iic" f, ##x) | |
71 | #else | |
72 | # define DBG(f,x...) ((void)0) | |
73 | #endif | |
74 | #if DBG_LEVEL > 1 | |
75 | # define DBG2(f,x...) DBG(f, ##x) | |
76 | #else | |
77 | # define DBG2(f,x...) ((void)0) | |
78 | #endif | |
79 | #if DBG_LEVEL > 2 | |
80 | static void dump_iic_regs(const char* header, struct ibm_iic_private* dev) | |
81 | { | |
82 | volatile struct iic_regs __iomem *iic = dev->vaddr; | |
83 | printk(KERN_DEBUG "ibm-iic%d: %s\n", dev->idx, header); | |
84 | printk(KERN_DEBUG | |
85 | " cntl = 0x%02x, mdcntl = 0x%02x\n" | |
86 | " sts = 0x%02x, extsts = 0x%02x\n" | |
87 | " clkdiv = 0x%02x, xfrcnt = 0x%02x\n" | |
88 | " xtcntlss = 0x%02x, directcntl = 0x%02x\n", | |
89 | in_8(&iic->cntl), in_8(&iic->mdcntl), in_8(&iic->sts), | |
90 | in_8(&iic->extsts), in_8(&iic->clkdiv), in_8(&iic->xfrcnt), | |
91 | in_8(&iic->xtcntlss), in_8(&iic->directcntl)); | |
92 | } | |
93 | # define DUMP_REGS(h,dev) dump_iic_regs((h),(dev)) | |
94 | #else | |
95 | # define DUMP_REGS(h,dev) ((void)0) | |
96 | #endif | |
97 | ||
98 | /* Bus timings (in ns) for bit-banging */ | |
99 | static struct ibm_iic_timings { | |
100 | unsigned int hd_sta; | |
101 | unsigned int su_sto; | |
102 | unsigned int low; | |
103 | unsigned int high; | |
104 | unsigned int buf; | |
105 | } timings [] = { | |
106 | /* Standard mode (100 KHz) */ | |
107 | { | |
108 | .hd_sta = 4000, | |
109 | .su_sto = 4000, | |
110 | .low = 4700, | |
111 | .high = 4000, | |
112 | .buf = 4700, | |
113 | }, | |
114 | /* Fast mode (400 KHz) */ | |
115 | { | |
116 | .hd_sta = 600, | |
117 | .su_sto = 600, | |
118 | .low = 1300, | |
119 | .high = 600, | |
120 | .buf = 1300, | |
121 | }}; | |
122 | ||
123 | /* Enable/disable interrupt generation */ | |
124 | static inline void iic_interrupt_mode(struct ibm_iic_private* dev, int enable) | |
125 | { | |
126 | out_8(&dev->vaddr->intmsk, enable ? INTRMSK_EIMTC : 0); | |
127 | } | |
128 | ||
129 | /* | |
130 | * Initialize IIC interface. | |
131 | */ | |
132 | static void iic_dev_init(struct ibm_iic_private* dev) | |
133 | { | |
134 | volatile struct iic_regs __iomem *iic = dev->vaddr; | |
135 | ||
136 | DBG("%d: init\n", dev->idx); | |
137 | ||
138 | /* Clear master address */ | |
139 | out_8(&iic->lmadr, 0); | |
140 | out_8(&iic->hmadr, 0); | |
141 | ||
142 | /* Clear slave address */ | |
143 | out_8(&iic->lsadr, 0); | |
144 | out_8(&iic->hsadr, 0); | |
145 | ||
146 | /* Clear status & extended status */ | |
147 | out_8(&iic->sts, STS_SCMP | STS_IRQA); | |
148 | out_8(&iic->extsts, EXTSTS_IRQP | EXTSTS_IRQD | EXTSTS_LA | |
149 | | EXTSTS_ICT | EXTSTS_XFRA); | |
150 | ||
151 | /* Set clock divider */ | |
152 | out_8(&iic->clkdiv, dev->clckdiv); | |
153 | ||
154 | /* Clear transfer count */ | |
155 | out_8(&iic->xfrcnt, 0); | |
156 | ||
157 | /* Clear extended control and status */ | |
158 | out_8(&iic->xtcntlss, XTCNTLSS_SRC | XTCNTLSS_SRS | XTCNTLSS_SWC | |
159 | | XTCNTLSS_SWS); | |
160 | ||
161 | /* Clear control register */ | |
162 | out_8(&iic->cntl, 0); | |
163 | ||
164 | /* Enable interrupts if possible */ | |
165 | iic_interrupt_mode(dev, dev->irq >= 0); | |
166 | ||
167 | /* Set mode control */ | |
168 | out_8(&iic->mdcntl, MDCNTL_FMDB | MDCNTL_EINT | MDCNTL_EUBS | |
169 | | (dev->fast_mode ? MDCNTL_FSM : 0)); | |
170 | ||
171 | DUMP_REGS("iic_init", dev); | |
172 | } | |
173 | ||
174 | /* | |
175 | * Reset IIC interface | |
176 | */ | |
177 | static void iic_dev_reset(struct ibm_iic_private* dev) | |
178 | { | |
179 | volatile struct iic_regs __iomem *iic = dev->vaddr; | |
180 | int i; | |
181 | u8 dc; | |
182 | ||
183 | DBG("%d: soft reset\n", dev->idx); | |
184 | DUMP_REGS("reset", dev); | |
185 | ||
186 | /* Place chip in the reset state */ | |
187 | out_8(&iic->xtcntlss, XTCNTLSS_SRST); | |
188 | ||
189 | /* Check if bus is free */ | |
190 | dc = in_8(&iic->directcntl); | |
191 | if (!DIRCTNL_FREE(dc)){ | |
192 | DBG("%d: trying to regain bus control\n", dev->idx); | |
193 | ||
194 | /* Try to set bus free state */ | |
195 | out_8(&iic->directcntl, DIRCNTL_SDAC | DIRCNTL_SCC); | |
196 | ||
197 | /* Wait until we regain bus control */ | |
198 | for (i = 0; i < 100; ++i){ | |
199 | dc = in_8(&iic->directcntl); | |
200 | if (DIRCTNL_FREE(dc)) | |
201 | break; | |
202 | ||
203 | /* Toggle SCL line */ | |
204 | dc ^= DIRCNTL_SCC; | |
205 | out_8(&iic->directcntl, dc); | |
206 | udelay(10); | |
207 | dc ^= DIRCNTL_SCC; | |
208 | out_8(&iic->directcntl, dc); | |
209 | ||
210 | /* be nice */ | |
211 | cond_resched(); | |
212 | } | |
213 | } | |
214 | ||
215 | /* Remove reset */ | |
216 | out_8(&iic->xtcntlss, 0); | |
217 | ||
218 | /* Reinitialize interface */ | |
219 | iic_dev_init(dev); | |
220 | } | |
221 | ||
222 | /* | |
223 | * Do 0-length transaction using bit-banging through IIC_DIRECTCNTL register. | |
224 | */ | |
225 | ||
226 | /* Wait for SCL and/or SDA to be high */ | |
227 | static int iic_dc_wait(volatile struct iic_regs __iomem *iic, u8 mask) | |
228 | { | |
229 | unsigned long x = jiffies + HZ / 28 + 2; | |
230 | while ((in_8(&iic->directcntl) & mask) != mask){ | |
231 | if (unlikely(time_after(jiffies, x))) | |
232 | return -1; | |
233 | cond_resched(); | |
234 | } | |
235 | return 0; | |
236 | } | |
237 | ||
238 | static int iic_smbus_quick(struct ibm_iic_private* dev, const struct i2c_msg* p) | |
239 | { | |
240 | volatile struct iic_regs __iomem *iic = dev->vaddr; | |
241 | const struct ibm_iic_timings *t = &timings[dev->fast_mode ? 1 : 0]; | |
242 | u8 mask, v, sda; | |
243 | int i, res; | |
244 | ||
245 | /* Only 7-bit addresses are supported */ | |
246 | if (unlikely(p->flags & I2C_M_TEN)){ | |
247 | DBG("%d: smbus_quick - 10 bit addresses are not supported\n", | |
248 | dev->idx); | |
249 | return -EINVAL; | |
250 | } | |
251 | ||
252 | DBG("%d: smbus_quick(0x%02x)\n", dev->idx, p->addr); | |
253 | ||
254 | /* Reset IIC interface */ | |
255 | out_8(&iic->xtcntlss, XTCNTLSS_SRST); | |
256 | ||
257 | /* Wait for bus to become free */ | |
258 | out_8(&iic->directcntl, DIRCNTL_SDAC | DIRCNTL_SCC); | |
259 | if (unlikely(iic_dc_wait(iic, DIRCNTL_MSDA | DIRCNTL_MSC))) | |
260 | goto err; | |
261 | ndelay(t->buf); | |
262 | ||
263 | /* START */ | |
264 | out_8(&iic->directcntl, DIRCNTL_SCC); | |
265 | sda = 0; | |
266 | ndelay(t->hd_sta); | |
267 | ||
268 | /* Send address */ | |
269 | v = i2c_8bit_addr_from_msg(p); | |
270 | for (i = 0, mask = 0x80; i < 8; ++i, mask >>= 1){ | |
271 | out_8(&iic->directcntl, sda); | |
272 | ndelay(t->low / 2); | |
273 | sda = (v & mask) ? DIRCNTL_SDAC : 0; | |
274 | out_8(&iic->directcntl, sda); | |
275 | ndelay(t->low / 2); | |
276 | ||
277 | out_8(&iic->directcntl, DIRCNTL_SCC | sda); | |
278 | if (unlikely(iic_dc_wait(iic, DIRCNTL_MSC))) | |
279 | goto err; | |
280 | ndelay(t->high); | |
281 | } | |
282 | ||
283 | /* ACK */ | |
284 | out_8(&iic->directcntl, sda); | |
285 | ndelay(t->low / 2); | |
286 | out_8(&iic->directcntl, DIRCNTL_SDAC); | |
287 | ndelay(t->low / 2); | |
288 | out_8(&iic->directcntl, DIRCNTL_SDAC | DIRCNTL_SCC); | |
289 | if (unlikely(iic_dc_wait(iic, DIRCNTL_MSC))) | |
290 | goto err; | |
291 | res = (in_8(&iic->directcntl) & DIRCNTL_MSDA) ? -EREMOTEIO : 1; | |
292 | ndelay(t->high); | |
293 | ||
294 | /* STOP */ | |
295 | out_8(&iic->directcntl, 0); | |
296 | ndelay(t->low); | |
297 | out_8(&iic->directcntl, DIRCNTL_SCC); | |
298 | if (unlikely(iic_dc_wait(iic, DIRCNTL_MSC))) | |
299 | goto err; | |
300 | ndelay(t->su_sto); | |
301 | out_8(&iic->directcntl, DIRCNTL_SDAC | DIRCNTL_SCC); | |
302 | ||
303 | ndelay(t->buf); | |
304 | ||
305 | DBG("%d: smbus_quick -> %s\n", dev->idx, res ? "NACK" : "ACK"); | |
306 | out: | |
307 | /* Remove reset */ | |
308 | out_8(&iic->xtcntlss, 0); | |
309 | ||
310 | /* Reinitialize interface */ | |
311 | iic_dev_init(dev); | |
312 | ||
313 | return res; | |
314 | err: | |
315 | DBG("%d: smbus_quick - bus is stuck\n", dev->idx); | |
316 | res = -EREMOTEIO; | |
317 | goto out; | |
318 | } | |
319 | ||
320 | /* | |
321 | * IIC interrupt handler | |
322 | */ | |
323 | static irqreturn_t iic_handler(int irq, void *dev_id) | |
324 | { | |
325 | struct ibm_iic_private* dev = (struct ibm_iic_private*)dev_id; | |
326 | volatile struct iic_regs __iomem *iic = dev->vaddr; | |
327 | ||
328 | DBG2("%d: irq handler, STS = 0x%02x, EXTSTS = 0x%02x\n", | |
329 | dev->idx, in_8(&iic->sts), in_8(&iic->extsts)); | |
330 | ||
331 | /* Acknowledge IRQ and wakeup iic_wait_for_tc */ | |
332 | out_8(&iic->sts, STS_IRQA | STS_SCMP); | |
333 | wake_up_interruptible(&dev->wq); | |
334 | ||
335 | return IRQ_HANDLED; | |
336 | } | |
337 | ||
338 | /* | |
339 | * Get master transfer result and clear errors if any. | |
340 | * Returns the number of actually transferred bytes or error (<0) | |
341 | */ | |
342 | static int iic_xfer_result(struct ibm_iic_private* dev) | |
343 | { | |
344 | volatile struct iic_regs __iomem *iic = dev->vaddr; | |
345 | ||
346 | if (unlikely(in_8(&iic->sts) & STS_ERR)){ | |
347 | DBG("%d: xfer error, EXTSTS = 0x%02x\n", dev->idx, | |
348 | in_8(&iic->extsts)); | |
349 | ||
350 | /* Clear errors and possible pending IRQs */ | |
351 | out_8(&iic->extsts, EXTSTS_IRQP | EXTSTS_IRQD | | |
352 | EXTSTS_LA | EXTSTS_ICT | EXTSTS_XFRA); | |
353 | ||
354 | /* Flush master data buffer */ | |
355 | out_8(&iic->mdcntl, in_8(&iic->mdcntl) | MDCNTL_FMDB); | |
356 | ||
357 | /* Is bus free? | |
358 | * If error happened during combined xfer | |
359 | * IIC interface is usually stuck in some strange | |
360 | * state, the only way out - soft reset. | |
361 | */ | |
362 | if ((in_8(&iic->extsts) & EXTSTS_BCS_MASK) != EXTSTS_BCS_FREE){ | |
363 | DBG("%d: bus is stuck, resetting\n", dev->idx); | |
364 | iic_dev_reset(dev); | |
365 | } | |
366 | return -EREMOTEIO; | |
367 | } | |
368 | else | |
369 | return in_8(&iic->xfrcnt) & XFRCNT_MTC_MASK; | |
370 | } | |
371 | ||
372 | /* | |
373 | * Try to abort active transfer. | |
374 | */ | |
375 | static void iic_abort_xfer(struct ibm_iic_private* dev) | |
376 | { | |
377 | volatile struct iic_regs __iomem *iic = dev->vaddr; | |
378 | unsigned long x; | |
379 | ||
380 | DBG("%d: iic_abort_xfer\n", dev->idx); | |
381 | ||
382 | out_8(&iic->cntl, CNTL_HMT); | |
383 | ||
384 | /* | |
385 | * Wait for the abort command to complete. | |
386 | * It's not worth to be optimized, just poll (timeout >= 1 tick) | |
387 | */ | |
388 | x = jiffies + 2; | |
389 | while ((in_8(&iic->extsts) & EXTSTS_BCS_MASK) != EXTSTS_BCS_FREE){ | |
390 | if (time_after(jiffies, x)){ | |
391 | DBG("%d: abort timeout, resetting...\n", dev->idx); | |
392 | iic_dev_reset(dev); | |
393 | return; | |
394 | } | |
395 | schedule(); | |
396 | } | |
397 | ||
398 | /* Just to clear errors */ | |
399 | iic_xfer_result(dev); | |
400 | } | |
401 | ||
402 | /* | |
403 | * Wait for master transfer to complete. | |
404 | * It puts current process to sleep until we get interrupt or timeout expires. | |
405 | * Returns the number of transferred bytes or error (<0) | |
406 | */ | |
407 | static int iic_wait_for_tc(struct ibm_iic_private* dev){ | |
408 | ||
409 | volatile struct iic_regs __iomem *iic = dev->vaddr; | |
410 | int ret = 0; | |
411 | ||
412 | if (dev->irq >= 0){ | |
413 | /* Interrupt mode */ | |
414 | ret = wait_event_interruptible_timeout(dev->wq, | |
415 | !(in_8(&iic->sts) & STS_PT), dev->adap.timeout); | |
416 | ||
417 | if (unlikely(ret < 0)) | |
418 | DBG("%d: wait interrupted\n", dev->idx); | |
419 | else if (unlikely(in_8(&iic->sts) & STS_PT)){ | |
420 | DBG("%d: wait timeout\n", dev->idx); | |
421 | ret = -ETIMEDOUT; | |
422 | } | |
423 | } | |
424 | else { | |
425 | /* Polling mode */ | |
426 | unsigned long x = jiffies + dev->adap.timeout; | |
427 | ||
428 | while (in_8(&iic->sts) & STS_PT){ | |
429 | if (unlikely(time_after(jiffies, x))){ | |
430 | DBG("%d: poll timeout\n", dev->idx); | |
431 | ret = -ETIMEDOUT; | |
432 | break; | |
433 | } | |
434 | ||
435 | if (signal_pending(current)){ | |
436 | DBG("%d: poll interrupted\n", dev->idx); | |
437 | ret = -ERESTARTSYS; | |
438 | break; | |
439 | } | |
440 | schedule(); | |
441 | } | |
442 | } | |
443 | ||
444 | if (unlikely(ret < 0)) | |
445 | iic_abort_xfer(dev); | |
446 | else | |
447 | ret = iic_xfer_result(dev); | |
448 | ||
449 | DBG2("%d: iic_wait_for_tc -> %d\n", dev->idx, ret); | |
450 | ||
451 | return ret; | |
452 | } | |
453 | ||
454 | /* | |
455 | * Low level master transfer routine | |
456 | */ | |
457 | static int iic_xfer_bytes(struct ibm_iic_private* dev, struct i2c_msg* pm, | |
458 | int combined_xfer) | |
459 | { | |
460 | volatile struct iic_regs __iomem *iic = dev->vaddr; | |
461 | char* buf = pm->buf; | |
462 | int i, j, loops, ret = 0; | |
463 | int len = pm->len; | |
464 | ||
465 | u8 cntl = (in_8(&iic->cntl) & CNTL_AMD) | CNTL_PT; | |
466 | if (pm->flags & I2C_M_RD) | |
467 | cntl |= CNTL_RW; | |
468 | ||
469 | loops = (len + 3) / 4; | |
470 | for (i = 0; i < loops; ++i, len -= 4){ | |
471 | int count = len > 4 ? 4 : len; | |
472 | u8 cmd = cntl | ((count - 1) << CNTL_TCT_SHIFT); | |
473 | ||
474 | if (!(cntl & CNTL_RW)) | |
475 | for (j = 0; j < count; ++j) | |
476 | out_8((void __iomem *)&iic->mdbuf, *buf++); | |
477 | ||
478 | if (i < loops - 1) | |
479 | cmd |= CNTL_CHT; | |
480 | else if (combined_xfer) | |
481 | cmd |= CNTL_RPST; | |
482 | ||
483 | DBG2("%d: xfer_bytes, %d, CNTL = 0x%02x\n", dev->idx, count, cmd); | |
484 | ||
485 | /* Start transfer */ | |
486 | out_8(&iic->cntl, cmd); | |
487 | ||
488 | /* Wait for completion */ | |
489 | ret = iic_wait_for_tc(dev); | |
490 | ||
491 | if (unlikely(ret < 0)) | |
492 | break; | |
493 | else if (unlikely(ret != count)){ | |
494 | DBG("%d: xfer_bytes, requested %d, transferred %d\n", | |
495 | dev->idx, count, ret); | |
496 | ||
497 | /* If it's not a last part of xfer, abort it */ | |
498 | if (combined_xfer || (i < loops - 1)) | |
499 | iic_abort_xfer(dev); | |
500 | ||
501 | ret = -EREMOTEIO; | |
502 | break; | |
503 | } | |
504 | ||
505 | if (cntl & CNTL_RW) | |
506 | for (j = 0; j < count; ++j) | |
507 | *buf++ = in_8((void __iomem *)&iic->mdbuf); | |
508 | } | |
509 | ||
510 | return ret > 0 ? 0 : ret; | |
511 | } | |
512 | ||
513 | /* | |
514 | * Set target slave address for master transfer | |
515 | */ | |
516 | static inline void iic_address(struct ibm_iic_private* dev, struct i2c_msg* msg) | |
517 | { | |
518 | volatile struct iic_regs __iomem *iic = dev->vaddr; | |
519 | u16 addr = msg->addr; | |
520 | ||
521 | DBG2("%d: iic_address, 0x%03x (%d-bit)\n", dev->idx, | |
522 | addr, msg->flags & I2C_M_TEN ? 10 : 7); | |
523 | ||
524 | if (msg->flags & I2C_M_TEN){ | |
525 | out_8(&iic->cntl, CNTL_AMD); | |
526 | out_8(&iic->lmadr, addr); | |
527 | out_8(&iic->hmadr, 0xf0 | ((addr >> 7) & 0x06)); | |
528 | } | |
529 | else { | |
530 | out_8(&iic->cntl, 0); | |
531 | out_8(&iic->lmadr, addr << 1); | |
532 | } | |
533 | } | |
534 | ||
535 | static inline int iic_invalid_address(const struct i2c_msg* p) | |
536 | { | |
537 | return (p->addr > 0x3ff) || (!(p->flags & I2C_M_TEN) && (p->addr > 0x7f)); | |
538 | } | |
539 | ||
540 | static inline int iic_address_neq(const struct i2c_msg* p1, | |
541 | const struct i2c_msg* p2) | |
542 | { | |
543 | return (p1->addr != p2->addr) | |
544 | || ((p1->flags & I2C_M_TEN) != (p2->flags & I2C_M_TEN)); | |
545 | } | |
546 | ||
547 | /* | |
548 | * Generic master transfer entrypoint. | |
549 | * Returns the number of processed messages or error (<0) | |
550 | */ | |
551 | static int iic_xfer(struct i2c_adapter *adap, struct i2c_msg *msgs, int num) | |
552 | { | |
553 | struct ibm_iic_private* dev = (struct ibm_iic_private*)(i2c_get_adapdata(adap)); | |
554 | volatile struct iic_regs __iomem *iic = dev->vaddr; | |
555 | int i, ret = 0; | |
556 | ||
557 | DBG2("%d: iic_xfer, %d msg(s)\n", dev->idx, num); | |
558 | ||
559 | /* Check the sanity of the passed messages. | |
560 | * Uhh, generic i2c layer is more suitable place for such code... | |
561 | */ | |
562 | if (unlikely(iic_invalid_address(&msgs[0]))){ | |
563 | DBG("%d: invalid address 0x%03x (%d-bit)\n", dev->idx, | |
564 | msgs[0].addr, msgs[0].flags & I2C_M_TEN ? 10 : 7); | |
565 | return -EINVAL; | |
566 | } | |
567 | for (i = 0; i < num; ++i){ | |
568 | if (unlikely(msgs[i].len <= 0)){ | |
569 | if (num == 1 && !msgs[0].len){ | |
570 | /* Special case for I2C_SMBUS_QUICK emulation. | |
571 | * IBM IIC doesn't support 0-length transactions | |
572 | * so we have to emulate them using bit-banging. | |
573 | */ | |
574 | return iic_smbus_quick(dev, &msgs[0]); | |
575 | } | |
576 | DBG("%d: invalid len %d in msg[%d]\n", dev->idx, | |
577 | msgs[i].len, i); | |
578 | return -EINVAL; | |
579 | } | |
580 | if (unlikely(iic_address_neq(&msgs[0], &msgs[i]))){ | |
581 | DBG("%d: invalid addr in msg[%d]\n", dev->idx, i); | |
582 | return -EINVAL; | |
583 | } | |
584 | } | |
585 | ||
586 | /* Check bus state */ | |
587 | if (unlikely((in_8(&iic->extsts) & EXTSTS_BCS_MASK) != EXTSTS_BCS_FREE)){ | |
588 | DBG("%d: iic_xfer, bus is not free\n", dev->idx); | |
589 | ||
590 | /* Usually it means something serious has happened. | |
591 | * We *cannot* have unfinished previous transfer | |
592 | * so it doesn't make any sense to try to stop it. | |
593 | * Probably we were not able to recover from the | |
594 | * previous error. | |
595 | * The only *reasonable* thing I can think of here | |
596 | * is soft reset. --ebs | |
597 | */ | |
598 | iic_dev_reset(dev); | |
599 | ||
600 | if ((in_8(&iic->extsts) & EXTSTS_BCS_MASK) != EXTSTS_BCS_FREE){ | |
601 | DBG("%d: iic_xfer, bus is still not free\n", dev->idx); | |
602 | return -EREMOTEIO; | |
603 | } | |
604 | } | |
605 | else { | |
606 | /* Flush master data buffer (just in case) */ | |
607 | out_8(&iic->mdcntl, in_8(&iic->mdcntl) | MDCNTL_FMDB); | |
608 | } | |
609 | ||
610 | /* Load slave address */ | |
611 | iic_address(dev, &msgs[0]); | |
612 | ||
613 | /* Do real transfer */ | |
614 | for (i = 0; i < num && !ret; ++i) | |
615 | ret = iic_xfer_bytes(dev, &msgs[i], i < num - 1); | |
616 | ||
617 | return ret < 0 ? ret : num; | |
618 | } | |
619 | ||
620 | static u32 iic_func(struct i2c_adapter *adap) | |
621 | { | |
622 | return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL | I2C_FUNC_10BIT_ADDR; | |
623 | } | |
624 | ||
625 | static const struct i2c_algorithm iic_algo = { | |
626 | .master_xfer = iic_xfer, | |
627 | .functionality = iic_func | |
628 | }; | |
629 | ||
630 | /* | |
631 | * Calculates IICx_CLCKDIV value for a specific OPB clock frequency | |
632 | */ | |
633 | static inline u8 iic_clckdiv(unsigned int opb) | |
634 | { | |
635 | /* Compatibility kludge, should go away after all cards | |
636 | * are fixed to fill correct value for opbfreq. | |
637 | * Previous driver version used hardcoded divider value 4, | |
638 | * it corresponds to OPB frequency from the range (40, 50] MHz | |
639 | */ | |
640 | if (!opb){ | |
641 | printk(KERN_WARNING "ibm-iic: using compatibility value for OPB freq," | |
642 | " fix your board specific setup\n"); | |
643 | opb = 50000000; | |
644 | } | |
645 | ||
646 | /* Convert to MHz */ | |
647 | opb /= 1000000; | |
648 | ||
649 | if (opb < 20 || opb > 150){ | |
650 | printk(KERN_WARNING "ibm-iic: invalid OPB clock frequency %u MHz\n", | |
651 | opb); | |
652 | opb = opb < 20 ? 20 : 150; | |
653 | } | |
654 | return (u8)((opb + 9) / 10 - 1); | |
655 | } | |
656 | ||
657 | static int iic_request_irq(struct platform_device *ofdev, | |
658 | struct ibm_iic_private *dev) | |
659 | { | |
660 | struct device_node *np = ofdev->dev.of_node; | |
661 | int irq; | |
662 | ||
663 | if (iic_force_poll) | |
664 | return 0; | |
665 | ||
666 | irq = irq_of_parse_and_map(np, 0); | |
667 | if (!irq) { | |
668 | dev_err(&ofdev->dev, "irq_of_parse_and_map failed\n"); | |
669 | return 0; | |
670 | } | |
671 | ||
672 | /* Disable interrupts until we finish initialization, assumes | |
673 | * level-sensitive IRQ setup... | |
674 | */ | |
675 | iic_interrupt_mode(dev, 0); | |
676 | if (request_irq(irq, iic_handler, 0, "IBM IIC", dev)) { | |
677 | dev_err(&ofdev->dev, "request_irq %d failed\n", irq); | |
678 | /* Fallback to the polling mode */ | |
679 | return 0; | |
680 | } | |
681 | ||
682 | return irq; | |
683 | } | |
684 | ||
685 | /* | |
686 | * Register single IIC interface | |
687 | */ | |
688 | static int iic_probe(struct platform_device *ofdev) | |
689 | { | |
690 | struct device_node *np = ofdev->dev.of_node; | |
691 | struct ibm_iic_private *dev; | |
692 | struct i2c_adapter *adap; | |
693 | const u32 *freq; | |
694 | int ret; | |
695 | ||
696 | dev = kzalloc(sizeof(*dev), GFP_KERNEL); | |
697 | if (!dev) { | |
698 | dev_err(&ofdev->dev, "failed to allocate device data\n"); | |
699 | return -ENOMEM; | |
700 | } | |
701 | ||
702 | platform_set_drvdata(ofdev, dev); | |
703 | ||
704 | dev->vaddr = of_iomap(np, 0); | |
705 | if (dev->vaddr == NULL) { | |
706 | dev_err(&ofdev->dev, "failed to iomap device\n"); | |
707 | ret = -ENXIO; | |
708 | goto error_cleanup; | |
709 | } | |
710 | ||
711 | init_waitqueue_head(&dev->wq); | |
712 | ||
713 | dev->irq = iic_request_irq(ofdev, dev); | |
714 | if (!dev->irq) | |
715 | dev_warn(&ofdev->dev, "using polling mode\n"); | |
716 | ||
717 | /* Board specific settings */ | |
718 | if (iic_force_fast || of_get_property(np, "fast-mode", NULL)) | |
719 | dev->fast_mode = 1; | |
720 | ||
721 | freq = of_get_property(np, "clock-frequency", NULL); | |
722 | if (freq == NULL) { | |
723 | freq = of_get_property(np->parent, "clock-frequency", NULL); | |
724 | if (freq == NULL) { | |
725 | dev_err(&ofdev->dev, "Unable to get bus frequency\n"); | |
726 | ret = -EINVAL; | |
727 | goto error_cleanup; | |
728 | } | |
729 | } | |
730 | ||
731 | dev->clckdiv = iic_clckdiv(*freq); | |
732 | dev_dbg(&ofdev->dev, "clckdiv = %d\n", dev->clckdiv); | |
733 | ||
734 | /* Initialize IIC interface */ | |
735 | iic_dev_init(dev); | |
736 | ||
737 | /* Register it with i2c layer */ | |
738 | adap = &dev->adap; | |
739 | adap->dev.parent = &ofdev->dev; | |
740 | adap->dev.of_node = of_node_get(np); | |
741 | strlcpy(adap->name, "IBM IIC", sizeof(adap->name)); | |
742 | i2c_set_adapdata(adap, dev); | |
743 | adap->class = I2C_CLASS_HWMON | I2C_CLASS_SPD; | |
744 | adap->algo = &iic_algo; | |
745 | adap->timeout = HZ; | |
746 | ||
747 | ret = i2c_add_adapter(adap); | |
748 | if (ret < 0) | |
749 | goto error_cleanup; | |
750 | ||
751 | dev_info(&ofdev->dev, "using %s mode\n", | |
752 | dev->fast_mode ? "fast (400 kHz)" : "standard (100 kHz)"); | |
753 | ||
754 | return 0; | |
755 | ||
756 | error_cleanup: | |
757 | if (dev->irq) { | |
758 | iic_interrupt_mode(dev, 0); | |
759 | free_irq(dev->irq, dev); | |
760 | } | |
761 | ||
762 | if (dev->vaddr) | |
763 | iounmap(dev->vaddr); | |
764 | ||
765 | kfree(dev); | |
766 | return ret; | |
767 | } | |
768 | ||
769 | /* | |
770 | * Cleanup initialized IIC interface | |
771 | */ | |
772 | static int iic_remove(struct platform_device *ofdev) | |
773 | { | |
774 | struct ibm_iic_private *dev = platform_get_drvdata(ofdev); | |
775 | ||
776 | i2c_del_adapter(&dev->adap); | |
777 | ||
778 | if (dev->irq) { | |
779 | iic_interrupt_mode(dev, 0); | |
780 | free_irq(dev->irq, dev); | |
781 | } | |
782 | ||
783 | iounmap(dev->vaddr); | |
784 | kfree(dev); | |
785 | ||
786 | return 0; | |
787 | } | |
788 | ||
789 | static const struct of_device_id ibm_iic_match[] = { | |
790 | { .compatible = "ibm,iic", }, | |
791 | {} | |
792 | }; | |
793 | MODULE_DEVICE_TABLE(of, ibm_iic_match); | |
794 | ||
795 | static struct platform_driver ibm_iic_driver = { | |
796 | .driver = { | |
797 | .name = "ibm-iic", | |
798 | .of_match_table = ibm_iic_match, | |
799 | }, | |
800 | .probe = iic_probe, | |
801 | .remove = iic_remove, | |
802 | }; | |
803 | ||
804 | module_platform_driver(ibm_iic_driver); |