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David Brownellfdb3c182007-02-12 00:52:37 -08001/*
2 * omap_uwire.c -- MicroWire interface driver for OMAP
3 *
4 * Copyright 2003 MontaVista Software Inc. <source@mvista.com>
5 *
6 * Ported to 2.6 OMAP uwire interface.
7 * Copyright (C) 2004 Texas Instruments.
8 *
9 * Generalization patches by Juha Yrjola <juha.yrjola@nokia.com>
10 *
11 * Copyright (C) 2005 David Brownell (ported to 2.6 SPI interface)
12 * Copyright (C) 2006 Nokia
13 *
14 * Many updates by Imre Deak <imre.deak@nokia.com>
15 *
16 * This program is free software; you can redistribute it and/or modify it
17 * under the terms of the GNU General Public License as published by the
18 * Free Software Foundation; either version 2 of the License, or (at your
19 * option) any later version.
20 *
21 * THIS SOFTWARE IS PROVIDED "AS IS" AND ANY EXPRESS OR IMPLIED
22 * WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
23 * MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
24 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
25 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
26 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
27 * USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON
28 * ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
29 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
30 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
31 *
32 * You should have received a copy of the GNU General Public License along
33 * with this program; if not, write to the Free Software Foundation, Inc.,
34 * 675 Mass Ave, Cambridge, MA 02139, USA.
35 */
36#include <linux/kernel.h>
37#include <linux/init.h>
38#include <linux/delay.h>
39#include <linux/platform_device.h>
40#include <linux/workqueue.h>
41#include <linux/interrupt.h>
42#include <linux/err.h>
43#include <linux/clk.h>
44
45#include <linux/spi/spi.h>
46#include <linux/spi/spi_bitbang.h>
47
48#include <asm/system.h>
49#include <asm/irq.h>
50#include <asm/hardware.h>
51#include <asm/io.h>
52#include <asm/mach-types.h>
53
54#include <asm/arch/mux.h>
55#include <asm/arch/omap730.h> /* OMAP730_IO_CONF registers */
56
57
58/* FIXME address is now a platform device resource,
59 * and irqs should show there too...
60 */
61#define UWIRE_BASE_PHYS 0xFFFB3000
62#define UWIRE_BASE ((void *__iomem)IO_ADDRESS(UWIRE_BASE_PHYS))
63
64/* uWire Registers: */
65#define UWIRE_IO_SIZE 0x20
66#define UWIRE_TDR 0x00
67#define UWIRE_RDR 0x00
68#define UWIRE_CSR 0x01
69#define UWIRE_SR1 0x02
70#define UWIRE_SR2 0x03
71#define UWIRE_SR3 0x04
72#define UWIRE_SR4 0x05
73#define UWIRE_SR5 0x06
74
75/* CSR bits */
76#define RDRB (1 << 15)
77#define CSRB (1 << 14)
78#define START (1 << 13)
79#define CS_CMD (1 << 12)
80
81/* SR1 or SR2 bits */
82#define UWIRE_READ_FALLING_EDGE 0x0001
83#define UWIRE_READ_RISING_EDGE 0x0000
84#define UWIRE_WRITE_FALLING_EDGE 0x0000
85#define UWIRE_WRITE_RISING_EDGE 0x0002
86#define UWIRE_CS_ACTIVE_LOW 0x0000
87#define UWIRE_CS_ACTIVE_HIGH 0x0004
88#define UWIRE_FREQ_DIV_2 0x0000
89#define UWIRE_FREQ_DIV_4 0x0008
90#define UWIRE_FREQ_DIV_8 0x0010
91#define UWIRE_CHK_READY 0x0020
92#define UWIRE_CLK_INVERTED 0x0040
93
94
95struct uwire_spi {
96 struct spi_bitbang bitbang;
97 struct clk *ck;
98};
99
100struct uwire_state {
101 unsigned bits_per_word;
102 unsigned div1_idx;
103};
104
105/* REVISIT compile time constant for idx_shift? */
106static unsigned int uwire_idx_shift;
107
108static inline void uwire_write_reg(int idx, u16 val)
109{
110 __raw_writew(val, UWIRE_BASE + (idx << uwire_idx_shift));
111}
112
113static inline u16 uwire_read_reg(int idx)
114{
115 return __raw_readw(UWIRE_BASE + (idx << uwire_idx_shift));
116}
117
118static inline void omap_uwire_configure_mode(u8 cs, unsigned long flags)
119{
120 u16 w, val = 0;
121 int shift, reg;
122
123 if (flags & UWIRE_CLK_INVERTED)
124 val ^= 0x03;
125 val = flags & 0x3f;
126 if (cs & 1)
127 shift = 6;
128 else
129 shift = 0;
130 if (cs <= 1)
131 reg = UWIRE_SR1;
132 else
133 reg = UWIRE_SR2;
134
135 w = uwire_read_reg(reg);
136 w &= ~(0x3f << shift);
137 w |= val << shift;
138 uwire_write_reg(reg, w);
139}
140
141static int wait_uwire_csr_flag(u16 mask, u16 val, int might_not_catch)
142{
143 u16 w;
144 int c = 0;
145 unsigned long max_jiffies = jiffies + HZ;
146
147 for (;;) {
148 w = uwire_read_reg(UWIRE_CSR);
149 if ((w & mask) == val)
150 break;
151 if (time_after(jiffies, max_jiffies)) {
152 printk(KERN_ERR "%s: timeout. reg=%#06x "
153 "mask=%#06x val=%#06x\n",
154 __FUNCTION__, w, mask, val);
155 return -1;
156 }
157 c++;
158 if (might_not_catch && c > 64)
159 break;
160 }
161 return 0;
162}
163
164static void uwire_set_clk1_div(int div1_idx)
165{
166 u16 w;
167
168 w = uwire_read_reg(UWIRE_SR3);
169 w &= ~(0x03 << 1);
170 w |= div1_idx << 1;
171 uwire_write_reg(UWIRE_SR3, w);
172}
173
174static void uwire_chipselect(struct spi_device *spi, int value)
175{
176 struct uwire_state *ust = spi->controller_state;
177 u16 w;
178 int old_cs;
179
180
181 BUG_ON(wait_uwire_csr_flag(CSRB, 0, 0));
182
183 w = uwire_read_reg(UWIRE_CSR);
184 old_cs = (w >> 10) & 0x03;
185 if (value == BITBANG_CS_INACTIVE || old_cs != spi->chip_select) {
186 /* Deselect this CS, or the previous CS */
187 w &= ~CS_CMD;
188 uwire_write_reg(UWIRE_CSR, w);
189 }
190 /* activate specfied chipselect */
191 if (value == BITBANG_CS_ACTIVE) {
192 uwire_set_clk1_div(ust->div1_idx);
193 /* invert clock? */
194 if (spi->mode & SPI_CPOL)
195 uwire_write_reg(UWIRE_SR4, 1);
196 else
197 uwire_write_reg(UWIRE_SR4, 0);
198
199 w = spi->chip_select << 10;
200 w |= CS_CMD;
201 uwire_write_reg(UWIRE_CSR, w);
202 }
203}
204
205static int uwire_txrx(struct spi_device *spi, struct spi_transfer *t)
206{
207 struct uwire_state *ust = spi->controller_state;
208 unsigned len = t->len;
209 unsigned bits = ust->bits_per_word;
210 unsigned bytes;
211 u16 val, w;
212 int status = 0;;
213
214 if (!t->tx_buf && !t->rx_buf)
215 return 0;
216
217 /* Microwire doesn't read and write concurrently */
218 if (t->tx_buf && t->rx_buf)
219 return -EPERM;
220
221 w = spi->chip_select << 10;
222 w |= CS_CMD;
223
224 if (t->tx_buf) {
225 const u8 *buf = t->tx_buf;
226
227 /* NOTE: DMA could be used for TX transfers */
228
229 /* write one or two bytes at a time */
230 while (len >= 1) {
231 /* tx bit 15 is first sent; we byteswap multibyte words
232 * (msb-first) on the way out from memory.
233 */
234 val = *buf++;
235 if (bits > 8) {
236 bytes = 2;
237 val |= *buf++ << 8;
238 } else
239 bytes = 1;
240 val <<= 16 - bits;
241
242#ifdef VERBOSE
243 pr_debug("%s: write-%d =%04x\n",
244 spi->dev.bus_id, bits, val);
245#endif
246 if (wait_uwire_csr_flag(CSRB, 0, 0))
247 goto eio;
248
249 uwire_write_reg(UWIRE_TDR, val);
250
251 /* start write */
252 val = START | w | (bits << 5);
253
254 uwire_write_reg(UWIRE_CSR, val);
255 len -= bytes;
256
257 /* Wait till write actually starts.
258 * This is needed with MPU clock 60+ MHz.
259 * REVISIT: we may not have time to catch it...
260 */
261 if (wait_uwire_csr_flag(CSRB, CSRB, 1))
262 goto eio;
263
264 status += bytes;
265 }
266
267 /* REVISIT: save this for later to get more i/o overlap */
268 if (wait_uwire_csr_flag(CSRB, 0, 0))
269 goto eio;
270
271 } else if (t->rx_buf) {
272 u8 *buf = t->rx_buf;
273
274 /* read one or two bytes at a time */
275 while (len) {
276 if (bits > 8) {
277 bytes = 2;
278 } else
279 bytes = 1;
280
281 /* start read */
282 val = START | w | (bits << 0);
283 uwire_write_reg(UWIRE_CSR, val);
284 len -= bytes;
285
286 /* Wait till read actually starts */
287 (void) wait_uwire_csr_flag(CSRB, CSRB, 1);
288
289 if (wait_uwire_csr_flag(RDRB | CSRB,
290 RDRB, 0))
291 goto eio;
292
293 /* rx bit 0 is last received; multibyte words will
294 * be properly byteswapped on the way to memory.
295 */
296 val = uwire_read_reg(UWIRE_RDR);
297 val &= (1 << bits) - 1;
298 *buf++ = (u8) val;
299 if (bytes == 2)
300 *buf++ = val >> 8;
301 status += bytes;
302#ifdef VERBOSE
303 pr_debug("%s: read-%d =%04x\n",
304 spi->dev.bus_id, bits, val);
305#endif
306
307 }
308 }
309 return status;
310eio:
311 return -EIO;
312}
313
314static int uwire_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
315{
316 struct uwire_state *ust = spi->controller_state;
317 struct uwire_spi *uwire;
318 unsigned flags = 0;
319 unsigned bits;
320 unsigned hz;
321 unsigned long rate;
322 int div1_idx;
323 int div1;
324 int div2;
325 int status;
326
327 uwire = spi_master_get_devdata(spi->master);
328
329 if (spi->chip_select > 3) {
330 pr_debug("%s: cs%d?\n", spi->dev.bus_id, spi->chip_select);
331 status = -ENODEV;
332 goto done;
333 }
334
335 bits = spi->bits_per_word;
336 if (t != NULL && t->bits_per_word)
337 bits = t->bits_per_word;
338 if (!bits)
339 bits = 8;
340
341 if (bits > 16) {
342 pr_debug("%s: wordsize %d?\n", spi->dev.bus_id, bits);
343 status = -ENODEV;
344 goto done;
345 }
346 ust->bits_per_word = bits;
347
348 /* mode 0..3, clock inverted separately;
349 * standard nCS signaling;
350 * don't treat DI=high as "not ready"
351 */
352 if (spi->mode & SPI_CS_HIGH)
353 flags |= UWIRE_CS_ACTIVE_HIGH;
354
355 if (spi->mode & SPI_CPOL)
356 flags |= UWIRE_CLK_INVERTED;
357
358 switch (spi->mode & (SPI_CPOL | SPI_CPHA)) {
359 case SPI_MODE_0:
360 case SPI_MODE_3:
Imre Deake5f1b192007-05-23 13:58:20 -0700361 flags |= UWIRE_WRITE_FALLING_EDGE | UWIRE_READ_RISING_EDGE;
David Brownellfdb3c182007-02-12 00:52:37 -0800362 break;
363 case SPI_MODE_1:
364 case SPI_MODE_2:
Imre Deake5f1b192007-05-23 13:58:20 -0700365 flags |= UWIRE_WRITE_RISING_EDGE | UWIRE_READ_FALLING_EDGE;
David Brownellfdb3c182007-02-12 00:52:37 -0800366 break;
367 }
368
369 /* assume it's already enabled */
370 rate = clk_get_rate(uwire->ck);
371
372 hz = spi->max_speed_hz;
373 if (t != NULL && t->speed_hz)
374 hz = t->speed_hz;
375
376 if (!hz) {
377 pr_debug("%s: zero speed?\n", spi->dev.bus_id);
378 status = -EINVAL;
379 goto done;
380 }
381
382 /* F_INT = mpu_xor_clk / DIV1 */
383 for (div1_idx = 0; div1_idx < 4; div1_idx++) {
384 switch (div1_idx) {
385 case 0:
386 div1 = 2;
387 break;
388 case 1:
389 div1 = 4;
390 break;
391 case 2:
392 div1 = 7;
393 break;
394 default:
395 case 3:
396 div1 = 10;
397 break;
398 }
399 div2 = (rate / div1 + hz - 1) / hz;
400 if (div2 <= 8)
401 break;
402 }
403 if (div1_idx == 4) {
404 pr_debug("%s: lowest clock %ld, need %d\n",
405 spi->dev.bus_id, rate / 10 / 8, hz);
406 status = -EDOM;
407 goto done;
408 }
409
410 /* we have to cache this and reset in uwire_chipselect as this is a
411 * global parameter and another uwire device can change it under
412 * us */
413 ust->div1_idx = div1_idx;
414 uwire_set_clk1_div(div1_idx);
415
416 rate /= div1;
417
418 switch (div2) {
419 case 0:
420 case 1:
421 case 2:
422 flags |= UWIRE_FREQ_DIV_2;
423 rate /= 2;
424 break;
425 case 3:
426 case 4:
427 flags |= UWIRE_FREQ_DIV_4;
428 rate /= 4;
429 break;
430 case 5:
431 case 6:
432 case 7:
433 case 8:
434 flags |= UWIRE_FREQ_DIV_8;
435 rate /= 8;
436 break;
437 }
438 omap_uwire_configure_mode(spi->chip_select, flags);
439 pr_debug("%s: uwire flags %02x, armxor %lu KHz, SCK %lu KHz\n",
440 __FUNCTION__, flags,
441 clk_get_rate(uwire->ck) / 1000,
442 rate / 1000);
443 status = 0;
444done:
445 return status;
446}
447
David Brownelldccd5732007-07-17 04:04:02 -0700448/* the spi->mode bits understood by this driver: */
449#define MODEBITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH)
450
David Brownellfdb3c182007-02-12 00:52:37 -0800451static int uwire_setup(struct spi_device *spi)
452{
453 struct uwire_state *ust = spi->controller_state;
454
David Brownelldccd5732007-07-17 04:04:02 -0700455 if (spi->mode & ~MODEBITS) {
456 dev_dbg(&spi->dev, "setup: unsupported mode bits %x\n",
457 spi->mode & ~MODEBITS);
458 return -EINVAL;
459 }
460
David Brownellfdb3c182007-02-12 00:52:37 -0800461 if (ust == NULL) {
462 ust = kzalloc(sizeof(*ust), GFP_KERNEL);
463 if (ust == NULL)
464 return -ENOMEM;
465 spi->controller_state = ust;
466 }
467
468 return uwire_setup_transfer(spi, NULL);
469}
470
David Brownellbb2d1c32007-02-20 13:58:19 -0800471static void uwire_cleanup(struct spi_device *spi)
David Brownellfdb3c182007-02-12 00:52:37 -0800472{
473 kfree(spi->controller_state);
474}
475
476static void uwire_off(struct uwire_spi *uwire)
477{
478 uwire_write_reg(UWIRE_SR3, 0);
479 clk_disable(uwire->ck);
480 clk_put(uwire->ck);
481 spi_master_put(uwire->bitbang.master);
482}
483
484static int uwire_probe(struct platform_device *pdev)
485{
486 struct spi_master *master;
487 struct uwire_spi *uwire;
488 int status;
489
490 master = spi_alloc_master(&pdev->dev, sizeof *uwire);
491 if (!master)
492 return -ENODEV;
493
494 uwire = spi_master_get_devdata(master);
495 dev_set_drvdata(&pdev->dev, uwire);
496
497 uwire->ck = clk_get(&pdev->dev, "armxor_ck");
498 if (!uwire->ck || IS_ERR(uwire->ck)) {
499 dev_dbg(&pdev->dev, "no mpu_xor_clk ?\n");
500 spi_master_put(master);
501 return -ENODEV;
502 }
503 clk_enable(uwire->ck);
504
505 if (cpu_is_omap730())
506 uwire_idx_shift = 1;
507 else
508 uwire_idx_shift = 2;
509
510 uwire_write_reg(UWIRE_SR3, 1);
511
512 master->bus_num = 2; /* "official" */
513 master->num_chipselect = 4;
514 master->setup = uwire_setup;
515 master->cleanup = uwire_cleanup;
516
517 uwire->bitbang.master = master;
518 uwire->bitbang.chipselect = uwire_chipselect;
519 uwire->bitbang.setup_transfer = uwire_setup_transfer;
520 uwire->bitbang.txrx_bufs = uwire_txrx;
521
522 status = spi_bitbang_start(&uwire->bitbang);
523 if (status < 0)
524 uwire_off(uwire);
525 return status;
526}
527
528static int uwire_remove(struct platform_device *pdev)
529{
530 struct uwire_spi *uwire = dev_get_drvdata(&pdev->dev);
531 int status;
532
533 // FIXME remove all child devices, somewhere ...
534
535 status = spi_bitbang_stop(&uwire->bitbang);
536 uwire_off(uwire);
537 return status;
538}
539
540static struct platform_driver uwire_driver = {
541 .driver = {
542 .name = "omap_uwire",
543 .bus = &platform_bus_type,
544 .owner = THIS_MODULE,
545 },
546 .probe = uwire_probe,
547 .remove = uwire_remove,
548 // suspend ... unuse ck
549 // resume ... use ck
550};
551
552static int __init omap_uwire_init(void)
553{
554 /* FIXME move these into the relevant board init code. also, include
555 * H3 support; it uses tsc2101 like H2 (on a different chipselect).
556 */
557
558 if (machine_is_omap_h2()) {
559 /* defaults: W21 SDO, U18 SDI, V19 SCL */
560 omap_cfg_reg(N14_1610_UWIRE_CS0);
561 omap_cfg_reg(N15_1610_UWIRE_CS1);
562 }
563 if (machine_is_omap_perseus2()) {
564 /* configure pins: MPU_UW_nSCS1, MPU_UW_SDO, MPU_UW_SCLK */
565 int val = omap_readl(OMAP730_IO_CONF_9) & ~0x00EEE000;
566 omap_writel(val | 0x00AAA000, OMAP730_IO_CONF_9);
567 }
568
569 return platform_driver_register(&uwire_driver);
570}
571
572static void __exit omap_uwire_exit(void)
573{
574 platform_driver_unregister(&uwire_driver);
575}
576
577subsys_initcall(omap_uwire_init);
578module_exit(omap_uwire_exit);
579
580MODULE_LICENSE("GPL");
581