1 /*
2 * 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 #include <linux/slab.h>
45
46 #include <linux/spi/spi.h>
47 #include <linux/spi/spi_bitbang.h>
48 #include <linux/module.h>
49
50 #include <asm/irq.h>
51 #include <mach/hardware.h>
52 #include <asm/io.h>
53 #include <asm/mach-types.h>
54
55 #include <plat/mux.h>
56 #include <plat/omap7xx.h> /* OMAP7XX_IO_CONF registers */
57
58
59 /* FIXME address is now a platform device resource,
60 * and irqs should show there too...
61 */
62 #define UWIRE_BASE_PHYS 0xFFFB3000
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
95 struct uwire_spi {
96 struct spi_bitbang bitbang;
97 struct clk *ck;
98 };
99
100 struct uwire_state {
101 unsigned bits_per_word;
102 unsigned div1_idx;
103 };
104
105 /* REVISIT compile time constant for idx_shift? */
106 /*
107 * Or, put it in a structure which is used throughout the driver;
108 * that avoids having to issue two loads for each bit of static data.
109 */
110 static unsigned int uwire_idx_shift;
111 static void __iomem *uwire_base;
112
uwire_write_reg(int idx,u16 val)113 static inline void uwire_write_reg(int idx, u16 val)
114 {
115 __raw_writew(val, uwire_base + (idx << uwire_idx_shift));
116 }
117
uwire_read_reg(int idx)118 static inline u16 uwire_read_reg(int idx)
119 {
120 return __raw_readw(uwire_base + (idx << uwire_idx_shift));
121 }
122
omap_uwire_configure_mode(u8 cs,unsigned long flags)123 static inline void omap_uwire_configure_mode(u8 cs, unsigned long flags)
124 {
125 u16 w, val = 0;
126 int shift, reg;
127
128 if (flags & UWIRE_CLK_INVERTED)
129 val ^= 0x03;
130 val = flags & 0x3f;
131 if (cs & 1)
132 shift = 6;
133 else
134 shift = 0;
135 if (cs <= 1)
136 reg = UWIRE_SR1;
137 else
138 reg = UWIRE_SR2;
139
140 w = uwire_read_reg(reg);
141 w &= ~(0x3f << shift);
142 w |= val << shift;
143 uwire_write_reg(reg, w);
144 }
145
wait_uwire_csr_flag(u16 mask,u16 val,int might_not_catch)146 static int wait_uwire_csr_flag(u16 mask, u16 val, int might_not_catch)
147 {
148 u16 w;
149 int c = 0;
150 unsigned long max_jiffies = jiffies + HZ;
151
152 for (;;) {
153 w = uwire_read_reg(UWIRE_CSR);
154 if ((w & mask) == val)
155 break;
156 if (time_after(jiffies, max_jiffies)) {
157 printk(KERN_ERR "%s: timeout. reg=%#06x "
158 "mask=%#06x val=%#06x\n",
159 __func__, w, mask, val);
160 return -1;
161 }
162 c++;
163 if (might_not_catch && c > 64)
164 break;
165 }
166 return 0;
167 }
168
uwire_set_clk1_div(int div1_idx)169 static void uwire_set_clk1_div(int div1_idx)
170 {
171 u16 w;
172
173 w = uwire_read_reg(UWIRE_SR3);
174 w &= ~(0x03 << 1);
175 w |= div1_idx << 1;
176 uwire_write_reg(UWIRE_SR3, w);
177 }
178
uwire_chipselect(struct spi_device * spi,int value)179 static void uwire_chipselect(struct spi_device *spi, int value)
180 {
181 struct uwire_state *ust = spi->controller_state;
182 u16 w;
183 int old_cs;
184
185
186 BUG_ON(wait_uwire_csr_flag(CSRB, 0, 0));
187
188 w = uwire_read_reg(UWIRE_CSR);
189 old_cs = (w >> 10) & 0x03;
190 if (value == BITBANG_CS_INACTIVE || old_cs != spi->chip_select) {
191 /* Deselect this CS, or the previous CS */
192 w &= ~CS_CMD;
193 uwire_write_reg(UWIRE_CSR, w);
194 }
195 /* activate specfied chipselect */
196 if (value == BITBANG_CS_ACTIVE) {
197 uwire_set_clk1_div(ust->div1_idx);
198 /* invert clock? */
199 if (spi->mode & SPI_CPOL)
200 uwire_write_reg(UWIRE_SR4, 1);
201 else
202 uwire_write_reg(UWIRE_SR4, 0);
203
204 w = spi->chip_select << 10;
205 w |= CS_CMD;
206 uwire_write_reg(UWIRE_CSR, w);
207 }
208 }
209
uwire_txrx(struct spi_device * spi,struct spi_transfer * t)210 static int uwire_txrx(struct spi_device *spi, struct spi_transfer *t)
211 {
212 struct uwire_state *ust = spi->controller_state;
213 unsigned len = t->len;
214 unsigned bits = ust->bits_per_word;
215 unsigned bytes;
216 u16 val, w;
217 int status = 0;
218
219 if (!t->tx_buf && !t->rx_buf)
220 return 0;
221
222 /* Microwire doesn't read and write concurrently */
223 if (t->tx_buf && t->rx_buf)
224 return -EPERM;
225
226 w = spi->chip_select << 10;
227 w |= CS_CMD;
228
229 if (t->tx_buf) {
230 const u8 *buf = t->tx_buf;
231
232 /* NOTE: DMA could be used for TX transfers */
233
234 /* write one or two bytes at a time */
235 while (len >= 1) {
236 /* tx bit 15 is first sent; we byteswap multibyte words
237 * (msb-first) on the way out from memory.
238 */
239 val = *buf++;
240 if (bits > 8) {
241 bytes = 2;
242 val |= *buf++ << 8;
243 } else
244 bytes = 1;
245 val <<= 16 - bits;
246
247 #ifdef VERBOSE
248 pr_debug("%s: write-%d =%04x\n",
249 dev_name(&spi->dev), bits, val);
250 #endif
251 if (wait_uwire_csr_flag(CSRB, 0, 0))
252 goto eio;
253
254 uwire_write_reg(UWIRE_TDR, val);
255
256 /* start write */
257 val = START | w | (bits << 5);
258
259 uwire_write_reg(UWIRE_CSR, val);
260 len -= bytes;
261
262 /* Wait till write actually starts.
263 * This is needed with MPU clock 60+ MHz.
264 * REVISIT: we may not have time to catch it...
265 */
266 if (wait_uwire_csr_flag(CSRB, CSRB, 1))
267 goto eio;
268
269 status += bytes;
270 }
271
272 /* REVISIT: save this for later to get more i/o overlap */
273 if (wait_uwire_csr_flag(CSRB, 0, 0))
274 goto eio;
275
276 } else if (t->rx_buf) {
277 u8 *buf = t->rx_buf;
278
279 /* read one or two bytes at a time */
280 while (len) {
281 if (bits > 8) {
282 bytes = 2;
283 } else
284 bytes = 1;
285
286 /* start read */
287 val = START | w | (bits << 0);
288 uwire_write_reg(UWIRE_CSR, val);
289 len -= bytes;
290
291 /* Wait till read actually starts */
292 (void) wait_uwire_csr_flag(CSRB, CSRB, 1);
293
294 if (wait_uwire_csr_flag(RDRB | CSRB,
295 RDRB, 0))
296 goto eio;
297
298 /* rx bit 0 is last received; multibyte words will
299 * be properly byteswapped on the way to memory.
300 */
301 val = uwire_read_reg(UWIRE_RDR);
302 val &= (1 << bits) - 1;
303 *buf++ = (u8) val;
304 if (bytes == 2)
305 *buf++ = val >> 8;
306 status += bytes;
307 #ifdef VERBOSE
308 pr_debug("%s: read-%d =%04x\n",
309 dev_name(&spi->dev), bits, val);
310 #endif
311
312 }
313 }
314 return status;
315 eio:
316 return -EIO;
317 }
318
uwire_setup_transfer(struct spi_device * spi,struct spi_transfer * t)319 static int uwire_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
320 {
321 struct uwire_state *ust = spi->controller_state;
322 struct uwire_spi *uwire;
323 unsigned flags = 0;
324 unsigned bits;
325 unsigned hz;
326 unsigned long rate;
327 int div1_idx;
328 int div1;
329 int div2;
330 int status;
331
332 uwire = spi_master_get_devdata(spi->master);
333
334 if (spi->chip_select > 3) {
335 pr_debug("%s: cs%d?\n", dev_name(&spi->dev), spi->chip_select);
336 status = -ENODEV;
337 goto done;
338 }
339
340 bits = spi->bits_per_word;
341 if (t != NULL && t->bits_per_word)
342 bits = t->bits_per_word;
343
344 if (bits > 16) {
345 pr_debug("%s: wordsize %d?\n", dev_name(&spi->dev), bits);
346 status = -ENODEV;
347 goto done;
348 }
349 ust->bits_per_word = bits;
350
351 /* mode 0..3, clock inverted separately;
352 * standard nCS signaling;
353 * don't treat DI=high as "not ready"
354 */
355 if (spi->mode & SPI_CS_HIGH)
356 flags |= UWIRE_CS_ACTIVE_HIGH;
357
358 if (spi->mode & SPI_CPOL)
359 flags |= UWIRE_CLK_INVERTED;
360
361 switch (spi->mode & (SPI_CPOL | SPI_CPHA)) {
362 case SPI_MODE_0:
363 case SPI_MODE_3:
364 flags |= UWIRE_WRITE_FALLING_EDGE | UWIRE_READ_RISING_EDGE;
365 break;
366 case SPI_MODE_1:
367 case SPI_MODE_2:
368 flags |= UWIRE_WRITE_RISING_EDGE | UWIRE_READ_FALLING_EDGE;
369 break;
370 }
371
372 /* assume it's already enabled */
373 rate = clk_get_rate(uwire->ck);
374
375 hz = spi->max_speed_hz;
376 if (t != NULL && t->speed_hz)
377 hz = t->speed_hz;
378
379 if (!hz) {
380 pr_debug("%s: zero speed?\n", dev_name(&spi->dev));
381 status = -EINVAL;
382 goto done;
383 }
384
385 /* F_INT = mpu_xor_clk / DIV1 */
386 for (div1_idx = 0; div1_idx < 4; div1_idx++) {
387 switch (div1_idx) {
388 case 0:
389 div1 = 2;
390 break;
391 case 1:
392 div1 = 4;
393 break;
394 case 2:
395 div1 = 7;
396 break;
397 default:
398 case 3:
399 div1 = 10;
400 break;
401 }
402 div2 = (rate / div1 + hz - 1) / hz;
403 if (div2 <= 8)
404 break;
405 }
406 if (div1_idx == 4) {
407 pr_debug("%s: lowest clock %ld, need %d\n",
408 dev_name(&spi->dev), rate / 10 / 8, hz);
409 status = -EDOM;
410 goto done;
411 }
412
413 /* we have to cache this and reset in uwire_chipselect as this is a
414 * global parameter and another uwire device can change it under
415 * us */
416 ust->div1_idx = div1_idx;
417 uwire_set_clk1_div(div1_idx);
418
419 rate /= div1;
420
421 switch (div2) {
422 case 0:
423 case 1:
424 case 2:
425 flags |= UWIRE_FREQ_DIV_2;
426 rate /= 2;
427 break;
428 case 3:
429 case 4:
430 flags |= UWIRE_FREQ_DIV_4;
431 rate /= 4;
432 break;
433 case 5:
434 case 6:
435 case 7:
436 case 8:
437 flags |= UWIRE_FREQ_DIV_8;
438 rate /= 8;
439 break;
440 }
441 omap_uwire_configure_mode(spi->chip_select, flags);
442 pr_debug("%s: uwire flags %02x, armxor %lu KHz, SCK %lu KHz\n",
443 __func__, flags,
444 clk_get_rate(uwire->ck) / 1000,
445 rate / 1000);
446 status = 0;
447 done:
448 return status;
449 }
450
uwire_setup(struct spi_device * spi)451 static int uwire_setup(struct spi_device *spi)
452 {
453 struct uwire_state *ust = spi->controller_state;
454
455 if (ust == NULL) {
456 ust = kzalloc(sizeof(*ust), GFP_KERNEL);
457 if (ust == NULL)
458 return -ENOMEM;
459 spi->controller_state = ust;
460 }
461
462 return uwire_setup_transfer(spi, NULL);
463 }
464
uwire_cleanup(struct spi_device * spi)465 static void uwire_cleanup(struct spi_device *spi)
466 {
467 kfree(spi->controller_state);
468 }
469
uwire_off(struct uwire_spi * uwire)470 static void uwire_off(struct uwire_spi *uwire)
471 {
472 uwire_write_reg(UWIRE_SR3, 0);
473 clk_disable(uwire->ck);
474 clk_put(uwire->ck);
475 spi_master_put(uwire->bitbang.master);
476 }
477
uwire_probe(struct platform_device * pdev)478 static int __init uwire_probe(struct platform_device *pdev)
479 {
480 struct spi_master *master;
481 struct uwire_spi *uwire;
482 int status;
483
484 master = spi_alloc_master(&pdev->dev, sizeof *uwire);
485 if (!master)
486 return -ENODEV;
487
488 uwire = spi_master_get_devdata(master);
489
490 uwire_base = ioremap(UWIRE_BASE_PHYS, UWIRE_IO_SIZE);
491 if (!uwire_base) {
492 dev_dbg(&pdev->dev, "can't ioremap UWIRE\n");
493 spi_master_put(master);
494 return -ENOMEM;
495 }
496
497 dev_set_drvdata(&pdev->dev, uwire);
498
499 uwire->ck = clk_get(&pdev->dev, "fck");
500 if (IS_ERR(uwire->ck)) {
501 status = PTR_ERR(uwire->ck);
502 dev_dbg(&pdev->dev, "no functional clock?\n");
503 spi_master_put(master);
504 return status;
505 }
506 clk_enable(uwire->ck);
507
508 if (cpu_is_omap7xx())
509 uwire_idx_shift = 1;
510 else
511 uwire_idx_shift = 2;
512
513 uwire_write_reg(UWIRE_SR3, 1);
514
515 /* the spi->mode bits understood by this driver: */
516 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
517
518 master->flags = SPI_MASTER_HALF_DUPLEX;
519
520 master->bus_num = 2; /* "official" */
521 master->num_chipselect = 4;
522 master->setup = uwire_setup;
523 master->cleanup = uwire_cleanup;
524
525 uwire->bitbang.master = master;
526 uwire->bitbang.chipselect = uwire_chipselect;
527 uwire->bitbang.setup_transfer = uwire_setup_transfer;
528 uwire->bitbang.txrx_bufs = uwire_txrx;
529
530 status = spi_bitbang_start(&uwire->bitbang);
531 if (status < 0) {
532 uwire_off(uwire);
533 iounmap(uwire_base);
534 }
535 return status;
536 }
537
uwire_remove(struct platform_device * pdev)538 static int __exit uwire_remove(struct platform_device *pdev)
539 {
540 struct uwire_spi *uwire = dev_get_drvdata(&pdev->dev);
541 int status;
542
543 // FIXME remove all child devices, somewhere ...
544
545 status = spi_bitbang_stop(&uwire->bitbang);
546 uwire_off(uwire);
547 iounmap(uwire_base);
548 return status;
549 }
550
551 /* work with hotplug and coldplug */
552 MODULE_ALIAS("platform:omap_uwire");
553
554 static struct platform_driver uwire_driver = {
555 .driver = {
556 .name = "omap_uwire",
557 .owner = THIS_MODULE,
558 },
559 .remove = __exit_p(uwire_remove),
560 // suspend ... unuse ck
561 // resume ... use ck
562 };
563
omap_uwire_init(void)564 static int __init omap_uwire_init(void)
565 {
566 /* FIXME move these into the relevant board init code. also, include
567 * H3 support; it uses tsc2101 like H2 (on a different chipselect).
568 */
569
570 if (machine_is_omap_h2()) {
571 /* defaults: W21 SDO, U18 SDI, V19 SCL */
572 omap_cfg_reg(N14_1610_UWIRE_CS0);
573 omap_cfg_reg(N15_1610_UWIRE_CS1);
574 }
575 if (machine_is_omap_perseus2()) {
576 /* configure pins: MPU_UW_nSCS1, MPU_UW_SDO, MPU_UW_SCLK */
577 int val = omap_readl(OMAP7XX_IO_CONF_9) & ~0x00EEE000;
578 omap_writel(val | 0x00AAA000, OMAP7XX_IO_CONF_9);
579 }
580
581 return platform_driver_probe(&uwire_driver, uwire_probe);
582 }
583
omap_uwire_exit(void)584 static void __exit omap_uwire_exit(void)
585 {
586 platform_driver_unregister(&uwire_driver);
587 }
588
589 subsys_initcall(omap_uwire_init);
590 module_exit(omap_uwire_exit);
591
592 MODULE_LICENSE("GPL");
593
594