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 #include <linux/kernel.h>
33 #include <linux/init.h>
34 #include <linux/delay.h>
35 #include <linux/platform_device.h>
36 #include <linux/interrupt.h>
37 #include <linux/err.h>
38 #include <linux/clk.h>
39 #include <linux/slab.h>
40 #include <linux/device.h>
41
42 #include <linux/spi/spi.h>
43 #include <linux/spi/spi_bitbang.h>
44 #include <linux/module.h>
45 #include <linux/io.h>
46
47 #include <mach/hardware.h>
48 #include <asm/mach-types.h>
49
50 #include <mach/mux.h>
51
52 #include <mach/omap7xx.h> /* OMAP7XX_IO_CONF registers */
53
54
55 /* FIXME address is now a platform device resource,
56 * and irqs should show there too...
57 */
58 #define UWIRE_BASE_PHYS 0xFFFB3000
59
60 /* uWire Registers: */
61 #define UWIRE_IO_SIZE 0x20
62 #define UWIRE_TDR 0x00
63 #define UWIRE_RDR 0x00
64 #define UWIRE_CSR 0x01
65 #define UWIRE_SR1 0x02
66 #define UWIRE_SR2 0x03
67 #define UWIRE_SR3 0x04
68 #define UWIRE_SR4 0x05
69 #define UWIRE_SR5 0x06
70
71 /* CSR bits */
72 #define RDRB (1 << 15)
73 #define CSRB (1 << 14)
74 #define START (1 << 13)
75 #define CS_CMD (1 << 12)
76
77 /* SR1 or SR2 bits */
78 #define UWIRE_READ_FALLING_EDGE 0x0001
79 #define UWIRE_READ_RISING_EDGE 0x0000
80 #define UWIRE_WRITE_FALLING_EDGE 0x0000
81 #define UWIRE_WRITE_RISING_EDGE 0x0002
82 #define UWIRE_CS_ACTIVE_LOW 0x0000
83 #define UWIRE_CS_ACTIVE_HIGH 0x0004
84 #define UWIRE_FREQ_DIV_2 0x0000
85 #define UWIRE_FREQ_DIV_4 0x0008
86 #define UWIRE_FREQ_DIV_8 0x0010
87 #define UWIRE_CHK_READY 0x0020
88 #define UWIRE_CLK_INVERTED 0x0040
89
90
91 struct uwire_spi {
92 struct spi_bitbang bitbang;
93 struct clk *ck;
94 };
95
96 struct uwire_state {
97 unsigned div1_idx;
98 };
99
100 /* REVISIT compile time constant for idx_shift? */
101 /*
102 * Or, put it in a structure which is used throughout the driver;
103 * that avoids having to issue two loads for each bit of static data.
104 */
105 static unsigned int uwire_idx_shift;
106 static void __iomem *uwire_base;
107
uwire_write_reg(int idx,u16 val)108 static inline void uwire_write_reg(int idx, u16 val)
109 {
110 __raw_writew(val, uwire_base + (idx << uwire_idx_shift));
111 }
112
uwire_read_reg(int idx)113 static inline u16 uwire_read_reg(int idx)
114 {
115 return __raw_readw(uwire_base + (idx << uwire_idx_shift));
116 }
117
omap_uwire_configure_mode(u8 cs,unsigned long flags)118 static 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
wait_uwire_csr_flag(u16 mask,u16 val,int might_not_catch)141 static 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 __func__, w, mask, val);
155 return -1;
156 }
157 c++;
158 if (might_not_catch && c > 64)
159 break;
160 }
161 return 0;
162 }
163
uwire_set_clk1_div(int div1_idx)164 static 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
uwire_chipselect(struct spi_device * spi,int value)174 static 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
uwire_txrx(struct spi_device * spi,struct spi_transfer * t)205 static int uwire_txrx(struct spi_device *spi, struct spi_transfer *t)
206 {
207 unsigned len = t->len;
208 unsigned bits = t->bits_per_word;
209 unsigned bytes;
210 u16 val, w;
211 int status = 0;
212
213 if (!t->tx_buf && !t->rx_buf)
214 return 0;
215
216 w = spi->chip_select << 10;
217 w |= CS_CMD;
218
219 if (t->tx_buf) {
220 const u8 *buf = t->tx_buf;
221
222 /* NOTE: DMA could be used for TX transfers */
223
224 /* write one or two bytes at a time */
225 while (len >= 1) {
226 /* tx bit 15 is first sent; we byteswap multibyte words
227 * (msb-first) on the way out from memory.
228 */
229 val = *buf++;
230 if (bits > 8) {
231 bytes = 2;
232 val |= *buf++ << 8;
233 } else
234 bytes = 1;
235 val <<= 16 - bits;
236
237 #ifdef VERBOSE
238 pr_debug("%s: write-%d =%04x\n",
239 dev_name(&spi->dev), bits, val);
240 #endif
241 if (wait_uwire_csr_flag(CSRB, 0, 0))
242 goto eio;
243
244 uwire_write_reg(UWIRE_TDR, val);
245
246 /* start write */
247 val = START | w | (bits << 5);
248
249 uwire_write_reg(UWIRE_CSR, val);
250 len -= bytes;
251
252 /* Wait till write actually starts.
253 * This is needed with MPU clock 60+ MHz.
254 * REVISIT: we may not have time to catch it...
255 */
256 if (wait_uwire_csr_flag(CSRB, CSRB, 1))
257 goto eio;
258
259 status += bytes;
260 }
261
262 /* REVISIT: save this for later to get more i/o overlap */
263 if (wait_uwire_csr_flag(CSRB, 0, 0))
264 goto eio;
265
266 } else if (t->rx_buf) {
267 u8 *buf = t->rx_buf;
268
269 /* read one or two bytes at a time */
270 while (len) {
271 if (bits > 8) {
272 bytes = 2;
273 } else
274 bytes = 1;
275
276 /* start read */
277 val = START | w | (bits << 0);
278 uwire_write_reg(UWIRE_CSR, val);
279 len -= bytes;
280
281 /* Wait till read actually starts */
282 (void) wait_uwire_csr_flag(CSRB, CSRB, 1);
283
284 if (wait_uwire_csr_flag(RDRB | CSRB,
285 RDRB, 0))
286 goto eio;
287
288 /* rx bit 0 is last received; multibyte words will
289 * be properly byteswapped on the way to memory.
290 */
291 val = uwire_read_reg(UWIRE_RDR);
292 val &= (1 << bits) - 1;
293 *buf++ = (u8) val;
294 if (bytes == 2)
295 *buf++ = val >> 8;
296 status += bytes;
297 #ifdef VERBOSE
298 pr_debug("%s: read-%d =%04x\n",
299 dev_name(&spi->dev), bits, val);
300 #endif
301
302 }
303 }
304 return status;
305 eio:
306 return -EIO;
307 }
308
uwire_setup_transfer(struct spi_device * spi,struct spi_transfer * t)309 static int uwire_setup_transfer(struct spi_device *spi, struct spi_transfer *t)
310 {
311 struct uwire_state *ust = spi->controller_state;
312 struct uwire_spi *uwire;
313 unsigned flags = 0;
314 unsigned hz;
315 unsigned long rate;
316 int div1_idx;
317 int div1;
318 int div2;
319 int status;
320
321 uwire = spi_master_get_devdata(spi->master);
322
323 /* mode 0..3, clock inverted separately;
324 * standard nCS signaling;
325 * don't treat DI=high as "not ready"
326 */
327 if (spi->mode & SPI_CS_HIGH)
328 flags |= UWIRE_CS_ACTIVE_HIGH;
329
330 if (spi->mode & SPI_CPOL)
331 flags |= UWIRE_CLK_INVERTED;
332
333 switch (spi->mode & SPI_MODE_X_MASK) {
334 case SPI_MODE_0:
335 case SPI_MODE_3:
336 flags |= UWIRE_WRITE_FALLING_EDGE | UWIRE_READ_RISING_EDGE;
337 break;
338 case SPI_MODE_1:
339 case SPI_MODE_2:
340 flags |= UWIRE_WRITE_RISING_EDGE | UWIRE_READ_FALLING_EDGE;
341 break;
342 }
343
344 /* assume it's already enabled */
345 rate = clk_get_rate(uwire->ck);
346
347 if (t != NULL)
348 hz = t->speed_hz;
349 else
350 hz = spi->max_speed_hz;
351
352 if (!hz) {
353 pr_debug("%s: zero speed?\n", dev_name(&spi->dev));
354 status = -EINVAL;
355 goto done;
356 }
357
358 /* F_INT = mpu_xor_clk / DIV1 */
359 for (div1_idx = 0; div1_idx < 4; div1_idx++) {
360 switch (div1_idx) {
361 case 0:
362 div1 = 2;
363 break;
364 case 1:
365 div1 = 4;
366 break;
367 case 2:
368 div1 = 7;
369 break;
370 default:
371 case 3:
372 div1 = 10;
373 break;
374 }
375 div2 = (rate / div1 + hz - 1) / hz;
376 if (div2 <= 8)
377 break;
378 }
379 if (div1_idx == 4) {
380 pr_debug("%s: lowest clock %ld, need %d\n",
381 dev_name(&spi->dev), rate / 10 / 8, hz);
382 status = -EDOM;
383 goto done;
384 }
385
386 /* we have to cache this and reset in uwire_chipselect as this is a
387 * global parameter and another uwire device can change it under
388 * us */
389 ust->div1_idx = div1_idx;
390 uwire_set_clk1_div(div1_idx);
391
392 rate /= div1;
393
394 switch (div2) {
395 case 0:
396 case 1:
397 case 2:
398 flags |= UWIRE_FREQ_DIV_2;
399 rate /= 2;
400 break;
401 case 3:
402 case 4:
403 flags |= UWIRE_FREQ_DIV_4;
404 rate /= 4;
405 break;
406 case 5:
407 case 6:
408 case 7:
409 case 8:
410 flags |= UWIRE_FREQ_DIV_8;
411 rate /= 8;
412 break;
413 }
414 omap_uwire_configure_mode(spi->chip_select, flags);
415 pr_debug("%s: uwire flags %02x, armxor %lu KHz, SCK %lu KHz\n",
416 __func__, flags,
417 clk_get_rate(uwire->ck) / 1000,
418 rate / 1000);
419 status = 0;
420 done:
421 return status;
422 }
423
uwire_setup(struct spi_device * spi)424 static int uwire_setup(struct spi_device *spi)
425 {
426 struct uwire_state *ust = spi->controller_state;
427 bool initial_setup = false;
428 int status;
429
430 if (ust == NULL) {
431 ust = kzalloc(sizeof(*ust), GFP_KERNEL);
432 if (ust == NULL)
433 return -ENOMEM;
434 spi->controller_state = ust;
435 initial_setup = true;
436 }
437
438 status = uwire_setup_transfer(spi, NULL);
439 if (status && initial_setup)
440 kfree(ust);
441
442 return status;
443 }
444
uwire_cleanup(struct spi_device * spi)445 static void uwire_cleanup(struct spi_device *spi)
446 {
447 kfree(spi->controller_state);
448 }
449
uwire_off(struct uwire_spi * uwire)450 static void uwire_off(struct uwire_spi *uwire)
451 {
452 uwire_write_reg(UWIRE_SR3, 0);
453 clk_disable_unprepare(uwire->ck);
454 spi_master_put(uwire->bitbang.master);
455 }
456
uwire_probe(struct platform_device * pdev)457 static int uwire_probe(struct platform_device *pdev)
458 {
459 struct spi_master *master;
460 struct uwire_spi *uwire;
461 int status;
462
463 master = spi_alloc_master(&pdev->dev, sizeof(*uwire));
464 if (!master)
465 return -ENODEV;
466
467 uwire = spi_master_get_devdata(master);
468
469 uwire_base = devm_ioremap(&pdev->dev, UWIRE_BASE_PHYS, UWIRE_IO_SIZE);
470 if (!uwire_base) {
471 dev_dbg(&pdev->dev, "can't ioremap UWIRE\n");
472 spi_master_put(master);
473 return -ENOMEM;
474 }
475
476 platform_set_drvdata(pdev, uwire);
477
478 uwire->ck = devm_clk_get(&pdev->dev, "fck");
479 if (IS_ERR(uwire->ck)) {
480 status = PTR_ERR(uwire->ck);
481 dev_dbg(&pdev->dev, "no functional clock?\n");
482 spi_master_put(master);
483 return status;
484 }
485 clk_prepare_enable(uwire->ck);
486
487 if (cpu_is_omap7xx())
488 uwire_idx_shift = 1;
489 else
490 uwire_idx_shift = 2;
491
492 uwire_write_reg(UWIRE_SR3, 1);
493
494 /* the spi->mode bits understood by this driver: */
495 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
496 master->bits_per_word_mask = SPI_BPW_RANGE_MASK(1, 16);
497 master->flags = SPI_MASTER_HALF_DUPLEX;
498
499 master->bus_num = 2; /* "official" */
500 master->num_chipselect = 4;
501 master->setup = uwire_setup;
502 master->cleanup = uwire_cleanup;
503
504 uwire->bitbang.master = master;
505 uwire->bitbang.chipselect = uwire_chipselect;
506 uwire->bitbang.setup_transfer = uwire_setup_transfer;
507 uwire->bitbang.txrx_bufs = uwire_txrx;
508
509 status = spi_bitbang_start(&uwire->bitbang);
510 if (status < 0) {
511 uwire_off(uwire);
512 }
513 return status;
514 }
515
uwire_remove(struct platform_device * pdev)516 static int uwire_remove(struct platform_device *pdev)
517 {
518 struct uwire_spi *uwire = platform_get_drvdata(pdev);
519
520 // FIXME remove all child devices, somewhere ...
521
522 spi_bitbang_stop(&uwire->bitbang);
523 uwire_off(uwire);
524 return 0;
525 }
526
527 /* work with hotplug and coldplug */
528 MODULE_ALIAS("platform:omap_uwire");
529
530 static struct platform_driver uwire_driver = {
531 .driver = {
532 .name = "omap_uwire",
533 },
534 .probe = uwire_probe,
535 .remove = uwire_remove,
536 // suspend ... unuse ck
537 // resume ... use ck
538 };
539
omap_uwire_init(void)540 static int __init omap_uwire_init(void)
541 {
542 /* FIXME move these into the relevant board init code. also, include
543 * H3 support; it uses tsc2101 like H2 (on a different chipselect).
544 */
545
546 if (machine_is_omap_h2()) {
547 /* defaults: W21 SDO, U18 SDI, V19 SCL */
548 omap_cfg_reg(N14_1610_UWIRE_CS0);
549 omap_cfg_reg(N15_1610_UWIRE_CS1);
550 }
551 if (machine_is_omap_perseus2()) {
552 /* configure pins: MPU_UW_nSCS1, MPU_UW_SDO, MPU_UW_SCLK */
553 int val = omap_readl(OMAP7XX_IO_CONF_9) & ~0x00EEE000;
554 omap_writel(val | 0x00AAA000, OMAP7XX_IO_CONF_9);
555 }
556
557 return platform_driver_register(&uwire_driver);
558 }
559
omap_uwire_exit(void)560 static void __exit omap_uwire_exit(void)
561 {
562 platform_driver_unregister(&uwire_driver);
563 }
564
565 subsys_initcall(omap_uwire_init);
566 module_exit(omap_uwire_exit);
567
568 MODULE_LICENSE("GPL");
569
570