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1/*
2 * Copyright (c) 2006 Ben Dooks
3 * Copyright 2006-2009 Simtec Electronics
4 * Ben Dooks <ben@simtec.co.uk>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License version 2 as
8 * published by the Free Software Foundation.
9 *
10*/
11
12#include <linux/init.h>
13#include <linux/spinlock.h>
14#include <linux/workqueue.h>
15#include <linux/interrupt.h>
16#include <linux/delay.h>
17#include <linux/errno.h>
18#include <linux/err.h>
19#include <linux/clk.h>
20#include <linux/platform_device.h>
21#include <linux/gpio.h>
22#include <linux/io.h>
23#include <linux/slab.h>
24
25#include <linux/spi/spi.h>
26#include <linux/spi/spi_bitbang.h>
27#include <linux/spi/s3c24xx.h>
28#include <linux/module.h>
29
30#include <plat/regs-spi.h>
31
32#include <plat/fiq.h>
33#include <asm/fiq.h>
34
35#include "spi-s3c24xx-fiq.h"
36
37/**
38 * s3c24xx_spi_devstate - per device data
39 * @hz: Last frequency calculated for @sppre field.
40 * @mode: Last mode setting for the @spcon field.
41 * @spcon: Value to write to the SPCON register.
42 * @sppre: Value to write to the SPPRE register.
43 */
44struct s3c24xx_spi_devstate {
45 unsigned int hz;
46 unsigned int mode;
47 u8 spcon;
48 u8 sppre;
49};
50
51enum spi_fiq_mode {
52 FIQ_MODE_NONE = 0,
53 FIQ_MODE_TX = 1,
54 FIQ_MODE_RX = 2,
55 FIQ_MODE_TXRX = 3,
56};
57
58struct s3c24xx_spi {
59 /* bitbang has to be first */
60 struct spi_bitbang bitbang;
61 struct completion done;
62
63 void __iomem *regs;
64 int irq;
65 int len;
66 int count;
67
68 struct fiq_handler fiq_handler;
69 enum spi_fiq_mode fiq_mode;
70 unsigned char fiq_inuse;
71 unsigned char fiq_claimed;
72
73 void (*set_cs)(struct s3c2410_spi_info *spi,
74 int cs, int pol);
75
76 /* data buffers */
77 const unsigned char *tx;
78 unsigned char *rx;
79
80 struct clk *clk;
81 struct resource *ioarea;
82 struct spi_master *master;
83 struct spi_device *curdev;
84 struct device *dev;
85 struct s3c2410_spi_info *pdata;
86};
87
88
89#define SPCON_DEFAULT (S3C2410_SPCON_MSTR | S3C2410_SPCON_SMOD_INT)
90#define SPPIN_DEFAULT (S3C2410_SPPIN_KEEP)
91
92static inline struct s3c24xx_spi *to_hw(struct spi_device *sdev)
93{
94 return spi_master_get_devdata(sdev->master);
95}
96
97static void s3c24xx_spi_gpiocs(struct s3c2410_spi_info *spi, int cs, int pol)
98{
99 gpio_set_value(spi->pin_cs, pol);
100}
101
102static void s3c24xx_spi_chipsel(struct spi_device *spi, int value)
103{
104 struct s3c24xx_spi_devstate *cs = spi->controller_state;
105 struct s3c24xx_spi *hw = to_hw(spi);
106 unsigned int cspol = spi->mode & SPI_CS_HIGH ? 1 : 0;
107
108 /* change the chipselect state and the state of the spi engine clock */
109
110 switch (value) {
111 case BITBANG_CS_INACTIVE:
112 hw->set_cs(hw->pdata, spi->chip_select, cspol^1);
113 writeb(cs->spcon, hw->regs + S3C2410_SPCON);
114 break;
115
116 case BITBANG_CS_ACTIVE:
117 writeb(cs->spcon | S3C2410_SPCON_ENSCK,
118 hw->regs + S3C2410_SPCON);
119 hw->set_cs(hw->pdata, spi->chip_select, cspol);
120 break;
121 }
122}
123
124static int s3c24xx_spi_update_state(struct spi_device *spi,
125 struct spi_transfer *t)
126{
127 struct s3c24xx_spi *hw = to_hw(spi);
128 struct s3c24xx_spi_devstate *cs = spi->controller_state;
129 unsigned int bpw;
130 unsigned int hz;
131 unsigned int div;
132 unsigned long clk;
133
134 bpw = t ? t->bits_per_word : spi->bits_per_word;
135 hz = t ? t->speed_hz : spi->max_speed_hz;
136
137 if (!bpw)
138 bpw = 8;
139
140 if (!hz)
141 hz = spi->max_speed_hz;
142
143 if (bpw != 8) {
144 dev_err(&spi->dev, "invalid bits-per-word (%d)\n", bpw);
145 return -EINVAL;
146 }
147
148 if (spi->mode != cs->mode) {
149 u8 spcon = SPCON_DEFAULT | S3C2410_SPCON_ENSCK;
150
151 if (spi->mode & SPI_CPHA)
152 spcon |= S3C2410_SPCON_CPHA_FMTB;
153
154 if (spi->mode & SPI_CPOL)
155 spcon |= S3C2410_SPCON_CPOL_HIGH;
156
157 cs->mode = spi->mode;
158 cs->spcon = spcon;
159 }
160
161 if (cs->hz != hz) {
162 clk = clk_get_rate(hw->clk);
163 div = DIV_ROUND_UP(clk, hz * 2) - 1;
164
165 if (div > 255)
166 div = 255;
167
168 dev_dbg(&spi->dev, "pre-scaler=%d (wanted %d, got %ld)\n",
169 div, hz, clk / (2 * (div + 1)));
170
171 cs->hz = hz;
172 cs->sppre = div;
173 }
174
175 return 0;
176}
177
178static int s3c24xx_spi_setupxfer(struct spi_device *spi,
179 struct spi_transfer *t)
180{
181 struct s3c24xx_spi_devstate *cs = spi->controller_state;
182 struct s3c24xx_spi *hw = to_hw(spi);
183 int ret;
184
185 ret = s3c24xx_spi_update_state(spi, t);
186 if (!ret)
187 writeb(cs->sppre, hw->regs + S3C2410_SPPRE);
188
189 return ret;
190}
191
192static int s3c24xx_spi_setup(struct spi_device *spi)
193{
194 struct s3c24xx_spi_devstate *cs = spi->controller_state;
195 struct s3c24xx_spi *hw = to_hw(spi);
196 int ret;
197
198 /* allocate settings on the first call */
199 if (!cs) {
200 cs = kzalloc(sizeof(struct s3c24xx_spi_devstate), GFP_KERNEL);
201 if (!cs) {
202 dev_err(&spi->dev, "no memory for controller state\n");
203 return -ENOMEM;
204 }
205
206 cs->spcon = SPCON_DEFAULT;
207 cs->hz = -1;
208 spi->controller_state = cs;
209 }
210
211 /* initialise the state from the device */
212 ret = s3c24xx_spi_update_state(spi, NULL);
213 if (ret)
214 return ret;
215
216 spin_lock(&hw->bitbang.lock);
217 if (!hw->bitbang.busy) {
218 hw->bitbang.chipselect(spi, BITBANG_CS_INACTIVE);
219 /* need to ndelay for 0.5 clocktick ? */
220 }
221 spin_unlock(&hw->bitbang.lock);
222
223 return 0;
224}
225
226static void s3c24xx_spi_cleanup(struct spi_device *spi)
227{
228 kfree(spi->controller_state);
229}
230
231static inline unsigned int hw_txbyte(struct s3c24xx_spi *hw, int count)
232{
233 return hw->tx ? hw->tx[count] : 0;
234}
235
236#ifdef CONFIG_SPI_S3C24XX_FIQ
237/* Support for FIQ based pseudo-DMA to improve the transfer speed.
238 *
239 * This code uses the assembly helper in spi_s3c24xx_spi.S which is
240 * used by the FIQ core to move data between main memory and the peripheral
241 * block. Since this is code running on the processor, there is no problem
242 * with cache coherency of the buffers, so we can use any buffer we like.
243 */
244
245/**
246 * struct spi_fiq_code - FIQ code and header
247 * @length: The length of the code fragment, excluding this header.
248 * @ack_offset: The offset from @data to the word to place the IRQ ACK bit at.
249 * @data: The code itself to install as a FIQ handler.
250 */
251struct spi_fiq_code {
252 u32 length;
253 u32 ack_offset;
254 u8 data[0];
255};
256
257extern struct spi_fiq_code s3c24xx_spi_fiq_txrx;
258extern struct spi_fiq_code s3c24xx_spi_fiq_tx;
259extern struct spi_fiq_code s3c24xx_spi_fiq_rx;
260
261/**
262 * ack_bit - turn IRQ into IRQ acknowledgement bit
263 * @irq: The interrupt number
264 *
265 * Returns the bit to write to the interrupt acknowledge register.
266 */
267static inline u32 ack_bit(unsigned int irq)
268{
269 return 1 << (irq - IRQ_EINT0);
270}
271
272/**
273 * s3c24xx_spi_tryfiq - attempt to claim and setup FIQ for transfer
274 * @hw: The hardware state.
275 *
276 * Claim the FIQ handler (only one can be active at any one time) and
277 * then setup the correct transfer code for this transfer.
278 *
279 * This call updates all the necessary state information if successful,
280 * so the caller does not need to do anything more than start the transfer
281 * as normal, since the IRQ will have been re-routed to the FIQ handler.
282*/
283void s3c24xx_spi_tryfiq(struct s3c24xx_spi *hw)
284{
285 struct pt_regs regs;
286 enum spi_fiq_mode mode;
287 struct spi_fiq_code *code;
288 int ret;
289
290 if (!hw->fiq_claimed) {
291 /* try and claim fiq if we haven't got it, and if not
292 * then return and simply use another transfer method */
293
294 ret = claim_fiq(&hw->fiq_handler);
295 if (ret)
296 return;
297 }
298
299 if (hw->tx && !hw->rx)
300 mode = FIQ_MODE_TX;
301 else if (hw->rx && !hw->tx)
302 mode = FIQ_MODE_RX;
303 else
304 mode = FIQ_MODE_TXRX;
305
306 regs.uregs[fiq_rspi] = (long)hw->regs;
307 regs.uregs[fiq_rrx] = (long)hw->rx;
308 regs.uregs[fiq_rtx] = (long)hw->tx + 1;
309 regs.uregs[fiq_rcount] = hw->len - 1;
310 regs.uregs[fiq_rirq] = (long)S3C24XX_VA_IRQ;
311
312 set_fiq_regs(®s);
313
314 if (hw->fiq_mode != mode) {
315 u32 *ack_ptr;
316
317 hw->fiq_mode = mode;
318
319 switch (mode) {
320 case FIQ_MODE_TX:
321 code = &s3c24xx_spi_fiq_tx;
322 break;
323 case FIQ_MODE_RX:
324 code = &s3c24xx_spi_fiq_rx;
325 break;
326 case FIQ_MODE_TXRX:
327 code = &s3c24xx_spi_fiq_txrx;
328 break;
329 default:
330 code = NULL;
331 }
332
333 BUG_ON(!code);
334
335 ack_ptr = (u32 *)&code->data[code->ack_offset];
336 *ack_ptr = ack_bit(hw->irq);
337
338 set_fiq_handler(&code->data, code->length);
339 }
340
341 s3c24xx_set_fiq(hw->irq, true);
342
343 hw->fiq_mode = mode;
344 hw->fiq_inuse = 1;
345}
346
347/**
348 * s3c24xx_spi_fiqop - FIQ core code callback
349 * @pw: Data registered with the handler
350 * @release: Whether this is a release or a return.
351 *
352 * Called by the FIQ code when another module wants to use the FIQ, so
353 * return whether we are currently using this or not and then update our
354 * internal state.
355 */
356static int s3c24xx_spi_fiqop(void *pw, int release)
357{
358 struct s3c24xx_spi *hw = pw;
359 int ret = 0;
360
361 if (release) {
362 if (hw->fiq_inuse)
363 ret = -EBUSY;
364
365 /* note, we do not need to unroute the FIQ, as the FIQ
366 * vector code de-routes it to signal the end of transfer */
367
368 hw->fiq_mode = FIQ_MODE_NONE;
369 hw->fiq_claimed = 0;
370 } else {
371 hw->fiq_claimed = 1;
372 }
373
374 return ret;
375}
376
377/**
378 * s3c24xx_spi_initfiq - setup the information for the FIQ core
379 * @hw: The hardware state.
380 *
381 * Setup the fiq_handler block to pass to the FIQ core.
382 */
383static inline void s3c24xx_spi_initfiq(struct s3c24xx_spi *hw)
384{
385 hw->fiq_handler.dev_id = hw;
386 hw->fiq_handler.name = dev_name(hw->dev);
387 hw->fiq_handler.fiq_op = s3c24xx_spi_fiqop;
388}
389
390/**
391 * s3c24xx_spi_usefiq - return if we should be using FIQ.
392 * @hw: The hardware state.
393 *
394 * Return true if the platform data specifies whether this channel is
395 * allowed to use the FIQ.
396 */
397static inline bool s3c24xx_spi_usefiq(struct s3c24xx_spi *hw)
398{
399 return hw->pdata->use_fiq;
400}
401
402/**
403 * s3c24xx_spi_usingfiq - return if channel is using FIQ
404 * @spi: The hardware state.
405 *
406 * Return whether the channel is currently using the FIQ (separate from
407 * whether the FIQ is claimed).
408 */
409static inline bool s3c24xx_spi_usingfiq(struct s3c24xx_spi *spi)
410{
411 return spi->fiq_inuse;
412}
413#else
414
415static inline void s3c24xx_spi_initfiq(struct s3c24xx_spi *s) { }
416static inline void s3c24xx_spi_tryfiq(struct s3c24xx_spi *s) { }
417static inline bool s3c24xx_spi_usefiq(struct s3c24xx_spi *s) { return false; }
418static inline bool s3c24xx_spi_usingfiq(struct s3c24xx_spi *s) { return false; }
419
420#endif /* CONFIG_SPI_S3C24XX_FIQ */
421
422static int s3c24xx_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
423{
424 struct s3c24xx_spi *hw = to_hw(spi);
425
426 hw->tx = t->tx_buf;
427 hw->rx = t->rx_buf;
428 hw->len = t->len;
429 hw->count = 0;
430
431 init_completion(&hw->done);
432
433 hw->fiq_inuse = 0;
434 if (s3c24xx_spi_usefiq(hw) && t->len >= 3)
435 s3c24xx_spi_tryfiq(hw);
436
437 /* send the first byte */
438 writeb(hw_txbyte(hw, 0), hw->regs + S3C2410_SPTDAT);
439
440 wait_for_completion(&hw->done);
441 return hw->count;
442}
443
444static irqreturn_t s3c24xx_spi_irq(int irq, void *dev)
445{
446 struct s3c24xx_spi *hw = dev;
447 unsigned int spsta = readb(hw->regs + S3C2410_SPSTA);
448 unsigned int count = hw->count;
449
450 if (spsta & S3C2410_SPSTA_DCOL) {
451 dev_dbg(hw->dev, "data-collision\n");
452 complete(&hw->done);
453 goto irq_done;
454 }
455
456 if (!(spsta & S3C2410_SPSTA_READY)) {
457 dev_dbg(hw->dev, "spi not ready for tx?\n");
458 complete(&hw->done);
459 goto irq_done;
460 }
461
462 if (!s3c24xx_spi_usingfiq(hw)) {
463 hw->count++;
464
465 if (hw->rx)
466 hw->rx[count] = readb(hw->regs + S3C2410_SPRDAT);
467
468 count++;
469
470 if (count < hw->len)
471 writeb(hw_txbyte(hw, count), hw->regs + S3C2410_SPTDAT);
472 else
473 complete(&hw->done);
474 } else {
475 hw->count = hw->len;
476 hw->fiq_inuse = 0;
477
478 if (hw->rx)
479 hw->rx[hw->len-1] = readb(hw->regs + S3C2410_SPRDAT);
480
481 complete(&hw->done);
482 }
483
484 irq_done:
485 return IRQ_HANDLED;
486}
487
488static void s3c24xx_spi_initialsetup(struct s3c24xx_spi *hw)
489{
490 /* for the moment, permanently enable the clock */
491
492 clk_enable(hw->clk);
493
494 /* program defaults into the registers */
495
496 writeb(0xff, hw->regs + S3C2410_SPPRE);
497 writeb(SPPIN_DEFAULT, hw->regs + S3C2410_SPPIN);
498 writeb(SPCON_DEFAULT, hw->regs + S3C2410_SPCON);
499
500 if (hw->pdata) {
501 if (hw->set_cs == s3c24xx_spi_gpiocs)
502 gpio_direction_output(hw->pdata->pin_cs, 1);
503
504 if (hw->pdata->gpio_setup)
505 hw->pdata->gpio_setup(hw->pdata, 1);
506 }
507}
508
509static int __devinit s3c24xx_spi_probe(struct platform_device *pdev)
510{
511 struct s3c2410_spi_info *pdata;
512 struct s3c24xx_spi *hw;
513 struct spi_master *master;
514 struct resource *res;
515 int err = 0;
516
517 master = spi_alloc_master(&pdev->dev, sizeof(struct s3c24xx_spi));
518 if (master == NULL) {
519 dev_err(&pdev->dev, "No memory for spi_master\n");
520 err = -ENOMEM;
521 goto err_nomem;
522 }
523
524 hw = spi_master_get_devdata(master);
525 memset(hw, 0, sizeof(struct s3c24xx_spi));
526
527 hw->master = spi_master_get(master);
528 hw->pdata = pdata = pdev->dev.platform_data;
529 hw->dev = &pdev->dev;
530
531 if (pdata == NULL) {
532 dev_err(&pdev->dev, "No platform data supplied\n");
533 err = -ENOENT;
534 goto err_no_pdata;
535 }
536
537 platform_set_drvdata(pdev, hw);
538 init_completion(&hw->done);
539
540 /* initialise fiq handler */
541
542 s3c24xx_spi_initfiq(hw);
543
544 /* setup the master state. */
545
546 /* the spi->mode bits understood by this driver: */
547 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
548
549 master->num_chipselect = hw->pdata->num_cs;
550 master->bus_num = pdata->bus_num;
551
552 /* setup the state for the bitbang driver */
553
554 hw->bitbang.master = hw->master;
555 hw->bitbang.setup_transfer = s3c24xx_spi_setupxfer;
556 hw->bitbang.chipselect = s3c24xx_spi_chipsel;
557 hw->bitbang.txrx_bufs = s3c24xx_spi_txrx;
558
559 hw->master->setup = s3c24xx_spi_setup;
560 hw->master->cleanup = s3c24xx_spi_cleanup;
561
562 dev_dbg(hw->dev, "bitbang at %p\n", &hw->bitbang);
563
564 /* find and map our resources */
565
566 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
567 if (res == NULL) {
568 dev_err(&pdev->dev, "Cannot get IORESOURCE_MEM\n");
569 err = -ENOENT;
570 goto err_no_iores;
571 }
572
573 hw->ioarea = request_mem_region(res->start, resource_size(res),
574 pdev->name);
575
576 if (hw->ioarea == NULL) {
577 dev_err(&pdev->dev, "Cannot reserve region\n");
578 err = -ENXIO;
579 goto err_no_iores;
580 }
581
582 hw->regs = ioremap(res->start, resource_size(res));
583 if (hw->regs == NULL) {
584 dev_err(&pdev->dev, "Cannot map IO\n");
585 err = -ENXIO;
586 goto err_no_iomap;
587 }
588
589 hw->irq = platform_get_irq(pdev, 0);
590 if (hw->irq < 0) {
591 dev_err(&pdev->dev, "No IRQ specified\n");
592 err = -ENOENT;
593 goto err_no_irq;
594 }
595
596 err = request_irq(hw->irq, s3c24xx_spi_irq, 0, pdev->name, hw);
597 if (err) {
598 dev_err(&pdev->dev, "Cannot claim IRQ\n");
599 goto err_no_irq;
600 }
601
602 hw->clk = clk_get(&pdev->dev, "spi");
603 if (IS_ERR(hw->clk)) {
604 dev_err(&pdev->dev, "No clock for device\n");
605 err = PTR_ERR(hw->clk);
606 goto err_no_clk;
607 }
608
609 /* setup any gpio we can */
610
611 if (!pdata->set_cs) {
612 if (pdata->pin_cs < 0) {
613 dev_err(&pdev->dev, "No chipselect pin\n");
614 goto err_register;
615 }
616
617 err = gpio_request(pdata->pin_cs, dev_name(&pdev->dev));
618 if (err) {
619 dev_err(&pdev->dev, "Failed to get gpio for cs\n");
620 goto err_register;
621 }
622
623 hw->set_cs = s3c24xx_spi_gpiocs;
624 gpio_direction_output(pdata->pin_cs, 1);
625 } else
626 hw->set_cs = pdata->set_cs;
627
628 s3c24xx_spi_initialsetup(hw);
629
630 /* register our spi controller */
631
632 err = spi_bitbang_start(&hw->bitbang);
633 if (err) {
634 dev_err(&pdev->dev, "Failed to register SPI master\n");
635 goto err_register;
636 }
637
638 return 0;
639
640 err_register:
641 if (hw->set_cs == s3c24xx_spi_gpiocs)
642 gpio_free(pdata->pin_cs);
643
644 clk_disable(hw->clk);
645 clk_put(hw->clk);
646
647 err_no_clk:
648 free_irq(hw->irq, hw);
649
650 err_no_irq:
651 iounmap(hw->regs);
652
653 err_no_iomap:
654 release_resource(hw->ioarea);
655 kfree(hw->ioarea);
656
657 err_no_iores:
658 err_no_pdata:
659 spi_master_put(hw->master);
660
661 err_nomem:
662 return err;
663}
664
665static int __devexit s3c24xx_spi_remove(struct platform_device *dev)
666{
667 struct s3c24xx_spi *hw = platform_get_drvdata(dev);
668
669 platform_set_drvdata(dev, NULL);
670
671 spi_bitbang_stop(&hw->bitbang);
672
673 clk_disable(hw->clk);
674 clk_put(hw->clk);
675
676 free_irq(hw->irq, hw);
677 iounmap(hw->regs);
678
679 if (hw->set_cs == s3c24xx_spi_gpiocs)
680 gpio_free(hw->pdata->pin_cs);
681
682 release_resource(hw->ioarea);
683 kfree(hw->ioarea);
684
685 spi_master_put(hw->master);
686 return 0;
687}
688
689
690#ifdef CONFIG_PM
691
692static int s3c24xx_spi_suspend(struct device *dev)
693{
694 struct s3c24xx_spi *hw = platform_get_drvdata(to_platform_device(dev));
695
696 if (hw->pdata && hw->pdata->gpio_setup)
697 hw->pdata->gpio_setup(hw->pdata, 0);
698
699 clk_disable(hw->clk);
700 return 0;
701}
702
703static int s3c24xx_spi_resume(struct device *dev)
704{
705 struct s3c24xx_spi *hw = platform_get_drvdata(to_platform_device(dev));
706
707 s3c24xx_spi_initialsetup(hw);
708 return 0;
709}
710
711static const struct dev_pm_ops s3c24xx_spi_pmops = {
712 .suspend = s3c24xx_spi_suspend,
713 .resume = s3c24xx_spi_resume,
714};
715
716#define S3C24XX_SPI_PMOPS &s3c24xx_spi_pmops
717#else
718#define S3C24XX_SPI_PMOPS NULL
719#endif /* CONFIG_PM */
720
721MODULE_ALIAS("platform:s3c2410-spi");
722static struct platform_driver s3c24xx_spi_driver = {
723 .probe = s3c24xx_spi_probe,
724 .remove = __devexit_p(s3c24xx_spi_remove),
725 .driver = {
726 .name = "s3c2410-spi",
727 .owner = THIS_MODULE,
728 .pm = S3C24XX_SPI_PMOPS,
729 },
730};
731module_platform_driver(s3c24xx_spi_driver);
732
733MODULE_DESCRIPTION("S3C24XX SPI Driver");
734MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
735MODULE_LICENSE("GPL");
1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * Copyright (c) 2006 Ben Dooks
4 * Copyright 2006-2009 Simtec Electronics
5 * Ben Dooks <ben@simtec.co.uk>
6*/
7
8#include <linux/spinlock.h>
9#include <linux/interrupt.h>
10#include <linux/delay.h>
11#include <linux/errno.h>
12#include <linux/err.h>
13#include <linux/clk.h>
14#include <linux/platform_device.h>
15#include <linux/io.h>
16#include <linux/slab.h>
17
18#include <linux/spi/spi.h>
19#include <linux/spi/spi_bitbang.h>
20#include <linux/spi/s3c24xx.h>
21#include <linux/spi/s3c24xx-fiq.h>
22#include <linux/module.h>
23
24#include <asm/fiq.h>
25
26#include "spi-s3c24xx-regs.h"
27
28/**
29 * struct s3c24xx_spi_devstate - per device data
30 * @hz: Last frequency calculated for @sppre field.
31 * @mode: Last mode setting for the @spcon field.
32 * @spcon: Value to write to the SPCON register.
33 * @sppre: Value to write to the SPPRE register.
34 */
35struct s3c24xx_spi_devstate {
36 unsigned int hz;
37 unsigned int mode;
38 u8 spcon;
39 u8 sppre;
40};
41
42enum spi_fiq_mode {
43 FIQ_MODE_NONE = 0,
44 FIQ_MODE_TX = 1,
45 FIQ_MODE_RX = 2,
46 FIQ_MODE_TXRX = 3,
47};
48
49struct s3c24xx_spi {
50 /* bitbang has to be first */
51 struct spi_bitbang bitbang;
52 struct completion done;
53
54 void __iomem *regs;
55 int irq;
56 int len;
57 int count;
58
59 struct fiq_handler fiq_handler;
60 enum spi_fiq_mode fiq_mode;
61 unsigned char fiq_inuse;
62 unsigned char fiq_claimed;
63
64 /* data buffers */
65 const unsigned char *tx;
66 unsigned char *rx;
67
68 struct clk *clk;
69 struct spi_master *master;
70 struct spi_device *curdev;
71 struct device *dev;
72 struct s3c2410_spi_info *pdata;
73};
74
75#define SPCON_DEFAULT (S3C2410_SPCON_MSTR | S3C2410_SPCON_SMOD_INT)
76#define SPPIN_DEFAULT (S3C2410_SPPIN_KEEP)
77
78static inline struct s3c24xx_spi *to_hw(struct spi_device *sdev)
79{
80 return spi_master_get_devdata(sdev->master);
81}
82
83static void s3c24xx_spi_chipsel(struct spi_device *spi, int value)
84{
85 struct s3c24xx_spi_devstate *cs = spi->controller_state;
86 struct s3c24xx_spi *hw = to_hw(spi);
87
88 /* change the chipselect state and the state of the spi engine clock */
89
90 switch (value) {
91 case BITBANG_CS_INACTIVE:
92 writeb(cs->spcon, hw->regs + S3C2410_SPCON);
93 break;
94
95 case BITBANG_CS_ACTIVE:
96 writeb(cs->spcon | S3C2410_SPCON_ENSCK,
97 hw->regs + S3C2410_SPCON);
98 break;
99 }
100}
101
102static int s3c24xx_spi_update_state(struct spi_device *spi,
103 struct spi_transfer *t)
104{
105 struct s3c24xx_spi *hw = to_hw(spi);
106 struct s3c24xx_spi_devstate *cs = spi->controller_state;
107 unsigned int hz;
108 unsigned int div;
109 unsigned long clk;
110
111 hz = t ? t->speed_hz : spi->max_speed_hz;
112
113 if (!hz)
114 hz = spi->max_speed_hz;
115
116 if (spi->mode != cs->mode) {
117 u8 spcon = SPCON_DEFAULT | S3C2410_SPCON_ENSCK;
118
119 if (spi->mode & SPI_CPHA)
120 spcon |= S3C2410_SPCON_CPHA_FMTB;
121
122 if (spi->mode & SPI_CPOL)
123 spcon |= S3C2410_SPCON_CPOL_HIGH;
124
125 cs->mode = spi->mode;
126 cs->spcon = spcon;
127 }
128
129 if (cs->hz != hz) {
130 clk = clk_get_rate(hw->clk);
131 div = DIV_ROUND_UP(clk, hz * 2) - 1;
132
133 if (div > 255)
134 div = 255;
135
136 dev_dbg(&spi->dev, "pre-scaler=%d (wanted %d, got %ld)\n",
137 div, hz, clk / (2 * (div + 1)));
138
139 cs->hz = hz;
140 cs->sppre = div;
141 }
142
143 return 0;
144}
145
146static int s3c24xx_spi_setupxfer(struct spi_device *spi,
147 struct spi_transfer *t)
148{
149 struct s3c24xx_spi_devstate *cs = spi->controller_state;
150 struct s3c24xx_spi *hw = to_hw(spi);
151 int ret;
152
153 ret = s3c24xx_spi_update_state(spi, t);
154 if (!ret)
155 writeb(cs->sppre, hw->regs + S3C2410_SPPRE);
156
157 return ret;
158}
159
160static int s3c24xx_spi_setup(struct spi_device *spi)
161{
162 struct s3c24xx_spi_devstate *cs = spi->controller_state;
163 struct s3c24xx_spi *hw = to_hw(spi);
164 int ret;
165
166 /* allocate settings on the first call */
167 if (!cs) {
168 cs = devm_kzalloc(&spi->dev,
169 sizeof(struct s3c24xx_spi_devstate),
170 GFP_KERNEL);
171 if (!cs)
172 return -ENOMEM;
173
174 cs->spcon = SPCON_DEFAULT;
175 cs->hz = -1;
176 spi->controller_state = cs;
177 }
178
179 /* initialise the state from the device */
180 ret = s3c24xx_spi_update_state(spi, NULL);
181 if (ret)
182 return ret;
183
184 mutex_lock(&hw->bitbang.lock);
185 if (!hw->bitbang.busy) {
186 hw->bitbang.chipselect(spi, BITBANG_CS_INACTIVE);
187 /* need to ndelay for 0.5 clocktick ? */
188 }
189 mutex_unlock(&hw->bitbang.lock);
190
191 return 0;
192}
193
194static inline unsigned int hw_txbyte(struct s3c24xx_spi *hw, int count)
195{
196 return hw->tx ? hw->tx[count] : 0;
197}
198
199#ifdef CONFIG_SPI_S3C24XX_FIQ
200/* Support for FIQ based pseudo-DMA to improve the transfer speed.
201 *
202 * This code uses the assembly helper in spi_s3c24xx_spi.S which is
203 * used by the FIQ core to move data between main memory and the peripheral
204 * block. Since this is code running on the processor, there is no problem
205 * with cache coherency of the buffers, so we can use any buffer we like.
206 */
207
208/**
209 * struct spi_fiq_code - FIQ code and header
210 * @length: The length of the code fragment, excluding this header.
211 * @ack_offset: The offset from @data to the word to place the IRQ ACK bit at.
212 * @data: The code itself to install as a FIQ handler.
213 */
214struct spi_fiq_code {
215 u32 length;
216 u32 ack_offset;
217 u8 data[];
218};
219
220/**
221 * s3c24xx_spi_tryfiq - attempt to claim and setup FIQ for transfer
222 * @hw: The hardware state.
223 *
224 * Claim the FIQ handler (only one can be active at any one time) and
225 * then setup the correct transfer code for this transfer.
226 *
227 * This call updates all the necessary state information if successful,
228 * so the caller does not need to do anything more than start the transfer
229 * as normal, since the IRQ will have been re-routed to the FIQ handler.
230*/
231static void s3c24xx_spi_tryfiq(struct s3c24xx_spi *hw)
232{
233 struct pt_regs regs;
234 enum spi_fiq_mode mode;
235 struct spi_fiq_code *code;
236 u32 *ack_ptr = NULL;
237 int ret;
238
239 if (!hw->fiq_claimed) {
240 /* try and claim fiq if we haven't got it, and if not
241 * then return and simply use another transfer method */
242
243 ret = claim_fiq(&hw->fiq_handler);
244 if (ret)
245 return;
246 }
247
248 if (hw->tx && !hw->rx)
249 mode = FIQ_MODE_TX;
250 else if (hw->rx && !hw->tx)
251 mode = FIQ_MODE_RX;
252 else
253 mode = FIQ_MODE_TXRX;
254
255 regs.uregs[fiq_rspi] = (long)hw->regs;
256 regs.uregs[fiq_rrx] = (long)hw->rx;
257 regs.uregs[fiq_rtx] = (long)hw->tx + 1;
258 regs.uregs[fiq_rcount] = hw->len - 1;
259
260 set_fiq_regs(®s);
261
262 if (hw->fiq_mode != mode) {
263 hw->fiq_mode = mode;
264
265 switch (mode) {
266 case FIQ_MODE_TX:
267 code = &s3c24xx_spi_fiq_tx;
268 break;
269 case FIQ_MODE_RX:
270 code = &s3c24xx_spi_fiq_rx;
271 break;
272 case FIQ_MODE_TXRX:
273 code = &s3c24xx_spi_fiq_txrx;
274 break;
275 default:
276 code = NULL;
277 }
278
279 BUG_ON(!code);
280
281 ack_ptr = (u32 *)&code->data[code->ack_offset];
282 set_fiq_handler(&code->data, code->length);
283 }
284
285 s3c24xx_set_fiq(hw->irq, ack_ptr, true);
286
287 hw->fiq_mode = mode;
288 hw->fiq_inuse = 1;
289}
290
291/**
292 * s3c24xx_spi_fiqop - FIQ core code callback
293 * @pw: Data registered with the handler
294 * @release: Whether this is a release or a return.
295 *
296 * Called by the FIQ code when another module wants to use the FIQ, so
297 * return whether we are currently using this or not and then update our
298 * internal state.
299 */
300static int s3c24xx_spi_fiqop(void *pw, int release)
301{
302 struct s3c24xx_spi *hw = pw;
303 int ret = 0;
304
305 if (release) {
306 if (hw->fiq_inuse)
307 ret = -EBUSY;
308
309 /* note, we do not need to unroute the FIQ, as the FIQ
310 * vector code de-routes it to signal the end of transfer */
311
312 hw->fiq_mode = FIQ_MODE_NONE;
313 hw->fiq_claimed = 0;
314 } else {
315 hw->fiq_claimed = 1;
316 }
317
318 return ret;
319}
320
321/**
322 * s3c24xx_spi_initfiq - setup the information for the FIQ core
323 * @hw: The hardware state.
324 *
325 * Setup the fiq_handler block to pass to the FIQ core.
326 */
327static inline void s3c24xx_spi_initfiq(struct s3c24xx_spi *hw)
328{
329 hw->fiq_handler.dev_id = hw;
330 hw->fiq_handler.name = dev_name(hw->dev);
331 hw->fiq_handler.fiq_op = s3c24xx_spi_fiqop;
332}
333
334/**
335 * s3c24xx_spi_usefiq - return if we should be using FIQ.
336 * @hw: The hardware state.
337 *
338 * Return true if the platform data specifies whether this channel is
339 * allowed to use the FIQ.
340 */
341static inline bool s3c24xx_spi_usefiq(struct s3c24xx_spi *hw)
342{
343 return hw->pdata->use_fiq;
344}
345
346/**
347 * s3c24xx_spi_usingfiq - return if channel is using FIQ
348 * @spi: The hardware state.
349 *
350 * Return whether the channel is currently using the FIQ (separate from
351 * whether the FIQ is claimed).
352 */
353static inline bool s3c24xx_spi_usingfiq(struct s3c24xx_spi *spi)
354{
355 return spi->fiq_inuse;
356}
357#else
358
359static inline void s3c24xx_spi_initfiq(struct s3c24xx_spi *s) { }
360static inline void s3c24xx_spi_tryfiq(struct s3c24xx_spi *s) { }
361static inline bool s3c24xx_spi_usefiq(struct s3c24xx_spi *s) { return false; }
362static inline bool s3c24xx_spi_usingfiq(struct s3c24xx_spi *s) { return false; }
363
364#endif /* CONFIG_SPI_S3C24XX_FIQ */
365
366static int s3c24xx_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
367{
368 struct s3c24xx_spi *hw = to_hw(spi);
369
370 hw->tx = t->tx_buf;
371 hw->rx = t->rx_buf;
372 hw->len = t->len;
373 hw->count = 0;
374
375 init_completion(&hw->done);
376
377 hw->fiq_inuse = 0;
378 if (s3c24xx_spi_usefiq(hw) && t->len >= 3)
379 s3c24xx_spi_tryfiq(hw);
380
381 /* send the first byte */
382 writeb(hw_txbyte(hw, 0), hw->regs + S3C2410_SPTDAT);
383
384 wait_for_completion(&hw->done);
385 return hw->count;
386}
387
388static irqreturn_t s3c24xx_spi_irq(int irq, void *dev)
389{
390 struct s3c24xx_spi *hw = dev;
391 unsigned int spsta = readb(hw->regs + S3C2410_SPSTA);
392 unsigned int count = hw->count;
393
394 if (spsta & S3C2410_SPSTA_DCOL) {
395 dev_dbg(hw->dev, "data-collision\n");
396 complete(&hw->done);
397 goto irq_done;
398 }
399
400 if (!(spsta & S3C2410_SPSTA_READY)) {
401 dev_dbg(hw->dev, "spi not ready for tx?\n");
402 complete(&hw->done);
403 goto irq_done;
404 }
405
406 if (!s3c24xx_spi_usingfiq(hw)) {
407 hw->count++;
408
409 if (hw->rx)
410 hw->rx[count] = readb(hw->regs + S3C2410_SPRDAT);
411
412 count++;
413
414 if (count < hw->len)
415 writeb(hw_txbyte(hw, count), hw->regs + S3C2410_SPTDAT);
416 else
417 complete(&hw->done);
418 } else {
419 hw->count = hw->len;
420 hw->fiq_inuse = 0;
421
422 if (hw->rx)
423 hw->rx[hw->len-1] = readb(hw->regs + S3C2410_SPRDAT);
424
425 complete(&hw->done);
426 }
427
428 irq_done:
429 return IRQ_HANDLED;
430}
431
432static void s3c24xx_spi_initialsetup(struct s3c24xx_spi *hw)
433{
434 /* for the moment, permanently enable the clock */
435
436 clk_enable(hw->clk);
437
438 /* program defaults into the registers */
439
440 writeb(0xff, hw->regs + S3C2410_SPPRE);
441 writeb(SPPIN_DEFAULT, hw->regs + S3C2410_SPPIN);
442 writeb(SPCON_DEFAULT, hw->regs + S3C2410_SPCON);
443}
444
445static int s3c24xx_spi_probe(struct platform_device *pdev)
446{
447 struct s3c2410_spi_info *pdata;
448 struct s3c24xx_spi *hw;
449 struct spi_master *master;
450 int err = 0;
451
452 master = devm_spi_alloc_master(&pdev->dev, sizeof(struct s3c24xx_spi));
453 if (master == NULL) {
454 dev_err(&pdev->dev, "No memory for spi_master\n");
455 return -ENOMEM;
456 }
457
458 hw = spi_master_get_devdata(master);
459
460 hw->master = master;
461 hw->pdata = pdata = dev_get_platdata(&pdev->dev);
462 hw->dev = &pdev->dev;
463
464 if (pdata == NULL) {
465 dev_err(&pdev->dev, "No platform data supplied\n");
466 return -ENOENT;
467 }
468
469 platform_set_drvdata(pdev, hw);
470 init_completion(&hw->done);
471
472 /* initialise fiq handler */
473
474 s3c24xx_spi_initfiq(hw);
475
476 /* setup the master state. */
477
478 /* the spi->mode bits understood by this driver: */
479 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
480
481 master->num_chipselect = hw->pdata->num_cs;
482 master->bus_num = pdata->bus_num;
483 master->bits_per_word_mask = SPI_BPW_MASK(8);
484 /* we need to call the local chipselect callback */
485 master->flags = SPI_MASTER_GPIO_SS;
486 master->use_gpio_descriptors = true;
487
488 /* setup the state for the bitbang driver */
489
490 hw->bitbang.master = hw->master;
491 hw->bitbang.setup_transfer = s3c24xx_spi_setupxfer;
492 hw->bitbang.chipselect = s3c24xx_spi_chipsel;
493 hw->bitbang.txrx_bufs = s3c24xx_spi_txrx;
494
495 hw->master->setup = s3c24xx_spi_setup;
496
497 dev_dbg(hw->dev, "bitbang at %p\n", &hw->bitbang);
498
499 /* find and map our resources */
500 hw->regs = devm_platform_ioremap_resource(pdev, 0);
501 if (IS_ERR(hw->regs))
502 return PTR_ERR(hw->regs);
503
504 hw->irq = platform_get_irq(pdev, 0);
505 if (hw->irq < 0)
506 return -ENOENT;
507
508 err = devm_request_irq(&pdev->dev, hw->irq, s3c24xx_spi_irq, 0,
509 pdev->name, hw);
510 if (err) {
511 dev_err(&pdev->dev, "Cannot claim IRQ\n");
512 return err;
513 }
514
515 hw->clk = devm_clk_get(&pdev->dev, "spi");
516 if (IS_ERR(hw->clk)) {
517 dev_err(&pdev->dev, "No clock for device\n");
518 return PTR_ERR(hw->clk);
519 }
520
521 s3c24xx_spi_initialsetup(hw);
522
523 /* register our spi controller */
524
525 err = spi_bitbang_start(&hw->bitbang);
526 if (err) {
527 dev_err(&pdev->dev, "Failed to register SPI master\n");
528 goto err_register;
529 }
530
531 return 0;
532
533 err_register:
534 clk_disable(hw->clk);
535
536 return err;
537}
538
539static int s3c24xx_spi_remove(struct platform_device *dev)
540{
541 struct s3c24xx_spi *hw = platform_get_drvdata(dev);
542
543 spi_bitbang_stop(&hw->bitbang);
544 clk_disable(hw->clk);
545 spi_master_put(hw->master);
546 return 0;
547}
548
549
550#ifdef CONFIG_PM
551
552static int s3c24xx_spi_suspend(struct device *dev)
553{
554 struct s3c24xx_spi *hw = dev_get_drvdata(dev);
555 int ret;
556
557 ret = spi_master_suspend(hw->master);
558 if (ret)
559 return ret;
560
561 clk_disable(hw->clk);
562 return 0;
563}
564
565static int s3c24xx_spi_resume(struct device *dev)
566{
567 struct s3c24xx_spi *hw = dev_get_drvdata(dev);
568
569 s3c24xx_spi_initialsetup(hw);
570 return spi_master_resume(hw->master);
571}
572
573static const struct dev_pm_ops s3c24xx_spi_pmops = {
574 .suspend = s3c24xx_spi_suspend,
575 .resume = s3c24xx_spi_resume,
576};
577
578#define S3C24XX_SPI_PMOPS &s3c24xx_spi_pmops
579#else
580#define S3C24XX_SPI_PMOPS NULL
581#endif /* CONFIG_PM */
582
583MODULE_ALIAS("platform:s3c2410-spi");
584static struct platform_driver s3c24xx_spi_driver = {
585 .probe = s3c24xx_spi_probe,
586 .remove = s3c24xx_spi_remove,
587 .driver = {
588 .name = "s3c2410-spi",
589 .pm = S3C24XX_SPI_PMOPS,
590 },
591};
592module_platform_driver(s3c24xx_spi_driver);
593
594MODULE_DESCRIPTION("S3C24XX SPI Driver");
595MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
596MODULE_LICENSE("GPL");