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