2 * Copyright (c) 2006 Ben Dooks
3 * Copyright 2006-2009 Simtec Electronics
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.
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>
21 #include <linux/slab.h>
23 #include <linux/spi/spi.h>
24 #include <linux/spi/spi_bitbang.h>
25 #include <linux/spi/s3c24xx.h>
26 #include <linux/module.h>
28 #include <plat/regs-spi.h>
32 #include "spi-s3c24xx-fiq.h"
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.
41 struct s3c24xx_spi_devstate {
56 /* bitbang has to be first */
57 struct spi_bitbang bitbang;
58 struct completion done;
65 struct fiq_handler fiq_handler;
66 enum spi_fiq_mode fiq_mode;
67 unsigned char fiq_inuse;
68 unsigned char fiq_claimed;
70 void (*set_cs)(struct s3c2410_spi_info *spi,
74 const unsigned char *tx;
78 struct spi_master *master;
79 struct spi_device *curdev;
81 struct s3c2410_spi_info *pdata;
84 #define SPCON_DEFAULT (S3C2410_SPCON_MSTR | S3C2410_SPCON_SMOD_INT)
85 #define SPPIN_DEFAULT (S3C2410_SPPIN_KEEP)
87 static inline struct s3c24xx_spi *to_hw(struct spi_device *sdev)
89 return spi_master_get_devdata(sdev->master);
92 static void s3c24xx_spi_gpiocs(struct s3c2410_spi_info *spi, int cs, int pol)
94 gpio_set_value(spi->pin_cs, pol);
97 static void s3c24xx_spi_chipsel(struct spi_device *spi, int value)
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;
103 /* change the chipselect state and the state of the spi engine clock */
106 case BITBANG_CS_INACTIVE:
107 hw->set_cs(hw->pdata, spi->chip_select, cspol^1);
108 writeb(cs->spcon, hw->regs + S3C2410_SPCON);
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);
119 static int s3c24xx_spi_update_state(struct spi_device *spi,
120 struct spi_transfer *t)
122 struct s3c24xx_spi *hw = to_hw(spi);
123 struct s3c24xx_spi_devstate *cs = spi->controller_state;
128 hz = t ? t->speed_hz : spi->max_speed_hz;
131 hz = spi->max_speed_hz;
133 if (spi->mode != cs->mode) {
134 u8 spcon = SPCON_DEFAULT | S3C2410_SPCON_ENSCK;
136 if (spi->mode & SPI_CPHA)
137 spcon |= S3C2410_SPCON_CPHA_FMTB;
139 if (spi->mode & SPI_CPOL)
140 spcon |= S3C2410_SPCON_CPOL_HIGH;
142 cs->mode = spi->mode;
147 clk = clk_get_rate(hw->clk);
148 div = DIV_ROUND_UP(clk, hz * 2) - 1;
153 dev_dbg(&spi->dev, "pre-scaler=%d (wanted %d, got %ld)\n",
154 div, hz, clk / (2 * (div + 1)));
163 static int s3c24xx_spi_setupxfer(struct spi_device *spi,
164 struct spi_transfer *t)
166 struct s3c24xx_spi_devstate *cs = spi->controller_state;
167 struct s3c24xx_spi *hw = to_hw(spi);
170 ret = s3c24xx_spi_update_state(spi, t);
172 writeb(cs->sppre, hw->regs + S3C2410_SPPRE);
177 static int s3c24xx_spi_setup(struct spi_device *spi)
179 struct s3c24xx_spi_devstate *cs = spi->controller_state;
180 struct s3c24xx_spi *hw = to_hw(spi);
183 /* allocate settings on the first call */
185 cs = devm_kzalloc(&spi->dev,
186 sizeof(struct s3c24xx_spi_devstate),
191 cs->spcon = SPCON_DEFAULT;
193 spi->controller_state = cs;
196 /* initialise the state from the device */
197 ret = s3c24xx_spi_update_state(spi, NULL);
201 spin_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 ? */
206 spin_unlock(&hw->bitbang.lock);
211 static inline unsigned int hw_txbyte(struct s3c24xx_spi *hw, int count)
213 return hw->tx ? hw->tx[count] : 0;
216 #ifdef CONFIG_SPI_S3C24XX_FIQ
217 /* Support for FIQ based pseudo-DMA to improve the transfer speed.
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.
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.
231 struct spi_fiq_code {
237 extern struct spi_fiq_code s3c24xx_spi_fiq_txrx;
238 extern struct spi_fiq_code s3c24xx_spi_fiq_tx;
239 extern struct spi_fiq_code s3c24xx_spi_fiq_rx;
242 * ack_bit - turn IRQ into IRQ acknowledgement bit
243 * @irq: The interrupt number
245 * Returns the bit to write to the interrupt acknowledge register.
247 static inline u32 ack_bit(unsigned int irq)
249 return 1 << (irq - IRQ_EINT0);
253 * s3c24xx_spi_tryfiq - attempt to claim and setup FIQ for transfer
254 * @hw: The hardware state.
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.
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.
263 static void s3c24xx_spi_tryfiq(struct s3c24xx_spi *hw)
266 enum spi_fiq_mode mode;
267 struct spi_fiq_code *code;
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 */
274 ret = claim_fiq(&hw->fiq_handler);
279 if (hw->tx && !hw->rx)
281 else if (hw->rx && !hw->tx)
284 mode = FIQ_MODE_TXRX;
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;
294 if (hw->fiq_mode != mode) {
301 code = &s3c24xx_spi_fiq_tx;
304 code = &s3c24xx_spi_fiq_rx;
307 code = &s3c24xx_spi_fiq_txrx;
315 ack_ptr = (u32 *)&code->data[code->ack_offset];
316 *ack_ptr = ack_bit(hw->irq);
318 set_fiq_handler(&code->data, code->length);
321 s3c24xx_set_fiq(hw->irq, true);
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.
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
336 static int s3c24xx_spi_fiqop(void *pw, int release)
338 struct s3c24xx_spi *hw = pw;
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 */
348 hw->fiq_mode = FIQ_MODE_NONE;
358 * s3c24xx_spi_initfiq - setup the information for the FIQ core
359 * @hw: The hardware state.
361 * Setup the fiq_handler block to pass to the FIQ core.
363 static inline void s3c24xx_spi_initfiq(struct s3c24xx_spi *hw)
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;
371 * s3c24xx_spi_usefiq - return if we should be using FIQ.
372 * @hw: The hardware state.
374 * Return true if the platform data specifies whether this channel is
375 * allowed to use the FIQ.
377 static inline bool s3c24xx_spi_usefiq(struct s3c24xx_spi *hw)
379 return hw->pdata->use_fiq;
383 * s3c24xx_spi_usingfiq - return if channel is using FIQ
384 * @spi: The hardware state.
386 * Return whether the channel is currently using the FIQ (separate from
387 * whether the FIQ is claimed).
389 static inline bool s3c24xx_spi_usingfiq(struct s3c24xx_spi *spi)
391 return spi->fiq_inuse;
395 static inline void s3c24xx_spi_initfiq(struct s3c24xx_spi *s) { }
396 static inline void s3c24xx_spi_tryfiq(struct s3c24xx_spi *s) { }
397 static inline bool s3c24xx_spi_usefiq(struct s3c24xx_spi *s) { return false; }
398 static inline bool s3c24xx_spi_usingfiq(struct s3c24xx_spi *s) { return false; }
400 #endif /* CONFIG_SPI_S3C24XX_FIQ */
402 static int s3c24xx_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
404 struct s3c24xx_spi *hw = to_hw(spi);
411 init_completion(&hw->done);
414 if (s3c24xx_spi_usefiq(hw) && t->len >= 3)
415 s3c24xx_spi_tryfiq(hw);
417 /* send the first byte */
418 writeb(hw_txbyte(hw, 0), hw->regs + S3C2410_SPTDAT);
420 wait_for_completion(&hw->done);
424 static irqreturn_t s3c24xx_spi_irq(int irq, void *dev)
426 struct s3c24xx_spi *hw = dev;
427 unsigned int spsta = readb(hw->regs + S3C2410_SPSTA);
428 unsigned int count = hw->count;
430 if (spsta & S3C2410_SPSTA_DCOL) {
431 dev_dbg(hw->dev, "data-collision\n");
436 if (!(spsta & S3C2410_SPSTA_READY)) {
437 dev_dbg(hw->dev, "spi not ready for tx?\n");
442 if (!s3c24xx_spi_usingfiq(hw)) {
446 hw->rx[count] = readb(hw->regs + S3C2410_SPRDAT);
451 writeb(hw_txbyte(hw, count), hw->regs + S3C2410_SPTDAT);
459 hw->rx[hw->len-1] = readb(hw->regs + S3C2410_SPRDAT);
468 static void s3c24xx_spi_initialsetup(struct s3c24xx_spi *hw)
470 /* for the moment, permanently enable the clock */
474 /* program defaults into the registers */
476 writeb(0xff, hw->regs + S3C2410_SPPRE);
477 writeb(SPPIN_DEFAULT, hw->regs + S3C2410_SPPIN);
478 writeb(SPCON_DEFAULT, hw->regs + S3C2410_SPCON);
481 if (hw->set_cs == s3c24xx_spi_gpiocs)
482 gpio_direction_output(hw->pdata->pin_cs, 1);
484 if (hw->pdata->gpio_setup)
485 hw->pdata->gpio_setup(hw->pdata, 1);
489 static int s3c24xx_spi_probe(struct platform_device *pdev)
491 struct s3c2410_spi_info *pdata;
492 struct s3c24xx_spi *hw;
493 struct spi_master *master;
494 struct resource *res;
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");
503 hw = spi_master_get_devdata(master);
504 memset(hw, 0, sizeof(struct s3c24xx_spi));
507 hw->pdata = pdata = dev_get_platdata(&pdev->dev);
508 hw->dev = &pdev->dev;
511 dev_err(&pdev->dev, "No platform data supplied\n");
516 platform_set_drvdata(pdev, hw);
517 init_completion(&hw->done);
519 /* initialise fiq handler */
521 s3c24xx_spi_initfiq(hw);
523 /* setup the master state. */
525 /* the spi->mode bits understood by this driver: */
526 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
528 master->num_chipselect = hw->pdata->num_cs;
529 master->bus_num = pdata->bus_num;
530 master->bits_per_word_mask = SPI_BPW_MASK(8);
532 /* setup the state for the bitbang driver */
534 hw->bitbang.master = hw->master;
535 hw->bitbang.setup_transfer = s3c24xx_spi_setupxfer;
536 hw->bitbang.chipselect = s3c24xx_spi_chipsel;
537 hw->bitbang.txrx_bufs = s3c24xx_spi_txrx;
539 hw->master->setup = s3c24xx_spi_setup;
541 dev_dbg(hw->dev, "bitbang at %p\n", &hw->bitbang);
543 /* find and map our resources */
544 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
545 hw->regs = devm_ioremap_resource(&pdev->dev, res);
546 if (IS_ERR(hw->regs)) {
547 err = PTR_ERR(hw->regs);
551 hw->irq = platform_get_irq(pdev, 0);
553 dev_err(&pdev->dev, "No IRQ specified\n");
558 err = devm_request_irq(&pdev->dev, hw->irq, s3c24xx_spi_irq, 0,
561 dev_err(&pdev->dev, "Cannot claim IRQ\n");
565 hw->clk = devm_clk_get(&pdev->dev, "spi");
566 if (IS_ERR(hw->clk)) {
567 dev_err(&pdev->dev, "No clock for device\n");
568 err = PTR_ERR(hw->clk);
572 /* setup any gpio we can */
574 if (!pdata->set_cs) {
575 if (pdata->pin_cs < 0) {
576 dev_err(&pdev->dev, "No chipselect pin\n");
581 err = devm_gpio_request(&pdev->dev, pdata->pin_cs,
582 dev_name(&pdev->dev));
584 dev_err(&pdev->dev, "Failed to get gpio for cs\n");
588 hw->set_cs = s3c24xx_spi_gpiocs;
589 gpio_direction_output(pdata->pin_cs, 1);
591 hw->set_cs = pdata->set_cs;
593 s3c24xx_spi_initialsetup(hw);
595 /* register our spi controller */
597 err = spi_bitbang_start(&hw->bitbang);
599 dev_err(&pdev->dev, "Failed to register SPI master\n");
606 clk_disable(hw->clk);
609 spi_master_put(hw->master);
613 static int s3c24xx_spi_remove(struct platform_device *dev)
615 struct s3c24xx_spi *hw = platform_get_drvdata(dev);
617 spi_bitbang_stop(&hw->bitbang);
618 clk_disable(hw->clk);
619 spi_master_put(hw->master);
626 static int s3c24xx_spi_suspend(struct device *dev)
628 struct s3c24xx_spi *hw = dev_get_drvdata(dev);
631 ret = spi_master_suspend(hw->master);
635 if (hw->pdata && hw->pdata->gpio_setup)
636 hw->pdata->gpio_setup(hw->pdata, 0);
638 clk_disable(hw->clk);
642 static int s3c24xx_spi_resume(struct device *dev)
644 struct s3c24xx_spi *hw = dev_get_drvdata(dev);
646 s3c24xx_spi_initialsetup(hw);
647 return spi_master_resume(hw->master);
650 static const struct dev_pm_ops s3c24xx_spi_pmops = {
651 .suspend = s3c24xx_spi_suspend,
652 .resume = s3c24xx_spi_resume,
655 #define S3C24XX_SPI_PMOPS &s3c24xx_spi_pmops
657 #define S3C24XX_SPI_PMOPS NULL
658 #endif /* CONFIG_PM */
660 MODULE_ALIAS("platform:s3c2410-spi");
661 static struct platform_driver s3c24xx_spi_driver = {
662 .probe = s3c24xx_spi_probe,
663 .remove = s3c24xx_spi_remove,
665 .name = "s3c2410-spi",
666 .owner = THIS_MODULE,
667 .pm = S3C24XX_SPI_PMOPS,
670 module_platform_driver(s3c24xx_spi_driver);
672 MODULE_DESCRIPTION("S3C24XX SPI Driver");
674 MODULE_LICENSE("GPL");