2 * Copyright (c) 2006 Ben Dooks
3 * Copyright 2006-2009 Simtec Electronics
4 * Ben Dooks <ben@simtec.co.uk>
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/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>
23 #include <linux/slab.h>
25 #include <linux/spi/spi.h>
26 #include <linux/spi/spi_bitbang.h>
27 #include <linux/spi/s3c24xx.h>
28 #include <linux/module.h>
30 #include <plat/regs-spi.h>
34 #include "spi-s3c24xx-fiq.h"
37 * s3c24xx_spi_devstate - per device data
38 * @hz: Last frequency calculated for @sppre field.
39 * @mode: Last mode setting for the @spcon field.
40 * @spcon: Value to write to the SPCON register.
41 * @sppre: Value to write to the SPPRE register.
43 struct s3c24xx_spi_devstate {
58 /* bitbang has to be first */
59 struct spi_bitbang bitbang;
60 struct completion done;
67 struct fiq_handler fiq_handler;
68 enum spi_fiq_mode fiq_mode;
69 unsigned char fiq_inuse;
70 unsigned char fiq_claimed;
72 void (*set_cs)(struct s3c2410_spi_info *spi,
76 const unsigned char *tx;
80 struct spi_master *master;
81 struct spi_device *curdev;
83 struct s3c2410_spi_info *pdata;
86 #define SPCON_DEFAULT (S3C2410_SPCON_MSTR | S3C2410_SPCON_SMOD_INT)
87 #define SPPIN_DEFAULT (S3C2410_SPPIN_KEEP)
89 static inline struct s3c24xx_spi *to_hw(struct spi_device *sdev)
91 return spi_master_get_devdata(sdev->master);
94 static void s3c24xx_spi_gpiocs(struct s3c2410_spi_info *spi, int cs, int pol)
96 gpio_set_value(spi->pin_cs, pol);
99 static void s3c24xx_spi_chipsel(struct spi_device *spi, int value)
101 struct s3c24xx_spi_devstate *cs = spi->controller_state;
102 struct s3c24xx_spi *hw = to_hw(spi);
103 unsigned int cspol = spi->mode & SPI_CS_HIGH ? 1 : 0;
105 /* change the chipselect state and the state of the spi engine clock */
108 case BITBANG_CS_INACTIVE:
109 hw->set_cs(hw->pdata, spi->chip_select, cspol^1);
110 writeb(cs->spcon, hw->regs + S3C2410_SPCON);
113 case BITBANG_CS_ACTIVE:
114 writeb(cs->spcon | S3C2410_SPCON_ENSCK,
115 hw->regs + S3C2410_SPCON);
116 hw->set_cs(hw->pdata, spi->chip_select, cspol);
121 static int s3c24xx_spi_update_state(struct spi_device *spi,
122 struct spi_transfer *t)
124 struct s3c24xx_spi *hw = to_hw(spi);
125 struct s3c24xx_spi_devstate *cs = spi->controller_state;
131 bpw = t ? t->bits_per_word : spi->bits_per_word;
132 hz = t ? t->speed_hz : spi->max_speed_hz;
138 hz = spi->max_speed_hz;
141 dev_err(&spi->dev, "invalid bits-per-word (%d)\n", bpw);
145 if (spi->mode != cs->mode) {
146 u8 spcon = SPCON_DEFAULT | S3C2410_SPCON_ENSCK;
148 if (spi->mode & SPI_CPHA)
149 spcon |= S3C2410_SPCON_CPHA_FMTB;
151 if (spi->mode & SPI_CPOL)
152 spcon |= S3C2410_SPCON_CPOL_HIGH;
154 cs->mode = spi->mode;
159 clk = clk_get_rate(hw->clk);
160 div = DIV_ROUND_UP(clk, hz * 2) - 1;
165 dev_dbg(&spi->dev, "pre-scaler=%d (wanted %d, got %ld)\n",
166 div, hz, clk / (2 * (div + 1)));
175 static int s3c24xx_spi_setupxfer(struct spi_device *spi,
176 struct spi_transfer *t)
178 struct s3c24xx_spi_devstate *cs = spi->controller_state;
179 struct s3c24xx_spi *hw = to_hw(spi);
182 ret = s3c24xx_spi_update_state(spi, t);
184 writeb(cs->sppre, hw->regs + S3C2410_SPPRE);
189 static int s3c24xx_spi_setup(struct spi_device *spi)
191 struct s3c24xx_spi_devstate *cs = spi->controller_state;
192 struct s3c24xx_spi *hw = to_hw(spi);
195 /* allocate settings on the first call */
197 cs = kzalloc(sizeof(struct s3c24xx_spi_devstate), GFP_KERNEL);
199 dev_err(&spi->dev, "no memory for controller state\n");
203 cs->spcon = SPCON_DEFAULT;
205 spi->controller_state = cs;
208 /* initialise the state from the device */
209 ret = s3c24xx_spi_update_state(spi, NULL);
213 spin_lock(&hw->bitbang.lock);
214 if (!hw->bitbang.busy) {
215 hw->bitbang.chipselect(spi, BITBANG_CS_INACTIVE);
216 /* need to ndelay for 0.5 clocktick ? */
218 spin_unlock(&hw->bitbang.lock);
223 static void s3c24xx_spi_cleanup(struct spi_device *spi)
225 kfree(spi->controller_state);
228 static inline unsigned int hw_txbyte(struct s3c24xx_spi *hw, int count)
230 return hw->tx ? hw->tx[count] : 0;
233 #ifdef CONFIG_SPI_S3C24XX_FIQ
234 /* Support for FIQ based pseudo-DMA to improve the transfer speed.
236 * This code uses the assembly helper in spi_s3c24xx_spi.S which is
237 * used by the FIQ core to move data between main memory and the peripheral
238 * block. Since this is code running on the processor, there is no problem
239 * with cache coherency of the buffers, so we can use any buffer we like.
243 * struct spi_fiq_code - FIQ code and header
244 * @length: The length of the code fragment, excluding this header.
245 * @ack_offset: The offset from @data to the word to place the IRQ ACK bit at.
246 * @data: The code itself to install as a FIQ handler.
248 struct spi_fiq_code {
254 extern struct spi_fiq_code s3c24xx_spi_fiq_txrx;
255 extern struct spi_fiq_code s3c24xx_spi_fiq_tx;
256 extern struct spi_fiq_code s3c24xx_spi_fiq_rx;
259 * ack_bit - turn IRQ into IRQ acknowledgement bit
260 * @irq: The interrupt number
262 * Returns the bit to write to the interrupt acknowledge register.
264 static inline u32 ack_bit(unsigned int irq)
266 return 1 << (irq - IRQ_EINT0);
270 * s3c24xx_spi_tryfiq - attempt to claim and setup FIQ for transfer
271 * @hw: The hardware state.
273 * Claim the FIQ handler (only one can be active at any one time) and
274 * then setup the correct transfer code for this transfer.
276 * This call updates all the necessary state information if successful,
277 * so the caller does not need to do anything more than start the transfer
278 * as normal, since the IRQ will have been re-routed to the FIQ handler.
280 static void s3c24xx_spi_tryfiq(struct s3c24xx_spi *hw)
283 enum spi_fiq_mode mode;
284 struct spi_fiq_code *code;
287 if (!hw->fiq_claimed) {
288 /* try and claim fiq if we haven't got it, and if not
289 * then return and simply use another transfer method */
291 ret = claim_fiq(&hw->fiq_handler);
296 if (hw->tx && !hw->rx)
298 else if (hw->rx && !hw->tx)
301 mode = FIQ_MODE_TXRX;
303 regs.uregs[fiq_rspi] = (long)hw->regs;
304 regs.uregs[fiq_rrx] = (long)hw->rx;
305 regs.uregs[fiq_rtx] = (long)hw->tx + 1;
306 regs.uregs[fiq_rcount] = hw->len - 1;
307 regs.uregs[fiq_rirq] = (long)S3C24XX_VA_IRQ;
311 if (hw->fiq_mode != mode) {
318 code = &s3c24xx_spi_fiq_tx;
321 code = &s3c24xx_spi_fiq_rx;
324 code = &s3c24xx_spi_fiq_txrx;
332 ack_ptr = (u32 *)&code->data[code->ack_offset];
333 *ack_ptr = ack_bit(hw->irq);
335 set_fiq_handler(&code->data, code->length);
338 s3c24xx_set_fiq(hw->irq, true);
345 * s3c24xx_spi_fiqop - FIQ core code callback
346 * @pw: Data registered with the handler
347 * @release: Whether this is a release or a return.
349 * Called by the FIQ code when another module wants to use the FIQ, so
350 * return whether we are currently using this or not and then update our
353 static int s3c24xx_spi_fiqop(void *pw, int release)
355 struct s3c24xx_spi *hw = pw;
362 /* note, we do not need to unroute the FIQ, as the FIQ
363 * vector code de-routes it to signal the end of transfer */
365 hw->fiq_mode = FIQ_MODE_NONE;
375 * s3c24xx_spi_initfiq - setup the information for the FIQ core
376 * @hw: The hardware state.
378 * Setup the fiq_handler block to pass to the FIQ core.
380 static inline void s3c24xx_spi_initfiq(struct s3c24xx_spi *hw)
382 hw->fiq_handler.dev_id = hw;
383 hw->fiq_handler.name = dev_name(hw->dev);
384 hw->fiq_handler.fiq_op = s3c24xx_spi_fiqop;
388 * s3c24xx_spi_usefiq - return if we should be using FIQ.
389 * @hw: The hardware state.
391 * Return true if the platform data specifies whether this channel is
392 * allowed to use the FIQ.
394 static inline bool s3c24xx_spi_usefiq(struct s3c24xx_spi *hw)
396 return hw->pdata->use_fiq;
400 * s3c24xx_spi_usingfiq - return if channel is using FIQ
401 * @spi: The hardware state.
403 * Return whether the channel is currently using the FIQ (separate from
404 * whether the FIQ is claimed).
406 static inline bool s3c24xx_spi_usingfiq(struct s3c24xx_spi *spi)
408 return spi->fiq_inuse;
412 static inline void s3c24xx_spi_initfiq(struct s3c24xx_spi *s) { }
413 static inline void s3c24xx_spi_tryfiq(struct s3c24xx_spi *s) { }
414 static inline bool s3c24xx_spi_usefiq(struct s3c24xx_spi *s) { return false; }
415 static inline bool s3c24xx_spi_usingfiq(struct s3c24xx_spi *s) { return false; }
417 #endif /* CONFIG_SPI_S3C24XX_FIQ */
419 static int s3c24xx_spi_txrx(struct spi_device *spi, struct spi_transfer *t)
421 struct s3c24xx_spi *hw = to_hw(spi);
428 init_completion(&hw->done);
431 if (s3c24xx_spi_usefiq(hw) && t->len >= 3)
432 s3c24xx_spi_tryfiq(hw);
434 /* send the first byte */
435 writeb(hw_txbyte(hw, 0), hw->regs + S3C2410_SPTDAT);
437 wait_for_completion(&hw->done);
441 static irqreturn_t s3c24xx_spi_irq(int irq, void *dev)
443 struct s3c24xx_spi *hw = dev;
444 unsigned int spsta = readb(hw->regs + S3C2410_SPSTA);
445 unsigned int count = hw->count;
447 if (spsta & S3C2410_SPSTA_DCOL) {
448 dev_dbg(hw->dev, "data-collision\n");
453 if (!(spsta & S3C2410_SPSTA_READY)) {
454 dev_dbg(hw->dev, "spi not ready for tx?\n");
459 if (!s3c24xx_spi_usingfiq(hw)) {
463 hw->rx[count] = readb(hw->regs + S3C2410_SPRDAT);
468 writeb(hw_txbyte(hw, count), hw->regs + S3C2410_SPTDAT);
476 hw->rx[hw->len-1] = readb(hw->regs + S3C2410_SPRDAT);
485 static void s3c24xx_spi_initialsetup(struct s3c24xx_spi *hw)
487 /* for the moment, permanently enable the clock */
491 /* program defaults into the registers */
493 writeb(0xff, hw->regs + S3C2410_SPPRE);
494 writeb(SPPIN_DEFAULT, hw->regs + S3C2410_SPPIN);
495 writeb(SPCON_DEFAULT, hw->regs + S3C2410_SPCON);
498 if (hw->set_cs == s3c24xx_spi_gpiocs)
499 gpio_direction_output(hw->pdata->pin_cs, 1);
501 if (hw->pdata->gpio_setup)
502 hw->pdata->gpio_setup(hw->pdata, 1);
506 static int s3c24xx_spi_probe(struct platform_device *pdev)
508 struct s3c2410_spi_info *pdata;
509 struct s3c24xx_spi *hw;
510 struct spi_master *master;
511 struct resource *res;
514 master = spi_alloc_master(&pdev->dev, sizeof(struct s3c24xx_spi));
515 if (master == NULL) {
516 dev_err(&pdev->dev, "No memory for spi_master\n");
520 hw = spi_master_get_devdata(master);
521 memset(hw, 0, sizeof(struct s3c24xx_spi));
524 hw->pdata = pdata = dev_get_platdata(&pdev->dev);
525 hw->dev = &pdev->dev;
528 dev_err(&pdev->dev, "No platform data supplied\n");
533 platform_set_drvdata(pdev, hw);
534 init_completion(&hw->done);
536 /* initialise fiq handler */
538 s3c24xx_spi_initfiq(hw);
540 /* setup the master state. */
542 /* the spi->mode bits understood by this driver: */
543 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
545 master->num_chipselect = hw->pdata->num_cs;
546 master->bus_num = pdata->bus_num;
548 /* setup the state for the bitbang driver */
550 hw->bitbang.master = hw->master;
551 hw->bitbang.setup_transfer = s3c24xx_spi_setupxfer;
552 hw->bitbang.chipselect = s3c24xx_spi_chipsel;
553 hw->bitbang.txrx_bufs = s3c24xx_spi_txrx;
555 hw->master->setup = s3c24xx_spi_setup;
556 hw->master->cleanup = s3c24xx_spi_cleanup;
558 dev_dbg(hw->dev, "bitbang at %p\n", &hw->bitbang);
560 /* find and map our resources */
561 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
562 hw->regs = devm_ioremap_resource(&pdev->dev, res);
563 if (IS_ERR(hw->regs)) {
564 err = PTR_ERR(hw->regs);
568 hw->irq = platform_get_irq(pdev, 0);
570 dev_err(&pdev->dev, "No IRQ specified\n");
575 err = devm_request_irq(&pdev->dev, hw->irq, s3c24xx_spi_irq, 0,
578 dev_err(&pdev->dev, "Cannot claim IRQ\n");
582 hw->clk = devm_clk_get(&pdev->dev, "spi");
583 if (IS_ERR(hw->clk)) {
584 dev_err(&pdev->dev, "No clock for device\n");
585 err = PTR_ERR(hw->clk);
589 /* setup any gpio we can */
591 if (!pdata->set_cs) {
592 if (pdata->pin_cs < 0) {
593 dev_err(&pdev->dev, "No chipselect pin\n");
598 err = devm_gpio_request(&pdev->dev, pdata->pin_cs,
599 dev_name(&pdev->dev));
601 dev_err(&pdev->dev, "Failed to get gpio for cs\n");
605 hw->set_cs = s3c24xx_spi_gpiocs;
606 gpio_direction_output(pdata->pin_cs, 1);
608 hw->set_cs = pdata->set_cs;
610 s3c24xx_spi_initialsetup(hw);
612 /* register our spi controller */
614 err = spi_bitbang_start(&hw->bitbang);
616 dev_err(&pdev->dev, "Failed to register SPI master\n");
623 clk_disable(hw->clk);
626 spi_master_put(hw->master);
630 static int s3c24xx_spi_remove(struct platform_device *dev)
632 struct s3c24xx_spi *hw = platform_get_drvdata(dev);
634 spi_bitbang_stop(&hw->bitbang);
635 clk_disable(hw->clk);
636 spi_master_put(hw->master);
643 static int s3c24xx_spi_suspend(struct device *dev)
645 struct s3c24xx_spi *hw = dev_get_drvdata(dev);
647 if (hw->pdata && hw->pdata->gpio_setup)
648 hw->pdata->gpio_setup(hw->pdata, 0);
650 clk_disable(hw->clk);
654 static int s3c24xx_spi_resume(struct device *dev)
656 struct s3c24xx_spi *hw = dev_get_drvdata(dev);
658 s3c24xx_spi_initialsetup(hw);
662 static const struct dev_pm_ops s3c24xx_spi_pmops = {
663 .suspend = s3c24xx_spi_suspend,
664 .resume = s3c24xx_spi_resume,
667 #define S3C24XX_SPI_PMOPS &s3c24xx_spi_pmops
669 #define S3C24XX_SPI_PMOPS NULL
670 #endif /* CONFIG_PM */
672 MODULE_ALIAS("platform:s3c2410-spi");
673 static struct platform_driver s3c24xx_spi_driver = {
674 .probe = s3c24xx_spi_probe,
675 .remove = s3c24xx_spi_remove,
677 .name = "s3c2410-spi",
678 .owner = THIS_MODULE,
679 .pm = S3C24XX_SPI_PMOPS,
682 module_platform_driver(s3c24xx_spi_driver);
684 MODULE_DESCRIPTION("S3C24XX SPI Driver");
685 MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
686 MODULE_LICENSE("GPL");