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>
35 #include "spi-s3c24xx-fiq.h"
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.
44 struct s3c24xx_spi_devstate
{
59 /* bitbang has to be first */
60 struct spi_bitbang bitbang
;
61 struct completion done
;
68 struct fiq_handler fiq_handler
;
69 enum spi_fiq_mode fiq_mode
;
70 unsigned char fiq_inuse
;
71 unsigned char fiq_claimed
;
73 void (*set_cs
)(struct s3c2410_spi_info
*spi
,
77 const unsigned char *tx
;
81 struct resource
*ioarea
;
82 struct spi_master
*master
;
83 struct spi_device
*curdev
;
85 struct s3c2410_spi_info
*pdata
;
89 #define SPCON_DEFAULT (S3C2410_SPCON_MSTR | S3C2410_SPCON_SMOD_INT)
90 #define SPPIN_DEFAULT (S3C2410_SPPIN_KEEP)
92 static inline struct s3c24xx_spi
*to_hw(struct spi_device
*sdev
)
94 return spi_master_get_devdata(sdev
->master
);
97 static void s3c24xx_spi_gpiocs(struct s3c2410_spi_info
*spi
, int cs
, int pol
)
99 gpio_set_value(spi
->pin_cs
, pol
);
102 static void s3c24xx_spi_chipsel(struct spi_device
*spi
, int value
)
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;
108 /* change the chipselect state and the state of the spi engine clock */
111 case BITBANG_CS_INACTIVE
:
112 hw
->set_cs(hw
->pdata
, spi
->chip_select
, cspol
^1);
113 writeb(cs
->spcon
, hw
->regs
+ S3C2410_SPCON
);
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
);
124 static int s3c24xx_spi_update_state(struct spi_device
*spi
,
125 struct spi_transfer
*t
)
127 struct s3c24xx_spi
*hw
= to_hw(spi
);
128 struct s3c24xx_spi_devstate
*cs
= spi
->controller_state
;
134 bpw
= t
? t
->bits_per_word
: spi
->bits_per_word
;
135 hz
= t
? t
->speed_hz
: spi
->max_speed_hz
;
141 hz
= spi
->max_speed_hz
;
144 dev_err(&spi
->dev
, "invalid bits-per-word (%d)\n", bpw
);
148 if (spi
->mode
!= cs
->mode
) {
149 u8 spcon
= SPCON_DEFAULT
| S3C2410_SPCON_ENSCK
;
151 if (spi
->mode
& SPI_CPHA
)
152 spcon
|= S3C2410_SPCON_CPHA_FMTB
;
154 if (spi
->mode
& SPI_CPOL
)
155 spcon
|= S3C2410_SPCON_CPOL_HIGH
;
157 cs
->mode
= spi
->mode
;
162 clk
= clk_get_rate(hw
->clk
);
163 div
= DIV_ROUND_UP(clk
, hz
* 2) - 1;
168 dev_dbg(&spi
->dev
, "pre-scaler=%d (wanted %d, got %ld)\n",
169 div
, hz
, clk
/ (2 * (div
+ 1)));
178 static int s3c24xx_spi_setupxfer(struct spi_device
*spi
,
179 struct spi_transfer
*t
)
181 struct s3c24xx_spi_devstate
*cs
= spi
->controller_state
;
182 struct s3c24xx_spi
*hw
= to_hw(spi
);
185 ret
= s3c24xx_spi_update_state(spi
, t
);
187 writeb(cs
->sppre
, hw
->regs
+ S3C2410_SPPRE
);
192 static int s3c24xx_spi_setup(struct spi_device
*spi
)
194 struct s3c24xx_spi_devstate
*cs
= spi
->controller_state
;
195 struct s3c24xx_spi
*hw
= to_hw(spi
);
198 /* allocate settings on the first call */
200 cs
= kzalloc(sizeof(struct s3c24xx_spi_devstate
), GFP_KERNEL
);
202 dev_err(&spi
->dev
, "no memory for controller state\n");
206 cs
->spcon
= SPCON_DEFAULT
;
208 spi
->controller_state
= cs
;
211 /* initialise the state from the device */
212 ret
= s3c24xx_spi_update_state(spi
, NULL
);
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 ? */
221 spin_unlock(&hw
->bitbang
.lock
);
226 static void s3c24xx_spi_cleanup(struct spi_device
*spi
)
228 kfree(spi
->controller_state
);
231 static inline unsigned int hw_txbyte(struct s3c24xx_spi
*hw
, int count
)
233 return hw
->tx
? hw
->tx
[count
] : 0;
236 #ifdef CONFIG_SPI_S3C24XX_FIQ
237 /* Support for FIQ based pseudo-DMA to improve the transfer speed.
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.
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.
251 struct spi_fiq_code
{
257 extern struct spi_fiq_code s3c24xx_spi_fiq_txrx
;
258 extern struct spi_fiq_code s3c24xx_spi_fiq_tx
;
259 extern struct spi_fiq_code s3c24xx_spi_fiq_rx
;
262 * ack_bit - turn IRQ into IRQ acknowledgement bit
263 * @irq: The interrupt number
265 * Returns the bit to write to the interrupt acknowledge register.
267 static inline u32
ack_bit(unsigned int irq
)
269 return 1 << (irq
- IRQ_EINT0
);
273 * s3c24xx_spi_tryfiq - attempt to claim and setup FIQ for transfer
274 * @hw: The hardware state.
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.
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.
283 void s3c24xx_spi_tryfiq(struct s3c24xx_spi
*hw
)
286 enum spi_fiq_mode mode
;
287 struct spi_fiq_code
*code
;
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 */
294 ret
= claim_fiq(&hw
->fiq_handler
);
299 if (hw
->tx
&& !hw
->rx
)
301 else if (hw
->rx
&& !hw
->tx
)
304 mode
= FIQ_MODE_TXRX
;
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
;
314 if (hw
->fiq_mode
!= mode
) {
321 code
= &s3c24xx_spi_fiq_tx
;
324 code
= &s3c24xx_spi_fiq_rx
;
327 code
= &s3c24xx_spi_fiq_txrx
;
335 ack_ptr
= (u32
*)&code
->data
[code
->ack_offset
];
336 *ack_ptr
= ack_bit(hw
->irq
);
338 set_fiq_handler(&code
->data
, code
->length
);
341 s3c24xx_set_fiq(hw
->irq
, true);
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.
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
356 static int s3c24xx_spi_fiqop(void *pw
, int release
)
358 struct s3c24xx_spi
*hw
= pw
;
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 */
368 hw
->fiq_mode
= FIQ_MODE_NONE
;
378 * s3c24xx_spi_initfiq - setup the information for the FIQ core
379 * @hw: The hardware state.
381 * Setup the fiq_handler block to pass to the FIQ core.
383 static inline void s3c24xx_spi_initfiq(struct s3c24xx_spi
*hw
)
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
;
391 * s3c24xx_spi_usefiq - return if we should be using FIQ.
392 * @hw: The hardware state.
394 * Return true if the platform data specifies whether this channel is
395 * allowed to use the FIQ.
397 static inline bool s3c24xx_spi_usefiq(struct s3c24xx_spi
*hw
)
399 return hw
->pdata
->use_fiq
;
403 * s3c24xx_spi_usingfiq - return if channel is using FIQ
404 * @spi: The hardware state.
406 * Return whether the channel is currently using the FIQ (separate from
407 * whether the FIQ is claimed).
409 static inline bool s3c24xx_spi_usingfiq(struct s3c24xx_spi
*spi
)
411 return spi
->fiq_inuse
;
415 static inline void s3c24xx_spi_initfiq(struct s3c24xx_spi
*s
) { }
416 static inline void s3c24xx_spi_tryfiq(struct s3c24xx_spi
*s
) { }
417 static inline bool s3c24xx_spi_usefiq(struct s3c24xx_spi
*s
) { return false; }
418 static inline bool s3c24xx_spi_usingfiq(struct s3c24xx_spi
*s
) { return false; }
420 #endif /* CONFIG_SPI_S3C24XX_FIQ */
422 static int s3c24xx_spi_txrx(struct spi_device
*spi
, struct spi_transfer
*t
)
424 struct s3c24xx_spi
*hw
= to_hw(spi
);
431 init_completion(&hw
->done
);
434 if (s3c24xx_spi_usefiq(hw
) && t
->len
>= 3)
435 s3c24xx_spi_tryfiq(hw
);
437 /* send the first byte */
438 writeb(hw_txbyte(hw
, 0), hw
->regs
+ S3C2410_SPTDAT
);
440 wait_for_completion(&hw
->done
);
444 static irqreturn_t
s3c24xx_spi_irq(int irq
, void *dev
)
446 struct s3c24xx_spi
*hw
= dev
;
447 unsigned int spsta
= readb(hw
->regs
+ S3C2410_SPSTA
);
448 unsigned int count
= hw
->count
;
450 if (spsta
& S3C2410_SPSTA_DCOL
) {
451 dev_dbg(hw
->dev
, "data-collision\n");
456 if (!(spsta
& S3C2410_SPSTA_READY
)) {
457 dev_dbg(hw
->dev
, "spi not ready for tx?\n");
462 if (!s3c24xx_spi_usingfiq(hw
)) {
466 hw
->rx
[count
] = readb(hw
->regs
+ S3C2410_SPRDAT
);
471 writeb(hw_txbyte(hw
, count
), hw
->regs
+ S3C2410_SPTDAT
);
479 hw
->rx
[hw
->len
-1] = readb(hw
->regs
+ S3C2410_SPRDAT
);
488 static void s3c24xx_spi_initialsetup(struct s3c24xx_spi
*hw
)
490 /* for the moment, permanently enable the clock */
494 /* program defaults into the registers */
496 writeb(0xff, hw
->regs
+ S3C2410_SPPRE
);
497 writeb(SPPIN_DEFAULT
, hw
->regs
+ S3C2410_SPPIN
);
498 writeb(SPCON_DEFAULT
, hw
->regs
+ S3C2410_SPCON
);
501 if (hw
->set_cs
== s3c24xx_spi_gpiocs
)
502 gpio_direction_output(hw
->pdata
->pin_cs
, 1);
504 if (hw
->pdata
->gpio_setup
)
505 hw
->pdata
->gpio_setup(hw
->pdata
, 1);
509 static int s3c24xx_spi_probe(struct platform_device
*pdev
)
511 struct s3c2410_spi_info
*pdata
;
512 struct s3c24xx_spi
*hw
;
513 struct spi_master
*master
;
514 struct resource
*res
;
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");
524 hw
= spi_master_get_devdata(master
);
525 memset(hw
, 0, sizeof(struct s3c24xx_spi
));
527 hw
->master
= spi_master_get(master
);
528 hw
->pdata
= pdata
= pdev
->dev
.platform_data
;
529 hw
->dev
= &pdev
->dev
;
532 dev_err(&pdev
->dev
, "No platform data supplied\n");
537 platform_set_drvdata(pdev
, hw
);
538 init_completion(&hw
->done
);
540 /* initialise fiq handler */
542 s3c24xx_spi_initfiq(hw
);
544 /* setup the master state. */
546 /* the spi->mode bits understood by this driver: */
547 master
->mode_bits
= SPI_CPOL
| SPI_CPHA
| SPI_CS_HIGH
;
549 master
->num_chipselect
= hw
->pdata
->num_cs
;
550 master
->bus_num
= pdata
->bus_num
;
552 /* setup the state for the bitbang driver */
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
;
559 hw
->master
->setup
= s3c24xx_spi_setup
;
560 hw
->master
->cleanup
= s3c24xx_spi_cleanup
;
562 dev_dbg(hw
->dev
, "bitbang at %p\n", &hw
->bitbang
);
564 /* find and map our resources */
566 res
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
568 dev_err(&pdev
->dev
, "Cannot get IORESOURCE_MEM\n");
573 hw
->ioarea
= request_mem_region(res
->start
, resource_size(res
),
576 if (hw
->ioarea
== NULL
) {
577 dev_err(&pdev
->dev
, "Cannot reserve region\n");
582 hw
->regs
= ioremap(res
->start
, resource_size(res
));
583 if (hw
->regs
== NULL
) {
584 dev_err(&pdev
->dev
, "Cannot map IO\n");
589 hw
->irq
= platform_get_irq(pdev
, 0);
591 dev_err(&pdev
->dev
, "No IRQ specified\n");
596 err
= request_irq(hw
->irq
, s3c24xx_spi_irq
, 0, pdev
->name
, hw
);
598 dev_err(&pdev
->dev
, "Cannot claim IRQ\n");
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
);
609 /* setup any gpio we can */
611 if (!pdata
->set_cs
) {
612 if (pdata
->pin_cs
< 0) {
613 dev_err(&pdev
->dev
, "No chipselect pin\n");
618 err
= gpio_request(pdata
->pin_cs
, dev_name(&pdev
->dev
));
620 dev_err(&pdev
->dev
, "Failed to get gpio for cs\n");
624 hw
->set_cs
= s3c24xx_spi_gpiocs
;
625 gpio_direction_output(pdata
->pin_cs
, 1);
627 hw
->set_cs
= pdata
->set_cs
;
629 s3c24xx_spi_initialsetup(hw
);
631 /* register our spi controller */
633 err
= spi_bitbang_start(&hw
->bitbang
);
635 dev_err(&pdev
->dev
, "Failed to register SPI master\n");
642 if (hw
->set_cs
== s3c24xx_spi_gpiocs
)
643 gpio_free(pdata
->pin_cs
);
645 clk_disable(hw
->clk
);
649 free_irq(hw
->irq
, hw
);
655 release_resource(hw
->ioarea
);
660 spi_master_put(hw
->master
);
666 static int s3c24xx_spi_remove(struct platform_device
*dev
)
668 struct s3c24xx_spi
*hw
= platform_get_drvdata(dev
);
670 platform_set_drvdata(dev
, NULL
);
672 spi_bitbang_stop(&hw
->bitbang
);
674 clk_disable(hw
->clk
);
677 free_irq(hw
->irq
, hw
);
680 if (hw
->set_cs
== s3c24xx_spi_gpiocs
)
681 gpio_free(hw
->pdata
->pin_cs
);
683 release_resource(hw
->ioarea
);
686 spi_master_put(hw
->master
);
693 static int s3c24xx_spi_suspend(struct device
*dev
)
695 struct s3c24xx_spi
*hw
= platform_get_drvdata(to_platform_device(dev
));
697 if (hw
->pdata
&& hw
->pdata
->gpio_setup
)
698 hw
->pdata
->gpio_setup(hw
->pdata
, 0);
700 clk_disable(hw
->clk
);
704 static int s3c24xx_spi_resume(struct device
*dev
)
706 struct s3c24xx_spi
*hw
= platform_get_drvdata(to_platform_device(dev
));
708 s3c24xx_spi_initialsetup(hw
);
712 static const struct dev_pm_ops s3c24xx_spi_pmops
= {
713 .suspend
= s3c24xx_spi_suspend
,
714 .resume
= s3c24xx_spi_resume
,
717 #define S3C24XX_SPI_PMOPS &s3c24xx_spi_pmops
719 #define S3C24XX_SPI_PMOPS NULL
720 #endif /* CONFIG_PM */
722 MODULE_ALIAS("platform:s3c2410-spi");
723 static struct platform_driver s3c24xx_spi_driver
= {
724 .probe
= s3c24xx_spi_probe
,
725 .remove
= s3c24xx_spi_remove
,
727 .name
= "s3c2410-spi",
728 .owner
= THIS_MODULE
,
729 .pm
= S3C24XX_SPI_PMOPS
,
732 module_platform_driver(s3c24xx_spi_driver
);
734 MODULE_DESCRIPTION("S3C24XX SPI Driver");
735 MODULE_AUTHOR("Ben Dooks, <ben@simtec.co.uk>");
736 MODULE_LICENSE("GPL");