2 * Driver for Broadcom BCM2835 SPI Controllers
4 * Copyright (C) 2012 Chris Boot
5 * Copyright (C) 2013 Stephen Warren
6 * Copyright (C) 2015 Martin Sperl
8 * This driver is inspired by:
9 * spi-ath79.c, Copyright (C) 2009-2011 Gabor Juhos <juhosg@openwrt.org>
10 * spi-atmel.c, Copyright (C) 2006 Atmel Corporation
12 * This program is free software; you can redistribute it and/or modify
13 * it under the terms of the GNU General Public License as published by
14 * the Free Software Foundation; either version 2 of the License, or
15 * (at your option) any later version.
17 * This program is distributed in the hope that it will be useful,
18 * but WITHOUT ANY WARRANTY; without even the implied warranty of
19 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
20 * GNU General Public License for more details.
24 #include <linux/clk.h>
25 #include <linux/completion.h>
26 #include <linux/delay.h>
27 #include <linux/dma-mapping.h>
28 #include <linux/dmaengine.h>
29 #include <linux/err.h>
30 #include <linux/interrupt.h>
32 #include <linux/kernel.h>
33 #include <linux/module.h>
35 #include <linux/of_address.h>
36 #include <linux/of_device.h>
37 #include <linux/of_gpio.h>
38 #include <linux/of_irq.h>
39 #include <linux/spi/spi.h>
41 /* SPI register offsets */
42 #define BCM2835_SPI_CS 0x00
43 #define BCM2835_SPI_FIFO 0x04
44 #define BCM2835_SPI_CLK 0x08
45 #define BCM2835_SPI_DLEN 0x0c
46 #define BCM2835_SPI_LTOH 0x10
47 #define BCM2835_SPI_DC 0x14
50 #define BCM2835_SPI_CS_LEN_LONG 0x02000000
51 #define BCM2835_SPI_CS_DMA_LEN 0x01000000
52 #define BCM2835_SPI_CS_CSPOL2 0x00800000
53 #define BCM2835_SPI_CS_CSPOL1 0x00400000
54 #define BCM2835_SPI_CS_CSPOL0 0x00200000
55 #define BCM2835_SPI_CS_RXF 0x00100000
56 #define BCM2835_SPI_CS_RXR 0x00080000
57 #define BCM2835_SPI_CS_TXD 0x00040000
58 #define BCM2835_SPI_CS_RXD 0x00020000
59 #define BCM2835_SPI_CS_DONE 0x00010000
60 #define BCM2835_SPI_CS_LEN 0x00002000
61 #define BCM2835_SPI_CS_REN 0x00001000
62 #define BCM2835_SPI_CS_ADCS 0x00000800
63 #define BCM2835_SPI_CS_INTR 0x00000400
64 #define BCM2835_SPI_CS_INTD 0x00000200
65 #define BCM2835_SPI_CS_DMAEN 0x00000100
66 #define BCM2835_SPI_CS_TA 0x00000080
67 #define BCM2835_SPI_CS_CSPOL 0x00000040
68 #define BCM2835_SPI_CS_CLEAR_RX 0x00000020
69 #define BCM2835_SPI_CS_CLEAR_TX 0x00000010
70 #define BCM2835_SPI_CS_CPOL 0x00000008
71 #define BCM2835_SPI_CS_CPHA 0x00000004
72 #define BCM2835_SPI_CS_CS_10 0x00000002
73 #define BCM2835_SPI_CS_CS_01 0x00000001
75 #define BCM2835_SPI_POLLING_LIMIT_US 30
76 #define BCM2835_SPI_POLLING_JIFFIES 2
77 #define BCM2835_SPI_DMA_MIN_LENGTH 96
78 #define BCM2835_SPI_MODE_BITS (SPI_CPOL | SPI_CPHA | SPI_CS_HIGH \
79 | SPI_NO_CS | SPI_3WIRE)
81 #define DRV_NAME "spi-bcm2835"
94 static inline u32
bcm2835_rd(struct bcm2835_spi
*bs
, unsigned reg
)
96 return readl(bs
->regs
+ reg
);
99 static inline void bcm2835_wr(struct bcm2835_spi
*bs
, unsigned reg
, u32 val
)
101 writel(val
, bs
->regs
+ reg
);
104 static inline void bcm2835_rd_fifo(struct bcm2835_spi
*bs
)
108 while ((bs
->rx_len
) &&
109 (bcm2835_rd(bs
, BCM2835_SPI_CS
) & BCM2835_SPI_CS_RXD
)) {
110 byte
= bcm2835_rd(bs
, BCM2835_SPI_FIFO
);
112 *bs
->rx_buf
++ = byte
;
117 static inline void bcm2835_wr_fifo(struct bcm2835_spi
*bs
)
121 while ((bs
->tx_len
) &&
122 (bcm2835_rd(bs
, BCM2835_SPI_CS
) & BCM2835_SPI_CS_TXD
)) {
123 byte
= bs
->tx_buf
? *bs
->tx_buf
++ : 0;
124 bcm2835_wr(bs
, BCM2835_SPI_FIFO
, byte
);
129 static void bcm2835_spi_reset_hw(struct spi_master
*master
)
131 struct bcm2835_spi
*bs
= spi_master_get_devdata(master
);
132 u32 cs
= bcm2835_rd(bs
, BCM2835_SPI_CS
);
134 /* Disable SPI interrupts and transfer */
135 cs
&= ~(BCM2835_SPI_CS_INTR
|
136 BCM2835_SPI_CS_INTD
|
137 BCM2835_SPI_CS_DMAEN
|
139 /* and reset RX/TX FIFOS */
140 cs
|= BCM2835_SPI_CS_CLEAR_RX
| BCM2835_SPI_CS_CLEAR_TX
;
142 /* and reset the SPI_HW */
143 bcm2835_wr(bs
, BCM2835_SPI_CS
, cs
);
144 /* as well as DLEN */
145 bcm2835_wr(bs
, BCM2835_SPI_DLEN
, 0);
148 static irqreturn_t
bcm2835_spi_interrupt(int irq
, void *dev_id
)
150 struct spi_master
*master
= dev_id
;
151 struct bcm2835_spi
*bs
= spi_master_get_devdata(master
);
153 /* Read as many bytes as possible from FIFO */
155 /* Write as many bytes as possible to FIFO */
158 /* based on flags decide if we can finish the transfer */
159 if (bcm2835_rd(bs
, BCM2835_SPI_CS
) & BCM2835_SPI_CS_DONE
) {
160 /* Transfer complete - reset SPI HW */
161 bcm2835_spi_reset_hw(master
);
162 /* wake up the framework */
163 complete(&master
->xfer_completion
);
169 static int bcm2835_spi_transfer_one_irq(struct spi_master
*master
,
170 struct spi_device
*spi
,
171 struct spi_transfer
*tfr
,
174 struct bcm2835_spi
*bs
= spi_master_get_devdata(master
);
176 /* fill in fifo if we have gpio-cs
177 * note that there have been rare events where the native-CS
178 * flapped for <1us which may change the behaviour
179 * with gpio-cs this does not happen, so it is implemented
182 if (gpio_is_valid(spi
->cs_gpio
)) {
183 /* enable HW block, but without interrupts enabled
184 * this would triggern an immediate interrupt
186 bcm2835_wr(bs
, BCM2835_SPI_CS
,
187 cs
| BCM2835_SPI_CS_TA
);
188 /* fill in tx fifo as much as possible */
193 * Enable the HW block. This will immediately trigger a DONE (TX
194 * empty) interrupt, upon which we will fill the TX FIFO with the
195 * first TX bytes. Pre-filling the TX FIFO here to avoid the
196 * interrupt doesn't work:-(
198 cs
|= BCM2835_SPI_CS_INTR
| BCM2835_SPI_CS_INTD
| BCM2835_SPI_CS_TA
;
199 bcm2835_wr(bs
, BCM2835_SPI_CS
, cs
);
201 /* signal that we need to wait for completion */
208 * this implementation has currently a few issues in so far as it does
209 * not work arrount limitations of the HW.
211 * the main one being that DMA transfers are limited to 16 bit
212 * (so 0 to 65535 bytes) by the SPI HW due to BCM2835_SPI_DLEN
214 * also we currently assume that the scatter-gather fragments are
215 * all multiple of 4 (except the last) - otherwise we would need
216 * to reset the FIFO before subsequent transfers...
217 * this also means that tx/rx transfers sg's need to be of equal size!
219 * there may be a few more border-cases we may need to address as well
220 * but unfortunately this would mean splitting up the scatter-gather
221 * list making it slightly unpractical...
223 static void bcm2835_spi_dma_done(void *data
)
225 struct spi_master
*master
= data
;
226 struct bcm2835_spi
*bs
= spi_master_get_devdata(master
);
228 /* reset fifo and HW */
229 bcm2835_spi_reset_hw(master
);
231 /* and terminate tx-dma as we do not have an irq for it
232 * because when the rx dma will terminate and this callback
233 * is called the tx-dma must have finished - can't get to this
234 * situation otherwise...
236 dmaengine_terminate_all(master
->dma_tx
);
238 /* mark as no longer pending */
241 /* and mark as completed */;
242 complete(&master
->xfer_completion
);
245 static int bcm2835_spi_prepare_sg(struct spi_master
*master
,
246 struct spi_transfer
*tfr
,
249 struct dma_chan
*chan
;
250 struct scatterlist
*sgl
;
252 enum dma_transfer_direction dir
;
255 struct dma_async_tx_descriptor
*desc
;
259 dir
= DMA_MEM_TO_DEV
;
260 chan
= master
->dma_tx
;
261 nents
= tfr
->tx_sg
.nents
;
262 sgl
= tfr
->tx_sg
.sgl
;
263 flags
= 0 /* no tx interrupt */;
266 dir
= DMA_DEV_TO_MEM
;
267 chan
= master
->dma_rx
;
268 nents
= tfr
->rx_sg
.nents
;
269 sgl
= tfr
->rx_sg
.sgl
;
270 flags
= DMA_PREP_INTERRUPT
;
272 /* prepare the channel */
273 desc
= dmaengine_prep_slave_sg(chan
, sgl
, nents
, dir
, flags
);
277 /* set callback for rx */
279 desc
->callback
= bcm2835_spi_dma_done
;
280 desc
->callback_param
= master
;
283 /* submit it to DMA-engine */
284 cookie
= dmaengine_submit(desc
);
286 return dma_submit_error(cookie
);
289 static inline int bcm2835_check_sg_length(struct sg_table
*sgt
)
292 struct scatterlist
*sgl
;
294 /* check that the sg entries are word-sized (except for last) */
295 for_each_sg(sgt
->sgl
, sgl
, (int)sgt
->nents
- 1, i
) {
296 if (sg_dma_len(sgl
) % 4)
303 static int bcm2835_spi_transfer_one_dma(struct spi_master
*master
,
304 struct spi_device
*spi
,
305 struct spi_transfer
*tfr
,
308 struct bcm2835_spi
*bs
= spi_master_get_devdata(master
);
311 /* check that the scatter gather segments are all a multiple of 4 */
312 if (bcm2835_check_sg_length(&tfr
->tx_sg
) ||
313 bcm2835_check_sg_length(&tfr
->rx_sg
)) {
314 dev_warn_once(&spi
->dev
,
315 "scatter gather segment length is not a multiple of 4 - falling back to interrupt mode\n");
316 return bcm2835_spi_transfer_one_irq(master
, spi
, tfr
, cs
);
320 ret
= bcm2835_spi_prepare_sg(master
, tfr
, true);
325 dma_async_issue_pending(master
->dma_tx
);
327 /* mark as dma pending */
330 /* set the DMA length */
331 bcm2835_wr(bs
, BCM2835_SPI_DLEN
, tfr
->len
);
334 bcm2835_wr(bs
, BCM2835_SPI_CS
,
335 cs
| BCM2835_SPI_CS_TA
| BCM2835_SPI_CS_DMAEN
);
337 /* setup rx-DMA late - to run transfers while
338 * mapping of the rx buffers still takes place
339 * this saves 10us or more.
341 ret
= bcm2835_spi_prepare_sg(master
, tfr
, false);
343 /* need to reset on errors */
344 dmaengine_terminate_all(master
->dma_tx
);
345 bcm2835_spi_reset_hw(master
);
349 /* start rx dma late */
350 dma_async_issue_pending(master
->dma_rx
);
352 /* wait for wakeup in framework */
356 static bool bcm2835_spi_can_dma(struct spi_master
*master
,
357 struct spi_device
*spi
,
358 struct spi_transfer
*tfr
)
360 /* only run for gpio_cs */
361 if (!gpio_is_valid(spi
->cs_gpio
))
364 /* we start DMA efforts only on bigger transfers */
365 if (tfr
->len
< BCM2835_SPI_DMA_MIN_LENGTH
)
368 /* BCM2835_SPI_DLEN has defined a max transfer size as
369 * 16 bit, so max is 65535
370 * we can revisit this by using an alternative transfer
371 * method - ideally this would get done without any more
374 if (tfr
->len
> 65535) {
375 dev_warn_once(&spi
->dev
,
376 "transfer size of %d too big for dma-transfer\n",
381 /* if we run rx/tx_buf with word aligned addresses then we are OK */
382 if ((((size_t)tfr
->rx_buf
& 3) == 0) &&
383 (((size_t)tfr
->tx_buf
& 3) == 0))
386 /* otherwise we only allow transfers within the same page
387 * to avoid wasting time on dma_mapping when it is not practical
389 if (((size_t)tfr
->tx_buf
& (PAGE_SIZE
- 1)) + tfr
->len
> PAGE_SIZE
) {
390 dev_warn_once(&spi
->dev
,
391 "Unaligned spi tx-transfer bridging page\n");
394 if (((size_t)tfr
->rx_buf
& (PAGE_SIZE
- 1)) + tfr
->len
> PAGE_SIZE
) {
395 dev_warn_once(&spi
->dev
,
396 "Unaligned spi rx-transfer bridging page\n");
404 static void bcm2835_dma_release(struct spi_master
*master
)
406 if (master
->dma_tx
) {
407 dmaengine_terminate_all(master
->dma_tx
);
408 dma_release_channel(master
->dma_tx
);
409 master
->dma_tx
= NULL
;
411 if (master
->dma_rx
) {
412 dmaengine_terminate_all(master
->dma_rx
);
413 dma_release_channel(master
->dma_rx
);
414 master
->dma_rx
= NULL
;
418 static void bcm2835_dma_init(struct spi_master
*master
, struct device
*dev
)
420 struct dma_slave_config slave_config
;
422 dma_addr_t dma_reg_base
;
425 /* base address in dma-space */
426 addr
= of_get_address(master
->dev
.of_node
, 0, NULL
, NULL
);
428 dev_err(dev
, "could not get DMA-register address - not using dma mode\n");
431 dma_reg_base
= be32_to_cpup(addr
);
434 master
->dma_tx
= dma_request_slave_channel(dev
, "tx");
435 if (!master
->dma_tx
) {
436 dev_err(dev
, "no tx-dma configuration found - not using dma mode\n");
439 master
->dma_rx
= dma_request_slave_channel(dev
, "rx");
440 if (!master
->dma_rx
) {
441 dev_err(dev
, "no rx-dma configuration found - not using dma mode\n");
446 slave_config
.direction
= DMA_MEM_TO_DEV
;
447 slave_config
.dst_addr
= (u32
)(dma_reg_base
+ BCM2835_SPI_FIFO
);
448 slave_config
.dst_addr_width
= DMA_SLAVE_BUSWIDTH_4_BYTES
;
450 ret
= dmaengine_slave_config(master
->dma_tx
, &slave_config
);
454 slave_config
.direction
= DMA_DEV_TO_MEM
;
455 slave_config
.src_addr
= (u32
)(dma_reg_base
+ BCM2835_SPI_FIFO
);
456 slave_config
.src_addr_width
= DMA_SLAVE_BUSWIDTH_4_BYTES
;
458 ret
= dmaengine_slave_config(master
->dma_rx
, &slave_config
);
462 /* all went well, so set can_dma */
463 master
->can_dma
= bcm2835_spi_can_dma
;
464 master
->max_dma_len
= 65535; /* limitation by BCM2835_SPI_DLEN */
465 /* need to do TX AND RX DMA, so we need dummy buffers */
466 master
->flags
= SPI_MASTER_MUST_RX
| SPI_MASTER_MUST_TX
;
471 dev_err(dev
, "issue configuring dma: %d - not using DMA mode\n",
474 bcm2835_dma_release(master
);
479 static int bcm2835_spi_transfer_one_poll(struct spi_master
*master
,
480 struct spi_device
*spi
,
481 struct spi_transfer
*tfr
,
483 unsigned long long xfer_time_us
)
485 struct bcm2835_spi
*bs
= spi_master_get_devdata(master
);
486 unsigned long timeout
;
488 /* enable HW block without interrupts */
489 bcm2835_wr(bs
, BCM2835_SPI_CS
, cs
| BCM2835_SPI_CS_TA
);
491 /* fill in the fifo before timeout calculations
492 * if we are interrupted here, then the data is
493 * getting transferred by the HW while we are interrupted
497 /* set the timeout */
498 timeout
= jiffies
+ BCM2835_SPI_POLLING_JIFFIES
;
500 /* loop until finished the transfer */
502 /* fill in tx fifo with remaining data */
505 /* read from fifo as much as possible */
508 /* if there is still data pending to read
509 * then check the timeout
511 if (bs
->rx_len
&& time_after(jiffies
, timeout
)) {
512 dev_dbg_ratelimited(&spi
->dev
,
513 "timeout period reached: jiffies: %lu remaining tx/rx: %d/%d - falling back to interrupt mode\n",
515 bs
->tx_len
, bs
->rx_len
);
516 /* fall back to interrupt mode */
517 return bcm2835_spi_transfer_one_irq(master
, spi
,
522 /* Transfer complete - reset SPI HW */
523 bcm2835_spi_reset_hw(master
);
524 /* and return without waiting for completion */
528 static int bcm2835_spi_transfer_one(struct spi_master
*master
,
529 struct spi_device
*spi
,
530 struct spi_transfer
*tfr
)
532 struct bcm2835_spi
*bs
= spi_master_get_devdata(master
);
533 unsigned long spi_hz
, clk_hz
, cdiv
;
534 unsigned long spi_used_hz
;
535 unsigned long long xfer_time_us
;
536 u32 cs
= bcm2835_rd(bs
, BCM2835_SPI_CS
);
539 spi_hz
= tfr
->speed_hz
;
540 clk_hz
= clk_get_rate(bs
->clk
);
542 if (spi_hz
>= clk_hz
/ 2) {
543 cdiv
= 2; /* clk_hz/2 is the fastest we can go */
545 /* CDIV must be a multiple of two */
546 cdiv
= DIV_ROUND_UP(clk_hz
, spi_hz
);
550 cdiv
= 0; /* 0 is the slowest we can go */
552 cdiv
= 0; /* 0 is the slowest we can go */
554 spi_used_hz
= cdiv
? (clk_hz
/ cdiv
) : (clk_hz
/ 65536);
555 bcm2835_wr(bs
, BCM2835_SPI_CLK
, cdiv
);
557 /* handle all the 3-wire mode */
558 if ((spi
->mode
& SPI_3WIRE
) && (tfr
->rx_buf
))
559 cs
|= BCM2835_SPI_CS_REN
;
561 cs
&= ~BCM2835_SPI_CS_REN
;
563 /* for gpio_cs set dummy CS so that no HW-CS get changed
564 * we can not run this in bcm2835_spi_set_cs, as it does
565 * not get called for cs_gpio cases, so we need to do it here
567 if (gpio_is_valid(spi
->cs_gpio
) || (spi
->mode
& SPI_NO_CS
))
568 cs
|= BCM2835_SPI_CS_CS_10
| BCM2835_SPI_CS_CS_01
;
570 /* set transmit buffers and length */
571 bs
->tx_buf
= tfr
->tx_buf
;
572 bs
->rx_buf
= tfr
->rx_buf
;
573 bs
->tx_len
= tfr
->len
;
574 bs
->rx_len
= tfr
->len
;
576 /* calculate the estimated time in us the transfer runs */
577 xfer_time_us
= (unsigned long long)tfr
->len
578 * 9 /* clocks/byte - SPI-HW waits 1 clock after each byte */
580 do_div(xfer_time_us
, spi_used_hz
);
582 /* for short requests run polling*/
583 if (xfer_time_us
<= BCM2835_SPI_POLLING_LIMIT_US
)
584 return bcm2835_spi_transfer_one_poll(master
, spi
, tfr
,
587 /* run in dma mode if conditions are right */
588 if (master
->can_dma
&& bcm2835_spi_can_dma(master
, spi
, tfr
))
589 return bcm2835_spi_transfer_one_dma(master
, spi
, tfr
, cs
);
591 /* run in interrupt-mode */
592 return bcm2835_spi_transfer_one_irq(master
, spi
, tfr
, cs
);
595 static int bcm2835_spi_prepare_message(struct spi_master
*master
,
596 struct spi_message
*msg
)
598 struct spi_device
*spi
= msg
->spi
;
599 struct bcm2835_spi
*bs
= spi_master_get_devdata(master
);
600 u32 cs
= bcm2835_rd(bs
, BCM2835_SPI_CS
);
602 cs
&= ~(BCM2835_SPI_CS_CPOL
| BCM2835_SPI_CS_CPHA
);
604 if (spi
->mode
& SPI_CPOL
)
605 cs
|= BCM2835_SPI_CS_CPOL
;
606 if (spi
->mode
& SPI_CPHA
)
607 cs
|= BCM2835_SPI_CS_CPHA
;
609 bcm2835_wr(bs
, BCM2835_SPI_CS
, cs
);
614 static void bcm2835_spi_handle_err(struct spi_master
*master
,
615 struct spi_message
*msg
)
617 struct bcm2835_spi
*bs
= spi_master_get_devdata(master
);
619 /* if an error occurred and we have an active dma, then terminate */
620 if (bs
->dma_pending
) {
621 dmaengine_terminate_all(master
->dma_tx
);
622 dmaengine_terminate_all(master
->dma_rx
);
626 bcm2835_spi_reset_hw(master
);
629 static void bcm2835_spi_set_cs(struct spi_device
*spi
, bool gpio_level
)
632 * we can assume that we are "native" as per spi_set_cs
633 * calling us ONLY when cs_gpio is not set
634 * we can also assume that we are CS < 3 as per bcm2835_spi_setup
635 * we would not get called because of error handling there.
636 * the level passed is the electrical level not enabled/disabled
637 * so it has to get translated back to enable/disable
638 * see spi_set_cs in spi.c for the implementation
641 struct spi_master
*master
= spi
->master
;
642 struct bcm2835_spi
*bs
= spi_master_get_devdata(master
);
643 u32 cs
= bcm2835_rd(bs
, BCM2835_SPI_CS
);
646 /* calculate the enable flag from the passed gpio_level */
647 enable
= (spi
->mode
& SPI_CS_HIGH
) ? gpio_level
: !gpio_level
;
649 /* set flags for "reverse" polarity in the registers */
650 if (spi
->mode
& SPI_CS_HIGH
) {
651 /* set the correct CS-bits */
652 cs
|= BCM2835_SPI_CS_CSPOL
;
653 cs
|= BCM2835_SPI_CS_CSPOL0
<< spi
->chip_select
;
655 /* clean the CS-bits */
656 cs
&= ~BCM2835_SPI_CS_CSPOL
;
657 cs
&= ~(BCM2835_SPI_CS_CSPOL0
<< spi
->chip_select
);
660 /* select the correct chip_select depending on disabled/enabled */
662 /* set cs correctly */
663 if (spi
->mode
& SPI_NO_CS
) {
664 /* use the "undefined" chip-select */
665 cs
|= BCM2835_SPI_CS_CS_10
| BCM2835_SPI_CS_CS_01
;
667 /* set the chip select */
668 cs
&= ~(BCM2835_SPI_CS_CS_10
| BCM2835_SPI_CS_CS_01
);
669 cs
|= spi
->chip_select
;
672 /* disable CSPOL which puts HW-CS into deselected state */
673 cs
&= ~BCM2835_SPI_CS_CSPOL
;
674 /* use the "undefined" chip-select as precaution */
675 cs
|= BCM2835_SPI_CS_CS_10
| BCM2835_SPI_CS_CS_01
;
678 /* finally set the calculated flags in SPI_CS */
679 bcm2835_wr(bs
, BCM2835_SPI_CS
, cs
);
682 static int chip_match_name(struct gpio_chip
*chip
, void *data
)
684 return !strcmp(chip
->label
, data
);
687 static int bcm2835_spi_setup(struct spi_device
*spi
)
690 struct gpio_chip
*chip
;
692 * sanity checking the native-chipselects
694 if (spi
->mode
& SPI_NO_CS
)
696 if (gpio_is_valid(spi
->cs_gpio
))
698 if (spi
->chip_select
> 1) {
699 /* error in the case of native CS requested with CS > 1
700 * officially there is a CS2, but it is not documented
701 * which GPIO is connected with that...
704 "setup: only two native chip-selects are supported\n");
707 /* now translate native cs to GPIO */
709 /* get the gpio chip for the base */
710 chip
= gpiochip_find("pinctrl-bcm2835", chip_match_name
);
714 /* and calculate the real CS */
715 spi
->cs_gpio
= chip
->base
+ 8 - spi
->chip_select
;
717 /* and set up the "mode" and level */
718 dev_info(&spi
->dev
, "setting up native-CS%i as GPIO %i\n",
719 spi
->chip_select
, spi
->cs_gpio
);
721 /* set up GPIO as output and pull to the correct level */
722 err
= gpio_direction_output(spi
->cs_gpio
,
723 (spi
->mode
& SPI_CS_HIGH
) ? 0 : 1);
726 "could not set CS%i gpio %i as output: %i",
727 spi
->chip_select
, spi
->cs_gpio
, err
);
730 /* the implementation of pinctrl-bcm2835 currently does not
731 * set the GPIO value when using gpio_direction_output
732 * so we are setting it here explicitly
734 gpio_set_value(spi
->cs_gpio
, (spi
->mode
& SPI_CS_HIGH
) ? 0 : 1);
739 static int bcm2835_spi_probe(struct platform_device
*pdev
)
741 struct spi_master
*master
;
742 struct bcm2835_spi
*bs
;
743 struct resource
*res
;
746 master
= spi_alloc_master(&pdev
->dev
, sizeof(*bs
));
748 dev_err(&pdev
->dev
, "spi_alloc_master() failed\n");
752 platform_set_drvdata(pdev
, master
);
754 master
->mode_bits
= BCM2835_SPI_MODE_BITS
;
755 master
->bits_per_word_mask
= SPI_BPW_MASK(8);
756 master
->num_chipselect
= 3;
757 master
->setup
= bcm2835_spi_setup
;
758 master
->set_cs
= bcm2835_spi_set_cs
;
759 master
->transfer_one
= bcm2835_spi_transfer_one
;
760 master
->handle_err
= bcm2835_spi_handle_err
;
761 master
->prepare_message
= bcm2835_spi_prepare_message
;
762 master
->dev
.of_node
= pdev
->dev
.of_node
;
764 bs
= spi_master_get_devdata(master
);
766 res
= platform_get_resource(pdev
, IORESOURCE_MEM
, 0);
767 bs
->regs
= devm_ioremap_resource(&pdev
->dev
, res
);
768 if (IS_ERR(bs
->regs
)) {
769 err
= PTR_ERR(bs
->regs
);
773 bs
->clk
= devm_clk_get(&pdev
->dev
, NULL
);
774 if (IS_ERR(bs
->clk
)) {
775 err
= PTR_ERR(bs
->clk
);
776 dev_err(&pdev
->dev
, "could not get clk: %d\n", err
);
780 bs
->irq
= platform_get_irq(pdev
, 0);
782 dev_err(&pdev
->dev
, "could not get IRQ: %d\n", bs
->irq
);
783 err
= bs
->irq
? bs
->irq
: -ENODEV
;
787 clk_prepare_enable(bs
->clk
);
789 bcm2835_dma_init(master
, &pdev
->dev
);
791 /* initialise the hardware with the default polarities */
792 bcm2835_wr(bs
, BCM2835_SPI_CS
,
793 BCM2835_SPI_CS_CLEAR_RX
| BCM2835_SPI_CS_CLEAR_TX
);
795 err
= devm_request_irq(&pdev
->dev
, bs
->irq
, bcm2835_spi_interrupt
, 0,
796 dev_name(&pdev
->dev
), master
);
798 dev_err(&pdev
->dev
, "could not request IRQ: %d\n", err
);
799 goto out_clk_disable
;
802 err
= devm_spi_register_master(&pdev
->dev
, master
);
804 dev_err(&pdev
->dev
, "could not register SPI master: %d\n", err
);
805 goto out_clk_disable
;
811 clk_disable_unprepare(bs
->clk
);
813 spi_master_put(master
);
817 static int bcm2835_spi_remove(struct platform_device
*pdev
)
819 struct spi_master
*master
= platform_get_drvdata(pdev
);
820 struct bcm2835_spi
*bs
= spi_master_get_devdata(master
);
822 /* Clear FIFOs, and disable the HW block */
823 bcm2835_wr(bs
, BCM2835_SPI_CS
,
824 BCM2835_SPI_CS_CLEAR_RX
| BCM2835_SPI_CS_CLEAR_TX
);
826 clk_disable_unprepare(bs
->clk
);
828 bcm2835_dma_release(master
);
833 static const struct of_device_id bcm2835_spi_match
[] = {
834 { .compatible
= "brcm,bcm2835-spi", },
837 MODULE_DEVICE_TABLE(of
, bcm2835_spi_match
);
839 static struct platform_driver bcm2835_spi_driver
= {
842 .of_match_table
= bcm2835_spi_match
,
844 .probe
= bcm2835_spi_probe
,
845 .remove
= bcm2835_spi_remove
,
847 module_platform_driver(bcm2835_spi_driver
);
849 MODULE_DESCRIPTION("SPI controller driver for Broadcom BCM2835");
850 MODULE_AUTHOR("Chris Boot <bootc@bootc.net>");
851 MODULE_LICENSE("GPL v2");