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Linux 3.3-rc6
[linux/fpc-iii.git] / drivers / spi / spi-xilinx.c
blob4c5a663b9fa897e4a510f6cf6dbba084efc6bfb6
1 /*
2 * Xilinx SPI controller driver (master mode only)
3 *
4 * Author: MontaVista Software, Inc.
5 * source@mvista.com
6 *
7 * Copyright (c) 2010 Secret Lab Technologies, Ltd.
8 * Copyright (c) 2009 Intel Corporation
9 * 2002-2007 (c) MontaVista Software, Inc.
10
11 * This program is free software; you can redistribute it and/or modify
12 * it under the terms of the GNU General Public License version 2 as
13 * published by the Free Software Foundation.
14 */
15
16 #include <linux/module.h>
17 #include <linux/init.h>
18 #include <linux/interrupt.h>
19 #include <linux/of.h>
20 #include <linux/platform_device.h>
21 #include <linux/spi/spi.h>
22 #include <linux/spi/spi_bitbang.h>
23 #include <linux/spi/xilinx_spi.h>
24 #include <linux/io.h>
25
26 #define XILINX_SPI_NAME "xilinx_spi"
27
28 /* Register definitions as per "OPB Serial Peripheral Interface (SPI) (v1.00e)
29 * Product Specification", DS464
30 */
31 #define XSPI_CR_OFFSET 0x60 /* Control Register */
32
33 #define XSPI_CR_ENABLE 0x02
34 #define XSPI_CR_MASTER_MODE 0x04
35 #define XSPI_CR_CPOL 0x08
36 #define XSPI_CR_CPHA 0x10
37 #define XSPI_CR_MODE_MASK (XSPI_CR_CPHA | XSPI_CR_CPOL)
38 #define XSPI_CR_TXFIFO_RESET 0x20
39 #define XSPI_CR_RXFIFO_RESET 0x40
40 #define XSPI_CR_MANUAL_SSELECT 0x80
41 #define XSPI_CR_TRANS_INHIBIT 0x100
42 #define XSPI_CR_LSB_FIRST 0x200
43
44 #define XSPI_SR_OFFSET 0x64 /* Status Register */
45
46 #define XSPI_SR_RX_EMPTY_MASK 0x01 /* Receive FIFO is empty */
47 #define XSPI_SR_RX_FULL_MASK 0x02 /* Receive FIFO is full */
48 #define XSPI_SR_TX_EMPTY_MASK 0x04 /* Transmit FIFO is empty */
49 #define XSPI_SR_TX_FULL_MASK 0x08 /* Transmit FIFO is full */
50 #define XSPI_SR_MODE_FAULT_MASK 0x10 /* Mode fault error */
51
52 #define XSPI_TXD_OFFSET 0x68 /* Data Transmit Register */
53 #define XSPI_RXD_OFFSET 0x6c /* Data Receive Register */
54
55 #define XSPI_SSR_OFFSET 0x70 /* 32-bit Slave Select Register */
56
57 /* Register definitions as per "OPB IPIF (v3.01c) Product Specification", DS414
58 * IPIF registers are 32 bit
59 */
60 #define XIPIF_V123B_DGIER_OFFSET 0x1c /* IPIF global int enable reg */
61 #define XIPIF_V123B_GINTR_ENABLE 0x80000000
62
63 #define XIPIF_V123B_IISR_OFFSET 0x20 /* IPIF interrupt status reg */
64 #define XIPIF_V123B_IIER_OFFSET 0x28 /* IPIF interrupt enable reg */
65
66 #define XSPI_INTR_MODE_FAULT 0x01 /* Mode fault error */
67 #define XSPI_INTR_SLAVE_MODE_FAULT 0x02 /* Selected as slave while
68 * disabled */
69 #define XSPI_INTR_TX_EMPTY 0x04 /* TxFIFO is empty */
70 #define XSPI_INTR_TX_UNDERRUN 0x08 /* TxFIFO was underrun */
71 #define XSPI_INTR_RX_FULL 0x10 /* RxFIFO is full */
72 #define XSPI_INTR_RX_OVERRUN 0x20 /* RxFIFO was overrun */
73 #define XSPI_INTR_TX_HALF_EMPTY 0x40 /* TxFIFO is half empty */
74
75 #define XIPIF_V123B_RESETR_OFFSET 0x40 /* IPIF reset register */
76 #define XIPIF_V123B_RESET_MASK 0x0a /* the value to write */
77
78 struct xilinx_spi {
79 /* bitbang has to be first */
80 struct spi_bitbang bitbang;
81 struct completion done;
82 struct resource mem; /* phys mem */
83 void __iomem *regs; /* virt. address of the control registers */
84
85 u32 irq;
86
87 u8 *rx_ptr; /* pointer in the Tx buffer */
88 const u8 *tx_ptr; /* pointer in the Rx buffer */
89 int remaining_bytes; /* the number of bytes left to transfer */
90 u8 bits_per_word;
91 unsigned int (*read_fn) (void __iomem *);
92 void (*write_fn) (u32, void __iomem *);
93 void (*tx_fn) (struct xilinx_spi *);
94 void (*rx_fn) (struct xilinx_spi *);
95 };
96
97 static void xspi_write32(u32 val, void __iomem *addr)
98 {
99 iowrite32(val, addr);
100 }
101
102 static unsigned int xspi_read32(void __iomem *addr)
103 {
104 return ioread32(addr);
105 }
106
107 static void xspi_write32_be(u32 val, void __iomem *addr)
108 {
109 iowrite32be(val, addr);
110 }
111
112 static unsigned int xspi_read32_be(void __iomem *addr)
113 {
114 return ioread32be(addr);
115 }
116
117 static void xspi_tx8(struct xilinx_spi *xspi)
118 {
119 xspi->write_fn(*xspi->tx_ptr, xspi->regs + XSPI_TXD_OFFSET);
120 xspi->tx_ptr++;
121 }
122
123 static void xspi_tx16(struct xilinx_spi *xspi)
124 {
125 xspi->write_fn(*(u16 *)(xspi->tx_ptr), xspi->regs + XSPI_TXD_OFFSET);
126 xspi->tx_ptr += 2;
127 }
128
129 static void xspi_tx32(struct xilinx_spi *xspi)
130 {
131 xspi->write_fn(*(u32 *)(xspi->tx_ptr), xspi->regs + XSPI_TXD_OFFSET);
132 xspi->tx_ptr += 4;
133 }
134
135 static void xspi_rx8(struct xilinx_spi *xspi)
136 {
137 u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
138 if (xspi->rx_ptr) {
139 *xspi->rx_ptr = data & 0xff;
140 xspi->rx_ptr++;
141 }
142 }
143
144 static void xspi_rx16(struct xilinx_spi *xspi)
145 {
146 u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
147 if (xspi->rx_ptr) {
148 *(u16 *)(xspi->rx_ptr) = data & 0xffff;
149 xspi->rx_ptr += 2;
150 }
151 }
152
153 static void xspi_rx32(struct xilinx_spi *xspi)
154 {
155 u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
156 if (xspi->rx_ptr) {
157 *(u32 *)(xspi->rx_ptr) = data;
158 xspi->rx_ptr += 4;
159 }
160 }
161
162 static void xspi_init_hw(struct xilinx_spi *xspi)
163 {
164 void __iomem *regs_base = xspi->regs;
165
166 /* Reset the SPI device */
167 xspi->write_fn(XIPIF_V123B_RESET_MASK,
168 regs_base + XIPIF_V123B_RESETR_OFFSET);
169 /* Disable all the interrupts just in case */
170 xspi->write_fn(0, regs_base + XIPIF_V123B_IIER_OFFSET);
171 /* Enable the global IPIF interrupt */
172 xspi->write_fn(XIPIF_V123B_GINTR_ENABLE,
173 regs_base + XIPIF_V123B_DGIER_OFFSET);
174 /* Deselect the slave on the SPI bus */
175 xspi->write_fn(0xffff, regs_base + XSPI_SSR_OFFSET);
176 /* Disable the transmitter, enable Manual Slave Select Assertion,
177 * put SPI controller into master mode, and enable it */
178 xspi->write_fn(XSPI_CR_TRANS_INHIBIT | XSPI_CR_MANUAL_SSELECT |
179 XSPI_CR_MASTER_MODE | XSPI_CR_ENABLE | XSPI_CR_TXFIFO_RESET |
180 XSPI_CR_RXFIFO_RESET, regs_base + XSPI_CR_OFFSET);
181 }
182
183 static void xilinx_spi_chipselect(struct spi_device *spi, int is_on)
184 {
185 struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
186
187 if (is_on == BITBANG_CS_INACTIVE) {
188 /* Deselect the slave on the SPI bus */
189 xspi->write_fn(0xffff, xspi->regs + XSPI_SSR_OFFSET);
190 } else if (is_on == BITBANG_CS_ACTIVE) {
191 /* Set the SPI clock phase and polarity */
192 u16 cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET)
193 & ~XSPI_CR_MODE_MASK;
194 if (spi->mode & SPI_CPHA)
195 cr |= XSPI_CR_CPHA;
196 if (spi->mode & SPI_CPOL)
197 cr |= XSPI_CR_CPOL;
198 xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
199
200 /* We do not check spi->max_speed_hz here as the SPI clock
201 * frequency is not software programmable (the IP block design
202 * parameter)
203 */
204
205 /* Activate the chip select */
206 xspi->write_fn(~(0x0001 << spi->chip_select),
207 xspi->regs + XSPI_SSR_OFFSET);
208 }
209 }
210
211 /* spi_bitbang requires custom setup_transfer() to be defined if there is a
212 * custom txrx_bufs(). We have nothing to setup here as the SPI IP block
213 * supports 8 or 16 bits per word which cannot be changed in software.
214 * SPI clock can't be changed in software either.
215 * Check for correct bits per word. Chip select delay calculations could be
216 * added here as soon as bitbang_work() can be made aware of the delay value.
217 */
218 static int xilinx_spi_setup_transfer(struct spi_device *spi,
219 struct spi_transfer *t)
220 {
221 struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
222 u8 bits_per_word;
223
224 bits_per_word = (t && t->bits_per_word)
225 ? t->bits_per_word : spi->bits_per_word;
226 if (bits_per_word != xspi->bits_per_word) {
227 dev_err(&spi->dev, "%s, unsupported bits_per_word=%d\n",
228 __func__, bits_per_word);
229 return -EINVAL;
230 }
231
232 return 0;
233 }
234
235 static int xilinx_spi_setup(struct spi_device *spi)
236 {
237 /* always return 0, we can not check the number of bits.
238 * There are cases when SPI setup is called before any driver is
239 * there, in that case the SPI core defaults to 8 bits, which we
240 * do not support in some cases. But if we return an error, the
241 * SPI device would not be registered and no driver can get hold of it
242 * When the driver is there, it will call SPI setup again with the
243 * correct number of bits per transfer.
244 * If a driver setups with the wrong bit number, it will fail when
245 * it tries to do a transfer
246 */
247 return 0;
248 }
249
250 static void xilinx_spi_fill_tx_fifo(struct xilinx_spi *xspi)
251 {
252 u8 sr;
253
254 /* Fill the Tx FIFO with as many bytes as possible */
255 sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
256 while ((sr & XSPI_SR_TX_FULL_MASK) == 0 && xspi->remaining_bytes > 0) {
257 if (xspi->tx_ptr)
258 xspi->tx_fn(xspi);
259 else
260 xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET);
261 xspi->remaining_bytes -= xspi->bits_per_word / 8;
262 sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
263 }
264 }
265
266 static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
267 {
268 struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
269 u32 ipif_ier;
270 u16 cr;
271
272 /* We get here with transmitter inhibited */
273
274 xspi->tx_ptr = t->tx_buf;
275 xspi->rx_ptr = t->rx_buf;
276 xspi->remaining_bytes = t->len;
277 INIT_COMPLETION(xspi->done);
278
279 xilinx_spi_fill_tx_fifo(xspi);
280
281 /* Enable the transmit empty interrupt, which we use to determine
282 * progress on the transmission.
283 */
284 ipif_ier = xspi->read_fn(xspi->regs + XIPIF_V123B_IIER_OFFSET);
285 xspi->write_fn(ipif_ier | XSPI_INTR_TX_EMPTY,
286 xspi->regs + XIPIF_V123B_IIER_OFFSET);
287
288 /* Start the transfer by not inhibiting the transmitter any longer */
289 cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET) &
290 ~XSPI_CR_TRANS_INHIBIT;
291 xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
292
293 wait_for_completion(&xspi->done);
294
295 /* Disable the transmit empty interrupt */
296 xspi->write_fn(ipif_ier, xspi->regs + XIPIF_V123B_IIER_OFFSET);
297
298 return t->len - xspi->remaining_bytes;
299 }
300
301
302 /* This driver supports single master mode only. Hence Tx FIFO Empty
303 * is the only interrupt we care about.
304 * Receive FIFO Overrun, Transmit FIFO Underrun, Mode Fault, and Slave Mode
305 * Fault are not to happen.
306 */
307 static irqreturn_t xilinx_spi_irq(int irq, void *dev_id)
308 {
309 struct xilinx_spi *xspi = dev_id;
310 u32 ipif_isr;
311
312 /* Get the IPIF interrupts, and clear them immediately */
313 ipif_isr = xspi->read_fn(xspi->regs + XIPIF_V123B_IISR_OFFSET);
314 xspi->write_fn(ipif_isr, xspi->regs + XIPIF_V123B_IISR_OFFSET);
315
316 if (ipif_isr & XSPI_INTR_TX_EMPTY) { /* Transmission completed */
317 u16 cr;
318 u8 sr;
319
320 /* A transmit has just completed. Process received data and
321 * check for more data to transmit. Always inhibit the
322 * transmitter while the Isr refills the transmit register/FIFO,
323 * or make sure it is stopped if we're done.
324 */
325 cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET);
326 xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT,
327 xspi->regs + XSPI_CR_OFFSET);
328
329 /* Read out all the data from the Rx FIFO */
330 sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
331 while ((sr & XSPI_SR_RX_EMPTY_MASK) == 0) {
332 xspi->rx_fn(xspi);
333 sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
334 }
335
336 /* See if there is more data to send */
337 if (xspi->remaining_bytes > 0) {
338 xilinx_spi_fill_tx_fifo(xspi);
339 /* Start the transfer by not inhibiting the
340 * transmitter any longer
341 */
342 xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
343 } else {
344 /* No more data to send.
345 * Indicate the transfer is completed.
346 */
347 complete(&xspi->done);
348 }
349 }
350
351 return IRQ_HANDLED;
352 }
353
354 static const struct of_device_id xilinx_spi_of_match[] = {
355 { .compatible = "xlnx,xps-spi-2.00.a", },
356 { .compatible = "xlnx,xps-spi-2.00.b", },
357 {}
358 };
359 MODULE_DEVICE_TABLE(of, xilinx_spi_of_match);
360
361 struct spi_master *xilinx_spi_init(struct device *dev, struct resource *mem,
362 u32 irq, s16 bus_num, int num_cs, int little_endian, int bits_per_word)
363 {
364 struct spi_master *master;
365 struct xilinx_spi *xspi;
366 int ret;
367
368 master = spi_alloc_master(dev, sizeof(struct xilinx_spi));
369 if (!master)
370 return NULL;
371
372 /* the spi->mode bits understood by this driver: */
373 master->mode_bits = SPI_CPOL | SPI_CPHA;
374
375 xspi = spi_master_get_devdata(master);
376 xspi->bitbang.master = spi_master_get(master);
377 xspi->bitbang.chipselect = xilinx_spi_chipselect;
378 xspi->bitbang.setup_transfer = xilinx_spi_setup_transfer;
379 xspi->bitbang.txrx_bufs = xilinx_spi_txrx_bufs;
380 xspi->bitbang.master->setup = xilinx_spi_setup;
381 init_completion(&xspi->done);
382
383 if (!request_mem_region(mem->start, resource_size(mem),
384 XILINX_SPI_NAME))
385 goto put_master;
386
387 xspi->regs = ioremap(mem->start, resource_size(mem));
388 if (xspi->regs == NULL) {
389 dev_warn(dev, "ioremap failure\n");
390 goto map_failed;
391 }
392
393 master->bus_num = bus_num;
394 master->num_chipselect = num_cs;
395 master->dev.of_node = dev->of_node;
396
397 xspi->mem = *mem;
398 xspi->irq = irq;
399 if (little_endian) {
400 xspi->read_fn = xspi_read32;
401 xspi->write_fn = xspi_write32;
402 } else {
403 xspi->read_fn = xspi_read32_be;
404 xspi->write_fn = xspi_write32_be;
405 }
406 xspi->bits_per_word = bits_per_word;
407 if (xspi->bits_per_word == 8) {
408 xspi->tx_fn = xspi_tx8;
409 xspi->rx_fn = xspi_rx8;
410 } else if (xspi->bits_per_word == 16) {
411 xspi->tx_fn = xspi_tx16;
412 xspi->rx_fn = xspi_rx16;
413 } else if (xspi->bits_per_word == 32) {
414 xspi->tx_fn = xspi_tx32;
415 xspi->rx_fn = xspi_rx32;
416 } else
417 goto unmap_io;
418
419
420 /* SPI controller initializations */
421 xspi_init_hw(xspi);
422
423 /* Register for SPI Interrupt */
424 ret = request_irq(xspi->irq, xilinx_spi_irq, 0, XILINX_SPI_NAME, xspi);
425 if (ret)
426 goto unmap_io;
427
428 ret = spi_bitbang_start(&xspi->bitbang);
429 if (ret) {
430 dev_err(dev, "spi_bitbang_start FAILED\n");
431 goto free_irq;
432 }
433
434 dev_info(dev, "at 0x%08llX mapped to 0x%p, irq=%d\n",
435 (unsigned long long)mem->start, xspi->regs, xspi->irq);
436 return master;
437
438 free_irq:
439 free_irq(xspi->irq, xspi);
440 unmap_io:
441 iounmap(xspi->regs);
442 map_failed:
443 release_mem_region(mem->start, resource_size(mem));
444 put_master:
445 spi_master_put(master);
446 return NULL;
447 }
448 EXPORT_SYMBOL(xilinx_spi_init);
449
450 void xilinx_spi_deinit(struct spi_master *master)
451 {
452 struct xilinx_spi *xspi;
453
454 xspi = spi_master_get_devdata(master);
455
456 spi_bitbang_stop(&xspi->bitbang);
457 free_irq(xspi->irq, xspi);
458 iounmap(xspi->regs);
459
460 release_mem_region(xspi->mem.start, resource_size(&xspi->mem));
461 spi_master_put(xspi->bitbang.master);
462 }
463 EXPORT_SYMBOL(xilinx_spi_deinit);
464
465 static int __devinit xilinx_spi_probe(struct platform_device *dev)
466 {
467 struct xspi_platform_data *pdata;
468 struct resource *r;
469 int irq, num_cs = 0, little_endian = 0, bits_per_word = 8;
470 struct spi_master *master;
471 u8 i;
472
473 pdata = dev->dev.platform_data;
474 if (pdata) {
475 num_cs = pdata->num_chipselect;
476 little_endian = pdata->little_endian;
477 bits_per_word = pdata->bits_per_word;
478 }
479
480 #ifdef CONFIG_OF
481 if (dev->dev.of_node) {
482 const __be32 *prop;
483 int len;
484
485 /* number of slave select bits is required */
486 prop = of_get_property(dev->dev.of_node, "xlnx,num-ss-bits",
487 &len);
488 if (prop && len >= sizeof(*prop))
489 num_cs = __be32_to_cpup(prop);
490 }
491 #endif
492
493 if (!num_cs) {
494 dev_err(&dev->dev, "Missing slave select configuration data\n");
495 return -EINVAL;
496 }
497
498
499 r = platform_get_resource(dev, IORESOURCE_MEM, 0);
500 if (!r)
501 return -ENODEV;
502
503 irq = platform_get_irq(dev, 0);
504 if (irq < 0)
505 return -ENXIO;
506
507 master = xilinx_spi_init(&dev->dev, r, irq, dev->id, num_cs,
508 little_endian, bits_per_word);
509 if (!master)
510 return -ENODEV;
511
512 if (pdata) {
513 for (i = 0; i < pdata->num_devices; i++)
514 spi_new_device(master, pdata->devices + i);
515 }
516
517 platform_set_drvdata(dev, master);
518 return 0;
519 }
520
521 static int __devexit xilinx_spi_remove(struct platform_device *dev)
522 {
523 xilinx_spi_deinit(platform_get_drvdata(dev));
524 platform_set_drvdata(dev, 0);
525
526 return 0;
527 }
528
529 /* work with hotplug and coldplug */
530 MODULE_ALIAS("platform:" XILINX_SPI_NAME);
531
532 static struct platform_driver xilinx_spi_driver = {
533 .probe = xilinx_spi_probe,
534 .remove = __devexit_p(xilinx_spi_remove),
535 .driver = {
536 .name = XILINX_SPI_NAME,
537 .owner = THIS_MODULE,
538 .of_match_table = xilinx_spi_of_match,
539 },
540 };
541 module_platform_driver(xilinx_spi_driver);
542
543 MODULE_AUTHOR("MontaVista Software, Inc. <source@mvista.com>");
544 MODULE_DESCRIPTION("Xilinx SPI driver");
545 MODULE_LICENSE("GPL");
Linux with added FPC-III support