?  search:
summary | log | graphiclog1 | graphiclog2 | commit | commitdiff | tree | refs | edit | fork
blame | history | raw | HEAD
Linux 4.1.16
[linux/fpc-iii.git] / drivers / spi / spi-xilinx.c
bloba339c1e9997a93a431cf5ce9be5947b6333ac3e9
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/interrupt.h>
18 #include <linux/of.h>
19 #include <linux/platform_device.h>
20 #include <linux/spi/spi.h>
21 #include <linux/spi/spi_bitbang.h>
22 #include <linux/spi/xilinx_spi.h>
23 #include <linux/io.h>
24
25 #define XILINX_SPI_MAX_CS 32
26
27 #define XILINX_SPI_NAME "xilinx_spi"
28
29 /* Register definitions as per "OPB Serial Peripheral Interface (SPI) (v1.00e)
30 * Product Specification", DS464
31 */
32 #define XSPI_CR_OFFSET 0x60 /* Control Register */
33
34 #define XSPI_CR_LOOP 0x01
35 #define XSPI_CR_ENABLE 0x02
36 #define XSPI_CR_MASTER_MODE 0x04
37 #define XSPI_CR_CPOL 0x08
38 #define XSPI_CR_CPHA 0x10
39 #define XSPI_CR_MODE_MASK (XSPI_CR_CPHA | XSPI_CR_CPOL | \
40 XSPI_CR_LSB_FIRST | XSPI_CR_LOOP)
41 #define XSPI_CR_TXFIFO_RESET 0x20
42 #define XSPI_CR_RXFIFO_RESET 0x40
43 #define XSPI_CR_MANUAL_SSELECT 0x80
44 #define XSPI_CR_TRANS_INHIBIT 0x100
45 #define XSPI_CR_LSB_FIRST 0x200
46
47 #define XSPI_SR_OFFSET 0x64 /* Status Register */
48
49 #define XSPI_SR_RX_EMPTY_MASK 0x01 /* Receive FIFO is empty */
50 #define XSPI_SR_RX_FULL_MASK 0x02 /* Receive FIFO is full */
51 #define XSPI_SR_TX_EMPTY_MASK 0x04 /* Transmit FIFO is empty */
52 #define XSPI_SR_TX_FULL_MASK 0x08 /* Transmit FIFO is full */
53 #define XSPI_SR_MODE_FAULT_MASK 0x10 /* Mode fault error */
54
55 #define XSPI_TXD_OFFSET 0x68 /* Data Transmit Register */
56 #define XSPI_RXD_OFFSET 0x6c /* Data Receive Register */
57
58 #define XSPI_SSR_OFFSET 0x70 /* 32-bit Slave Select Register */
59
60 /* Register definitions as per "OPB IPIF (v3.01c) Product Specification", DS414
61 * IPIF registers are 32 bit
62 */
63 #define XIPIF_V123B_DGIER_OFFSET 0x1c /* IPIF global int enable reg */
64 #define XIPIF_V123B_GINTR_ENABLE 0x80000000
65
66 #define XIPIF_V123B_IISR_OFFSET 0x20 /* IPIF interrupt status reg */
67 #define XIPIF_V123B_IIER_OFFSET 0x28 /* IPIF interrupt enable reg */
68
69 #define XSPI_INTR_MODE_FAULT 0x01 /* Mode fault error */
70 #define XSPI_INTR_SLAVE_MODE_FAULT 0x02 /* Selected as slave while
71 * disabled */
72 #define XSPI_INTR_TX_EMPTY 0x04 /* TxFIFO is empty */
73 #define XSPI_INTR_TX_UNDERRUN 0x08 /* TxFIFO was underrun */
74 #define XSPI_INTR_RX_FULL 0x10 /* RxFIFO is full */
75 #define XSPI_INTR_RX_OVERRUN 0x20 /* RxFIFO was overrun */
76 #define XSPI_INTR_TX_HALF_EMPTY 0x40 /* TxFIFO is half empty */
77
78 #define XIPIF_V123B_RESETR_OFFSET 0x40 /* IPIF reset register */
79 #define XIPIF_V123B_RESET_MASK 0x0a /* the value to write */
80
81 struct xilinx_spi {
82 /* bitbang has to be first */
83 struct spi_bitbang bitbang;
84 struct completion done;
85 void __iomem *regs; /* virt. address of the control registers */
86
87 int irq;
88
89 u8 *rx_ptr; /* pointer in the Tx buffer */
90 const u8 *tx_ptr; /* pointer in the Rx buffer */
91 u8 bytes_per_word;
92 int buffer_size; /* buffer size in words */
93 u32 cs_inactive; /* Level of the CS pins when inactive*/
94 unsigned int (*read_fn)(void __iomem *);
95 void (*write_fn)(u32, void __iomem *);
96 };
97
98 static void xspi_write32(u32 val, void __iomem *addr)
99 {
100 iowrite32(val, addr);
101 }
102
103 static unsigned int xspi_read32(void __iomem *addr)
104 {
105 return ioread32(addr);
106 }
107
108 static void xspi_write32_be(u32 val, void __iomem *addr)
109 {
110 iowrite32be(val, addr);
111 }
112
113 static unsigned int xspi_read32_be(void __iomem *addr)
114 {
115 return ioread32be(addr);
116 }
117
118 static void xilinx_spi_tx(struct xilinx_spi *xspi)
119 {
120 u32 data = 0;
121
122 if (!xspi->tx_ptr) {
123 xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET);
124 return;
125 }
126
127 switch (xspi->bytes_per_word) {
128 case 1:
129 data = *(u8 *)(xspi->tx_ptr);
130 break;
131 case 2:
132 data = *(u16 *)(xspi->tx_ptr);
133 break;
134 case 4:
135 data = *(u32 *)(xspi->tx_ptr);
136 break;
137 }
138
139 xspi->write_fn(data, xspi->regs + XSPI_TXD_OFFSET);
140 xspi->tx_ptr += xspi->bytes_per_word;
141 }
142
143 static void xilinx_spi_rx(struct xilinx_spi *xspi)
144 {
145 u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
146
147 if (!xspi->rx_ptr)
148 return;
149
150 switch (xspi->bytes_per_word) {
151 case 1:
152 *(u8 *)(xspi->rx_ptr) = data;
153 break;
154 case 2:
155 *(u16 *)(xspi->rx_ptr) = data;
156 break;
157 case 4:
158 *(u32 *)(xspi->rx_ptr) = data;
159 break;
160 }
161
162 xspi->rx_ptr += xspi->bytes_per_word;
163 }
164
165 static void xspi_init_hw(struct xilinx_spi *xspi)
166 {
167 void __iomem *regs_base = xspi->regs;
168
169 /* Reset the SPI device */
170 xspi->write_fn(XIPIF_V123B_RESET_MASK,
171 regs_base + XIPIF_V123B_RESETR_OFFSET);
172 /* Enable the transmit empty interrupt, which we use to determine
173 * progress on the transmission.
174 */
175 xspi->write_fn(XSPI_INTR_TX_EMPTY,
176 regs_base + XIPIF_V123B_IIER_OFFSET);
177 /* Disable the global IPIF interrupt */
178 xspi->write_fn(0, regs_base + XIPIF_V123B_DGIER_OFFSET);
179 /* Deselect the slave on the SPI bus */
180 xspi->write_fn(0xffff, regs_base + XSPI_SSR_OFFSET);
181 /* Disable the transmitter, enable Manual Slave Select Assertion,
182 * put SPI controller into master mode, and enable it */
183 xspi->write_fn(XSPI_CR_MANUAL_SSELECT | XSPI_CR_MASTER_MODE |
184 XSPI_CR_ENABLE | XSPI_CR_TXFIFO_RESET | XSPI_CR_RXFIFO_RESET,
185 regs_base + XSPI_CR_OFFSET);
186 }
187
188 static void xilinx_spi_chipselect(struct spi_device *spi, int is_on)
189 {
190 struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
191 u16 cr;
192 u32 cs;
193
194 if (is_on == BITBANG_CS_INACTIVE) {
195 /* Deselect the slave on the SPI bus */
196 xspi->write_fn(xspi->cs_inactive, xspi->regs + XSPI_SSR_OFFSET);
197 return;
198 }
199
200 /* Set the SPI clock phase and polarity */
201 cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET) & ~XSPI_CR_MODE_MASK;
202 if (spi->mode & SPI_CPHA)
203 cr |= XSPI_CR_CPHA;
204 if (spi->mode & SPI_CPOL)
205 cr |= XSPI_CR_CPOL;
206 if (spi->mode & SPI_LSB_FIRST)
207 cr |= XSPI_CR_LSB_FIRST;
208 if (spi->mode & SPI_LOOP)
209 cr |= XSPI_CR_LOOP;
210 xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
211
212 /* We do not check spi->max_speed_hz here as the SPI clock
213 * frequency is not software programmable (the IP block design
214 * parameter)
215 */
216
217 cs = xspi->cs_inactive;
218 cs ^= BIT(spi->chip_select);
219
220 /* Activate the chip select */
221 xspi->write_fn(cs, xspi->regs + XSPI_SSR_OFFSET);
222 }
223
224 /* spi_bitbang requires custom setup_transfer() to be defined if there is a
225 * custom txrx_bufs().
226 */
227 static int xilinx_spi_setup_transfer(struct spi_device *spi,
228 struct spi_transfer *t)
229 {
230 struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
231
232 if (spi->mode & SPI_CS_HIGH)
233 xspi->cs_inactive &= ~BIT(spi->chip_select);
234 else
235 xspi->cs_inactive |= BIT(spi->chip_select);
236
237 return 0;
238 }
239
240 static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
241 {
242 struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
243 int remaining_words; /* the number of words left to transfer */
244 bool use_irq = false;
245 u16 cr = 0;
246
247 /* We get here with transmitter inhibited */
248
249 xspi->tx_ptr = t->tx_buf;
250 xspi->rx_ptr = t->rx_buf;
251 remaining_words = t->len / xspi->bytes_per_word;
252
253 if (xspi->irq >= 0 && remaining_words > xspi->buffer_size) {
254 u32 isr;
255 use_irq = true;
256 /* Inhibit irq to avoid spurious irqs on tx_empty*/
257 cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET);
258 xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT,
259 xspi->regs + XSPI_CR_OFFSET);
260 /* ACK old irqs (if any) */
261 isr = xspi->read_fn(xspi->regs + XIPIF_V123B_IISR_OFFSET);
262 if (isr)
263 xspi->write_fn(isr,
264 xspi->regs + XIPIF_V123B_IISR_OFFSET);
265 /* Enable the global IPIF interrupt */
266 xspi->write_fn(XIPIF_V123B_GINTR_ENABLE,
267 xspi->regs + XIPIF_V123B_DGIER_OFFSET);
268 reinit_completion(&xspi->done);
269 }
270
271 while (remaining_words) {
272 int n_words, tx_words, rx_words;
273
274 n_words = min(remaining_words, xspi->buffer_size);
275
276 tx_words = n_words;
277 while (tx_words--)
278 xilinx_spi_tx(xspi);
279
280 /* Start the transfer by not inhibiting the transmitter any
281 * longer
282 */
283
284 if (use_irq) {
285 xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
286 wait_for_completion(&xspi->done);
287 } else
288 while (!(xspi->read_fn(xspi->regs + XSPI_SR_OFFSET) &
289 XSPI_SR_TX_EMPTY_MASK))
290 ;
291
292 /* A transmit has just completed. Process received data and
293 * check for more data to transmit. Always inhibit the
294 * transmitter while the Isr refills the transmit register/FIFO,
295 * or make sure it is stopped if we're done.
296 */
297 if (use_irq)
298 xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT,
299 xspi->regs + XSPI_CR_OFFSET);
300
301 /* Read out all the data from the Rx FIFO */
302 rx_words = n_words;
303 while (rx_words--)
304 xilinx_spi_rx(xspi);
305
306 remaining_words -= n_words;
307 }
308
309 if (use_irq) {
310 xspi->write_fn(0, xspi->regs + XIPIF_V123B_DGIER_OFFSET);
311 xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
312 }
313
314 return t->len;
315 }
316
317
318 /* This driver supports single master mode only. Hence Tx FIFO Empty
319 * is the only interrupt we care about.
320 * Receive FIFO Overrun, Transmit FIFO Underrun, Mode Fault, and Slave Mode
321 * Fault are not to happen.
322 */
323 static irqreturn_t xilinx_spi_irq(int irq, void *dev_id)
324 {
325 struct xilinx_spi *xspi = dev_id;
326 u32 ipif_isr;
327
328 /* Get the IPIF interrupts, and clear them immediately */
329 ipif_isr = xspi->read_fn(xspi->regs + XIPIF_V123B_IISR_OFFSET);
330 xspi->write_fn(ipif_isr, xspi->regs + XIPIF_V123B_IISR_OFFSET);
331
332 if (ipif_isr & XSPI_INTR_TX_EMPTY) { /* Transmission completed */
333 complete(&xspi->done);
334 }
335
336 return IRQ_HANDLED;
337 }
338
339 static int xilinx_spi_find_buffer_size(struct xilinx_spi *xspi)
340 {
341 u8 sr;
342 int n_words = 0;
343
344 /*
345 * Before the buffer_size detection we reset the core
346 * to make sure we start with a clean state.
347 */
348 xspi->write_fn(XIPIF_V123B_RESET_MASK,
349 xspi->regs + XIPIF_V123B_RESETR_OFFSET);
350
351 /* Fill the Tx FIFO with as many words as possible */
352 do {
353 xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET);
354 sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
355 n_words++;
356 } while (!(sr & XSPI_SR_TX_FULL_MASK));
357
358 return n_words;
359 }
360
361 static const struct of_device_id xilinx_spi_of_match[] = {
362 { .compatible = "xlnx,xps-spi-2.00.a", },
363 { .compatible = "xlnx,xps-spi-2.00.b", },
364 {}
365 };
366 MODULE_DEVICE_TABLE(of, xilinx_spi_of_match);
367
368 static int xilinx_spi_probe(struct platform_device *pdev)
369 {
370 struct xilinx_spi *xspi;
371 struct xspi_platform_data *pdata;
372 struct resource *res;
373 int ret, num_cs = 0, bits_per_word = 8;
374 struct spi_master *master;
375 u32 tmp;
376 u8 i;
377
378 pdata = dev_get_platdata(&pdev->dev);
379 if (pdata) {
380 num_cs = pdata->num_chipselect;
381 bits_per_word = pdata->bits_per_word;
382 } else {
383 of_property_read_u32(pdev->dev.of_node, "xlnx,num-ss-bits",
384 &num_cs);
385 }
386
387 if (!num_cs) {
388 dev_err(&pdev->dev,
389 "Missing slave select configuration data\n");
390 return -EINVAL;
391 }
392
393 if (num_cs > XILINX_SPI_MAX_CS) {
394 dev_err(&pdev->dev, "Invalid number of spi slaves\n");
395 return -EINVAL;
396 }
397
398 master = spi_alloc_master(&pdev->dev, sizeof(struct xilinx_spi));
399 if (!master)
400 return -ENODEV;
401
402 /* the spi->mode bits understood by this driver: */
403 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_LSB_FIRST | SPI_LOOP |
404 SPI_CS_HIGH;
405
406 xspi = spi_master_get_devdata(master);
407 xspi->cs_inactive = 0xffffffff;
408 xspi->bitbang.master = master;
409 xspi->bitbang.chipselect = xilinx_spi_chipselect;
410 xspi->bitbang.setup_transfer = xilinx_spi_setup_transfer;
411 xspi->bitbang.txrx_bufs = xilinx_spi_txrx_bufs;
412 init_completion(&xspi->done);
413
414 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
415 xspi->regs = devm_ioremap_resource(&pdev->dev, res);
416 if (IS_ERR(xspi->regs)) {
417 ret = PTR_ERR(xspi->regs);
418 goto put_master;
419 }
420
421 master->bus_num = pdev->id;
422 master->num_chipselect = num_cs;
423 master->dev.of_node = pdev->dev.of_node;
424
425 /*
426 * Detect endianess on the IP via loop bit in CR. Detection
427 * must be done before reset is sent because incorrect reset
428 * value generates error interrupt.
429 * Setup little endian helper functions first and try to use them
430 * and check if bit was correctly setup or not.
431 */
432 xspi->read_fn = xspi_read32;
433 xspi->write_fn = xspi_write32;
434
435 xspi->write_fn(XSPI_CR_LOOP, xspi->regs + XSPI_CR_OFFSET);
436 tmp = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET);
437 tmp &= XSPI_CR_LOOP;
438 if (tmp != XSPI_CR_LOOP) {
439 xspi->read_fn = xspi_read32_be;
440 xspi->write_fn = xspi_write32_be;
441 }
442
443 master->bits_per_word_mask = SPI_BPW_MASK(bits_per_word);
444 xspi->bytes_per_word = bits_per_word / 8;
445 xspi->buffer_size = xilinx_spi_find_buffer_size(xspi);
446
447 xspi->irq = platform_get_irq(pdev, 0);
448 if (xspi->irq >= 0) {
449 /* Register for SPI Interrupt */
450 ret = devm_request_irq(&pdev->dev, xspi->irq, xilinx_spi_irq, 0,
451 dev_name(&pdev->dev), xspi);
452 if (ret)
453 goto put_master;
454 }
455
456 /* SPI controller initializations */
457 xspi_init_hw(xspi);
458
459 ret = spi_bitbang_start(&xspi->bitbang);
460 if (ret) {
461 dev_err(&pdev->dev, "spi_bitbang_start FAILED\n");
462 goto put_master;
463 }
464
465 dev_info(&pdev->dev, "at 0x%08llX mapped to 0x%p, irq=%d\n",
466 (unsigned long long)res->start, xspi->regs, xspi->irq);
467
468 if (pdata) {
469 for (i = 0; i < pdata->num_devices; i++)
470 spi_new_device(master, pdata->devices + i);
471 }
472
473 platform_set_drvdata(pdev, master);
474 return 0;
475
476 put_master:
477 spi_master_put(master);
478
479 return ret;
480 }
481
482 static int xilinx_spi_remove(struct platform_device *pdev)
483 {
484 struct spi_master *master = platform_get_drvdata(pdev);
485 struct xilinx_spi *xspi = spi_master_get_devdata(master);
486 void __iomem *regs_base = xspi->regs;
487
488 spi_bitbang_stop(&xspi->bitbang);
489
490 /* Disable all the interrupts just in case */
491 xspi->write_fn(0, regs_base + XIPIF_V123B_IIER_OFFSET);
492 /* Disable the global IPIF interrupt */
493 xspi->write_fn(0, regs_base + XIPIF_V123B_DGIER_OFFSET);
494
495 spi_master_put(xspi->bitbang.master);
496
497 return 0;
498 }
499
500 /* work with hotplug and coldplug */
501 MODULE_ALIAS("platform:" XILINX_SPI_NAME);
502
503 static struct platform_driver xilinx_spi_driver = {
504 .probe = xilinx_spi_probe,
505 .remove = xilinx_spi_remove,
506 .driver = {
507 .name = XILINX_SPI_NAME,
508 .of_match_table = xilinx_spi_of_match,
509 },
510 };
511 module_platform_driver(xilinx_spi_driver);
512
513 MODULE_AUTHOR("MontaVista Software, Inc. <source@mvista.com>");
514 MODULE_DESCRIPTION("Xilinx SPI driver");
515 MODULE_LICENSE("GPL");
Linux with added FPC-III support