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Merge tag 'pm+acpi-3.16-rc1-2' of git://git.kernel.org/pub/scm/linux/kernel/git/rafae...
[deliverable/linux.git] / drivers / spi / spi-xilinx.c
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_NAME "xilinx_spi"
26
27 /* Register definitions as per "OPB Serial Peripheral Interface (SPI) (v1.00e)
28 * Product Specification", DS464
29 */
30 #define XSPI_CR_OFFSET 0x60 /* Control Register */
31
32 #define XSPI_CR_LOOP 0x01
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 void __iomem *regs; /* virt. address of the control registers */
83
84 int irq;
85
86 u8 *rx_ptr; /* pointer in the Tx buffer */
87 const u8 *tx_ptr; /* pointer in the Rx buffer */
88 int remaining_bytes; /* the number of bytes left to transfer */
89 u8 bits_per_word;
90 unsigned int (*read_fn)(void __iomem *);
91 void (*write_fn)(u32, void __iomem *);
92 void (*tx_fn)(struct xilinx_spi *);
93 void (*rx_fn)(struct xilinx_spi *);
94 };
95
96 static void xspi_write32(u32 val, void __iomem *addr)
97 {
98 iowrite32(val, addr);
99 }
100
101 static unsigned int xspi_read32(void __iomem *addr)
102 {
103 return ioread32(addr);
104 }
105
106 static void xspi_write32_be(u32 val, void __iomem *addr)
107 {
108 iowrite32be(val, addr);
109 }
110
111 static unsigned int xspi_read32_be(void __iomem *addr)
112 {
113 return ioread32be(addr);
114 }
115
116 static void xspi_tx8(struct xilinx_spi *xspi)
117 {
118 xspi->write_fn(*xspi->tx_ptr, xspi->regs + XSPI_TXD_OFFSET);
119 xspi->tx_ptr++;
120 }
121
122 static void xspi_tx16(struct xilinx_spi *xspi)
123 {
124 xspi->write_fn(*(u16 *)(xspi->tx_ptr), xspi->regs + XSPI_TXD_OFFSET);
125 xspi->tx_ptr += 2;
126 }
127
128 static void xspi_tx32(struct xilinx_spi *xspi)
129 {
130 xspi->write_fn(*(u32 *)(xspi->tx_ptr), xspi->regs + XSPI_TXD_OFFSET);
131 xspi->tx_ptr += 4;
132 }
133
134 static void xspi_rx8(struct xilinx_spi *xspi)
135 {
136 u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
137 if (xspi->rx_ptr) {
138 *xspi->rx_ptr = data & 0xff;
139 xspi->rx_ptr++;
140 }
141 }
142
143 static void xspi_rx16(struct xilinx_spi *xspi)
144 {
145 u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
146 if (xspi->rx_ptr) {
147 *(u16 *)(xspi->rx_ptr) = data & 0xffff;
148 xspi->rx_ptr += 2;
149 }
150 }
151
152 static void xspi_rx32(struct xilinx_spi *xspi)
153 {
154 u32 data = xspi->read_fn(xspi->regs + XSPI_RXD_OFFSET);
155 if (xspi->rx_ptr) {
156 *(u32 *)(xspi->rx_ptr) = data;
157 xspi->rx_ptr += 4;
158 }
159 }
160
161 static void xspi_init_hw(struct xilinx_spi *xspi)
162 {
163 void __iomem *regs_base = xspi->regs;
164
165 /* Reset the SPI device */
166 xspi->write_fn(XIPIF_V123B_RESET_MASK,
167 regs_base + XIPIF_V123B_RESETR_OFFSET);
168 /* Disable all the interrupts just in case */
169 xspi->write_fn(0, regs_base + XIPIF_V123B_IIER_OFFSET);
170 /* Enable the global IPIF interrupt */
171 xspi->write_fn(XIPIF_V123B_GINTR_ENABLE,
172 regs_base + XIPIF_V123B_DGIER_OFFSET);
173 /* Deselect the slave on the SPI bus */
174 xspi->write_fn(0xffff, regs_base + XSPI_SSR_OFFSET);
175 /* Disable the transmitter, enable Manual Slave Select Assertion,
176 * put SPI controller into master mode, and enable it */
177 xspi->write_fn(XSPI_CR_TRANS_INHIBIT | XSPI_CR_MANUAL_SSELECT |
178 XSPI_CR_MASTER_MODE | XSPI_CR_ENABLE | XSPI_CR_TXFIFO_RESET |
179 XSPI_CR_RXFIFO_RESET, regs_base + XSPI_CR_OFFSET);
180 }
181
182 static void xilinx_spi_chipselect(struct spi_device *spi, int is_on)
183 {
184 struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
185
186 if (is_on == BITBANG_CS_INACTIVE) {
187 /* Deselect the slave on the SPI bus */
188 xspi->write_fn(0xffff, xspi->regs + XSPI_SSR_OFFSET);
189 } else if (is_on == BITBANG_CS_ACTIVE) {
190 /* Set the SPI clock phase and polarity */
191 u16 cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET)
192 & ~XSPI_CR_MODE_MASK;
193 if (spi->mode & SPI_CPHA)
194 cr |= XSPI_CR_CPHA;
195 if (spi->mode & SPI_CPOL)
196 cr |= XSPI_CR_CPOL;
197 xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
198
199 /* We do not check spi->max_speed_hz here as the SPI clock
200 * frequency is not software programmable (the IP block design
201 * parameter)
202 */
203
204 /* Activate the chip select */
205 xspi->write_fn(~(0x0001 << spi->chip_select),
206 xspi->regs + XSPI_SSR_OFFSET);
207 }
208 }
209
210 /* spi_bitbang requires custom setup_transfer() to be defined if there is a
211 * custom txrx_bufs().
212 */
213 static int xilinx_spi_setup_transfer(struct spi_device *spi,
214 struct spi_transfer *t)
215 {
216 return 0;
217 }
218
219 static void xilinx_spi_fill_tx_fifo(struct xilinx_spi *xspi)
220 {
221 u8 sr;
222
223 /* Fill the Tx FIFO with as many bytes as possible */
224 sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
225 while ((sr & XSPI_SR_TX_FULL_MASK) == 0 && xspi->remaining_bytes > 0) {
226 if (xspi->tx_ptr)
227 xspi->tx_fn(xspi);
228 else
229 xspi->write_fn(0, xspi->regs + XSPI_TXD_OFFSET);
230 xspi->remaining_bytes -= xspi->bits_per_word / 8;
231 sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
232 }
233 }
234
235 static int xilinx_spi_txrx_bufs(struct spi_device *spi, struct spi_transfer *t)
236 {
237 struct xilinx_spi *xspi = spi_master_get_devdata(spi->master);
238 u32 ipif_ier;
239
240 /* We get here with transmitter inhibited */
241
242 xspi->tx_ptr = t->tx_buf;
243 xspi->rx_ptr = t->rx_buf;
244 xspi->remaining_bytes = t->len;
245 reinit_completion(&xspi->done);
246
247
248 /* Enable the transmit empty interrupt, which we use to determine
249 * progress on the transmission.
250 */
251 ipif_ier = xspi->read_fn(xspi->regs + XIPIF_V123B_IIER_OFFSET);
252 xspi->write_fn(ipif_ier | XSPI_INTR_TX_EMPTY,
253 xspi->regs + XIPIF_V123B_IIER_OFFSET);
254
255 for (;;) {
256 u16 cr;
257 u8 sr;
258
259 xilinx_spi_fill_tx_fifo(xspi);
260
261 /* Start the transfer by not inhibiting the transmitter any
262 * longer
263 */
264 cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET) &
265 ~XSPI_CR_TRANS_INHIBIT;
266 xspi->write_fn(cr, xspi->regs + XSPI_CR_OFFSET);
267
268 wait_for_completion(&xspi->done);
269
270 /* A transmit has just completed. Process received data and
271 * check for more data to transmit. Always inhibit the
272 * transmitter while the Isr refills the transmit register/FIFO,
273 * or make sure it is stopped if we're done.
274 */
275 cr = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET);
276 xspi->write_fn(cr | XSPI_CR_TRANS_INHIBIT,
277 xspi->regs + XSPI_CR_OFFSET);
278
279 /* Read out all the data from the Rx FIFO */
280 sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
281 while ((sr & XSPI_SR_RX_EMPTY_MASK) == 0) {
282 xspi->rx_fn(xspi);
283 sr = xspi->read_fn(xspi->regs + XSPI_SR_OFFSET);
284 }
285
286 /* See if there is more data to send */
287 if (xspi->remaining_bytes <= 0)
288 break;
289 }
290
291 /* Disable the transmit empty interrupt */
292 xspi->write_fn(ipif_ier, xspi->regs + XIPIF_V123B_IIER_OFFSET);
293
294 return t->len - xspi->remaining_bytes;
295 }
296
297
298 /* This driver supports single master mode only. Hence Tx FIFO Empty
299 * is the only interrupt we care about.
300 * Receive FIFO Overrun, Transmit FIFO Underrun, Mode Fault, and Slave Mode
301 * Fault are not to happen.
302 */
303 static irqreturn_t xilinx_spi_irq(int irq, void *dev_id)
304 {
305 struct xilinx_spi *xspi = dev_id;
306 u32 ipif_isr;
307
308 /* Get the IPIF interrupts, and clear them immediately */
309 ipif_isr = xspi->read_fn(xspi->regs + XIPIF_V123B_IISR_OFFSET);
310 xspi->write_fn(ipif_isr, xspi->regs + XIPIF_V123B_IISR_OFFSET);
311
312 if (ipif_isr & XSPI_INTR_TX_EMPTY) { /* Transmission completed */
313 complete(&xspi->done);
314 }
315
316 return IRQ_HANDLED;
317 }
318
319 static const struct of_device_id xilinx_spi_of_match[] = {
320 { .compatible = "xlnx,xps-spi-2.00.a", },
321 { .compatible = "xlnx,xps-spi-2.00.b", },
322 {}
323 };
324 MODULE_DEVICE_TABLE(of, xilinx_spi_of_match);
325
326 static int xilinx_spi_probe(struct platform_device *pdev)
327 {
328 struct xilinx_spi *xspi;
329 struct xspi_platform_data *pdata;
330 struct resource *res;
331 int ret, num_cs = 0, bits_per_word = 8;
332 struct spi_master *master;
333 u32 tmp;
334 u8 i;
335
336 pdata = dev_get_platdata(&pdev->dev);
337 if (pdata) {
338 num_cs = pdata->num_chipselect;
339 bits_per_word = pdata->bits_per_word;
340 } else {
341 of_property_read_u32(pdev->dev.of_node, "xlnx,num-ss-bits",
342 &num_cs);
343 }
344
345 if (!num_cs) {
346 dev_err(&pdev->dev,
347 "Missing slave select configuration data\n");
348 return -EINVAL;
349 }
350
351 master = spi_alloc_master(&pdev->dev, sizeof(struct xilinx_spi));
352 if (!master)
353 return -ENODEV;
354
355 /* the spi->mode bits understood by this driver: */
356 master->mode_bits = SPI_CPOL | SPI_CPHA;
357
358 xspi = spi_master_get_devdata(master);
359 xspi->bitbang.master = master;
360 xspi->bitbang.chipselect = xilinx_spi_chipselect;
361 xspi->bitbang.setup_transfer = xilinx_spi_setup_transfer;
362 xspi->bitbang.txrx_bufs = xilinx_spi_txrx_bufs;
363 init_completion(&xspi->done);
364
365 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
366 xspi->regs = devm_ioremap_resource(&pdev->dev, res);
367 if (IS_ERR(xspi->regs)) {
368 ret = PTR_ERR(xspi->regs);
369 goto put_master;
370 }
371
372 master->bus_num = pdev->dev.id;
373 master->num_chipselect = num_cs;
374 master->dev.of_node = pdev->dev.of_node;
375
376 /*
377 * Detect endianess on the IP via loop bit in CR. Detection
378 * must be done before reset is sent because incorrect reset
379 * value generates error interrupt.
380 * Setup little endian helper functions first and try to use them
381 * and check if bit was correctly setup or not.
382 */
383 xspi->read_fn = xspi_read32;
384 xspi->write_fn = xspi_write32;
385
386 xspi->write_fn(XSPI_CR_LOOP, xspi->regs + XSPI_CR_OFFSET);
387 tmp = xspi->read_fn(xspi->regs + XSPI_CR_OFFSET);
388 tmp &= XSPI_CR_LOOP;
389 if (tmp != XSPI_CR_LOOP) {
390 xspi->read_fn = xspi_read32_be;
391 xspi->write_fn = xspi_write32_be;
392 }
393
394 master->bits_per_word_mask = SPI_BPW_MASK(bits_per_word);
395 xspi->bits_per_word = bits_per_word;
396 if (xspi->bits_per_word == 8) {
397 xspi->tx_fn = xspi_tx8;
398 xspi->rx_fn = xspi_rx8;
399 } else if (xspi->bits_per_word == 16) {
400 xspi->tx_fn = xspi_tx16;
401 xspi->rx_fn = xspi_rx16;
402 } else if (xspi->bits_per_word == 32) {
403 xspi->tx_fn = xspi_tx32;
404 xspi->rx_fn = xspi_rx32;
405 } else {
406 ret = -EINVAL;
407 goto put_master;
408 }
409
410 /* SPI controller initializations */
411 xspi_init_hw(xspi);
412
413 xspi->irq = platform_get_irq(pdev, 0);
414 if (xspi->irq < 0) {
415 ret = xspi->irq;
416 goto put_master;
417 }
418
419 /* Register for SPI Interrupt */
420 ret = devm_request_irq(&pdev->dev, xspi->irq, xilinx_spi_irq, 0,
421 dev_name(&pdev->dev), xspi);
422 if (ret)
423 goto put_master;
424
425 ret = spi_bitbang_start(&xspi->bitbang);
426 if (ret) {
427 dev_err(&pdev->dev, "spi_bitbang_start FAILED\n");
428 goto put_master;
429 }
430
431 dev_info(&pdev->dev, "at 0x%08llX mapped to 0x%p, irq=%d\n",
432 (unsigned long long)res->start, xspi->regs, xspi->irq);
433
434 if (pdata) {
435 for (i = 0; i < pdata->num_devices; i++)
436 spi_new_device(master, pdata->devices + i);
437 }
438
439 platform_set_drvdata(pdev, master);
440 return 0;
441
442 put_master:
443 spi_master_put(master);
444
445 return ret;
446 }
447
448 static int xilinx_spi_remove(struct platform_device *pdev)
449 {
450 struct spi_master *master = platform_get_drvdata(pdev);
451 struct xilinx_spi *xspi = spi_master_get_devdata(master);
452 void __iomem *regs_base = xspi->regs;
453
454 spi_bitbang_stop(&xspi->bitbang);
455
456 /* Disable all the interrupts just in case */
457 xspi->write_fn(0, regs_base + XIPIF_V123B_IIER_OFFSET);
458 /* Disable the global IPIF interrupt */
459 xspi->write_fn(0, regs_base + XIPIF_V123B_DGIER_OFFSET);
460
461 spi_master_put(xspi->bitbang.master);
462
463 return 0;
464 }
465
466 /* work with hotplug and coldplug */
467 MODULE_ALIAS("platform:" XILINX_SPI_NAME);
468
469 static struct platform_driver xilinx_spi_driver = {
470 .probe = xilinx_spi_probe,
471 .remove = xilinx_spi_remove,
472 .driver = {
473 .name = XILINX_SPI_NAME,
474 .owner = THIS_MODULE,
475 .of_match_table = xilinx_spi_of_match,
476 },
477 };
478 module_platform_driver(xilinx_spi_driver);
479
480 MODULE_AUTHOR("MontaVista Software, Inc. <source@mvista.com>");
481 MODULE_DESCRIPTION("Xilinx SPI driver");
482 MODULE_LICENSE("GPL");
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