Linux 3.16-rc1
[linux-2.6-block.git] / drivers / spi / spi-cadence.c
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c474b386
HK
1/*
2 * Cadence SPI controller driver (master mode only)
3 *
4 * Copyright (C) 2008 - 2014 Xilinx, Inc.
5 *
6 * based on Blackfin On-Chip SPI Driver (spi_bfin5xx.c)
7 *
8 * This program is free software; you can redistribute it and/or modify it under
9 * the terms of the GNU General Public License version 2 as published by the
10 * Free Software Foundation; either version 2 of the License, or (at your
11 * option) any later version.
12 */
13
14#include <linux/clk.h>
15#include <linux/delay.h>
16#include <linux/interrupt.h>
17#include <linux/io.h>
18#include <linux/module.h>
19#include <linux/of_irq.h>
20#include <linux/of_address.h>
21#include <linux/platform_device.h>
22#include <linux/spi/spi.h>
23
24/* Name of this driver */
25#define CDNS_SPI_NAME "cdns-spi"
26
27/* Register offset definitions */
28#define CDNS_SPI_CR_OFFSET 0x00 /* Configuration Register, RW */
29#define CDNS_SPI_ISR_OFFSET 0x04 /* Interrupt Status Register, RO */
30#define CDNS_SPI_IER_OFFSET 0x08 /* Interrupt Enable Register, WO */
31#define CDNS_SPI_IDR_OFFSET 0x0c /* Interrupt Disable Register, WO */
32#define CDNS_SPI_IMR_OFFSET 0x10 /* Interrupt Enabled Mask Register, RO */
33#define CDNS_SPI_ER_OFFSET 0x14 /* Enable/Disable Register, RW */
34#define CDNS_SPI_DR_OFFSET 0x18 /* Delay Register, RW */
35#define CDNS_SPI_TXD_OFFSET 0x1C /* Data Transmit Register, WO */
36#define CDNS_SPI_RXD_OFFSET 0x20 /* Data Receive Register, RO */
37#define CDNS_SPI_SICR_OFFSET 0x24 /* Slave Idle Count Register, RW */
38#define CDNS_SPI_THLD_OFFSET 0x28 /* Transmit FIFO Watermark Register,RW */
39
40/*
41 * SPI Configuration Register bit Masks
42 *
43 * This register contains various control bits that affect the operation
44 * of the SPI controller
45 */
46#define CDNS_SPI_CR_MANSTRT_MASK 0x00010000 /* Manual TX Start */
47#define CDNS_SPI_CR_CPHA_MASK 0x00000004 /* Clock Phase Control */
48#define CDNS_SPI_CR_CPOL_MASK 0x00000002 /* Clock Polarity Control */
49#define CDNS_SPI_CR_SSCTRL_MASK 0x00003C00 /* Slave Select Mask */
50#define CDNS_SPI_CR_BAUD_DIV_MASK 0x00000038 /* Baud Rate Divisor Mask */
51#define CDNS_SPI_CR_MSTREN_MASK 0x00000001 /* Master Enable Mask */
52#define CDNS_SPI_CR_MANSTRTEN_MASK 0x00008000 /* Manual TX Enable Mask */
53#define CDNS_SPI_CR_SSFORCE_MASK 0x00004000 /* Manual SS Enable Mask */
54#define CDNS_SPI_CR_BAUD_DIV_4_MASK 0x00000008 /* Default Baud Div Mask */
55#define CDNS_SPI_CR_DEFAULT_MASK (CDNS_SPI_CR_MSTREN_MASK | \
56 CDNS_SPI_CR_SSCTRL_MASK | \
57 CDNS_SPI_CR_SSFORCE_MASK | \
58 CDNS_SPI_CR_BAUD_DIV_4_MASK)
59
60/*
61 * SPI Configuration Register - Baud rate and slave select
62 *
63 * These are the values used in the calculation of baud rate divisor and
64 * setting the slave select.
65 */
66
67#define CDNS_SPI_BAUD_DIV_MAX 7 /* Baud rate divisor maximum */
68#define CDNS_SPI_BAUD_DIV_MIN 1 /* Baud rate divisor minimum */
69#define CDNS_SPI_BAUD_DIV_SHIFT 3 /* Baud rate divisor shift in CR */
70#define CDNS_SPI_SS_SHIFT 10 /* Slave Select field shift in CR */
71#define CDNS_SPI_SS0 0x1 /* Slave Select zero */
72
73/*
74 * SPI Interrupt Registers bit Masks
75 *
76 * All the four interrupt registers (Status/Mask/Enable/Disable) have the same
77 * bit definitions.
78 */
79#define CDNS_SPI_IXR_TXOW_MASK 0x00000004 /* SPI TX FIFO Overwater */
80#define CDNS_SPI_IXR_MODF_MASK 0x00000002 /* SPI Mode Fault */
81#define CDNS_SPI_IXR_RXNEMTY_MASK 0x00000010 /* SPI RX FIFO Not Empty */
82#define CDNS_SPI_IXR_DEFAULT_MASK (CDNS_SPI_IXR_TXOW_MASK | \
83 CDNS_SPI_IXR_MODF_MASK)
84#define CDNS_SPI_IXR_TXFULL_MASK 0x00000008 /* SPI TX Full */
85#define CDNS_SPI_IXR_ALL_MASK 0x0000007F /* SPI all interrupts */
86
87/*
88 * SPI Enable Register bit Masks
89 *
90 * This register is used to enable or disable the SPI controller
91 */
92#define CDNS_SPI_ER_ENABLE_MASK 0x00000001 /* SPI Enable Bit Mask */
93#define CDNS_SPI_ER_DISABLE_MASK 0x0 /* SPI Disable Bit Mask */
94
95/* SPI FIFO depth in bytes */
96#define CDNS_SPI_FIFO_DEPTH 128
97
98/* Default number of chip select lines */
99#define CDNS_SPI_DEFAULT_NUM_CS 4
100
101/**
102 * struct cdns_spi - This definition defines spi driver instance
103 * @regs: Virtual address of the SPI controller registers
104 * @ref_clk: Pointer to the peripheral clock
105 * @pclk: Pointer to the APB clock
106 * @speed_hz: Current SPI bus clock speed in Hz
107 * @txbuf: Pointer to the TX buffer
108 * @rxbuf: Pointer to the RX buffer
109 * @tx_bytes: Number of bytes left to transfer
110 * @rx_bytes: Number of bytes requested
111 * @dev_busy: Device busy flag
112 * @is_decoded_cs: Flag for decoder property set or not
113 */
114struct cdns_spi {
115 void __iomem *regs;
116 struct clk *ref_clk;
117 struct clk *pclk;
118 u32 speed_hz;
119 const u8 *txbuf;
120 u8 *rxbuf;
121 int tx_bytes;
122 int rx_bytes;
123 u8 dev_busy;
124 u32 is_decoded_cs;
125};
126
127/* Macros for the SPI controller read/write */
128static inline u32 cdns_spi_read(struct cdns_spi *xspi, u32 offset)
129{
130 return readl_relaxed(xspi->regs + offset);
131}
132
133static inline void cdns_spi_write(struct cdns_spi *xspi, u32 offset, u32 val)
134{
135 writel_relaxed(val, xspi->regs + offset);
136}
137
138/**
139 * cdns_spi_init_hw - Initialize the hardware and configure the SPI controller
140 * @xspi: Pointer to the cdns_spi structure
141 *
142 * On reset the SPI controller is configured to be in master mode, baud rate
143 * divisor is set to 4, threshold value for TX FIFO not full interrupt is set
144 * to 1 and size of the word to be transferred as 8 bit.
145 * This function initializes the SPI controller to disable and clear all the
146 * interrupts, enable manual slave select and manual start, deselect all the
147 * chip select lines, and enable the SPI controller.
148 */
149static void cdns_spi_init_hw(struct cdns_spi *xspi)
150{
151 cdns_spi_write(xspi, CDNS_SPI_ER_OFFSET,
152 CDNS_SPI_ER_DISABLE_MASK);
153 cdns_spi_write(xspi, CDNS_SPI_IDR_OFFSET,
154 CDNS_SPI_IXR_ALL_MASK);
155
156 /* Clear the RX FIFO */
157 while (cdns_spi_read(xspi, CDNS_SPI_ISR_OFFSET) &
158 CDNS_SPI_IXR_RXNEMTY_MASK)
159 cdns_spi_read(xspi, CDNS_SPI_RXD_OFFSET);
160
161 cdns_spi_write(xspi, CDNS_SPI_ISR_OFFSET,
162 CDNS_SPI_IXR_ALL_MASK);
163 cdns_spi_write(xspi, CDNS_SPI_CR_OFFSET,
164 CDNS_SPI_CR_DEFAULT_MASK);
165 cdns_spi_write(xspi, CDNS_SPI_ER_OFFSET,
166 CDNS_SPI_ER_ENABLE_MASK);
167}
168
169/**
170 * cdns_spi_chipselect - Select or deselect the chip select line
171 * @spi: Pointer to the spi_device structure
172 * @is_on: Select(0) or deselect (1) the chip select line
173 */
174static void cdns_spi_chipselect(struct spi_device *spi, bool is_high)
175{
176 struct cdns_spi *xspi = spi_master_get_devdata(spi->master);
177 u32 ctrl_reg;
178
179 ctrl_reg = cdns_spi_read(xspi, CDNS_SPI_CR_OFFSET);
180
181 if (is_high) {
182 /* Deselect the slave */
183 ctrl_reg |= CDNS_SPI_CR_SSCTRL_MASK;
184 } else {
185 /* Select the slave */
186 ctrl_reg &= ~CDNS_SPI_CR_SSCTRL_MASK;
187 if (!(xspi->is_decoded_cs))
188 ctrl_reg |= ((~(CDNS_SPI_SS0 << spi->chip_select)) <<
189 CDNS_SPI_SS_SHIFT) &
190 CDNS_SPI_CR_SSCTRL_MASK;
191 else
192 ctrl_reg |= (spi->chip_select << CDNS_SPI_SS_SHIFT) &
193 CDNS_SPI_CR_SSCTRL_MASK;
194 }
195
196 cdns_spi_write(xspi, CDNS_SPI_CR_OFFSET, ctrl_reg);
197}
198
199/**
200 * cdns_spi_config_clock_mode - Sets clock polarity and phase
201 * @spi: Pointer to the spi_device structure
202 *
203 * Sets the requested clock polarity and phase.
204 */
205static void cdns_spi_config_clock_mode(struct spi_device *spi)
206{
207 struct cdns_spi *xspi = spi_master_get_devdata(spi->master);
208 u32 ctrl_reg;
209
210 ctrl_reg = cdns_spi_read(xspi, CDNS_SPI_CR_OFFSET);
211
212 /* Set the SPI clock phase and clock polarity */
213 ctrl_reg &= ~(CDNS_SPI_CR_CPHA_MASK | CDNS_SPI_CR_CPOL_MASK);
214 if (spi->mode & SPI_CPHA)
215 ctrl_reg |= CDNS_SPI_CR_CPHA_MASK;
216 if (spi->mode & SPI_CPOL)
217 ctrl_reg |= CDNS_SPI_CR_CPOL_MASK;
218
219 cdns_spi_write(xspi, CDNS_SPI_CR_OFFSET, ctrl_reg);
220}
221
222/**
223 * cdns_spi_config_clock_freq - Sets clock frequency
224 * @spi: Pointer to the spi_device structure
225 * @transfer: Pointer to the spi_transfer structure which provides
226 * information about next transfer setup parameters
227 *
228 * Sets the requested clock frequency.
229 * Note: If the requested frequency is not an exact match with what can be
230 * obtained using the prescalar value the driver sets the clock frequency which
231 * is lower than the requested frequency (maximum lower) for the transfer. If
232 * the requested frequency is higher or lower than that is supported by the SPI
233 * controller the driver will set the highest or lowest frequency supported by
234 * controller.
235 */
236static void cdns_spi_config_clock_freq(struct spi_device *spi,
237 struct spi_transfer *transfer)
238{
239 struct cdns_spi *xspi = spi_master_get_devdata(spi->master);
240 u32 ctrl_reg, baud_rate_val;
241 unsigned long frequency;
242
243 frequency = clk_get_rate(xspi->ref_clk);
244
245 ctrl_reg = cdns_spi_read(xspi, CDNS_SPI_CR_OFFSET);
246
247 /* Set the clock frequency */
248 if (xspi->speed_hz != transfer->speed_hz) {
249 /* first valid value is 1 */
250 baud_rate_val = CDNS_SPI_BAUD_DIV_MIN;
251 while ((baud_rate_val < CDNS_SPI_BAUD_DIV_MAX) &&
252 (frequency / (2 << baud_rate_val)) > transfer->speed_hz)
253 baud_rate_val++;
254
255 ctrl_reg &= ~CDNS_SPI_CR_BAUD_DIV_MASK;
256 ctrl_reg |= baud_rate_val << CDNS_SPI_BAUD_DIV_SHIFT;
257
258 xspi->speed_hz = frequency / (2 << baud_rate_val);
259 }
260 cdns_spi_write(xspi, CDNS_SPI_CR_OFFSET, ctrl_reg);
261}
262
263/**
264 * cdns_spi_setup_transfer - Configure SPI controller for specified transfer
265 * @spi: Pointer to the spi_device structure
266 * @transfer: Pointer to the spi_transfer structure which provides
267 * information about next transfer setup parameters
268 *
269 * Sets the operational mode of SPI controller for the next SPI transfer and
270 * sets the requested clock frequency.
271 *
272 * Return: Always 0
273 */
274static int cdns_spi_setup_transfer(struct spi_device *spi,
275 struct spi_transfer *transfer)
276{
277 struct cdns_spi *xspi = spi_master_get_devdata(spi->master);
278
279 cdns_spi_config_clock_freq(spi, transfer);
280
281 dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u clock speed\n",
282 __func__, spi->mode, spi->bits_per_word,
283 xspi->speed_hz);
284
285 return 0;
286}
287
288/**
289 * cdns_spi_fill_tx_fifo - Fills the TX FIFO with as many bytes as possible
290 * @xspi: Pointer to the cdns_spi structure
291 */
292static void cdns_spi_fill_tx_fifo(struct cdns_spi *xspi)
293{
294 unsigned long trans_cnt = 0;
295
296 while ((trans_cnt < CDNS_SPI_FIFO_DEPTH) &&
297 (xspi->tx_bytes > 0)) {
298 if (xspi->txbuf)
299 cdns_spi_write(xspi, CDNS_SPI_TXD_OFFSET,
300 *xspi->txbuf++);
301 else
302 cdns_spi_write(xspi, CDNS_SPI_TXD_OFFSET, 0);
303
304 xspi->tx_bytes--;
305 trans_cnt++;
306 }
307}
308
309/**
310 * cdns_spi_irq - Interrupt service routine of the SPI controller
311 * @irq: IRQ number
312 * @dev_id: Pointer to the xspi structure
313 *
314 * This function handles TX empty and Mode Fault interrupts only.
315 * On TX empty interrupt this function reads the received data from RX FIFO and
316 * fills the TX FIFO if there is any data remaining to be transferred.
317 * On Mode Fault interrupt this function indicates that transfer is completed,
318 * the SPI subsystem will identify the error as the remaining bytes to be
319 * transferred is non-zero.
320 *
321 * Return: IRQ_HANDLED when handled; IRQ_NONE otherwise.
322 */
323static irqreturn_t cdns_spi_irq(int irq, void *dev_id)
324{
325 struct spi_master *master = dev_id;
326 struct cdns_spi *xspi = spi_master_get_devdata(master);
327 u32 intr_status, status;
328
329 status = IRQ_NONE;
330 intr_status = cdns_spi_read(xspi, CDNS_SPI_ISR_OFFSET);
331 cdns_spi_write(xspi, CDNS_SPI_ISR_OFFSET, intr_status);
332
333 if (intr_status & CDNS_SPI_IXR_MODF_MASK) {
334 /* Indicate that transfer is completed, the SPI subsystem will
335 * identify the error as the remaining bytes to be
336 * transferred is non-zero
337 */
338 cdns_spi_write(xspi, CDNS_SPI_IDR_OFFSET,
339 CDNS_SPI_IXR_DEFAULT_MASK);
340 spi_finalize_current_transfer(master);
341 status = IRQ_HANDLED;
342 } else if (intr_status & CDNS_SPI_IXR_TXOW_MASK) {
343 unsigned long trans_cnt;
344
345 trans_cnt = xspi->rx_bytes - xspi->tx_bytes;
346
347 /* Read out the data from the RX FIFO */
348 while (trans_cnt) {
349 u8 data;
350
351 data = cdns_spi_read(xspi, CDNS_SPI_RXD_OFFSET);
352 if (xspi->rxbuf)
353 *xspi->rxbuf++ = data;
354
355 xspi->rx_bytes--;
356 trans_cnt--;
357 }
358
359 if (xspi->tx_bytes) {
360 /* There is more data to send */
361 cdns_spi_fill_tx_fifo(xspi);
362 } else {
363 /* Transfer is completed */
364 cdns_spi_write(xspi, CDNS_SPI_IDR_OFFSET,
365 CDNS_SPI_IXR_DEFAULT_MASK);
366 spi_finalize_current_transfer(master);
367 }
368 status = IRQ_HANDLED;
369 }
370
371 return status;
372}
373
374/**
375 * cdns_transfer_one - Initiates the SPI transfer
376 * @master: Pointer to spi_master structure
377 * @spi: Pointer to the spi_device structure
378 * @transfer: Pointer to the spi_transfer structure which provides
379 * information about next transfer parameters
380 *
381 * This function fills the TX FIFO, starts the SPI transfer and
382 * returns a positive transfer count so that core will wait for completion.
383 *
384 * Return: Number of bytes transferred in the last transfer
385 */
386static int cdns_transfer_one(struct spi_master *master,
387 struct spi_device *spi,
388 struct spi_transfer *transfer)
389{
390 struct cdns_spi *xspi = spi_master_get_devdata(master);
391
392 xspi->txbuf = transfer->tx_buf;
393 xspi->rxbuf = transfer->rx_buf;
394 xspi->tx_bytes = transfer->len;
395 xspi->rx_bytes = transfer->len;
396
397 cdns_spi_setup_transfer(spi, transfer);
398
399 cdns_spi_fill_tx_fifo(xspi);
400
401 cdns_spi_write(xspi, CDNS_SPI_IER_OFFSET,
402 CDNS_SPI_IXR_DEFAULT_MASK);
403 return transfer->len;
404}
405
406/**
407 * cdns_prepare_transfer_hardware - Prepares hardware for transfer.
408 * @master: Pointer to the spi_master structure which provides
409 * information about the controller.
410 *
411 * This function enables SPI master controller.
412 *
413 * Return: 0 always
414 */
415static int cdns_prepare_transfer_hardware(struct spi_master *master)
416{
417 struct cdns_spi *xspi = spi_master_get_devdata(master);
418
419 cdns_spi_config_clock_mode(master->cur_msg->spi);
420
421 cdns_spi_write(xspi, CDNS_SPI_ER_OFFSET,
422 CDNS_SPI_ER_ENABLE_MASK);
423
424 return 0;
425}
426
427/**
428 * cdns_unprepare_transfer_hardware - Relaxes hardware after transfer
429 * @master: Pointer to the spi_master structure which provides
430 * information about the controller.
431 *
432 * This function disables the SPI master controller.
433 *
434 * Return: 0 always
435 */
436static int cdns_unprepare_transfer_hardware(struct spi_master *master)
437{
438 struct cdns_spi *xspi = spi_master_get_devdata(master);
439
440 cdns_spi_write(xspi, CDNS_SPI_ER_OFFSET,
441 CDNS_SPI_ER_DISABLE_MASK);
442
443 return 0;
444}
445
446/**
447 * cdns_spi_probe - Probe method for the SPI driver
448 * @pdev: Pointer to the platform_device structure
449 *
450 * This function initializes the driver data structures and the hardware.
451 *
452 * Return: 0 on success and error value on error
453 */
454static int cdns_spi_probe(struct platform_device *pdev)
455{
456 int ret = 0, irq;
457 struct spi_master *master;
458 struct cdns_spi *xspi;
459 struct resource *res;
460 u32 num_cs;
461
462 master = spi_alloc_master(&pdev->dev, sizeof(*xspi));
463 if (master == NULL)
464 return -ENOMEM;
465
466 xspi = spi_master_get_devdata(master);
467 master->dev.of_node = pdev->dev.of_node;
468 platform_set_drvdata(pdev, master);
469
470 res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
471 xspi->regs = devm_ioremap_resource(&pdev->dev, res);
472 if (IS_ERR(xspi->regs)) {
473 ret = PTR_ERR(xspi->regs);
474 goto remove_master;
475 }
476
477 xspi->pclk = devm_clk_get(&pdev->dev, "pclk");
478 if (IS_ERR(xspi->pclk)) {
479 dev_err(&pdev->dev, "pclk clock not found.\n");
480 ret = PTR_ERR(xspi->pclk);
481 goto remove_master;
482 }
483
484 xspi->ref_clk = devm_clk_get(&pdev->dev, "ref_clk");
485 if (IS_ERR(xspi->ref_clk)) {
486 dev_err(&pdev->dev, "ref_clk clock not found.\n");
487 ret = PTR_ERR(xspi->ref_clk);
488 goto remove_master;
489 }
490
491 ret = clk_prepare_enable(xspi->pclk);
492 if (ret) {
493 dev_err(&pdev->dev, "Unable to enable APB clock.\n");
494 goto remove_master;
495 }
496
497 ret = clk_prepare_enable(xspi->ref_clk);
498 if (ret) {
499 dev_err(&pdev->dev, "Unable to enable device clock.\n");
500 goto clk_dis_apb;
501 }
502
503 /* SPI controller initializations */
504 cdns_spi_init_hw(xspi);
505
506 irq = platform_get_irq(pdev, 0);
507 if (irq <= 0) {
508 ret = -ENXIO;
509 dev_err(&pdev->dev, "irq number is invalid\n");
510 goto remove_master;
511 }
512
513 ret = devm_request_irq(&pdev->dev, irq, cdns_spi_irq,
514 0, pdev->name, master);
515 if (ret != 0) {
516 ret = -ENXIO;
517 dev_err(&pdev->dev, "request_irq failed\n");
518 goto remove_master;
519 }
520
521 ret = of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs);
522
523 if (ret < 0)
524 master->num_chipselect = CDNS_SPI_DEFAULT_NUM_CS;
525 else
526 master->num_chipselect = num_cs;
527
528 ret = of_property_read_u32(pdev->dev.of_node, "is-decoded-cs",
529 &xspi->is_decoded_cs);
530
531 if (ret < 0)
532 xspi->is_decoded_cs = 0;
533
534 master->prepare_transfer_hardware = cdns_prepare_transfer_hardware;
535 master->transfer_one = cdns_transfer_one;
536 master->unprepare_transfer_hardware = cdns_unprepare_transfer_hardware;
537 master->set_cs = cdns_spi_chipselect;
538 master->mode_bits = SPI_CPOL | SPI_CPHA;
539
540 /* Set to default valid value */
541 master->max_speed_hz = clk_get_rate(xspi->ref_clk) / 4;
542 xspi->speed_hz = master->max_speed_hz;
543
544 master->bits_per_word_mask = SPI_BPW_MASK(8);
545
546 ret = spi_register_master(master);
547 if (ret) {
548 dev_err(&pdev->dev, "spi_register_master failed\n");
549 goto clk_dis_all;
550 }
551
552 return ret;
553
554clk_dis_all:
555 clk_disable_unprepare(xspi->ref_clk);
556clk_dis_apb:
557 clk_disable_unprepare(xspi->pclk);
558remove_master:
559 spi_master_put(master);
560 return ret;
561}
562
563/**
564 * cdns_spi_remove - Remove method for the SPI driver
565 * @pdev: Pointer to the platform_device structure
566 *
567 * This function is called if a device is physically removed from the system or
568 * if the driver module is being unloaded. It frees all resources allocated to
569 * the device.
570 *
571 * Return: 0 on success and error value on error
572 */
573static int cdns_spi_remove(struct platform_device *pdev)
574{
575 struct spi_master *master = platform_get_drvdata(pdev);
576 struct cdns_spi *xspi = spi_master_get_devdata(master);
577
578 cdns_spi_write(xspi, CDNS_SPI_ER_OFFSET,
579 CDNS_SPI_ER_DISABLE_MASK);
580
581 clk_disable_unprepare(xspi->ref_clk);
582 clk_disable_unprepare(xspi->pclk);
583
584 spi_unregister_master(master);
585
586 return 0;
587}
588
589/**
590 * cdns_spi_suspend - Suspend method for the SPI driver
591 * @dev: Address of the platform_device structure
592 *
593 * This function disables the SPI controller and
594 * changes the driver state to "suspend"
595 *
596 * Return: Always 0
597 */
598static int __maybe_unused cdns_spi_suspend(struct device *dev)
599{
600 struct platform_device *pdev = container_of(dev,
601 struct platform_device, dev);
602 struct spi_master *master = platform_get_drvdata(pdev);
603 struct cdns_spi *xspi = spi_master_get_devdata(master);
604
605 spi_master_suspend(master);
606
607 clk_disable_unprepare(xspi->ref_clk);
608
609 clk_disable_unprepare(xspi->pclk);
610
611 return 0;
612}
613
614/**
615 * cdns_spi_resume - Resume method for the SPI driver
616 * @dev: Address of the platform_device structure
617 *
618 * This function changes the driver state to "ready"
619 *
620 * Return: 0 on success and error value on error
621 */
622static int __maybe_unused cdns_spi_resume(struct device *dev)
623{
624 struct platform_device *pdev = container_of(dev,
625 struct platform_device, dev);
626 struct spi_master *master = platform_get_drvdata(pdev);
627 struct cdns_spi *xspi = spi_master_get_devdata(master);
628 int ret = 0;
629
630 ret = clk_prepare_enable(xspi->pclk);
631 if (ret) {
632 dev_err(dev, "Cannot enable APB clock.\n");
633 return ret;
634 }
635
636 ret = clk_prepare_enable(xspi->ref_clk);
637 if (ret) {
638 dev_err(dev, "Cannot enable device clock.\n");
639 clk_disable(xspi->pclk);
640 return ret;
641 }
642 spi_master_resume(master);
643
644 return 0;
645}
646
647static SIMPLE_DEV_PM_OPS(cdns_spi_dev_pm_ops, cdns_spi_suspend,
648 cdns_spi_resume);
649
650static struct of_device_id cdns_spi_of_match[] = {
651 { .compatible = "xlnx,zynq-spi-r1p6" },
652 { .compatible = "cdns,spi-r1p6" },
653 { /* end of table */ }
654};
655MODULE_DEVICE_TABLE(of, cdns_spi_of_match);
656
657/* cdns_spi_driver - This structure defines the SPI subsystem platform driver */
658static struct platform_driver cdns_spi_driver = {
659 .probe = cdns_spi_probe,
660 .remove = cdns_spi_remove,
661 .driver = {
662 .name = CDNS_SPI_NAME,
663 .owner = THIS_MODULE,
664 .of_match_table = cdns_spi_of_match,
665 .pm = &cdns_spi_dev_pm_ops,
666 },
667};
668
669module_platform_driver(cdns_spi_driver);
670
671MODULE_AUTHOR("Xilinx, Inc.");
672MODULE_DESCRIPTION("Cadence SPI driver");
673MODULE_LICENSE("GPL");