1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Cadence SPI controller driver (host and target mode)
4 *
5 * Copyright (C) 2008 - 2014 Xilinx, Inc.
6 *
7 * based on Blackfin On-Chip SPI Driver (spi_bfin5xx.c)
8 */
9
10 #include <linux/clk.h>
11 #include <linux/delay.h>
12 #include <linux/gpio/consumer.h>
13 #include <linux/interrupt.h>
14 #include <linux/io.h>
15 #include <linux/kernel.h>
16 #include <linux/module.h>
17 #include <linux/of_irq.h>
18 #include <linux/of_address.h>
19 #include <linux/platform_device.h>
20 #include <linux/pm_runtime.h>
21 #include <linux/spi/spi.h>
22
23 /* Name of this driver */
24 #define CDNS_SPI_NAME "cdns-spi"
25
26 /* Register offset definitions */
27 #define CDNS_SPI_CR 0x00 /* Configuration Register, RW */
28 #define CDNS_SPI_ISR 0x04 /* Interrupt Status Register, RO */
29 #define CDNS_SPI_IER 0x08 /* Interrupt Enable Register, WO */
30 #define CDNS_SPI_IDR 0x0c /* Interrupt Disable Register, WO */
31 #define CDNS_SPI_IMR 0x10 /* Interrupt Enabled Mask Register, RO */
32 #define CDNS_SPI_ER 0x14 /* Enable/Disable Register, RW */
33 #define CDNS_SPI_DR 0x18 /* Delay Register, RW */
34 #define CDNS_SPI_TXD 0x1C /* Data Transmit Register, WO */
35 #define CDNS_SPI_RXD 0x20 /* Data Receive Register, RO */
36 #define CDNS_SPI_SICR 0x24 /* Slave Idle Count Register, RW */
37 #define CDNS_SPI_THLD 0x28 /* Transmit FIFO Watermark Register,RW */
38
39 #define SPI_AUTOSUSPEND_TIMEOUT 3000
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 0x00010000 /* Manual TX Start */
47 #define CDNS_SPI_CR_CPHA 0x00000004 /* Clock Phase Control */
48 #define CDNS_SPI_CR_CPOL 0x00000002 /* Clock Polarity Control */
49 #define CDNS_SPI_CR_SSCTRL 0x00003C00 /* Slave Select Mask */
50 #define CDNS_SPI_CR_PERI_SEL 0x00000200 /* Peripheral Select Decode */
51 #define CDNS_SPI_CR_BAUD_DIV 0x00000038 /* Baud Rate Divisor Mask */
52 #define CDNS_SPI_CR_MSTREN 0x00000001 /* Master Enable Mask */
53 #define CDNS_SPI_CR_MANSTRTEN 0x00008000 /* Manual TX Enable Mask */
54 #define CDNS_SPI_CR_SSFORCE 0x00004000 /* Manual SS Enable Mask */
55 #define CDNS_SPI_CR_BAUD_DIV_4 0x00000008 /* Default Baud Div Mask */
56 #define CDNS_SPI_CR_DEFAULT (CDNS_SPI_CR_MSTREN | \
57 CDNS_SPI_CR_SSCTRL | \
58 CDNS_SPI_CR_SSFORCE | \
59 CDNS_SPI_CR_BAUD_DIV_4)
60
61 /*
62 * SPI Configuration Register - Baud rate and target select
63 *
64 * These are the values used in the calculation of baud rate divisor and
65 * setting the target select.
66 */
67
68 #define CDNS_SPI_BAUD_DIV_MAX 7 /* Baud rate divisor maximum */
69 #define CDNS_SPI_BAUD_DIV_MIN 1 /* Baud rate divisor minimum */
70 #define CDNS_SPI_BAUD_DIV_SHIFT 3 /* Baud rate divisor shift in CR */
71 #define CDNS_SPI_SS_SHIFT 10 /* Slave Select field shift in CR */
72 #define CDNS_SPI_SS0 0x1 /* Slave Select zero */
73 #define CDNS_SPI_NOSS 0xF /* No Slave select */
74
75 /*
76 * SPI Interrupt Registers bit Masks
77 *
78 * All the four interrupt registers (Status/Mask/Enable/Disable) have the same
79 * bit definitions.
80 */
81 #define CDNS_SPI_IXR_TXOW 0x00000004 /* SPI TX FIFO Overwater */
82 #define CDNS_SPI_IXR_MODF 0x00000002 /* SPI Mode Fault */
83 #define CDNS_SPI_IXR_RXNEMTY 0x00000010 /* SPI RX FIFO Not Empty */
84 #define CDNS_SPI_IXR_DEFAULT (CDNS_SPI_IXR_TXOW | \
85 CDNS_SPI_IXR_MODF)
86 #define CDNS_SPI_IXR_TXFULL 0x00000008 /* SPI TX Full */
87 #define CDNS_SPI_IXR_ALL 0x0000007F /* SPI all interrupts */
88
89 /*
90 * SPI Enable Register bit Masks
91 *
92 * This register is used to enable or disable the SPI controller
93 */
94 #define CDNS_SPI_ER_ENABLE 0x00000001 /* SPI Enable Bit Mask */
95 #define CDNS_SPI_ER_DISABLE 0x0 /* SPI Disable Bit Mask */
96
97 /* Default number of chip select lines */
98 #define CDNS_SPI_DEFAULT_NUM_CS 4
99
100 /**
101 * struct cdns_spi - This definition defines spi driver instance
102 * @regs: Virtual address of the SPI controller registers
103 * @ref_clk: Pointer to the peripheral clock
104 * @pclk: Pointer to the APB clock
105 * @clk_rate: Reference clock frequency, taken from @ref_clk
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 * @tx_fifo_depth: Depth of the TX FIFO
114 */
115 struct cdns_spi {
116 void __iomem *regs;
117 struct clk *ref_clk;
118 struct clk *pclk;
119 unsigned int clk_rate;
120 u32 speed_hz;
121 const u8 *txbuf;
122 u8 *rxbuf;
123 int tx_bytes;
124 int rx_bytes;
125 u8 dev_busy;
126 u32 is_decoded_cs;
127 unsigned int tx_fifo_depth;
128 };
129
130 /* Macros for the SPI controller read/write */
cdns_spi_read(struct cdns_spi * xspi,u32 offset)131 static inline u32 cdns_spi_read(struct cdns_spi *xspi, u32 offset)
132 {
133 return readl_relaxed(xspi->regs + offset);
134 }
135
cdns_spi_write(struct cdns_spi * xspi,u32 offset,u32 val)136 static inline void cdns_spi_write(struct cdns_spi *xspi, u32 offset, u32 val)
137 {
138 writel_relaxed(val, xspi->regs + offset);
139 }
140
141 /**
142 * cdns_spi_init_hw - Initialize the hardware and configure the SPI controller
143 * @xspi: Pointer to the cdns_spi structure
144 * @is_target: Flag to indicate target or host mode
145 * * On reset the SPI controller is configured to target or host mode.
146 * In host mode baud rate divisor is set to 4, threshold value for TX FIFO
147 * not full interrupt is set to 1 and size of the word to be transferred as 8 bit.
148 *
149 * This function initializes the SPI controller to disable and clear all the
150 * interrupts, enable manual target select and manual start, deselect all the
151 * chip select lines, and enable the SPI controller.
152 */
cdns_spi_init_hw(struct cdns_spi * xspi,bool is_target)153 static void cdns_spi_init_hw(struct cdns_spi *xspi, bool is_target)
154 {
155 u32 ctrl_reg = 0;
156
157 if (!is_target)
158 ctrl_reg |= CDNS_SPI_CR_DEFAULT;
159
160 if (xspi->is_decoded_cs)
161 ctrl_reg |= CDNS_SPI_CR_PERI_SEL;
162
163 cdns_spi_write(xspi, CDNS_SPI_ER, CDNS_SPI_ER_DISABLE);
164 cdns_spi_write(xspi, CDNS_SPI_IDR, CDNS_SPI_IXR_ALL);
165
166 /* Clear the RX FIFO */
167 while (cdns_spi_read(xspi, CDNS_SPI_ISR) & CDNS_SPI_IXR_RXNEMTY)
168 cdns_spi_read(xspi, CDNS_SPI_RXD);
169
170 cdns_spi_write(xspi, CDNS_SPI_ISR, CDNS_SPI_IXR_ALL);
171 cdns_spi_write(xspi, CDNS_SPI_CR, ctrl_reg);
172 cdns_spi_write(xspi, CDNS_SPI_ER, CDNS_SPI_ER_ENABLE);
173 }
174
175 /**
176 * cdns_spi_chipselect - Select or deselect the chip select line
177 * @spi: Pointer to the spi_device structure
178 * @is_high: Select(0) or deselect (1) the chip select line
179 */
cdns_spi_chipselect(struct spi_device * spi,bool is_high)180 static void cdns_spi_chipselect(struct spi_device *spi, bool is_high)
181 {
182 struct cdns_spi *xspi = spi_controller_get_devdata(spi->controller);
183 u32 ctrl_reg;
184
185 ctrl_reg = cdns_spi_read(xspi, CDNS_SPI_CR);
186
187 if (is_high) {
188 /* Deselect the target */
189 ctrl_reg |= CDNS_SPI_CR_SSCTRL;
190 } else {
191 /* Select the target */
192 ctrl_reg &= ~CDNS_SPI_CR_SSCTRL;
193 if (!(xspi->is_decoded_cs))
194 ctrl_reg |= ((~(CDNS_SPI_SS0 << spi_get_chipselect(spi, 0))) <<
195 CDNS_SPI_SS_SHIFT) &
196 CDNS_SPI_CR_SSCTRL;
197 else
198 ctrl_reg |= (spi_get_chipselect(spi, 0) << CDNS_SPI_SS_SHIFT) &
199 CDNS_SPI_CR_SSCTRL;
200 }
201
202 cdns_spi_write(xspi, CDNS_SPI_CR, ctrl_reg);
203 }
204
205 /**
206 * cdns_spi_config_clock_mode - Sets clock polarity and phase
207 * @spi: Pointer to the spi_device structure
208 *
209 * Sets the requested clock polarity and phase.
210 */
cdns_spi_config_clock_mode(struct spi_device * spi)211 static void cdns_spi_config_clock_mode(struct spi_device *spi)
212 {
213 struct cdns_spi *xspi = spi_controller_get_devdata(spi->controller);
214 u32 ctrl_reg, new_ctrl_reg;
215
216 new_ctrl_reg = cdns_spi_read(xspi, CDNS_SPI_CR);
217 ctrl_reg = new_ctrl_reg;
218
219 /* Set the SPI clock phase and clock polarity */
220 new_ctrl_reg &= ~(CDNS_SPI_CR_CPHA | CDNS_SPI_CR_CPOL);
221 if (spi->mode & SPI_CPHA)
222 new_ctrl_reg |= CDNS_SPI_CR_CPHA;
223 if (spi->mode & SPI_CPOL)
224 new_ctrl_reg |= CDNS_SPI_CR_CPOL;
225
226 if (new_ctrl_reg != ctrl_reg) {
227 /*
228 * Just writing the CR register does not seem to apply the clock
229 * setting changes. This is problematic when changing the clock
230 * polarity as it will cause the SPI target to see spurious clock
231 * transitions. To workaround the issue toggle the ER register.
232 */
233 cdns_spi_write(xspi, CDNS_SPI_ER, CDNS_SPI_ER_DISABLE);
234 cdns_spi_write(xspi, CDNS_SPI_CR, new_ctrl_reg);
235 cdns_spi_write(xspi, CDNS_SPI_ER, CDNS_SPI_ER_ENABLE);
236 }
237 }
238
239 /**
240 * cdns_spi_config_clock_freq - Sets clock frequency
241 * @spi: Pointer to the spi_device structure
242 * @transfer: Pointer to the spi_transfer structure which provides
243 * information about next transfer setup parameters
244 *
245 * Sets the requested clock frequency.
246 * Note: If the requested frequency is not an exact match with what can be
247 * obtained using the prescalar value the driver sets the clock frequency which
248 * is lower than the requested frequency (maximum lower) for the transfer. If
249 * the requested frequency is higher or lower than that is supported by the SPI
250 * controller the driver will set the highest or lowest frequency supported by
251 * controller.
252 */
cdns_spi_config_clock_freq(struct spi_device * spi,struct spi_transfer * transfer)253 static void cdns_spi_config_clock_freq(struct spi_device *spi,
254 struct spi_transfer *transfer)
255 {
256 struct cdns_spi *xspi = spi_controller_get_devdata(spi->controller);
257 u32 ctrl_reg, baud_rate_val;
258 unsigned long frequency;
259
260 frequency = xspi->clk_rate;
261
262 ctrl_reg = cdns_spi_read(xspi, CDNS_SPI_CR);
263
264 /* Set the clock frequency */
265 if (xspi->speed_hz != transfer->speed_hz) {
266 /* first valid value is 1 */
267 baud_rate_val = CDNS_SPI_BAUD_DIV_MIN;
268 while ((baud_rate_val < CDNS_SPI_BAUD_DIV_MAX) &&
269 (frequency / (2 << baud_rate_val)) > transfer->speed_hz)
270 baud_rate_val++;
271
272 ctrl_reg &= ~CDNS_SPI_CR_BAUD_DIV;
273 ctrl_reg |= baud_rate_val << CDNS_SPI_BAUD_DIV_SHIFT;
274
275 xspi->speed_hz = frequency / (2 << baud_rate_val);
276 }
277 cdns_spi_write(xspi, CDNS_SPI_CR, ctrl_reg);
278 }
279
280 /**
281 * cdns_spi_setup_transfer - Configure SPI controller for specified transfer
282 * @spi: Pointer to the spi_device structure
283 * @transfer: Pointer to the spi_transfer structure which provides
284 * information about next transfer setup parameters
285 *
286 * Sets the operational mode of SPI controller for the next SPI transfer and
287 * sets the requested clock frequency.
288 *
289 * Return: Always 0
290 */
cdns_spi_setup_transfer(struct spi_device * spi,struct spi_transfer * transfer)291 static int cdns_spi_setup_transfer(struct spi_device *spi,
292 struct spi_transfer *transfer)
293 {
294 struct cdns_spi *xspi = spi_controller_get_devdata(spi->controller);
295
296 cdns_spi_config_clock_freq(spi, transfer);
297
298 dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u clock speed\n",
299 __func__, spi->mode, spi->bits_per_word,
300 xspi->speed_hz);
301
302 return 0;
303 }
304
305 /**
306 * cdns_spi_process_fifo - Fills the TX FIFO, and drain the RX FIFO
307 * @xspi: Pointer to the cdns_spi structure
308 * @ntx: Number of bytes to pack into the TX FIFO
309 * @nrx: Number of bytes to drain from the RX FIFO
310 */
cdns_spi_process_fifo(struct cdns_spi * xspi,int ntx,int nrx)311 static void cdns_spi_process_fifo(struct cdns_spi *xspi, int ntx, int nrx)
312 {
313 ntx = clamp(ntx, 0, xspi->tx_bytes);
314 nrx = clamp(nrx, 0, xspi->rx_bytes);
315
316 xspi->tx_bytes -= ntx;
317 xspi->rx_bytes -= nrx;
318
319 while (ntx || nrx) {
320 if (nrx) {
321 u8 data = cdns_spi_read(xspi, CDNS_SPI_RXD);
322
323 if (xspi->rxbuf)
324 *xspi->rxbuf++ = data;
325
326 nrx--;
327 }
328
329 if (ntx) {
330 if (xspi->txbuf)
331 cdns_spi_write(xspi, CDNS_SPI_TXD, *xspi->txbuf++);
332 else
333 cdns_spi_write(xspi, CDNS_SPI_TXD, 0);
334
335 ntx--;
336 }
337
338 }
339 }
340
341 /**
342 * cdns_spi_irq - Interrupt service routine of the SPI controller
343 * @irq: IRQ number
344 * @dev_id: Pointer to the xspi structure
345 *
346 * This function handles TX empty and Mode Fault interrupts only.
347 * On TX empty interrupt this function reads the received data from RX FIFO and
348 * fills the TX FIFO if there is any data remaining to be transferred.
349 * On Mode Fault interrupt this function indicates that transfer is completed,
350 * the SPI subsystem will identify the error as the remaining bytes to be
351 * transferred is non-zero.
352 *
353 * Return: IRQ_HANDLED when handled; IRQ_NONE otherwise.
354 */
cdns_spi_irq(int irq,void * dev_id)355 static irqreturn_t cdns_spi_irq(int irq, void *dev_id)
356 {
357 struct spi_controller *ctlr = dev_id;
358 struct cdns_spi *xspi = spi_controller_get_devdata(ctlr);
359 irqreturn_t status;
360 u32 intr_status;
361
362 status = IRQ_NONE;
363 intr_status = cdns_spi_read(xspi, CDNS_SPI_ISR);
364 cdns_spi_write(xspi, CDNS_SPI_ISR, intr_status);
365
366 if (intr_status & CDNS_SPI_IXR_MODF) {
367 /* Indicate that transfer is completed, the SPI subsystem will
368 * identify the error as the remaining bytes to be
369 * transferred is non-zero
370 */
371 cdns_spi_write(xspi, CDNS_SPI_IDR, CDNS_SPI_IXR_DEFAULT);
372 spi_finalize_current_transfer(ctlr);
373 status = IRQ_HANDLED;
374 } else if (intr_status & CDNS_SPI_IXR_TXOW) {
375 int threshold = cdns_spi_read(xspi, CDNS_SPI_THLD);
376 int trans_cnt = xspi->rx_bytes - xspi->tx_bytes;
377
378 if (threshold > 1)
379 trans_cnt -= threshold;
380
381 /* Set threshold to one if number of pending are
382 * less than half fifo
383 */
384 if (xspi->tx_bytes < xspi->tx_fifo_depth >> 1)
385 cdns_spi_write(xspi, CDNS_SPI_THLD, 1);
386
387 if (xspi->tx_bytes) {
388 cdns_spi_process_fifo(xspi, trans_cnt, trans_cnt);
389 } else {
390 /* Fixed delay due to controller limitation with
391 * RX_NEMPTY incorrect status
392 * Xilinx AR:65885 contains more details
393 */
394 udelay(10);
395 cdns_spi_process_fifo(xspi, 0, trans_cnt);
396 cdns_spi_write(xspi, CDNS_SPI_IDR,
397 CDNS_SPI_IXR_DEFAULT);
398 spi_finalize_current_transfer(ctlr);
399 }
400 status = IRQ_HANDLED;
401 }
402
403 return status;
404 }
405
cdns_prepare_message(struct spi_controller * ctlr,struct spi_message * msg)406 static int cdns_prepare_message(struct spi_controller *ctlr,
407 struct spi_message *msg)
408 {
409 if (!spi_controller_is_target(ctlr))
410 cdns_spi_config_clock_mode(msg->spi);
411 return 0;
412 }
413
414 /**
415 * cdns_transfer_one - Initiates the SPI transfer
416 * @ctlr: Pointer to spi_controller structure
417 * @spi: Pointer to the spi_device structure
418 * @transfer: Pointer to the spi_transfer structure which provides
419 * information about next transfer parameters
420 *
421 * This function in host mode fills the TX FIFO, starts the SPI transfer and
422 * returns a positive transfer count so that core will wait for completion.
423 * This function in target mode fills the TX FIFO and wait for transfer trigger.
424 *
425 * Return: Number of bytes transferred in the last transfer
426 */
cdns_transfer_one(struct spi_controller * ctlr,struct spi_device * spi,struct spi_transfer * transfer)427 static int cdns_transfer_one(struct spi_controller *ctlr,
428 struct spi_device *spi,
429 struct spi_transfer *transfer)
430 {
431 struct cdns_spi *xspi = spi_controller_get_devdata(ctlr);
432
433 xspi->txbuf = transfer->tx_buf;
434 xspi->rxbuf = transfer->rx_buf;
435 xspi->tx_bytes = transfer->len;
436 xspi->rx_bytes = transfer->len;
437
438 if (!spi_controller_is_target(ctlr)) {
439 cdns_spi_setup_transfer(spi, transfer);
440 } else {
441 /* Set TX empty threshold to half of FIFO depth
442 * only if TX bytes are more than FIFO depth.
443 */
444 if (xspi->tx_bytes > xspi->tx_fifo_depth)
445 cdns_spi_write(xspi, CDNS_SPI_THLD, xspi->tx_fifo_depth >> 1);
446 }
447
448 /* When xspi in busy condition, bytes may send failed,
449 * then spi control didn't work thoroughly, add one byte delay
450 */
451 if (cdns_spi_read(xspi, CDNS_SPI_ISR) & CDNS_SPI_IXR_TXFULL)
452 udelay(10);
453
454 cdns_spi_process_fifo(xspi, xspi->tx_fifo_depth, 0);
455
456 cdns_spi_write(xspi, CDNS_SPI_IER, CDNS_SPI_IXR_DEFAULT);
457 return transfer->len;
458 }
459
460 /**
461 * cdns_prepare_transfer_hardware - Prepares hardware for transfer.
462 * @ctlr: Pointer to the spi_controller structure which provides
463 * information about the controller.
464 *
465 * This function enables SPI host controller.
466 *
467 * Return: 0 always
468 */
cdns_prepare_transfer_hardware(struct spi_controller * ctlr)469 static int cdns_prepare_transfer_hardware(struct spi_controller *ctlr)
470 {
471 struct cdns_spi *xspi = spi_controller_get_devdata(ctlr);
472
473 cdns_spi_write(xspi, CDNS_SPI_ER, CDNS_SPI_ER_ENABLE);
474
475 return 0;
476 }
477
478 /**
479 * cdns_unprepare_transfer_hardware - Relaxes hardware after transfer
480 * @ctlr: Pointer to the spi_controller structure which provides
481 * information about the controller.
482 *
483 * This function disables the SPI host controller when no target selected.
484 * This function flush out if any pending data in FIFO.
485 *
486 * Return: 0 always
487 */
cdns_unprepare_transfer_hardware(struct spi_controller * ctlr)488 static int cdns_unprepare_transfer_hardware(struct spi_controller *ctlr)
489 {
490 struct cdns_spi *xspi = spi_controller_get_devdata(ctlr);
491 u32 ctrl_reg;
492 unsigned int cnt = xspi->tx_fifo_depth;
493
494 if (spi_controller_is_target(ctlr)) {
495 while (cnt--)
496 cdns_spi_read(xspi, CDNS_SPI_RXD);
497 }
498
499 /* Disable the SPI if target is deselected */
500 ctrl_reg = cdns_spi_read(xspi, CDNS_SPI_CR);
501 ctrl_reg = (ctrl_reg & CDNS_SPI_CR_SSCTRL) >> CDNS_SPI_SS_SHIFT;
502 if (ctrl_reg == CDNS_SPI_NOSS || spi_controller_is_target(ctlr))
503 cdns_spi_write(xspi, CDNS_SPI_ER, CDNS_SPI_ER_DISABLE);
504
505 /* Reset to default */
506 cdns_spi_write(xspi, CDNS_SPI_THLD, 0x1);
507 return 0;
508 }
509
510 /**
511 * cdns_spi_detect_fifo_depth - Detect the FIFO depth of the hardware
512 * @xspi: Pointer to the cdns_spi structure
513 *
514 * The depth of the TX FIFO is a synthesis configuration parameter of the SPI
515 * IP. The FIFO threshold register is sized so that its maximum value can be the
516 * FIFO size - 1. This is used to detect the size of the FIFO.
517 */
cdns_spi_detect_fifo_depth(struct cdns_spi * xspi)518 static void cdns_spi_detect_fifo_depth(struct cdns_spi *xspi)
519 {
520 /* The MSBs will get truncated giving us the size of the FIFO */
521 cdns_spi_write(xspi, CDNS_SPI_THLD, 0xffff);
522 xspi->tx_fifo_depth = cdns_spi_read(xspi, CDNS_SPI_THLD) + 1;
523
524 /* Reset to default */
525 cdns_spi_write(xspi, CDNS_SPI_THLD, 0x1);
526 }
527
528 /**
529 * cdns_target_abort - Abort target transfer
530 * @ctlr: Pointer to the spi_controller structure
531 *
532 * This function abort target transfer if there any transfer timeout.
533 *
534 * Return: 0 always
535 */
cdns_target_abort(struct spi_controller * ctlr)536 static int cdns_target_abort(struct spi_controller *ctlr)
537 {
538 struct cdns_spi *xspi = spi_controller_get_devdata(ctlr);
539 u32 intr_status;
540
541 intr_status = cdns_spi_read(xspi, CDNS_SPI_ISR);
542 cdns_spi_write(xspi, CDNS_SPI_ISR, intr_status);
543 cdns_spi_write(xspi, CDNS_SPI_IDR, (CDNS_SPI_IXR_MODF | CDNS_SPI_IXR_RXNEMTY));
544 spi_finalize_current_transfer(ctlr);
545
546 return 0;
547 }
548
549 /**
550 * cdns_spi_probe - Probe method for the SPI driver
551 * @pdev: Pointer to the platform_device structure
552 *
553 * This function initializes the driver data structures and the hardware.
554 *
555 * Return: 0 on success and error value on error
556 */
cdns_spi_probe(struct platform_device * pdev)557 static int cdns_spi_probe(struct platform_device *pdev)
558 {
559 int ret = 0, irq;
560 struct spi_controller *ctlr;
561 struct cdns_spi *xspi;
562 u32 num_cs;
563 bool target;
564
565 target = of_property_read_bool(pdev->dev.of_node, "spi-slave");
566 if (target)
567 ctlr = spi_alloc_target(&pdev->dev, sizeof(*xspi));
568 else
569 ctlr = spi_alloc_host(&pdev->dev, sizeof(*xspi));
570
571 if (!ctlr)
572 return -ENOMEM;
573
574 xspi = spi_controller_get_devdata(ctlr);
575 ctlr->dev.of_node = pdev->dev.of_node;
576 platform_set_drvdata(pdev, ctlr);
577
578 xspi->regs = devm_platform_ioremap_resource(pdev, 0);
579 if (IS_ERR(xspi->regs)) {
580 ret = PTR_ERR(xspi->regs);
581 goto remove_ctlr;
582 }
583
584 xspi->pclk = devm_clk_get_enabled(&pdev->dev, "pclk");
585 if (IS_ERR(xspi->pclk)) {
586 dev_err(&pdev->dev, "pclk clock not found.\n");
587 ret = PTR_ERR(xspi->pclk);
588 goto remove_ctlr;
589 }
590
591 if (!spi_controller_is_target(ctlr)) {
592 xspi->ref_clk = devm_clk_get_enabled(&pdev->dev, "ref_clk");
593 if (IS_ERR(xspi->ref_clk)) {
594 dev_err(&pdev->dev, "ref_clk clock not found.\n");
595 ret = PTR_ERR(xspi->ref_clk);
596 goto remove_ctlr;
597 }
598
599 pm_runtime_use_autosuspend(&pdev->dev);
600 pm_runtime_set_autosuspend_delay(&pdev->dev, SPI_AUTOSUSPEND_TIMEOUT);
601 pm_runtime_get_noresume(&pdev->dev);
602 pm_runtime_set_active(&pdev->dev);
603 pm_runtime_enable(&pdev->dev);
604
605 ret = of_property_read_u32(pdev->dev.of_node, "num-cs", &num_cs);
606 if (ret < 0)
607 ctlr->num_chipselect = CDNS_SPI_DEFAULT_NUM_CS;
608 else
609 ctlr->num_chipselect = num_cs;
610
611 ret = of_property_read_u32(pdev->dev.of_node, "is-decoded-cs",
612 &xspi->is_decoded_cs);
613 if (ret < 0)
614 xspi->is_decoded_cs = 0;
615 }
616
617 cdns_spi_detect_fifo_depth(xspi);
618
619 /* SPI controller initializations */
620 cdns_spi_init_hw(xspi, spi_controller_is_target(ctlr));
621
622 irq = platform_get_irq(pdev, 0);
623 if (irq < 0) {
624 ret = irq;
625 goto clk_dis_all;
626 }
627
628 ret = devm_request_irq(&pdev->dev, irq, cdns_spi_irq,
629 0, pdev->name, ctlr);
630 if (ret != 0) {
631 ret = -ENXIO;
632 dev_err(&pdev->dev, "request_irq failed\n");
633 goto clk_dis_all;
634 }
635
636 ctlr->use_gpio_descriptors = true;
637 ctlr->prepare_transfer_hardware = cdns_prepare_transfer_hardware;
638 ctlr->prepare_message = cdns_prepare_message;
639 ctlr->transfer_one = cdns_transfer_one;
640 ctlr->unprepare_transfer_hardware = cdns_unprepare_transfer_hardware;
641 ctlr->mode_bits = SPI_CPOL | SPI_CPHA;
642 ctlr->bits_per_word_mask = SPI_BPW_MASK(8);
643
644 if (!spi_controller_is_target(ctlr)) {
645 ctlr->mode_bits |= SPI_CS_HIGH;
646 ctlr->set_cs = cdns_spi_chipselect;
647 ctlr->auto_runtime_pm = true;
648 xspi->clk_rate = clk_get_rate(xspi->ref_clk);
649 /* Set to default valid value */
650 ctlr->max_speed_hz = xspi->clk_rate / 4;
651 xspi->speed_hz = ctlr->max_speed_hz;
652 pm_runtime_mark_last_busy(&pdev->dev);
653 pm_runtime_put_autosuspend(&pdev->dev);
654 } else {
655 ctlr->mode_bits |= SPI_NO_CS;
656 ctlr->target_abort = cdns_target_abort;
657 }
658 ret = spi_register_controller(ctlr);
659 if (ret) {
660 dev_err(&pdev->dev, "spi_register_controller failed\n");
661 goto clk_dis_all;
662 }
663
664 return ret;
665
666 clk_dis_all:
667 if (!spi_controller_is_target(ctlr)) {
668 pm_runtime_disable(&pdev->dev);
669 pm_runtime_set_suspended(&pdev->dev);
670 }
671 remove_ctlr:
672 spi_controller_put(ctlr);
673 return ret;
674 }
675
676 /**
677 * cdns_spi_remove - Remove method for the SPI driver
678 * @pdev: Pointer to the platform_device structure
679 *
680 * This function is called if a device is physically removed from the system or
681 * if the driver module is being unloaded. It frees all resources allocated to
682 * the device.
683 */
cdns_spi_remove(struct platform_device * pdev)684 static void cdns_spi_remove(struct platform_device *pdev)
685 {
686 struct spi_controller *ctlr = platform_get_drvdata(pdev);
687 struct cdns_spi *xspi = spi_controller_get_devdata(ctlr);
688
689 cdns_spi_write(xspi, CDNS_SPI_ER, CDNS_SPI_ER_DISABLE);
690
691 if (!spi_controller_is_target(ctlr)) {
692 pm_runtime_disable(&pdev->dev);
693 pm_runtime_set_suspended(&pdev->dev);
694 }
695
696 spi_unregister_controller(ctlr);
697 }
698
699 /**
700 * cdns_spi_suspend - Suspend method for the SPI driver
701 * @dev: Address of the platform_device structure
702 *
703 * This function disables the SPI controller and
704 * changes the driver state to "suspend"
705 *
706 * Return: 0 on success and error value on error
707 */
cdns_spi_suspend(struct device * dev)708 static int __maybe_unused cdns_spi_suspend(struct device *dev)
709 {
710 struct spi_controller *ctlr = dev_get_drvdata(dev);
711
712 return spi_controller_suspend(ctlr);
713 }
714
715 /**
716 * cdns_spi_resume - Resume method for the SPI driver
717 * @dev: Address of the platform_device structure
718 *
719 * This function changes the driver state to "ready"
720 *
721 * Return: 0 on success and error value on error
722 */
cdns_spi_resume(struct device * dev)723 static int __maybe_unused cdns_spi_resume(struct device *dev)
724 {
725 struct spi_controller *ctlr = dev_get_drvdata(dev);
726 struct cdns_spi *xspi = spi_controller_get_devdata(ctlr);
727
728 cdns_spi_init_hw(xspi, spi_controller_is_target(ctlr));
729 return spi_controller_resume(ctlr);
730 }
731
732 /**
733 * cdns_spi_runtime_resume - Runtime resume method for the SPI driver
734 * @dev: Address of the platform_device structure
735 *
736 * This function enables the clocks
737 *
738 * Return: 0 on success and error value on error
739 */
cdns_spi_runtime_resume(struct device * dev)740 static int __maybe_unused cdns_spi_runtime_resume(struct device *dev)
741 {
742 struct spi_controller *ctlr = dev_get_drvdata(dev);
743 struct cdns_spi *xspi = spi_controller_get_devdata(ctlr);
744 int ret;
745
746 ret = clk_prepare_enable(xspi->pclk);
747 if (ret) {
748 dev_err(dev, "Cannot enable APB clock.\n");
749 return ret;
750 }
751
752 ret = clk_prepare_enable(xspi->ref_clk);
753 if (ret) {
754 dev_err(dev, "Cannot enable device clock.\n");
755 clk_disable_unprepare(xspi->pclk);
756 return ret;
757 }
758 return 0;
759 }
760
761 /**
762 * cdns_spi_runtime_suspend - Runtime suspend method for the SPI driver
763 * @dev: Address of the platform_device structure
764 *
765 * This function disables the clocks
766 *
767 * Return: Always 0
768 */
cdns_spi_runtime_suspend(struct device * dev)769 static int __maybe_unused cdns_spi_runtime_suspend(struct device *dev)
770 {
771 struct spi_controller *ctlr = dev_get_drvdata(dev);
772 struct cdns_spi *xspi = spi_controller_get_devdata(ctlr);
773
774 clk_disable_unprepare(xspi->ref_clk);
775 clk_disable_unprepare(xspi->pclk);
776
777 return 0;
778 }
779
780 static const struct dev_pm_ops cdns_spi_dev_pm_ops = {
781 SET_RUNTIME_PM_OPS(cdns_spi_runtime_suspend,
782 cdns_spi_runtime_resume, NULL)
783 SET_SYSTEM_SLEEP_PM_OPS(cdns_spi_suspend, cdns_spi_resume)
784 };
785
786 static const struct of_device_id cdns_spi_of_match[] = {
787 { .compatible = "xlnx,zynq-spi-r1p6" },
788 { .compatible = "cdns,spi-r1p6" },
789 { /* end of table */ }
790 };
791 MODULE_DEVICE_TABLE(of, cdns_spi_of_match);
792
793 /* cdns_spi_driver - This structure defines the SPI subsystem platform driver */
794 static struct platform_driver cdns_spi_driver = {
795 .probe = cdns_spi_probe,
796 .remove_new = cdns_spi_remove,
797 .driver = {
798 .name = CDNS_SPI_NAME,
799 .of_match_table = cdns_spi_of_match,
800 .pm = &cdns_spi_dev_pm_ops,
801 },
802 };
803
804 module_platform_driver(cdns_spi_driver);
805
806 MODULE_AUTHOR("Xilinx, Inc.");
807 MODULE_DESCRIPTION("Cadence SPI driver");
808 MODULE_LICENSE("GPL");
809