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[mirror_ubuntu-jammy-kernel.git] / drivers / spi / spi-tegra20-slink.c
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * SPI driver for Nvidia's Tegra20/Tegra30 SLINK Controller.
4 *
5 * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
6 */
7
8 #include <linux/clk.h>
9 #include <linux/completion.h>
10 #include <linux/delay.h>
11 #include <linux/dmaengine.h>
12 #include <linux/dma-mapping.h>
13 #include <linux/dmapool.h>
14 #include <linux/err.h>
15 #include <linux/interrupt.h>
16 #include <linux/io.h>
17 #include <linux/kernel.h>
18 #include <linux/kthread.h>
19 #include <linux/module.h>
20 #include <linux/platform_device.h>
21 #include <linux/pm_runtime.h>
22 #include <linux/of.h>
23 #include <linux/of_device.h>
24 #include <linux/reset.h>
25 #include <linux/spi/spi.h>
26
27 #define SLINK_COMMAND 0x000
28 #define SLINK_BIT_LENGTH(x) (((x) & 0x1f) << 0)
29 #define SLINK_WORD_SIZE(x) (((x) & 0x1f) << 5)
30 #define SLINK_BOTH_EN (1 << 10)
31 #define SLINK_CS_SW (1 << 11)
32 #define SLINK_CS_VALUE (1 << 12)
33 #define SLINK_CS_POLARITY (1 << 13)
34 #define SLINK_IDLE_SDA_DRIVE_LOW (0 << 16)
35 #define SLINK_IDLE_SDA_DRIVE_HIGH (1 << 16)
36 #define SLINK_IDLE_SDA_PULL_LOW (2 << 16)
37 #define SLINK_IDLE_SDA_PULL_HIGH (3 << 16)
38 #define SLINK_IDLE_SDA_MASK (3 << 16)
39 #define SLINK_CS_POLARITY1 (1 << 20)
40 #define SLINK_CK_SDA (1 << 21)
41 #define SLINK_CS_POLARITY2 (1 << 22)
42 #define SLINK_CS_POLARITY3 (1 << 23)
43 #define SLINK_IDLE_SCLK_DRIVE_LOW (0 << 24)
44 #define SLINK_IDLE_SCLK_DRIVE_HIGH (1 << 24)
45 #define SLINK_IDLE_SCLK_PULL_LOW (2 << 24)
46 #define SLINK_IDLE_SCLK_PULL_HIGH (3 << 24)
47 #define SLINK_IDLE_SCLK_MASK (3 << 24)
48 #define SLINK_M_S (1 << 28)
49 #define SLINK_WAIT (1 << 29)
50 #define SLINK_GO (1 << 30)
51 #define SLINK_ENB (1 << 31)
52
53 #define SLINK_MODES (SLINK_IDLE_SCLK_MASK | SLINK_CK_SDA)
54
55 #define SLINK_COMMAND2 0x004
56 #define SLINK_LSBFE (1 << 0)
57 #define SLINK_SSOE (1 << 1)
58 #define SLINK_SPIE (1 << 4)
59 #define SLINK_BIDIROE (1 << 6)
60 #define SLINK_MODFEN (1 << 7)
61 #define SLINK_INT_SIZE(x) (((x) & 0x1f) << 8)
62 #define SLINK_CS_ACTIVE_BETWEEN (1 << 17)
63 #define SLINK_SS_EN_CS(x) (((x) & 0x3) << 18)
64 #define SLINK_SS_SETUP(x) (((x) & 0x3) << 20)
65 #define SLINK_FIFO_REFILLS_0 (0 << 22)
66 #define SLINK_FIFO_REFILLS_1 (1 << 22)
67 #define SLINK_FIFO_REFILLS_2 (2 << 22)
68 #define SLINK_FIFO_REFILLS_3 (3 << 22)
69 #define SLINK_FIFO_REFILLS_MASK (3 << 22)
70 #define SLINK_WAIT_PACK_INT(x) (((x) & 0x7) << 26)
71 #define SLINK_SPC0 (1 << 29)
72 #define SLINK_TXEN (1 << 30)
73 #define SLINK_RXEN (1 << 31)
74
75 #define SLINK_STATUS 0x008
76 #define SLINK_COUNT(val) (((val) >> 0) & 0x1f)
77 #define SLINK_WORD(val) (((val) >> 5) & 0x1f)
78 #define SLINK_BLK_CNT(val) (((val) >> 0) & 0xffff)
79 #define SLINK_MODF (1 << 16)
80 #define SLINK_RX_UNF (1 << 18)
81 #define SLINK_TX_OVF (1 << 19)
82 #define SLINK_TX_FULL (1 << 20)
83 #define SLINK_TX_EMPTY (1 << 21)
84 #define SLINK_RX_FULL (1 << 22)
85 #define SLINK_RX_EMPTY (1 << 23)
86 #define SLINK_TX_UNF (1 << 24)
87 #define SLINK_RX_OVF (1 << 25)
88 #define SLINK_TX_FLUSH (1 << 26)
89 #define SLINK_RX_FLUSH (1 << 27)
90 #define SLINK_SCLK (1 << 28)
91 #define SLINK_ERR (1 << 29)
92 #define SLINK_RDY (1 << 30)
93 #define SLINK_BSY (1 << 31)
94 #define SLINK_FIFO_ERROR (SLINK_TX_OVF | SLINK_RX_UNF | \
95 SLINK_TX_UNF | SLINK_RX_OVF)
96
97 #define SLINK_FIFO_EMPTY (SLINK_TX_EMPTY | SLINK_RX_EMPTY)
98
99 #define SLINK_MAS_DATA 0x010
100 #define SLINK_SLAVE_DATA 0x014
101
102 #define SLINK_DMA_CTL 0x018
103 #define SLINK_DMA_BLOCK_SIZE(x) (((x) & 0xffff) << 0)
104 #define SLINK_TX_TRIG_1 (0 << 16)
105 #define SLINK_TX_TRIG_4 (1 << 16)
106 #define SLINK_TX_TRIG_8 (2 << 16)
107 #define SLINK_TX_TRIG_16 (3 << 16)
108 #define SLINK_TX_TRIG_MASK (3 << 16)
109 #define SLINK_RX_TRIG_1 (0 << 18)
110 #define SLINK_RX_TRIG_4 (1 << 18)
111 #define SLINK_RX_TRIG_8 (2 << 18)
112 #define SLINK_RX_TRIG_16 (3 << 18)
113 #define SLINK_RX_TRIG_MASK (3 << 18)
114 #define SLINK_PACKED (1 << 20)
115 #define SLINK_PACK_SIZE_4 (0 << 21)
116 #define SLINK_PACK_SIZE_8 (1 << 21)
117 #define SLINK_PACK_SIZE_16 (2 << 21)
118 #define SLINK_PACK_SIZE_32 (3 << 21)
119 #define SLINK_PACK_SIZE_MASK (3 << 21)
120 #define SLINK_IE_TXC (1 << 26)
121 #define SLINK_IE_RXC (1 << 27)
122 #define SLINK_DMA_EN (1 << 31)
123
124 #define SLINK_STATUS2 0x01c
125 #define SLINK_TX_FIFO_EMPTY_COUNT(val) (((val) & 0x3f) >> 0)
126 #define SLINK_RX_FIFO_FULL_COUNT(val) (((val) & 0x3f0000) >> 16)
127 #define SLINK_SS_HOLD_TIME(val) (((val) & 0xF) << 6)
128
129 #define SLINK_TX_FIFO 0x100
130 #define SLINK_RX_FIFO 0x180
131
132 #define DATA_DIR_TX (1 << 0)
133 #define DATA_DIR_RX (1 << 1)
134
135 #define SLINK_DMA_TIMEOUT (msecs_to_jiffies(1000))
136
137 #define DEFAULT_SPI_DMA_BUF_LEN (16*1024)
138 #define TX_FIFO_EMPTY_COUNT_MAX SLINK_TX_FIFO_EMPTY_COUNT(0x20)
139 #define RX_FIFO_FULL_COUNT_ZERO SLINK_RX_FIFO_FULL_COUNT(0)
140
141 #define SLINK_STATUS2_RESET \
142 (TX_FIFO_EMPTY_COUNT_MAX | RX_FIFO_FULL_COUNT_ZERO << 16)
143
144 #define MAX_CHIP_SELECT 4
145 #define SLINK_FIFO_DEPTH 32
146
147 struct tegra_slink_chip_data {
148 bool cs_hold_time;
149 };
150
151 struct tegra_slink_data {
152 struct device *dev;
153 struct spi_master *master;
154 const struct tegra_slink_chip_data *chip_data;
155 spinlock_t lock;
156
157 struct clk *clk;
158 struct reset_control *rst;
159 void __iomem *base;
160 phys_addr_t phys;
161 unsigned irq;
162 u32 cur_speed;
163
164 struct spi_device *cur_spi;
165 unsigned cur_pos;
166 unsigned cur_len;
167 unsigned words_per_32bit;
168 unsigned bytes_per_word;
169 unsigned curr_dma_words;
170 unsigned cur_direction;
171
172 unsigned cur_rx_pos;
173 unsigned cur_tx_pos;
174
175 unsigned dma_buf_size;
176 unsigned max_buf_size;
177 bool is_curr_dma_xfer;
178
179 struct completion rx_dma_complete;
180 struct completion tx_dma_complete;
181
182 u32 tx_status;
183 u32 rx_status;
184 u32 status_reg;
185 bool is_packed;
186 u32 packed_size;
187
188 u32 command_reg;
189 u32 command2_reg;
190 u32 dma_control_reg;
191 u32 def_command_reg;
192 u32 def_command2_reg;
193
194 struct completion xfer_completion;
195 struct spi_transfer *curr_xfer;
196 struct dma_chan *rx_dma_chan;
197 u32 *rx_dma_buf;
198 dma_addr_t rx_dma_phys;
199 struct dma_async_tx_descriptor *rx_dma_desc;
200
201 struct dma_chan *tx_dma_chan;
202 u32 *tx_dma_buf;
203 dma_addr_t tx_dma_phys;
204 struct dma_async_tx_descriptor *tx_dma_desc;
205 };
206
207 static inline u32 tegra_slink_readl(struct tegra_slink_data *tspi,
208 unsigned long reg)
209 {
210 return readl(tspi->base + reg);
211 }
212
213 static inline void tegra_slink_writel(struct tegra_slink_data *tspi,
214 u32 val, unsigned long reg)
215 {
216 writel(val, tspi->base + reg);
217
218 /* Read back register to make sure that register writes completed */
219 if (reg != SLINK_TX_FIFO)
220 readl(tspi->base + SLINK_MAS_DATA);
221 }
222
223 static void tegra_slink_clear_status(struct tegra_slink_data *tspi)
224 {
225 u32 val_write;
226
227 tegra_slink_readl(tspi, SLINK_STATUS);
228
229 /* Write 1 to clear status register */
230 val_write = SLINK_RDY | SLINK_FIFO_ERROR;
231 tegra_slink_writel(tspi, val_write, SLINK_STATUS);
232 }
233
234 static u32 tegra_slink_get_packed_size(struct tegra_slink_data *tspi,
235 struct spi_transfer *t)
236 {
237 switch (tspi->bytes_per_word) {
238 case 0:
239 return SLINK_PACK_SIZE_4;
240 case 1:
241 return SLINK_PACK_SIZE_8;
242 case 2:
243 return SLINK_PACK_SIZE_16;
244 case 4:
245 return SLINK_PACK_SIZE_32;
246 default:
247 return 0;
248 }
249 }
250
251 static unsigned tegra_slink_calculate_curr_xfer_param(
252 struct spi_device *spi, struct tegra_slink_data *tspi,
253 struct spi_transfer *t)
254 {
255 unsigned remain_len = t->len - tspi->cur_pos;
256 unsigned max_word;
257 unsigned bits_per_word;
258 unsigned max_len;
259 unsigned total_fifo_words;
260
261 bits_per_word = t->bits_per_word;
262 tspi->bytes_per_word = DIV_ROUND_UP(bits_per_word, 8);
263
264 if (bits_per_word == 8 || bits_per_word == 16) {
265 tspi->is_packed = true;
266 tspi->words_per_32bit = 32/bits_per_word;
267 } else {
268 tspi->is_packed = false;
269 tspi->words_per_32bit = 1;
270 }
271 tspi->packed_size = tegra_slink_get_packed_size(tspi, t);
272
273 if (tspi->is_packed) {
274 max_len = min(remain_len, tspi->max_buf_size);
275 tspi->curr_dma_words = max_len/tspi->bytes_per_word;
276 total_fifo_words = max_len/4;
277 } else {
278 max_word = (remain_len - 1) / tspi->bytes_per_word + 1;
279 max_word = min(max_word, tspi->max_buf_size/4);
280 tspi->curr_dma_words = max_word;
281 total_fifo_words = max_word;
282 }
283 return total_fifo_words;
284 }
285
286 static unsigned tegra_slink_fill_tx_fifo_from_client_txbuf(
287 struct tegra_slink_data *tspi, struct spi_transfer *t)
288 {
289 unsigned nbytes;
290 unsigned tx_empty_count;
291 u32 fifo_status;
292 unsigned max_n_32bit;
293 unsigned i, count;
294 unsigned int written_words;
295 unsigned fifo_words_left;
296 u8 *tx_buf = (u8 *)t->tx_buf + tspi->cur_tx_pos;
297
298 fifo_status = tegra_slink_readl(tspi, SLINK_STATUS2);
299 tx_empty_count = SLINK_TX_FIFO_EMPTY_COUNT(fifo_status);
300
301 if (tspi->is_packed) {
302 fifo_words_left = tx_empty_count * tspi->words_per_32bit;
303 written_words = min(fifo_words_left, tspi->curr_dma_words);
304 nbytes = written_words * tspi->bytes_per_word;
305 max_n_32bit = DIV_ROUND_UP(nbytes, 4);
306 for (count = 0; count < max_n_32bit; count++) {
307 u32 x = 0;
308 for (i = 0; (i < 4) && nbytes; i++, nbytes--)
309 x |= (u32)(*tx_buf++) << (i * 8);
310 tegra_slink_writel(tspi, x, SLINK_TX_FIFO);
311 }
312 } else {
313 max_n_32bit = min(tspi->curr_dma_words, tx_empty_count);
314 written_words = max_n_32bit;
315 nbytes = written_words * tspi->bytes_per_word;
316 for (count = 0; count < max_n_32bit; count++) {
317 u32 x = 0;
318 for (i = 0; nbytes && (i < tspi->bytes_per_word);
319 i++, nbytes--)
320 x |= (u32)(*tx_buf++) << (i * 8);
321 tegra_slink_writel(tspi, x, SLINK_TX_FIFO);
322 }
323 }
324 tspi->cur_tx_pos += written_words * tspi->bytes_per_word;
325 return written_words;
326 }
327
328 static unsigned int tegra_slink_read_rx_fifo_to_client_rxbuf(
329 struct tegra_slink_data *tspi, struct spi_transfer *t)
330 {
331 unsigned rx_full_count;
332 u32 fifo_status;
333 unsigned i, count;
334 unsigned int read_words = 0;
335 unsigned len;
336 u8 *rx_buf = (u8 *)t->rx_buf + tspi->cur_rx_pos;
337
338 fifo_status = tegra_slink_readl(tspi, SLINK_STATUS2);
339 rx_full_count = SLINK_RX_FIFO_FULL_COUNT(fifo_status);
340 if (tspi->is_packed) {
341 len = tspi->curr_dma_words * tspi->bytes_per_word;
342 for (count = 0; count < rx_full_count; count++) {
343 u32 x = tegra_slink_readl(tspi, SLINK_RX_FIFO);
344 for (i = 0; len && (i < 4); i++, len--)
345 *rx_buf++ = (x >> i*8) & 0xFF;
346 }
347 tspi->cur_rx_pos += tspi->curr_dma_words * tspi->bytes_per_word;
348 read_words += tspi->curr_dma_words;
349 } else {
350 for (count = 0; count < rx_full_count; count++) {
351 u32 x = tegra_slink_readl(tspi, SLINK_RX_FIFO);
352 for (i = 0; (i < tspi->bytes_per_word); i++)
353 *rx_buf++ = (x >> (i*8)) & 0xFF;
354 }
355 tspi->cur_rx_pos += rx_full_count * tspi->bytes_per_word;
356 read_words += rx_full_count;
357 }
358 return read_words;
359 }
360
361 static void tegra_slink_copy_client_txbuf_to_spi_txbuf(
362 struct tegra_slink_data *tspi, struct spi_transfer *t)
363 {
364 /* Make the dma buffer to read by cpu */
365 dma_sync_single_for_cpu(tspi->dev, tspi->tx_dma_phys,
366 tspi->dma_buf_size, DMA_TO_DEVICE);
367
368 if (tspi->is_packed) {
369 unsigned len = tspi->curr_dma_words * tspi->bytes_per_word;
370 memcpy(tspi->tx_dma_buf, t->tx_buf + tspi->cur_pos, len);
371 } else {
372 unsigned int i;
373 unsigned int count;
374 u8 *tx_buf = (u8 *)t->tx_buf + tspi->cur_tx_pos;
375 unsigned consume = tspi->curr_dma_words * tspi->bytes_per_word;
376
377 for (count = 0; count < tspi->curr_dma_words; count++) {
378 u32 x = 0;
379 for (i = 0; consume && (i < tspi->bytes_per_word);
380 i++, consume--)
381 x |= (u32)(*tx_buf++) << (i * 8);
382 tspi->tx_dma_buf[count] = x;
383 }
384 }
385 tspi->cur_tx_pos += tspi->curr_dma_words * tspi->bytes_per_word;
386
387 /* Make the dma buffer to read by dma */
388 dma_sync_single_for_device(tspi->dev, tspi->tx_dma_phys,
389 tspi->dma_buf_size, DMA_TO_DEVICE);
390 }
391
392 static void tegra_slink_copy_spi_rxbuf_to_client_rxbuf(
393 struct tegra_slink_data *tspi, struct spi_transfer *t)
394 {
395 unsigned len;
396
397 /* Make the dma buffer to read by cpu */
398 dma_sync_single_for_cpu(tspi->dev, tspi->rx_dma_phys,
399 tspi->dma_buf_size, DMA_FROM_DEVICE);
400
401 if (tspi->is_packed) {
402 len = tspi->curr_dma_words * tspi->bytes_per_word;
403 memcpy(t->rx_buf + tspi->cur_rx_pos, tspi->rx_dma_buf, len);
404 } else {
405 unsigned int i;
406 unsigned int count;
407 unsigned char *rx_buf = t->rx_buf + tspi->cur_rx_pos;
408 u32 rx_mask = ((u32)1 << t->bits_per_word) - 1;
409
410 for (count = 0; count < tspi->curr_dma_words; count++) {
411 u32 x = tspi->rx_dma_buf[count] & rx_mask;
412 for (i = 0; (i < tspi->bytes_per_word); i++)
413 *rx_buf++ = (x >> (i*8)) & 0xFF;
414 }
415 }
416 tspi->cur_rx_pos += tspi->curr_dma_words * tspi->bytes_per_word;
417
418 /* Make the dma buffer to read by dma */
419 dma_sync_single_for_device(tspi->dev, tspi->rx_dma_phys,
420 tspi->dma_buf_size, DMA_FROM_DEVICE);
421 }
422
423 static void tegra_slink_dma_complete(void *args)
424 {
425 struct completion *dma_complete = args;
426
427 complete(dma_complete);
428 }
429
430 static int tegra_slink_start_tx_dma(struct tegra_slink_data *tspi, int len)
431 {
432 reinit_completion(&tspi->tx_dma_complete);
433 tspi->tx_dma_desc = dmaengine_prep_slave_single(tspi->tx_dma_chan,
434 tspi->tx_dma_phys, len, DMA_MEM_TO_DEV,
435 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
436 if (!tspi->tx_dma_desc) {
437 dev_err(tspi->dev, "Not able to get desc for Tx\n");
438 return -EIO;
439 }
440
441 tspi->tx_dma_desc->callback = tegra_slink_dma_complete;
442 tspi->tx_dma_desc->callback_param = &tspi->tx_dma_complete;
443
444 dmaengine_submit(tspi->tx_dma_desc);
445 dma_async_issue_pending(tspi->tx_dma_chan);
446 return 0;
447 }
448
449 static int tegra_slink_start_rx_dma(struct tegra_slink_data *tspi, int len)
450 {
451 reinit_completion(&tspi->rx_dma_complete);
452 tspi->rx_dma_desc = dmaengine_prep_slave_single(tspi->rx_dma_chan,
453 tspi->rx_dma_phys, len, DMA_DEV_TO_MEM,
454 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
455 if (!tspi->rx_dma_desc) {
456 dev_err(tspi->dev, "Not able to get desc for Rx\n");
457 return -EIO;
458 }
459
460 tspi->rx_dma_desc->callback = tegra_slink_dma_complete;
461 tspi->rx_dma_desc->callback_param = &tspi->rx_dma_complete;
462
463 dmaengine_submit(tspi->rx_dma_desc);
464 dma_async_issue_pending(tspi->rx_dma_chan);
465 return 0;
466 }
467
468 static int tegra_slink_start_dma_based_transfer(
469 struct tegra_slink_data *tspi, struct spi_transfer *t)
470 {
471 u32 val;
472 unsigned int len;
473 int ret = 0;
474 u32 status;
475
476 /* Make sure that Rx and Tx fifo are empty */
477 status = tegra_slink_readl(tspi, SLINK_STATUS);
478 if ((status & SLINK_FIFO_EMPTY) != SLINK_FIFO_EMPTY) {
479 dev_err(tspi->dev, "Rx/Tx fifo are not empty status 0x%08x\n",
480 (unsigned)status);
481 return -EIO;
482 }
483
484 val = SLINK_DMA_BLOCK_SIZE(tspi->curr_dma_words - 1);
485 val |= tspi->packed_size;
486 if (tspi->is_packed)
487 len = DIV_ROUND_UP(tspi->curr_dma_words * tspi->bytes_per_word,
488 4) * 4;
489 else
490 len = tspi->curr_dma_words * 4;
491
492 /* Set attention level based on length of transfer */
493 if (len & 0xF)
494 val |= SLINK_TX_TRIG_1 | SLINK_RX_TRIG_1;
495 else if (((len) >> 4) & 0x1)
496 val |= SLINK_TX_TRIG_4 | SLINK_RX_TRIG_4;
497 else
498 val |= SLINK_TX_TRIG_8 | SLINK_RX_TRIG_8;
499
500 if (tspi->cur_direction & DATA_DIR_TX)
501 val |= SLINK_IE_TXC;
502
503 if (tspi->cur_direction & DATA_DIR_RX)
504 val |= SLINK_IE_RXC;
505
506 tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
507 tspi->dma_control_reg = val;
508
509 if (tspi->cur_direction & DATA_DIR_TX) {
510 tegra_slink_copy_client_txbuf_to_spi_txbuf(tspi, t);
511 wmb();
512 ret = tegra_slink_start_tx_dma(tspi, len);
513 if (ret < 0) {
514 dev_err(tspi->dev,
515 "Starting tx dma failed, err %d\n", ret);
516 return ret;
517 }
518
519 /* Wait for tx fifo to be fill before starting slink */
520 status = tegra_slink_readl(tspi, SLINK_STATUS);
521 while (!(status & SLINK_TX_FULL))
522 status = tegra_slink_readl(tspi, SLINK_STATUS);
523 }
524
525 if (tspi->cur_direction & DATA_DIR_RX) {
526 /* Make the dma buffer to read by dma */
527 dma_sync_single_for_device(tspi->dev, tspi->rx_dma_phys,
528 tspi->dma_buf_size, DMA_FROM_DEVICE);
529
530 ret = tegra_slink_start_rx_dma(tspi, len);
531 if (ret < 0) {
532 dev_err(tspi->dev,
533 "Starting rx dma failed, err %d\n", ret);
534 if (tspi->cur_direction & DATA_DIR_TX)
535 dmaengine_terminate_all(tspi->tx_dma_chan);
536 return ret;
537 }
538 }
539 tspi->is_curr_dma_xfer = true;
540 if (tspi->is_packed) {
541 val |= SLINK_PACKED;
542 tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
543 /* HW need small delay after settign Packed mode */
544 udelay(1);
545 }
546 tspi->dma_control_reg = val;
547
548 val |= SLINK_DMA_EN;
549 tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
550 return ret;
551 }
552
553 static int tegra_slink_start_cpu_based_transfer(
554 struct tegra_slink_data *tspi, struct spi_transfer *t)
555 {
556 u32 val;
557 unsigned cur_words;
558
559 val = tspi->packed_size;
560 if (tspi->cur_direction & DATA_DIR_TX)
561 val |= SLINK_IE_TXC;
562
563 if (tspi->cur_direction & DATA_DIR_RX)
564 val |= SLINK_IE_RXC;
565
566 tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
567 tspi->dma_control_reg = val;
568
569 if (tspi->cur_direction & DATA_DIR_TX)
570 cur_words = tegra_slink_fill_tx_fifo_from_client_txbuf(tspi, t);
571 else
572 cur_words = tspi->curr_dma_words;
573 val |= SLINK_DMA_BLOCK_SIZE(cur_words - 1);
574 tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
575 tspi->dma_control_reg = val;
576
577 tspi->is_curr_dma_xfer = false;
578 if (tspi->is_packed) {
579 val |= SLINK_PACKED;
580 tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
581 udelay(1);
582 wmb();
583 }
584 tspi->dma_control_reg = val;
585 val |= SLINK_DMA_EN;
586 tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
587 return 0;
588 }
589
590 static int tegra_slink_init_dma_param(struct tegra_slink_data *tspi,
591 bool dma_to_memory)
592 {
593 struct dma_chan *dma_chan;
594 u32 *dma_buf;
595 dma_addr_t dma_phys;
596 int ret;
597 struct dma_slave_config dma_sconfig;
598
599 dma_chan = dma_request_chan(tspi->dev, dma_to_memory ? "rx" : "tx");
600 if (IS_ERR(dma_chan))
601 return dev_err_probe(tspi->dev, PTR_ERR(dma_chan),
602 "Dma channel is not available\n");
603
604 dma_buf = dma_alloc_coherent(tspi->dev, tspi->dma_buf_size,
605 &dma_phys, GFP_KERNEL);
606 if (!dma_buf) {
607 dev_err(tspi->dev, " Not able to allocate the dma buffer\n");
608 dma_release_channel(dma_chan);
609 return -ENOMEM;
610 }
611
612 if (dma_to_memory) {
613 dma_sconfig.src_addr = tspi->phys + SLINK_RX_FIFO;
614 dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
615 dma_sconfig.src_maxburst = 0;
616 } else {
617 dma_sconfig.dst_addr = tspi->phys + SLINK_TX_FIFO;
618 dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
619 dma_sconfig.dst_maxburst = 0;
620 }
621
622 ret = dmaengine_slave_config(dma_chan, &dma_sconfig);
623 if (ret)
624 goto scrub;
625 if (dma_to_memory) {
626 tspi->rx_dma_chan = dma_chan;
627 tspi->rx_dma_buf = dma_buf;
628 tspi->rx_dma_phys = dma_phys;
629 } else {
630 tspi->tx_dma_chan = dma_chan;
631 tspi->tx_dma_buf = dma_buf;
632 tspi->tx_dma_phys = dma_phys;
633 }
634 return 0;
635
636 scrub:
637 dma_free_coherent(tspi->dev, tspi->dma_buf_size, dma_buf, dma_phys);
638 dma_release_channel(dma_chan);
639 return ret;
640 }
641
642 static void tegra_slink_deinit_dma_param(struct tegra_slink_data *tspi,
643 bool dma_to_memory)
644 {
645 u32 *dma_buf;
646 dma_addr_t dma_phys;
647 struct dma_chan *dma_chan;
648
649 if (dma_to_memory) {
650 dma_buf = tspi->rx_dma_buf;
651 dma_chan = tspi->rx_dma_chan;
652 dma_phys = tspi->rx_dma_phys;
653 tspi->rx_dma_chan = NULL;
654 tspi->rx_dma_buf = NULL;
655 } else {
656 dma_buf = tspi->tx_dma_buf;
657 dma_chan = tspi->tx_dma_chan;
658 dma_phys = tspi->tx_dma_phys;
659 tspi->tx_dma_buf = NULL;
660 tspi->tx_dma_chan = NULL;
661 }
662 if (!dma_chan)
663 return;
664
665 dma_free_coherent(tspi->dev, tspi->dma_buf_size, dma_buf, dma_phys);
666 dma_release_channel(dma_chan);
667 }
668
669 static int tegra_slink_start_transfer_one(struct spi_device *spi,
670 struct spi_transfer *t)
671 {
672 struct tegra_slink_data *tspi = spi_master_get_devdata(spi->master);
673 u32 speed;
674 u8 bits_per_word;
675 unsigned total_fifo_words;
676 int ret;
677 u32 command;
678 u32 command2;
679
680 bits_per_word = t->bits_per_word;
681 speed = t->speed_hz;
682 if (speed != tspi->cur_speed) {
683 clk_set_rate(tspi->clk, speed * 4);
684 tspi->cur_speed = speed;
685 }
686
687 tspi->cur_spi = spi;
688 tspi->cur_pos = 0;
689 tspi->cur_rx_pos = 0;
690 tspi->cur_tx_pos = 0;
691 tspi->curr_xfer = t;
692 total_fifo_words = tegra_slink_calculate_curr_xfer_param(spi, tspi, t);
693
694 command = tspi->command_reg;
695 command &= ~SLINK_BIT_LENGTH(~0);
696 command |= SLINK_BIT_LENGTH(bits_per_word - 1);
697
698 command2 = tspi->command2_reg;
699 command2 &= ~(SLINK_RXEN | SLINK_TXEN);
700
701 tspi->cur_direction = 0;
702 if (t->rx_buf) {
703 command2 |= SLINK_RXEN;
704 tspi->cur_direction |= DATA_DIR_RX;
705 }
706 if (t->tx_buf) {
707 command2 |= SLINK_TXEN;
708 tspi->cur_direction |= DATA_DIR_TX;
709 }
710
711 /*
712 * Writing to the command2 register bevore the command register prevents
713 * a spike in chip_select line 0. This selects the chip_select line
714 * before changing the chip_select value.
715 */
716 tegra_slink_writel(tspi, command2, SLINK_COMMAND2);
717 tspi->command2_reg = command2;
718
719 tegra_slink_writel(tspi, command, SLINK_COMMAND);
720 tspi->command_reg = command;
721
722 if (total_fifo_words > SLINK_FIFO_DEPTH)
723 ret = tegra_slink_start_dma_based_transfer(tspi, t);
724 else
725 ret = tegra_slink_start_cpu_based_transfer(tspi, t);
726 return ret;
727 }
728
729 static int tegra_slink_setup(struct spi_device *spi)
730 {
731 static const u32 cs_pol_bit[MAX_CHIP_SELECT] = {
732 SLINK_CS_POLARITY,
733 SLINK_CS_POLARITY1,
734 SLINK_CS_POLARITY2,
735 SLINK_CS_POLARITY3,
736 };
737
738 struct tegra_slink_data *tspi = spi_master_get_devdata(spi->master);
739 u32 val;
740 unsigned long flags;
741 int ret;
742
743 dev_dbg(&spi->dev, "setup %d bpw, %scpol, %scpha, %dHz\n",
744 spi->bits_per_word,
745 spi->mode & SPI_CPOL ? "" : "~",
746 spi->mode & SPI_CPHA ? "" : "~",
747 spi->max_speed_hz);
748
749 ret = pm_runtime_get_sync(tspi->dev);
750 if (ret < 0) {
751 pm_runtime_put_noidle(tspi->dev);
752 dev_err(tspi->dev, "pm runtime failed, e = %d\n", ret);
753 return ret;
754 }
755
756 spin_lock_irqsave(&tspi->lock, flags);
757 val = tspi->def_command_reg;
758 if (spi->mode & SPI_CS_HIGH)
759 val |= cs_pol_bit[spi->chip_select];
760 else
761 val &= ~cs_pol_bit[spi->chip_select];
762 tspi->def_command_reg = val;
763 tegra_slink_writel(tspi, tspi->def_command_reg, SLINK_COMMAND);
764 spin_unlock_irqrestore(&tspi->lock, flags);
765
766 pm_runtime_put(tspi->dev);
767 return 0;
768 }
769
770 static int tegra_slink_prepare_message(struct spi_master *master,
771 struct spi_message *msg)
772 {
773 struct tegra_slink_data *tspi = spi_master_get_devdata(master);
774 struct spi_device *spi = msg->spi;
775
776 tegra_slink_clear_status(tspi);
777
778 tspi->command_reg = tspi->def_command_reg;
779 tspi->command_reg |= SLINK_CS_SW | SLINK_CS_VALUE;
780
781 tspi->command2_reg = tspi->def_command2_reg;
782 tspi->command2_reg |= SLINK_SS_EN_CS(spi->chip_select);
783
784 tspi->command_reg &= ~SLINK_MODES;
785 if (spi->mode & SPI_CPHA)
786 tspi->command_reg |= SLINK_CK_SDA;
787
788 if (spi->mode & SPI_CPOL)
789 tspi->command_reg |= SLINK_IDLE_SCLK_DRIVE_HIGH;
790 else
791 tspi->command_reg |= SLINK_IDLE_SCLK_DRIVE_LOW;
792
793 return 0;
794 }
795
796 static int tegra_slink_transfer_one(struct spi_master *master,
797 struct spi_device *spi,
798 struct spi_transfer *xfer)
799 {
800 struct tegra_slink_data *tspi = spi_master_get_devdata(master);
801 int ret;
802
803 reinit_completion(&tspi->xfer_completion);
804 ret = tegra_slink_start_transfer_one(spi, xfer);
805 if (ret < 0) {
806 dev_err(tspi->dev,
807 "spi can not start transfer, err %d\n", ret);
808 return ret;
809 }
810
811 ret = wait_for_completion_timeout(&tspi->xfer_completion,
812 SLINK_DMA_TIMEOUT);
813 if (WARN_ON(ret == 0)) {
814 dev_err(tspi->dev,
815 "spi transfer timeout, err %d\n", ret);
816 return -EIO;
817 }
818
819 if (tspi->tx_status)
820 return tspi->tx_status;
821 if (tspi->rx_status)
822 return tspi->rx_status;
823
824 return 0;
825 }
826
827 static int tegra_slink_unprepare_message(struct spi_master *master,
828 struct spi_message *msg)
829 {
830 struct tegra_slink_data *tspi = spi_master_get_devdata(master);
831
832 tegra_slink_writel(tspi, tspi->def_command_reg, SLINK_COMMAND);
833 tegra_slink_writel(tspi, tspi->def_command2_reg, SLINK_COMMAND2);
834
835 return 0;
836 }
837
838 static irqreturn_t handle_cpu_based_xfer(struct tegra_slink_data *tspi)
839 {
840 struct spi_transfer *t = tspi->curr_xfer;
841 unsigned long flags;
842
843 spin_lock_irqsave(&tspi->lock, flags);
844 if (tspi->tx_status || tspi->rx_status ||
845 (tspi->status_reg & SLINK_BSY)) {
846 dev_err(tspi->dev,
847 "CpuXfer ERROR bit set 0x%x\n", tspi->status_reg);
848 dev_err(tspi->dev,
849 "CpuXfer 0x%08x:0x%08x:0x%08x\n", tspi->command_reg,
850 tspi->command2_reg, tspi->dma_control_reg);
851 reset_control_assert(tspi->rst);
852 udelay(2);
853 reset_control_deassert(tspi->rst);
854 complete(&tspi->xfer_completion);
855 goto exit;
856 }
857
858 if (tspi->cur_direction & DATA_DIR_RX)
859 tegra_slink_read_rx_fifo_to_client_rxbuf(tspi, t);
860
861 if (tspi->cur_direction & DATA_DIR_TX)
862 tspi->cur_pos = tspi->cur_tx_pos;
863 else
864 tspi->cur_pos = tspi->cur_rx_pos;
865
866 if (tspi->cur_pos == t->len) {
867 complete(&tspi->xfer_completion);
868 goto exit;
869 }
870
871 tegra_slink_calculate_curr_xfer_param(tspi->cur_spi, tspi, t);
872 tegra_slink_start_cpu_based_transfer(tspi, t);
873 exit:
874 spin_unlock_irqrestore(&tspi->lock, flags);
875 return IRQ_HANDLED;
876 }
877
878 static irqreturn_t handle_dma_based_xfer(struct tegra_slink_data *tspi)
879 {
880 struct spi_transfer *t = tspi->curr_xfer;
881 long wait_status;
882 int err = 0;
883 unsigned total_fifo_words;
884 unsigned long flags;
885
886 /* Abort dmas if any error */
887 if (tspi->cur_direction & DATA_DIR_TX) {
888 if (tspi->tx_status) {
889 dmaengine_terminate_all(tspi->tx_dma_chan);
890 err += 1;
891 } else {
892 wait_status = wait_for_completion_interruptible_timeout(
893 &tspi->tx_dma_complete, SLINK_DMA_TIMEOUT);
894 if (wait_status <= 0) {
895 dmaengine_terminate_all(tspi->tx_dma_chan);
896 dev_err(tspi->dev, "TxDma Xfer failed\n");
897 err += 1;
898 }
899 }
900 }
901
902 if (tspi->cur_direction & DATA_DIR_RX) {
903 if (tspi->rx_status) {
904 dmaengine_terminate_all(tspi->rx_dma_chan);
905 err += 2;
906 } else {
907 wait_status = wait_for_completion_interruptible_timeout(
908 &tspi->rx_dma_complete, SLINK_DMA_TIMEOUT);
909 if (wait_status <= 0) {
910 dmaengine_terminate_all(tspi->rx_dma_chan);
911 dev_err(tspi->dev, "RxDma Xfer failed\n");
912 err += 2;
913 }
914 }
915 }
916
917 spin_lock_irqsave(&tspi->lock, flags);
918 if (err) {
919 dev_err(tspi->dev,
920 "DmaXfer: ERROR bit set 0x%x\n", tspi->status_reg);
921 dev_err(tspi->dev,
922 "DmaXfer 0x%08x:0x%08x:0x%08x\n", tspi->command_reg,
923 tspi->command2_reg, tspi->dma_control_reg);
924 reset_control_assert(tspi->rst);
925 udelay(2);
926 reset_control_assert(tspi->rst);
927 complete(&tspi->xfer_completion);
928 spin_unlock_irqrestore(&tspi->lock, flags);
929 return IRQ_HANDLED;
930 }
931
932 if (tspi->cur_direction & DATA_DIR_RX)
933 tegra_slink_copy_spi_rxbuf_to_client_rxbuf(tspi, t);
934
935 if (tspi->cur_direction & DATA_DIR_TX)
936 tspi->cur_pos = tspi->cur_tx_pos;
937 else
938 tspi->cur_pos = tspi->cur_rx_pos;
939
940 if (tspi->cur_pos == t->len) {
941 complete(&tspi->xfer_completion);
942 goto exit;
943 }
944
945 /* Continue transfer in current message */
946 total_fifo_words = tegra_slink_calculate_curr_xfer_param(tspi->cur_spi,
947 tspi, t);
948 if (total_fifo_words > SLINK_FIFO_DEPTH)
949 err = tegra_slink_start_dma_based_transfer(tspi, t);
950 else
951 err = tegra_slink_start_cpu_based_transfer(tspi, t);
952
953 exit:
954 spin_unlock_irqrestore(&tspi->lock, flags);
955 return IRQ_HANDLED;
956 }
957
958 static irqreturn_t tegra_slink_isr_thread(int irq, void *context_data)
959 {
960 struct tegra_slink_data *tspi = context_data;
961
962 if (!tspi->is_curr_dma_xfer)
963 return handle_cpu_based_xfer(tspi);
964 return handle_dma_based_xfer(tspi);
965 }
966
967 static irqreturn_t tegra_slink_isr(int irq, void *context_data)
968 {
969 struct tegra_slink_data *tspi = context_data;
970
971 tspi->status_reg = tegra_slink_readl(tspi, SLINK_STATUS);
972 if (tspi->cur_direction & DATA_DIR_TX)
973 tspi->tx_status = tspi->status_reg &
974 (SLINK_TX_OVF | SLINK_TX_UNF);
975
976 if (tspi->cur_direction & DATA_DIR_RX)
977 tspi->rx_status = tspi->status_reg &
978 (SLINK_RX_OVF | SLINK_RX_UNF);
979 tegra_slink_clear_status(tspi);
980
981 return IRQ_WAKE_THREAD;
982 }
983
984 static const struct tegra_slink_chip_data tegra30_spi_cdata = {
985 .cs_hold_time = true,
986 };
987
988 static const struct tegra_slink_chip_data tegra20_spi_cdata = {
989 .cs_hold_time = false,
990 };
991
992 static const struct of_device_id tegra_slink_of_match[] = {
993 { .compatible = "nvidia,tegra30-slink", .data = &tegra30_spi_cdata, },
994 { .compatible = "nvidia,tegra20-slink", .data = &tegra20_spi_cdata, },
995 {}
996 };
997 MODULE_DEVICE_TABLE(of, tegra_slink_of_match);
998
999 static int tegra_slink_probe(struct platform_device *pdev)
1000 {
1001 struct spi_master *master;
1002 struct tegra_slink_data *tspi;
1003 struct resource *r;
1004 int ret, spi_irq;
1005 const struct tegra_slink_chip_data *cdata = NULL;
1006
1007 cdata = of_device_get_match_data(&pdev->dev);
1008
1009 master = spi_alloc_master(&pdev->dev, sizeof(*tspi));
1010 if (!master) {
1011 dev_err(&pdev->dev, "master allocation failed\n");
1012 return -ENOMEM;
1013 }
1014
1015 /* the spi->mode bits understood by this driver: */
1016 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
1017 master->setup = tegra_slink_setup;
1018 master->prepare_message = tegra_slink_prepare_message;
1019 master->transfer_one = tegra_slink_transfer_one;
1020 master->unprepare_message = tegra_slink_unprepare_message;
1021 master->auto_runtime_pm = true;
1022 master->num_chipselect = MAX_CHIP_SELECT;
1023
1024 platform_set_drvdata(pdev, master);
1025 tspi = spi_master_get_devdata(master);
1026 tspi->master = master;
1027 tspi->dev = &pdev->dev;
1028 tspi->chip_data = cdata;
1029 spin_lock_init(&tspi->lock);
1030
1031 if (of_property_read_u32(tspi->dev->of_node, "spi-max-frequency",
1032 &master->max_speed_hz))
1033 master->max_speed_hz = 25000000; /* 25MHz */
1034
1035 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1036 if (!r) {
1037 dev_err(&pdev->dev, "No IO memory resource\n");
1038 ret = -ENODEV;
1039 goto exit_free_master;
1040 }
1041 tspi->phys = r->start;
1042 tspi->base = devm_ioremap_resource(&pdev->dev, r);
1043 if (IS_ERR(tspi->base)) {
1044 ret = PTR_ERR(tspi->base);
1045 goto exit_free_master;
1046 }
1047
1048 /* disabled clock may cause interrupt storm upon request */
1049 tspi->clk = devm_clk_get(&pdev->dev, NULL);
1050 if (IS_ERR(tspi->clk)) {
1051 ret = PTR_ERR(tspi->clk);
1052 dev_err(&pdev->dev, "Can not get clock %d\n", ret);
1053 goto exit_free_master;
1054 }
1055
1056 tspi->rst = devm_reset_control_get_exclusive(&pdev->dev, "spi");
1057 if (IS_ERR(tspi->rst)) {
1058 dev_err(&pdev->dev, "can not get reset\n");
1059 ret = PTR_ERR(tspi->rst);
1060 goto exit_free_master;
1061 }
1062
1063 tspi->max_buf_size = SLINK_FIFO_DEPTH << 2;
1064 tspi->dma_buf_size = DEFAULT_SPI_DMA_BUF_LEN;
1065
1066 ret = tegra_slink_init_dma_param(tspi, true);
1067 if (ret < 0)
1068 goto exit_free_master;
1069 ret = tegra_slink_init_dma_param(tspi, false);
1070 if (ret < 0)
1071 goto exit_rx_dma_free;
1072 tspi->max_buf_size = tspi->dma_buf_size;
1073 init_completion(&tspi->tx_dma_complete);
1074 init_completion(&tspi->rx_dma_complete);
1075
1076 init_completion(&tspi->xfer_completion);
1077
1078 pm_runtime_enable(&pdev->dev);
1079 ret = pm_runtime_resume_and_get(&pdev->dev);
1080 if (ret) {
1081 dev_err(&pdev->dev, "pm runtime get failed, e = %d\n", ret);
1082 goto exit_pm_disable;
1083 }
1084
1085 reset_control_assert(tspi->rst);
1086 udelay(2);
1087 reset_control_deassert(tspi->rst);
1088
1089 spi_irq = platform_get_irq(pdev, 0);
1090 tspi->irq = spi_irq;
1091 ret = request_threaded_irq(tspi->irq, tegra_slink_isr,
1092 tegra_slink_isr_thread, IRQF_ONESHOT,
1093 dev_name(&pdev->dev), tspi);
1094 if (ret < 0) {
1095 dev_err(&pdev->dev, "Failed to register ISR for IRQ %d\n",
1096 tspi->irq);
1097 goto exit_pm_put;
1098 }
1099
1100 tspi->def_command_reg = SLINK_M_S;
1101 tspi->def_command2_reg = SLINK_CS_ACTIVE_BETWEEN;
1102 tegra_slink_writel(tspi, tspi->def_command_reg, SLINK_COMMAND);
1103 tegra_slink_writel(tspi, tspi->def_command2_reg, SLINK_COMMAND2);
1104
1105 master->dev.of_node = pdev->dev.of_node;
1106 ret = spi_register_master(master);
1107 if (ret < 0) {
1108 dev_err(&pdev->dev, "can not register to master err %d\n", ret);
1109 goto exit_free_irq;
1110 }
1111
1112 pm_runtime_put(&pdev->dev);
1113
1114 return ret;
1115
1116 exit_free_irq:
1117 free_irq(spi_irq, tspi);
1118 exit_pm_put:
1119 pm_runtime_put(&pdev->dev);
1120 exit_pm_disable:
1121 pm_runtime_disable(&pdev->dev);
1122
1123 tegra_slink_deinit_dma_param(tspi, false);
1124 exit_rx_dma_free:
1125 tegra_slink_deinit_dma_param(tspi, true);
1126 exit_free_master:
1127 spi_master_put(master);
1128 return ret;
1129 }
1130
1131 static int tegra_slink_remove(struct platform_device *pdev)
1132 {
1133 struct spi_master *master = platform_get_drvdata(pdev);
1134 struct tegra_slink_data *tspi = spi_master_get_devdata(master);
1135
1136 spi_unregister_master(master);
1137
1138 free_irq(tspi->irq, tspi);
1139
1140 pm_runtime_disable(&pdev->dev);
1141
1142 if (tspi->tx_dma_chan)
1143 tegra_slink_deinit_dma_param(tspi, false);
1144
1145 if (tspi->rx_dma_chan)
1146 tegra_slink_deinit_dma_param(tspi, true);
1147
1148 return 0;
1149 }
1150
1151 #ifdef CONFIG_PM_SLEEP
1152 static int tegra_slink_suspend(struct device *dev)
1153 {
1154 struct spi_master *master = dev_get_drvdata(dev);
1155
1156 return spi_master_suspend(master);
1157 }
1158
1159 static int tegra_slink_resume(struct device *dev)
1160 {
1161 struct spi_master *master = dev_get_drvdata(dev);
1162 struct tegra_slink_data *tspi = spi_master_get_devdata(master);
1163 int ret;
1164
1165 ret = pm_runtime_get_sync(dev);
1166 if (ret < 0) {
1167 pm_runtime_put_noidle(dev);
1168 dev_err(dev, "pm runtime failed, e = %d\n", ret);
1169 return ret;
1170 }
1171 tegra_slink_writel(tspi, tspi->command_reg, SLINK_COMMAND);
1172 tegra_slink_writel(tspi, tspi->command2_reg, SLINK_COMMAND2);
1173 pm_runtime_put(dev);
1174
1175 return spi_master_resume(master);
1176 }
1177 #endif
1178
1179 static int __maybe_unused tegra_slink_runtime_suspend(struct device *dev)
1180 {
1181 struct spi_master *master = dev_get_drvdata(dev);
1182 struct tegra_slink_data *tspi = spi_master_get_devdata(master);
1183
1184 /* Flush all write which are in PPSB queue by reading back */
1185 tegra_slink_readl(tspi, SLINK_MAS_DATA);
1186
1187 clk_disable_unprepare(tspi->clk);
1188 return 0;
1189 }
1190
1191 static int __maybe_unused tegra_slink_runtime_resume(struct device *dev)
1192 {
1193 struct spi_master *master = dev_get_drvdata(dev);
1194 struct tegra_slink_data *tspi = spi_master_get_devdata(master);
1195 int ret;
1196
1197 ret = clk_prepare_enable(tspi->clk);
1198 if (ret < 0) {
1199 dev_err(tspi->dev, "clk_prepare failed: %d\n", ret);
1200 return ret;
1201 }
1202 return 0;
1203 }
1204
1205 static const struct dev_pm_ops slink_pm_ops = {
1206 SET_RUNTIME_PM_OPS(tegra_slink_runtime_suspend,
1207 tegra_slink_runtime_resume, NULL)
1208 SET_SYSTEM_SLEEP_PM_OPS(tegra_slink_suspend, tegra_slink_resume)
1209 };
1210 static struct platform_driver tegra_slink_driver = {
1211 .driver = {
1212 .name = "spi-tegra-slink",
1213 .pm = &slink_pm_ops,
1214 .of_match_table = tegra_slink_of_match,
1215 },
1216 .probe = tegra_slink_probe,
1217 .remove = tegra_slink_remove,
1218 };
1219 module_platform_driver(tegra_slink_driver);
1220
1221 MODULE_ALIAS("platform:spi-tegra-slink");
1222 MODULE_DESCRIPTION("NVIDIA Tegra20/Tegra30 SLINK Controller Driver");
1223 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
1224 MODULE_LICENSE("GPL v2");
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