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[mirror_ubuntu-artful-kernel.git] / drivers / spi / spi-tegra20-slink.c
1 /*
2 * SPI driver for Nvidia's Tegra20/Tegra30 SLINK Controller.
3 *
4 * Copyright (c) 2012, NVIDIA CORPORATION. All rights reserved.
5 *
6 * This program is free software; you can redistribute it and/or modify it
7 * under the terms and conditions of the GNU General Public License,
8 * version 2, as published by the Free Software Foundation.
9 *
10 * This program is distributed in the hope it will be useful, but WITHOUT
11 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
12 * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
13 * more details.
14 *
15 * You should have received a copy of the GNU General Public License
16 * along with this program. If not, see <http://www.gnu.org/licenses/>.
17 */
18
19 #include <linux/clk.h>
20 #include <linux/completion.h>
21 #include <linux/delay.h>
22 #include <linux/dmaengine.h>
23 #include <linux/dma-mapping.h>
24 #include <linux/dmapool.h>
25 #include <linux/err.h>
26 #include <linux/interrupt.h>
27 #include <linux/io.h>
28 #include <linux/kernel.h>
29 #include <linux/kthread.h>
30 #include <linux/module.h>
31 #include <linux/platform_device.h>
32 #include <linux/pm_runtime.h>
33 #include <linux/of.h>
34 #include <linux/of_device.h>
35 #include <linux/reset.h>
36 #include <linux/spi/spi.h>
37
38 #define SLINK_COMMAND 0x000
39 #define SLINK_BIT_LENGTH(x) (((x) & 0x1f) << 0)
40 #define SLINK_WORD_SIZE(x) (((x) & 0x1f) << 5)
41 #define SLINK_BOTH_EN (1 << 10)
42 #define SLINK_CS_SW (1 << 11)
43 #define SLINK_CS_VALUE (1 << 12)
44 #define SLINK_CS_POLARITY (1 << 13)
45 #define SLINK_IDLE_SDA_DRIVE_LOW (0 << 16)
46 #define SLINK_IDLE_SDA_DRIVE_HIGH (1 << 16)
47 #define SLINK_IDLE_SDA_PULL_LOW (2 << 16)
48 #define SLINK_IDLE_SDA_PULL_HIGH (3 << 16)
49 #define SLINK_IDLE_SDA_MASK (3 << 16)
50 #define SLINK_CS_POLARITY1 (1 << 20)
51 #define SLINK_CK_SDA (1 << 21)
52 #define SLINK_CS_POLARITY2 (1 << 22)
53 #define SLINK_CS_POLARITY3 (1 << 23)
54 #define SLINK_IDLE_SCLK_DRIVE_LOW (0 << 24)
55 #define SLINK_IDLE_SCLK_DRIVE_HIGH (1 << 24)
56 #define SLINK_IDLE_SCLK_PULL_LOW (2 << 24)
57 #define SLINK_IDLE_SCLK_PULL_HIGH (3 << 24)
58 #define SLINK_IDLE_SCLK_MASK (3 << 24)
59 #define SLINK_M_S (1 << 28)
60 #define SLINK_WAIT (1 << 29)
61 #define SLINK_GO (1 << 30)
62 #define SLINK_ENB (1 << 31)
63
64 #define SLINK_MODES (SLINK_IDLE_SCLK_MASK | SLINK_CK_SDA)
65
66 #define SLINK_COMMAND2 0x004
67 #define SLINK_LSBFE (1 << 0)
68 #define SLINK_SSOE (1 << 1)
69 #define SLINK_SPIE (1 << 4)
70 #define SLINK_BIDIROE (1 << 6)
71 #define SLINK_MODFEN (1 << 7)
72 #define SLINK_INT_SIZE(x) (((x) & 0x1f) << 8)
73 #define SLINK_CS_ACTIVE_BETWEEN (1 << 17)
74 #define SLINK_SS_EN_CS(x) (((x) & 0x3) << 18)
75 #define SLINK_SS_SETUP(x) (((x) & 0x3) << 20)
76 #define SLINK_FIFO_REFILLS_0 (0 << 22)
77 #define SLINK_FIFO_REFILLS_1 (1 << 22)
78 #define SLINK_FIFO_REFILLS_2 (2 << 22)
79 #define SLINK_FIFO_REFILLS_3 (3 << 22)
80 #define SLINK_FIFO_REFILLS_MASK (3 << 22)
81 #define SLINK_WAIT_PACK_INT(x) (((x) & 0x7) << 26)
82 #define SLINK_SPC0 (1 << 29)
83 #define SLINK_TXEN (1 << 30)
84 #define SLINK_RXEN (1 << 31)
85
86 #define SLINK_STATUS 0x008
87 #define SLINK_COUNT(val) (((val) >> 0) & 0x1f)
88 #define SLINK_WORD(val) (((val) >> 5) & 0x1f)
89 #define SLINK_BLK_CNT(val) (((val) >> 0) & 0xffff)
90 #define SLINK_MODF (1 << 16)
91 #define SLINK_RX_UNF (1 << 18)
92 #define SLINK_TX_OVF (1 << 19)
93 #define SLINK_TX_FULL (1 << 20)
94 #define SLINK_TX_EMPTY (1 << 21)
95 #define SLINK_RX_FULL (1 << 22)
96 #define SLINK_RX_EMPTY (1 << 23)
97 #define SLINK_TX_UNF (1 << 24)
98 #define SLINK_RX_OVF (1 << 25)
99 #define SLINK_TX_FLUSH (1 << 26)
100 #define SLINK_RX_FLUSH (1 << 27)
101 #define SLINK_SCLK (1 << 28)
102 #define SLINK_ERR (1 << 29)
103 #define SLINK_RDY (1 << 30)
104 #define SLINK_BSY (1 << 31)
105 #define SLINK_FIFO_ERROR (SLINK_TX_OVF | SLINK_RX_UNF | \
106 SLINK_TX_UNF | SLINK_RX_OVF)
107
108 #define SLINK_FIFO_EMPTY (SLINK_TX_EMPTY | SLINK_RX_EMPTY)
109
110 #define SLINK_MAS_DATA 0x010
111 #define SLINK_SLAVE_DATA 0x014
112
113 #define SLINK_DMA_CTL 0x018
114 #define SLINK_DMA_BLOCK_SIZE(x) (((x) & 0xffff) << 0)
115 #define SLINK_TX_TRIG_1 (0 << 16)
116 #define SLINK_TX_TRIG_4 (1 << 16)
117 #define SLINK_TX_TRIG_8 (2 << 16)
118 #define SLINK_TX_TRIG_16 (3 << 16)
119 #define SLINK_TX_TRIG_MASK (3 << 16)
120 #define SLINK_RX_TRIG_1 (0 << 18)
121 #define SLINK_RX_TRIG_4 (1 << 18)
122 #define SLINK_RX_TRIG_8 (2 << 18)
123 #define SLINK_RX_TRIG_16 (3 << 18)
124 #define SLINK_RX_TRIG_MASK (3 << 18)
125 #define SLINK_PACKED (1 << 20)
126 #define SLINK_PACK_SIZE_4 (0 << 21)
127 #define SLINK_PACK_SIZE_8 (1 << 21)
128 #define SLINK_PACK_SIZE_16 (2 << 21)
129 #define SLINK_PACK_SIZE_32 (3 << 21)
130 #define SLINK_PACK_SIZE_MASK (3 << 21)
131 #define SLINK_IE_TXC (1 << 26)
132 #define SLINK_IE_RXC (1 << 27)
133 #define SLINK_DMA_EN (1 << 31)
134
135 #define SLINK_STATUS2 0x01c
136 #define SLINK_TX_FIFO_EMPTY_COUNT(val) (((val) & 0x3f) >> 0)
137 #define SLINK_RX_FIFO_FULL_COUNT(val) (((val) & 0x3f0000) >> 16)
138 #define SLINK_SS_HOLD_TIME(val) (((val) & 0xF) << 6)
139
140 #define SLINK_TX_FIFO 0x100
141 #define SLINK_RX_FIFO 0x180
142
143 #define DATA_DIR_TX (1 << 0)
144 #define DATA_DIR_RX (1 << 1)
145
146 #define SLINK_DMA_TIMEOUT (msecs_to_jiffies(1000))
147
148 #define DEFAULT_SPI_DMA_BUF_LEN (16*1024)
149 #define TX_FIFO_EMPTY_COUNT_MAX SLINK_TX_FIFO_EMPTY_COUNT(0x20)
150 #define RX_FIFO_FULL_COUNT_ZERO SLINK_RX_FIFO_FULL_COUNT(0)
151
152 #define SLINK_STATUS2_RESET \
153 (TX_FIFO_EMPTY_COUNT_MAX | RX_FIFO_FULL_COUNT_ZERO << 16)
154
155 #define MAX_CHIP_SELECT 4
156 #define SLINK_FIFO_DEPTH 32
157
158 struct tegra_slink_chip_data {
159 bool cs_hold_time;
160 };
161
162 struct tegra_slink_data {
163 struct device *dev;
164 struct spi_master *master;
165 const struct tegra_slink_chip_data *chip_data;
166 spinlock_t lock;
167
168 struct clk *clk;
169 struct reset_control *rst;
170 void __iomem *base;
171 phys_addr_t phys;
172 unsigned irq;
173 u32 cur_speed;
174
175 struct spi_device *cur_spi;
176 unsigned cur_pos;
177 unsigned cur_len;
178 unsigned words_per_32bit;
179 unsigned bytes_per_word;
180 unsigned curr_dma_words;
181 unsigned cur_direction;
182
183 unsigned cur_rx_pos;
184 unsigned cur_tx_pos;
185
186 unsigned dma_buf_size;
187 unsigned max_buf_size;
188 bool is_curr_dma_xfer;
189
190 struct completion rx_dma_complete;
191 struct completion tx_dma_complete;
192
193 u32 tx_status;
194 u32 rx_status;
195 u32 status_reg;
196 bool is_packed;
197 u32 packed_size;
198
199 u32 command_reg;
200 u32 command2_reg;
201 u32 dma_control_reg;
202 u32 def_command_reg;
203 u32 def_command2_reg;
204
205 struct completion xfer_completion;
206 struct spi_transfer *curr_xfer;
207 struct dma_chan *rx_dma_chan;
208 u32 *rx_dma_buf;
209 dma_addr_t rx_dma_phys;
210 struct dma_async_tx_descriptor *rx_dma_desc;
211
212 struct dma_chan *tx_dma_chan;
213 u32 *tx_dma_buf;
214 dma_addr_t tx_dma_phys;
215 struct dma_async_tx_descriptor *tx_dma_desc;
216 };
217
218 static int tegra_slink_runtime_suspend(struct device *dev);
219 static int tegra_slink_runtime_resume(struct device *dev);
220
221 static inline u32 tegra_slink_readl(struct tegra_slink_data *tspi,
222 unsigned long reg)
223 {
224 return readl(tspi->base + reg);
225 }
226
227 static inline void tegra_slink_writel(struct tegra_slink_data *tspi,
228 u32 val, unsigned long reg)
229 {
230 writel(val, tspi->base + reg);
231
232 /* Read back register to make sure that register writes completed */
233 if (reg != SLINK_TX_FIFO)
234 readl(tspi->base + SLINK_MAS_DATA);
235 }
236
237 static void tegra_slink_clear_status(struct tegra_slink_data *tspi)
238 {
239 u32 val_write;
240
241 tegra_slink_readl(tspi, SLINK_STATUS);
242
243 /* Write 1 to clear status register */
244 val_write = SLINK_RDY | SLINK_FIFO_ERROR;
245 tegra_slink_writel(tspi, val_write, SLINK_STATUS);
246 }
247
248 static u32 tegra_slink_get_packed_size(struct tegra_slink_data *tspi,
249 struct spi_transfer *t)
250 {
251 switch (tspi->bytes_per_word) {
252 case 0:
253 return SLINK_PACK_SIZE_4;
254 case 1:
255 return SLINK_PACK_SIZE_8;
256 case 2:
257 return SLINK_PACK_SIZE_16;
258 case 4:
259 return SLINK_PACK_SIZE_32;
260 default:
261 return 0;
262 }
263 }
264
265 static unsigned tegra_slink_calculate_curr_xfer_param(
266 struct spi_device *spi, struct tegra_slink_data *tspi,
267 struct spi_transfer *t)
268 {
269 unsigned remain_len = t->len - tspi->cur_pos;
270 unsigned max_word;
271 unsigned bits_per_word;
272 unsigned max_len;
273 unsigned total_fifo_words;
274
275 bits_per_word = t->bits_per_word;
276 tspi->bytes_per_word = DIV_ROUND_UP(bits_per_word, 8);
277
278 if (bits_per_word == 8 || bits_per_word == 16) {
279 tspi->is_packed = 1;
280 tspi->words_per_32bit = 32/bits_per_word;
281 } else {
282 tspi->is_packed = 0;
283 tspi->words_per_32bit = 1;
284 }
285 tspi->packed_size = tegra_slink_get_packed_size(tspi, t);
286
287 if (tspi->is_packed) {
288 max_len = min(remain_len, tspi->max_buf_size);
289 tspi->curr_dma_words = max_len/tspi->bytes_per_word;
290 total_fifo_words = max_len/4;
291 } else {
292 max_word = (remain_len - 1) / tspi->bytes_per_word + 1;
293 max_word = min(max_word, tspi->max_buf_size/4);
294 tspi->curr_dma_words = max_word;
295 total_fifo_words = max_word;
296 }
297 return total_fifo_words;
298 }
299
300 static unsigned tegra_slink_fill_tx_fifo_from_client_txbuf(
301 struct tegra_slink_data *tspi, struct spi_transfer *t)
302 {
303 unsigned nbytes;
304 unsigned tx_empty_count;
305 u32 fifo_status;
306 unsigned max_n_32bit;
307 unsigned i, count;
308 unsigned int written_words;
309 unsigned fifo_words_left;
310 u8 *tx_buf = (u8 *)t->tx_buf + tspi->cur_tx_pos;
311
312 fifo_status = tegra_slink_readl(tspi, SLINK_STATUS2);
313 tx_empty_count = SLINK_TX_FIFO_EMPTY_COUNT(fifo_status);
314
315 if (tspi->is_packed) {
316 fifo_words_left = tx_empty_count * tspi->words_per_32bit;
317 written_words = min(fifo_words_left, tspi->curr_dma_words);
318 nbytes = written_words * tspi->bytes_per_word;
319 max_n_32bit = DIV_ROUND_UP(nbytes, 4);
320 for (count = 0; count < max_n_32bit; count++) {
321 u32 x = 0;
322 for (i = 0; (i < 4) && nbytes; i++, nbytes--)
323 x |= (u32)(*tx_buf++) << (i * 8);
324 tegra_slink_writel(tspi, x, SLINK_TX_FIFO);
325 }
326 } else {
327 max_n_32bit = min(tspi->curr_dma_words, tx_empty_count);
328 written_words = max_n_32bit;
329 nbytes = written_words * tspi->bytes_per_word;
330 for (count = 0; count < max_n_32bit; count++) {
331 u32 x = 0;
332 for (i = 0; nbytes && (i < tspi->bytes_per_word);
333 i++, nbytes--)
334 x |= (u32)(*tx_buf++) << (i * 8);
335 tegra_slink_writel(tspi, x, SLINK_TX_FIFO);
336 }
337 }
338 tspi->cur_tx_pos += written_words * tspi->bytes_per_word;
339 return written_words;
340 }
341
342 static unsigned int tegra_slink_read_rx_fifo_to_client_rxbuf(
343 struct tegra_slink_data *tspi, struct spi_transfer *t)
344 {
345 unsigned rx_full_count;
346 u32 fifo_status;
347 unsigned i, count;
348 unsigned int read_words = 0;
349 unsigned len;
350 u8 *rx_buf = (u8 *)t->rx_buf + tspi->cur_rx_pos;
351
352 fifo_status = tegra_slink_readl(tspi, SLINK_STATUS2);
353 rx_full_count = SLINK_RX_FIFO_FULL_COUNT(fifo_status);
354 if (tspi->is_packed) {
355 len = tspi->curr_dma_words * tspi->bytes_per_word;
356 for (count = 0; count < rx_full_count; count++) {
357 u32 x = tegra_slink_readl(tspi, SLINK_RX_FIFO);
358 for (i = 0; len && (i < 4); i++, len--)
359 *rx_buf++ = (x >> i*8) & 0xFF;
360 }
361 tspi->cur_rx_pos += tspi->curr_dma_words * tspi->bytes_per_word;
362 read_words += tspi->curr_dma_words;
363 } else {
364 for (count = 0; count < rx_full_count; count++) {
365 u32 x = tegra_slink_readl(tspi, SLINK_RX_FIFO);
366 for (i = 0; (i < tspi->bytes_per_word); i++)
367 *rx_buf++ = (x >> (i*8)) & 0xFF;
368 }
369 tspi->cur_rx_pos += rx_full_count * tspi->bytes_per_word;
370 read_words += rx_full_count;
371 }
372 return read_words;
373 }
374
375 static void tegra_slink_copy_client_txbuf_to_spi_txbuf(
376 struct tegra_slink_data *tspi, struct spi_transfer *t)
377 {
378 /* Make the dma buffer to read by cpu */
379 dma_sync_single_for_cpu(tspi->dev, tspi->tx_dma_phys,
380 tspi->dma_buf_size, DMA_TO_DEVICE);
381
382 if (tspi->is_packed) {
383 unsigned len = tspi->curr_dma_words * tspi->bytes_per_word;
384 memcpy(tspi->tx_dma_buf, t->tx_buf + tspi->cur_pos, len);
385 } else {
386 unsigned int i;
387 unsigned int count;
388 u8 *tx_buf = (u8 *)t->tx_buf + tspi->cur_tx_pos;
389 unsigned consume = tspi->curr_dma_words * tspi->bytes_per_word;
390
391 for (count = 0; count < tspi->curr_dma_words; count++) {
392 u32 x = 0;
393 for (i = 0; consume && (i < tspi->bytes_per_word);
394 i++, consume--)
395 x |= (u32)(*tx_buf++) << (i * 8);
396 tspi->tx_dma_buf[count] = x;
397 }
398 }
399 tspi->cur_tx_pos += tspi->curr_dma_words * tspi->bytes_per_word;
400
401 /* Make the dma buffer to read by dma */
402 dma_sync_single_for_device(tspi->dev, tspi->tx_dma_phys,
403 tspi->dma_buf_size, DMA_TO_DEVICE);
404 }
405
406 static void tegra_slink_copy_spi_rxbuf_to_client_rxbuf(
407 struct tegra_slink_data *tspi, struct spi_transfer *t)
408 {
409 unsigned len;
410
411 /* Make the dma buffer to read by cpu */
412 dma_sync_single_for_cpu(tspi->dev, tspi->rx_dma_phys,
413 tspi->dma_buf_size, DMA_FROM_DEVICE);
414
415 if (tspi->is_packed) {
416 len = tspi->curr_dma_words * tspi->bytes_per_word;
417 memcpy(t->rx_buf + tspi->cur_rx_pos, tspi->rx_dma_buf, len);
418 } else {
419 unsigned int i;
420 unsigned int count;
421 unsigned char *rx_buf = t->rx_buf + tspi->cur_rx_pos;
422 u32 rx_mask = ((u32)1 << t->bits_per_word) - 1;
423
424 for (count = 0; count < tspi->curr_dma_words; count++) {
425 u32 x = tspi->rx_dma_buf[count] & rx_mask;
426 for (i = 0; (i < tspi->bytes_per_word); i++)
427 *rx_buf++ = (x >> (i*8)) & 0xFF;
428 }
429 }
430 tspi->cur_rx_pos += tspi->curr_dma_words * tspi->bytes_per_word;
431
432 /* Make the dma buffer to read by dma */
433 dma_sync_single_for_device(tspi->dev, tspi->rx_dma_phys,
434 tspi->dma_buf_size, DMA_FROM_DEVICE);
435 }
436
437 static void tegra_slink_dma_complete(void *args)
438 {
439 struct completion *dma_complete = args;
440
441 complete(dma_complete);
442 }
443
444 static int tegra_slink_start_tx_dma(struct tegra_slink_data *tspi, int len)
445 {
446 reinit_completion(&tspi->tx_dma_complete);
447 tspi->tx_dma_desc = dmaengine_prep_slave_single(tspi->tx_dma_chan,
448 tspi->tx_dma_phys, len, DMA_MEM_TO_DEV,
449 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
450 if (!tspi->tx_dma_desc) {
451 dev_err(tspi->dev, "Not able to get desc for Tx\n");
452 return -EIO;
453 }
454
455 tspi->tx_dma_desc->callback = tegra_slink_dma_complete;
456 tspi->tx_dma_desc->callback_param = &tspi->tx_dma_complete;
457
458 dmaengine_submit(tspi->tx_dma_desc);
459 dma_async_issue_pending(tspi->tx_dma_chan);
460 return 0;
461 }
462
463 static int tegra_slink_start_rx_dma(struct tegra_slink_data *tspi, int len)
464 {
465 reinit_completion(&tspi->rx_dma_complete);
466 tspi->rx_dma_desc = dmaengine_prep_slave_single(tspi->rx_dma_chan,
467 tspi->rx_dma_phys, len, DMA_DEV_TO_MEM,
468 DMA_PREP_INTERRUPT | DMA_CTRL_ACK);
469 if (!tspi->rx_dma_desc) {
470 dev_err(tspi->dev, "Not able to get desc for Rx\n");
471 return -EIO;
472 }
473
474 tspi->rx_dma_desc->callback = tegra_slink_dma_complete;
475 tspi->rx_dma_desc->callback_param = &tspi->rx_dma_complete;
476
477 dmaengine_submit(tspi->rx_dma_desc);
478 dma_async_issue_pending(tspi->rx_dma_chan);
479 return 0;
480 }
481
482 static int tegra_slink_start_dma_based_transfer(
483 struct tegra_slink_data *tspi, struct spi_transfer *t)
484 {
485 u32 val;
486 unsigned int len;
487 int ret = 0;
488 u32 status;
489
490 /* Make sure that Rx and Tx fifo are empty */
491 status = tegra_slink_readl(tspi, SLINK_STATUS);
492 if ((status & SLINK_FIFO_EMPTY) != SLINK_FIFO_EMPTY) {
493 dev_err(tspi->dev, "Rx/Tx fifo are not empty status 0x%08x\n",
494 (unsigned)status);
495 return -EIO;
496 }
497
498 val = SLINK_DMA_BLOCK_SIZE(tspi->curr_dma_words - 1);
499 val |= tspi->packed_size;
500 if (tspi->is_packed)
501 len = DIV_ROUND_UP(tspi->curr_dma_words * tspi->bytes_per_word,
502 4) * 4;
503 else
504 len = tspi->curr_dma_words * 4;
505
506 /* Set attention level based on length of transfer */
507 if (len & 0xF)
508 val |= SLINK_TX_TRIG_1 | SLINK_RX_TRIG_1;
509 else if (((len) >> 4) & 0x1)
510 val |= SLINK_TX_TRIG_4 | SLINK_RX_TRIG_4;
511 else
512 val |= SLINK_TX_TRIG_8 | SLINK_RX_TRIG_8;
513
514 if (tspi->cur_direction & DATA_DIR_TX)
515 val |= SLINK_IE_TXC;
516
517 if (tspi->cur_direction & DATA_DIR_RX)
518 val |= SLINK_IE_RXC;
519
520 tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
521 tspi->dma_control_reg = val;
522
523 if (tspi->cur_direction & DATA_DIR_TX) {
524 tegra_slink_copy_client_txbuf_to_spi_txbuf(tspi, t);
525 wmb();
526 ret = tegra_slink_start_tx_dma(tspi, len);
527 if (ret < 0) {
528 dev_err(tspi->dev,
529 "Starting tx dma failed, err %d\n", ret);
530 return ret;
531 }
532
533 /* Wait for tx fifo to be fill before starting slink */
534 status = tegra_slink_readl(tspi, SLINK_STATUS);
535 while (!(status & SLINK_TX_FULL))
536 status = tegra_slink_readl(tspi, SLINK_STATUS);
537 }
538
539 if (tspi->cur_direction & DATA_DIR_RX) {
540 /* Make the dma buffer to read by dma */
541 dma_sync_single_for_device(tspi->dev, tspi->rx_dma_phys,
542 tspi->dma_buf_size, DMA_FROM_DEVICE);
543
544 ret = tegra_slink_start_rx_dma(tspi, len);
545 if (ret < 0) {
546 dev_err(tspi->dev,
547 "Starting rx dma failed, err %d\n", ret);
548 if (tspi->cur_direction & DATA_DIR_TX)
549 dmaengine_terminate_all(tspi->tx_dma_chan);
550 return ret;
551 }
552 }
553 tspi->is_curr_dma_xfer = true;
554 if (tspi->is_packed) {
555 val |= SLINK_PACKED;
556 tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
557 /* HW need small delay after settign Packed mode */
558 udelay(1);
559 }
560 tspi->dma_control_reg = val;
561
562 val |= SLINK_DMA_EN;
563 tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
564 return ret;
565 }
566
567 static int tegra_slink_start_cpu_based_transfer(
568 struct tegra_slink_data *tspi, struct spi_transfer *t)
569 {
570 u32 val;
571 unsigned cur_words;
572
573 val = tspi->packed_size;
574 if (tspi->cur_direction & DATA_DIR_TX)
575 val |= SLINK_IE_TXC;
576
577 if (tspi->cur_direction & DATA_DIR_RX)
578 val |= SLINK_IE_RXC;
579
580 tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
581 tspi->dma_control_reg = val;
582
583 if (tspi->cur_direction & DATA_DIR_TX)
584 cur_words = tegra_slink_fill_tx_fifo_from_client_txbuf(tspi, t);
585 else
586 cur_words = tspi->curr_dma_words;
587 val |= SLINK_DMA_BLOCK_SIZE(cur_words - 1);
588 tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
589 tspi->dma_control_reg = val;
590
591 tspi->is_curr_dma_xfer = false;
592 if (tspi->is_packed) {
593 val |= SLINK_PACKED;
594 tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
595 udelay(1);
596 wmb();
597 }
598 tspi->dma_control_reg = val;
599 val |= SLINK_DMA_EN;
600 tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
601 return 0;
602 }
603
604 static int tegra_slink_init_dma_param(struct tegra_slink_data *tspi,
605 bool dma_to_memory)
606 {
607 struct dma_chan *dma_chan;
608 u32 *dma_buf;
609 dma_addr_t dma_phys;
610 int ret;
611 struct dma_slave_config dma_sconfig;
612
613 dma_chan = dma_request_slave_channel_reason(tspi->dev,
614 dma_to_memory ? "rx" : "tx");
615 if (IS_ERR(dma_chan)) {
616 ret = PTR_ERR(dma_chan);
617 if (ret != -EPROBE_DEFER)
618 dev_err(tspi->dev,
619 "Dma channel is not available: %d\n", ret);
620 return ret;
621 }
622
623 dma_buf = dma_alloc_coherent(tspi->dev, tspi->dma_buf_size,
624 &dma_phys, GFP_KERNEL);
625 if (!dma_buf) {
626 dev_err(tspi->dev, " Not able to allocate the dma buffer\n");
627 dma_release_channel(dma_chan);
628 return -ENOMEM;
629 }
630
631 if (dma_to_memory) {
632 dma_sconfig.src_addr = tspi->phys + SLINK_RX_FIFO;
633 dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
634 dma_sconfig.src_maxburst = 0;
635 } else {
636 dma_sconfig.dst_addr = tspi->phys + SLINK_TX_FIFO;
637 dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
638 dma_sconfig.dst_maxburst = 0;
639 }
640
641 ret = dmaengine_slave_config(dma_chan, &dma_sconfig);
642 if (ret)
643 goto scrub;
644 if (dma_to_memory) {
645 tspi->rx_dma_chan = dma_chan;
646 tspi->rx_dma_buf = dma_buf;
647 tspi->rx_dma_phys = dma_phys;
648 } else {
649 tspi->tx_dma_chan = dma_chan;
650 tspi->tx_dma_buf = dma_buf;
651 tspi->tx_dma_phys = dma_phys;
652 }
653 return 0;
654
655 scrub:
656 dma_free_coherent(tspi->dev, tspi->dma_buf_size, dma_buf, dma_phys);
657 dma_release_channel(dma_chan);
658 return ret;
659 }
660
661 static void tegra_slink_deinit_dma_param(struct tegra_slink_data *tspi,
662 bool dma_to_memory)
663 {
664 u32 *dma_buf;
665 dma_addr_t dma_phys;
666 struct dma_chan *dma_chan;
667
668 if (dma_to_memory) {
669 dma_buf = tspi->rx_dma_buf;
670 dma_chan = tspi->rx_dma_chan;
671 dma_phys = tspi->rx_dma_phys;
672 tspi->rx_dma_chan = NULL;
673 tspi->rx_dma_buf = NULL;
674 } else {
675 dma_buf = tspi->tx_dma_buf;
676 dma_chan = tspi->tx_dma_chan;
677 dma_phys = tspi->tx_dma_phys;
678 tspi->tx_dma_buf = NULL;
679 tspi->tx_dma_chan = NULL;
680 }
681 if (!dma_chan)
682 return;
683
684 dma_free_coherent(tspi->dev, tspi->dma_buf_size, dma_buf, dma_phys);
685 dma_release_channel(dma_chan);
686 }
687
688 static int tegra_slink_start_transfer_one(struct spi_device *spi,
689 struct spi_transfer *t)
690 {
691 struct tegra_slink_data *tspi = spi_master_get_devdata(spi->master);
692 u32 speed;
693 u8 bits_per_word;
694 unsigned total_fifo_words;
695 int ret;
696 u32 command;
697 u32 command2;
698
699 bits_per_word = t->bits_per_word;
700 speed = t->speed_hz;
701 if (speed != tspi->cur_speed) {
702 clk_set_rate(tspi->clk, speed * 4);
703 tspi->cur_speed = speed;
704 }
705
706 tspi->cur_spi = spi;
707 tspi->cur_pos = 0;
708 tspi->cur_rx_pos = 0;
709 tspi->cur_tx_pos = 0;
710 tspi->curr_xfer = t;
711 total_fifo_words = tegra_slink_calculate_curr_xfer_param(spi, tspi, t);
712
713 command = tspi->command_reg;
714 command &= ~SLINK_BIT_LENGTH(~0);
715 command |= SLINK_BIT_LENGTH(bits_per_word - 1);
716
717 command2 = tspi->command2_reg;
718 command2 &= ~(SLINK_RXEN | SLINK_TXEN);
719
720 tegra_slink_writel(tspi, command, SLINK_COMMAND);
721 tspi->command_reg = command;
722
723 tspi->cur_direction = 0;
724 if (t->rx_buf) {
725 command2 |= SLINK_RXEN;
726 tspi->cur_direction |= DATA_DIR_RX;
727 }
728 if (t->tx_buf) {
729 command2 |= SLINK_TXEN;
730 tspi->cur_direction |= DATA_DIR_TX;
731 }
732 tegra_slink_writel(tspi, command2, SLINK_COMMAND2);
733 tspi->command2_reg = command2;
734
735 if (total_fifo_words > SLINK_FIFO_DEPTH)
736 ret = tegra_slink_start_dma_based_transfer(tspi, t);
737 else
738 ret = tegra_slink_start_cpu_based_transfer(tspi, t);
739 return ret;
740 }
741
742 static int tegra_slink_setup(struct spi_device *spi)
743 {
744 static const u32 cs_pol_bit[MAX_CHIP_SELECT] = {
745 SLINK_CS_POLARITY,
746 SLINK_CS_POLARITY1,
747 SLINK_CS_POLARITY2,
748 SLINK_CS_POLARITY3,
749 };
750
751 struct tegra_slink_data *tspi = spi_master_get_devdata(spi->master);
752 u32 val;
753 unsigned long flags;
754 int ret;
755
756 dev_dbg(&spi->dev, "setup %d bpw, %scpol, %scpha, %dHz\n",
757 spi->bits_per_word,
758 spi->mode & SPI_CPOL ? "" : "~",
759 spi->mode & SPI_CPHA ? "" : "~",
760 spi->max_speed_hz);
761
762 ret = pm_runtime_get_sync(tspi->dev);
763 if (ret < 0) {
764 dev_err(tspi->dev, "pm runtime failed, e = %d\n", ret);
765 return ret;
766 }
767
768 spin_lock_irqsave(&tspi->lock, flags);
769 val = tspi->def_command_reg;
770 if (spi->mode & SPI_CS_HIGH)
771 val |= cs_pol_bit[spi->chip_select];
772 else
773 val &= ~cs_pol_bit[spi->chip_select];
774 tspi->def_command_reg = val;
775 tegra_slink_writel(tspi, tspi->def_command_reg, SLINK_COMMAND);
776 spin_unlock_irqrestore(&tspi->lock, flags);
777
778 pm_runtime_put(tspi->dev);
779 return 0;
780 }
781
782 static int tegra_slink_prepare_message(struct spi_master *master,
783 struct spi_message *msg)
784 {
785 struct tegra_slink_data *tspi = spi_master_get_devdata(master);
786 struct spi_device *spi = msg->spi;
787
788 tegra_slink_clear_status(tspi);
789
790 tspi->command_reg = tspi->def_command_reg;
791 tspi->command_reg |= SLINK_CS_SW | SLINK_CS_VALUE;
792
793 tspi->command2_reg = tspi->def_command2_reg;
794 tspi->command2_reg |= SLINK_SS_EN_CS(spi->chip_select);
795
796 tspi->command_reg &= ~SLINK_MODES;
797 if (spi->mode & SPI_CPHA)
798 tspi->command_reg |= SLINK_CK_SDA;
799
800 if (spi->mode & SPI_CPOL)
801 tspi->command_reg |= SLINK_IDLE_SCLK_DRIVE_HIGH;
802 else
803 tspi->command_reg |= SLINK_IDLE_SCLK_DRIVE_LOW;
804
805 return 0;
806 }
807
808 static int tegra_slink_transfer_one(struct spi_master *master,
809 struct spi_device *spi,
810 struct spi_transfer *xfer)
811 {
812 struct tegra_slink_data *tspi = spi_master_get_devdata(master);
813 int ret;
814
815 reinit_completion(&tspi->xfer_completion);
816 ret = tegra_slink_start_transfer_one(spi, xfer);
817 if (ret < 0) {
818 dev_err(tspi->dev,
819 "spi can not start transfer, err %d\n", ret);
820 return ret;
821 }
822
823 ret = wait_for_completion_timeout(&tspi->xfer_completion,
824 SLINK_DMA_TIMEOUT);
825 if (WARN_ON(ret == 0)) {
826 dev_err(tspi->dev,
827 "spi transfer timeout, err %d\n", ret);
828 return -EIO;
829 }
830
831 if (tspi->tx_status)
832 return tspi->tx_status;
833 if (tspi->rx_status)
834 return tspi->rx_status;
835
836 return 0;
837 }
838
839 static int tegra_slink_unprepare_message(struct spi_master *master,
840 struct spi_message *msg)
841 {
842 struct tegra_slink_data *tspi = spi_master_get_devdata(master);
843
844 tegra_slink_writel(tspi, tspi->def_command_reg, SLINK_COMMAND);
845 tegra_slink_writel(tspi, tspi->def_command2_reg, SLINK_COMMAND2);
846
847 return 0;
848 }
849
850 static irqreturn_t handle_cpu_based_xfer(struct tegra_slink_data *tspi)
851 {
852 struct spi_transfer *t = tspi->curr_xfer;
853 unsigned long flags;
854
855 spin_lock_irqsave(&tspi->lock, flags);
856 if (tspi->tx_status || tspi->rx_status ||
857 (tspi->status_reg & SLINK_BSY)) {
858 dev_err(tspi->dev,
859 "CpuXfer ERROR bit set 0x%x\n", tspi->status_reg);
860 dev_err(tspi->dev,
861 "CpuXfer 0x%08x:0x%08x:0x%08x\n", tspi->command_reg,
862 tspi->command2_reg, tspi->dma_control_reg);
863 reset_control_assert(tspi->rst);
864 udelay(2);
865 reset_control_deassert(tspi->rst);
866 complete(&tspi->xfer_completion);
867 goto exit;
868 }
869
870 if (tspi->cur_direction & DATA_DIR_RX)
871 tegra_slink_read_rx_fifo_to_client_rxbuf(tspi, t);
872
873 if (tspi->cur_direction & DATA_DIR_TX)
874 tspi->cur_pos = tspi->cur_tx_pos;
875 else
876 tspi->cur_pos = tspi->cur_rx_pos;
877
878 if (tspi->cur_pos == t->len) {
879 complete(&tspi->xfer_completion);
880 goto exit;
881 }
882
883 tegra_slink_calculate_curr_xfer_param(tspi->cur_spi, tspi, t);
884 tegra_slink_start_cpu_based_transfer(tspi, t);
885 exit:
886 spin_unlock_irqrestore(&tspi->lock, flags);
887 return IRQ_HANDLED;
888 }
889
890 static irqreturn_t handle_dma_based_xfer(struct tegra_slink_data *tspi)
891 {
892 struct spi_transfer *t = tspi->curr_xfer;
893 long wait_status;
894 int err = 0;
895 unsigned total_fifo_words;
896 unsigned long flags;
897
898 /* Abort dmas if any error */
899 if (tspi->cur_direction & DATA_DIR_TX) {
900 if (tspi->tx_status) {
901 dmaengine_terminate_all(tspi->tx_dma_chan);
902 err += 1;
903 } else {
904 wait_status = wait_for_completion_interruptible_timeout(
905 &tspi->tx_dma_complete, SLINK_DMA_TIMEOUT);
906 if (wait_status <= 0) {
907 dmaengine_terminate_all(tspi->tx_dma_chan);
908 dev_err(tspi->dev, "TxDma Xfer failed\n");
909 err += 1;
910 }
911 }
912 }
913
914 if (tspi->cur_direction & DATA_DIR_RX) {
915 if (tspi->rx_status) {
916 dmaengine_terminate_all(tspi->rx_dma_chan);
917 err += 2;
918 } else {
919 wait_status = wait_for_completion_interruptible_timeout(
920 &tspi->rx_dma_complete, SLINK_DMA_TIMEOUT);
921 if (wait_status <= 0) {
922 dmaengine_terminate_all(tspi->rx_dma_chan);
923 dev_err(tspi->dev, "RxDma Xfer failed\n");
924 err += 2;
925 }
926 }
927 }
928
929 spin_lock_irqsave(&tspi->lock, flags);
930 if (err) {
931 dev_err(tspi->dev,
932 "DmaXfer: ERROR bit set 0x%x\n", tspi->status_reg);
933 dev_err(tspi->dev,
934 "DmaXfer 0x%08x:0x%08x:0x%08x\n", tspi->command_reg,
935 tspi->command2_reg, tspi->dma_control_reg);
936 reset_control_assert(tspi->rst);
937 udelay(2);
938 reset_control_assert(tspi->rst);
939 complete(&tspi->xfer_completion);
940 spin_unlock_irqrestore(&tspi->lock, flags);
941 return IRQ_HANDLED;
942 }
943
944 if (tspi->cur_direction & DATA_DIR_RX)
945 tegra_slink_copy_spi_rxbuf_to_client_rxbuf(tspi, t);
946
947 if (tspi->cur_direction & DATA_DIR_TX)
948 tspi->cur_pos = tspi->cur_tx_pos;
949 else
950 tspi->cur_pos = tspi->cur_rx_pos;
951
952 if (tspi->cur_pos == t->len) {
953 complete(&tspi->xfer_completion);
954 goto exit;
955 }
956
957 /* Continue transfer in current message */
958 total_fifo_words = tegra_slink_calculate_curr_xfer_param(tspi->cur_spi,
959 tspi, t);
960 if (total_fifo_words > SLINK_FIFO_DEPTH)
961 err = tegra_slink_start_dma_based_transfer(tspi, t);
962 else
963 err = tegra_slink_start_cpu_based_transfer(tspi, t);
964
965 exit:
966 spin_unlock_irqrestore(&tspi->lock, flags);
967 return IRQ_HANDLED;
968 }
969
970 static irqreturn_t tegra_slink_isr_thread(int irq, void *context_data)
971 {
972 struct tegra_slink_data *tspi = context_data;
973
974 if (!tspi->is_curr_dma_xfer)
975 return handle_cpu_based_xfer(tspi);
976 return handle_dma_based_xfer(tspi);
977 }
978
979 static irqreturn_t tegra_slink_isr(int irq, void *context_data)
980 {
981 struct tegra_slink_data *tspi = context_data;
982
983 tspi->status_reg = tegra_slink_readl(tspi, SLINK_STATUS);
984 if (tspi->cur_direction & DATA_DIR_TX)
985 tspi->tx_status = tspi->status_reg &
986 (SLINK_TX_OVF | SLINK_TX_UNF);
987
988 if (tspi->cur_direction & DATA_DIR_RX)
989 tspi->rx_status = tspi->status_reg &
990 (SLINK_RX_OVF | SLINK_RX_UNF);
991 tegra_slink_clear_status(tspi);
992
993 return IRQ_WAKE_THREAD;
994 }
995
996 static const struct tegra_slink_chip_data tegra30_spi_cdata = {
997 .cs_hold_time = true,
998 };
999
1000 static const struct tegra_slink_chip_data tegra20_spi_cdata = {
1001 .cs_hold_time = false,
1002 };
1003
1004 static const struct of_device_id tegra_slink_of_match[] = {
1005 { .compatible = "nvidia,tegra30-slink", .data = &tegra30_spi_cdata, },
1006 { .compatible = "nvidia,tegra20-slink", .data = &tegra20_spi_cdata, },
1007 {}
1008 };
1009 MODULE_DEVICE_TABLE(of, tegra_slink_of_match);
1010
1011 static int tegra_slink_probe(struct platform_device *pdev)
1012 {
1013 struct spi_master *master;
1014 struct tegra_slink_data *tspi;
1015 struct resource *r;
1016 int ret, spi_irq;
1017 const struct tegra_slink_chip_data *cdata = NULL;
1018 const struct of_device_id *match;
1019
1020 match = of_match_device(tegra_slink_of_match, &pdev->dev);
1021 if (!match) {
1022 dev_err(&pdev->dev, "Error: No device match found\n");
1023 return -ENODEV;
1024 }
1025 cdata = match->data;
1026
1027 master = spi_alloc_master(&pdev->dev, sizeof(*tspi));
1028 if (!master) {
1029 dev_err(&pdev->dev, "master allocation failed\n");
1030 return -ENOMEM;
1031 }
1032
1033 /* the spi->mode bits understood by this driver: */
1034 master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
1035 master->setup = tegra_slink_setup;
1036 master->prepare_message = tegra_slink_prepare_message;
1037 master->transfer_one = tegra_slink_transfer_one;
1038 master->unprepare_message = tegra_slink_unprepare_message;
1039 master->auto_runtime_pm = true;
1040 master->num_chipselect = MAX_CHIP_SELECT;
1041
1042 platform_set_drvdata(pdev, master);
1043 tspi = spi_master_get_devdata(master);
1044 tspi->master = master;
1045 tspi->dev = &pdev->dev;
1046 tspi->chip_data = cdata;
1047 spin_lock_init(&tspi->lock);
1048
1049 if (of_property_read_u32(tspi->dev->of_node, "spi-max-frequency",
1050 &master->max_speed_hz))
1051 master->max_speed_hz = 25000000; /* 25MHz */
1052
1053 r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
1054 if (!r) {
1055 dev_err(&pdev->dev, "No IO memory resource\n");
1056 ret = -ENODEV;
1057 goto exit_free_master;
1058 }
1059 tspi->phys = r->start;
1060 tspi->base = devm_ioremap_resource(&pdev->dev, r);
1061 if (IS_ERR(tspi->base)) {
1062 ret = PTR_ERR(tspi->base);
1063 goto exit_free_master;
1064 }
1065
1066 spi_irq = platform_get_irq(pdev, 0);
1067 tspi->irq = spi_irq;
1068 ret = request_threaded_irq(tspi->irq, tegra_slink_isr,
1069 tegra_slink_isr_thread, IRQF_ONESHOT,
1070 dev_name(&pdev->dev), tspi);
1071 if (ret < 0) {
1072 dev_err(&pdev->dev, "Failed to register ISR for IRQ %d\n",
1073 tspi->irq);
1074 goto exit_free_master;
1075 }
1076
1077 tspi->clk = devm_clk_get(&pdev->dev, NULL);
1078 if (IS_ERR(tspi->clk)) {
1079 dev_err(&pdev->dev, "can not get clock\n");
1080 ret = PTR_ERR(tspi->clk);
1081 goto exit_free_irq;
1082 }
1083
1084 tspi->rst = devm_reset_control_get(&pdev->dev, "spi");
1085 if (IS_ERR(tspi->rst)) {
1086 dev_err(&pdev->dev, "can not get reset\n");
1087 ret = PTR_ERR(tspi->rst);
1088 goto exit_free_irq;
1089 }
1090
1091 tspi->max_buf_size = SLINK_FIFO_DEPTH << 2;
1092 tspi->dma_buf_size = DEFAULT_SPI_DMA_BUF_LEN;
1093
1094 ret = tegra_slink_init_dma_param(tspi, true);
1095 if (ret < 0)
1096 goto exit_free_irq;
1097 ret = tegra_slink_init_dma_param(tspi, false);
1098 if (ret < 0)
1099 goto exit_rx_dma_free;
1100 tspi->max_buf_size = tspi->dma_buf_size;
1101 init_completion(&tspi->tx_dma_complete);
1102 init_completion(&tspi->rx_dma_complete);
1103
1104 init_completion(&tspi->xfer_completion);
1105
1106 pm_runtime_enable(&pdev->dev);
1107 if (!pm_runtime_enabled(&pdev->dev)) {
1108 ret = tegra_slink_runtime_resume(&pdev->dev);
1109 if (ret)
1110 goto exit_pm_disable;
1111 }
1112
1113 ret = pm_runtime_get_sync(&pdev->dev);
1114 if (ret < 0) {
1115 dev_err(&pdev->dev, "pm runtime get failed, e = %d\n", ret);
1116 goto exit_pm_disable;
1117 }
1118 tspi->def_command_reg = SLINK_M_S;
1119 tspi->def_command2_reg = SLINK_CS_ACTIVE_BETWEEN;
1120 tegra_slink_writel(tspi, tspi->def_command_reg, SLINK_COMMAND);
1121 tegra_slink_writel(tspi, tspi->def_command2_reg, SLINK_COMMAND2);
1122 pm_runtime_put(&pdev->dev);
1123
1124 master->dev.of_node = pdev->dev.of_node;
1125 ret = devm_spi_register_master(&pdev->dev, master);
1126 if (ret < 0) {
1127 dev_err(&pdev->dev, "can not register to master err %d\n", ret);
1128 goto exit_pm_disable;
1129 }
1130 return ret;
1131
1132 exit_pm_disable:
1133 pm_runtime_disable(&pdev->dev);
1134 if (!pm_runtime_status_suspended(&pdev->dev))
1135 tegra_slink_runtime_suspend(&pdev->dev);
1136 tegra_slink_deinit_dma_param(tspi, false);
1137 exit_rx_dma_free:
1138 tegra_slink_deinit_dma_param(tspi, true);
1139 exit_free_irq:
1140 free_irq(spi_irq, tspi);
1141 exit_free_master:
1142 spi_master_put(master);
1143 return ret;
1144 }
1145
1146 static int tegra_slink_remove(struct platform_device *pdev)
1147 {
1148 struct spi_master *master = platform_get_drvdata(pdev);
1149 struct tegra_slink_data *tspi = spi_master_get_devdata(master);
1150
1151 free_irq(tspi->irq, tspi);
1152
1153 if (tspi->tx_dma_chan)
1154 tegra_slink_deinit_dma_param(tspi, false);
1155
1156 if (tspi->rx_dma_chan)
1157 tegra_slink_deinit_dma_param(tspi, true);
1158
1159 pm_runtime_disable(&pdev->dev);
1160 if (!pm_runtime_status_suspended(&pdev->dev))
1161 tegra_slink_runtime_suspend(&pdev->dev);
1162
1163 return 0;
1164 }
1165
1166 #ifdef CONFIG_PM_SLEEP
1167 static int tegra_slink_suspend(struct device *dev)
1168 {
1169 struct spi_master *master = dev_get_drvdata(dev);
1170
1171 return spi_master_suspend(master);
1172 }
1173
1174 static int tegra_slink_resume(struct device *dev)
1175 {
1176 struct spi_master *master = dev_get_drvdata(dev);
1177 struct tegra_slink_data *tspi = spi_master_get_devdata(master);
1178 int ret;
1179
1180 ret = pm_runtime_get_sync(dev);
1181 if (ret < 0) {
1182 dev_err(dev, "pm runtime failed, e = %d\n", ret);
1183 return ret;
1184 }
1185 tegra_slink_writel(tspi, tspi->command_reg, SLINK_COMMAND);
1186 tegra_slink_writel(tspi, tspi->command2_reg, SLINK_COMMAND2);
1187 pm_runtime_put(dev);
1188
1189 return spi_master_resume(master);
1190 }
1191 #endif
1192
1193 static int tegra_slink_runtime_suspend(struct device *dev)
1194 {
1195 struct spi_master *master = dev_get_drvdata(dev);
1196 struct tegra_slink_data *tspi = spi_master_get_devdata(master);
1197
1198 /* Flush all write which are in PPSB queue by reading back */
1199 tegra_slink_readl(tspi, SLINK_MAS_DATA);
1200
1201 clk_disable_unprepare(tspi->clk);
1202 return 0;
1203 }
1204
1205 static int tegra_slink_runtime_resume(struct device *dev)
1206 {
1207 struct spi_master *master = dev_get_drvdata(dev);
1208 struct tegra_slink_data *tspi = spi_master_get_devdata(master);
1209 int ret;
1210
1211 ret = clk_prepare_enable(tspi->clk);
1212 if (ret < 0) {
1213 dev_err(tspi->dev, "clk_prepare failed: %d\n", ret);
1214 return ret;
1215 }
1216 return 0;
1217 }
1218
1219 static const struct dev_pm_ops slink_pm_ops = {
1220 SET_RUNTIME_PM_OPS(tegra_slink_runtime_suspend,
1221 tegra_slink_runtime_resume, NULL)
1222 SET_SYSTEM_SLEEP_PM_OPS(tegra_slink_suspend, tegra_slink_resume)
1223 };
1224 static struct platform_driver tegra_slink_driver = {
1225 .driver = {
1226 .name = "spi-tegra-slink",
1227 .pm = &slink_pm_ops,
1228 .of_match_table = tegra_slink_of_match,
1229 },
1230 .probe = tegra_slink_probe,
1231 .remove = tegra_slink_remove,
1232 };
1233 module_platform_driver(tegra_slink_driver);
1234
1235 MODULE_ALIAS("platform:spi-tegra-slink");
1236 MODULE_DESCRIPTION("NVIDIA Tegra20/Tegra30 SLINK Controller Driver");
1237 MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
1238 MODULE_LICENSE("GPL v2");
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