1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * ALSA SoC I2S Audio Layer for Broadcom BCM2835 SoC
4 *
5 * Author: Florian Meier <florian.meier@koalo.de>
6 * Copyright 2013
7 *
8 * Based on
9 * Raspberry Pi PCM I2S ALSA Driver
10 * Copyright (c) by Phil Poole 2013
11 *
12 * ALSA SoC I2S (McBSP) Audio Layer for TI DAVINCI processor
13 * Vladimir Barinov, <vbarinov@embeddedalley.com>
14 * Copyright (C) 2007 MontaVista Software, Inc., <source@mvista.com>
15 *
16 * OMAP ALSA SoC DAI driver using McBSP port
17 * Copyright (C) 2008 Nokia Corporation
18 * Contact: Jarkko Nikula <jarkko.nikula@bitmer.com>
19 * Peter Ujfalusi <peter.ujfalusi@ti.com>
20 *
21 * Freescale SSI ALSA SoC Digital Audio Interface (DAI) driver
22 * Author: Timur Tabi <timur@freescale.com>
23 * Copyright 2007-2010 Freescale Semiconductor, Inc.
24 */
25
26 #include <linux/bitops.h>
27 #include <linux/clk.h>
28 #include <linux/delay.h>
29 #include <linux/device.h>
30 #include <linux/init.h>
31 #include <linux/io.h>
32 #include <linux/module.h>
33 #include <linux/of_address.h>
34 #include <linux/slab.h>
35
36 #include <sound/core.h>
37 #include <sound/dmaengine_pcm.h>
38 #include <sound/initval.h>
39 #include <sound/pcm.h>
40 #include <sound/pcm_params.h>
41 #include <sound/soc.h>
42
43 /* I2S registers */
44 #define BCM2835_I2S_CS_A_REG 0x00
45 #define BCM2835_I2S_FIFO_A_REG 0x04
46 #define BCM2835_I2S_MODE_A_REG 0x08
47 #define BCM2835_I2S_RXC_A_REG 0x0c
48 #define BCM2835_I2S_TXC_A_REG 0x10
49 #define BCM2835_I2S_DREQ_A_REG 0x14
50 #define BCM2835_I2S_INTEN_A_REG 0x18
51 #define BCM2835_I2S_INTSTC_A_REG 0x1c
52 #define BCM2835_I2S_GRAY_REG 0x20
53
54 /* I2S register settings */
55 #define BCM2835_I2S_STBY BIT(25)
56 #define BCM2835_I2S_SYNC BIT(24)
57 #define BCM2835_I2S_RXSEX BIT(23)
58 #define BCM2835_I2S_RXF BIT(22)
59 #define BCM2835_I2S_TXE BIT(21)
60 #define BCM2835_I2S_RXD BIT(20)
61 #define BCM2835_I2S_TXD BIT(19)
62 #define BCM2835_I2S_RXR BIT(18)
63 #define BCM2835_I2S_TXW BIT(17)
64 #define BCM2835_I2S_CS_RXERR BIT(16)
65 #define BCM2835_I2S_CS_TXERR BIT(15)
66 #define BCM2835_I2S_RXSYNC BIT(14)
67 #define BCM2835_I2S_TXSYNC BIT(13)
68 #define BCM2835_I2S_DMAEN BIT(9)
69 #define BCM2835_I2S_RXTHR(v) ((v) << 7)
70 #define BCM2835_I2S_TXTHR(v) ((v) << 5)
71 #define BCM2835_I2S_RXCLR BIT(4)
72 #define BCM2835_I2S_TXCLR BIT(3)
73 #define BCM2835_I2S_TXON BIT(2)
74 #define BCM2835_I2S_RXON BIT(1)
75 #define BCM2835_I2S_EN (1)
76
77 #define BCM2835_I2S_CLKDIS BIT(28)
78 #define BCM2835_I2S_PDMN BIT(27)
79 #define BCM2835_I2S_PDME BIT(26)
80 #define BCM2835_I2S_FRXP BIT(25)
81 #define BCM2835_I2S_FTXP BIT(24)
82 #define BCM2835_I2S_CLKM BIT(23)
83 #define BCM2835_I2S_CLKI BIT(22)
84 #define BCM2835_I2S_FSM BIT(21)
85 #define BCM2835_I2S_FSI BIT(20)
86 #define BCM2835_I2S_FLEN(v) ((v) << 10)
87 #define BCM2835_I2S_FSLEN(v) (v)
88
89 #define BCM2835_I2S_CHWEX BIT(15)
90 #define BCM2835_I2S_CHEN BIT(14)
91 #define BCM2835_I2S_CHPOS(v) ((v) << 4)
92 #define BCM2835_I2S_CHWID(v) (v)
93 #define BCM2835_I2S_CH1(v) ((v) << 16)
94 #define BCM2835_I2S_CH2(v) (v)
95 #define BCM2835_I2S_CH1_POS(v) BCM2835_I2S_CH1(BCM2835_I2S_CHPOS(v))
96 #define BCM2835_I2S_CH2_POS(v) BCM2835_I2S_CH2(BCM2835_I2S_CHPOS(v))
97
98 #define BCM2835_I2S_TX_PANIC(v) ((v) << 24)
99 #define BCM2835_I2S_RX_PANIC(v) ((v) << 16)
100 #define BCM2835_I2S_TX(v) ((v) << 8)
101 #define BCM2835_I2S_RX(v) (v)
102
103 #define BCM2835_I2S_INT_RXERR BIT(3)
104 #define BCM2835_I2S_INT_TXERR BIT(2)
105 #define BCM2835_I2S_INT_RXR BIT(1)
106 #define BCM2835_I2S_INT_TXW BIT(0)
107
108 /* Frame length register is 10 bit, maximum length 1024 */
109 #define BCM2835_I2S_MAX_FRAME_LENGTH 1024
110
111 /* General device struct */
112 struct bcm2835_i2s_dev {
113 struct device *dev;
114 struct snd_dmaengine_dai_dma_data dma_data[2];
115 unsigned int fmt;
116 unsigned int tdm_slots;
117 unsigned int rx_mask;
118 unsigned int tx_mask;
119 unsigned int slot_width;
120 unsigned int frame_length;
121
122 struct regmap *i2s_regmap;
123 struct clk *clk;
124 bool clk_prepared;
125 int clk_rate;
126 };
127
128 static void bcm2835_i2s_start_clock(struct bcm2835_i2s_dev *dev)
129 {
130 unsigned int provider = dev->fmt & SND_SOC_DAIFMT_CLOCK_PROVIDER_MASK;
131
132 if (dev->clk_prepared)
133 return;
134
135 switch (provider) {
136 case SND_SOC_DAIFMT_BP_FP:
137 case SND_SOC_DAIFMT_BP_FC:
138 clk_prepare_enable(dev->clk);
139 dev->clk_prepared = true;
140 break;
141 default:
142 break;
143 }
144 }
145
146 static void bcm2835_i2s_stop_clock(struct bcm2835_i2s_dev *dev)
147 {
148 if (dev->clk_prepared)
149 clk_disable_unprepare(dev->clk);
150 dev->clk_prepared = false;
151 }
152
153 static void bcm2835_i2s_clear_fifos(struct bcm2835_i2s_dev *dev,
154 bool tx, bool rx)
155 {
156 int timeout = 1000;
157 uint32_t syncval;
158 uint32_t csreg;
159 uint32_t i2s_active_state;
160 bool clk_was_prepared;
161 uint32_t off;
162 uint32_t clr;
163
164 off = tx ? BCM2835_I2S_TXON : 0;
165 off |= rx ? BCM2835_I2S_RXON : 0;
166
167 clr = tx ? BCM2835_I2S_TXCLR : 0;
168 clr |= rx ? BCM2835_I2S_RXCLR : 0;
169
170 /* Backup the current state */
171 regmap_read(dev->i2s_regmap, BCM2835_I2S_CS_A_REG, &csreg);
172 i2s_active_state = csreg & (BCM2835_I2S_RXON | BCM2835_I2S_TXON);
173
174 /* Start clock if not running */
175 clk_was_prepared = dev->clk_prepared;
176 if (!clk_was_prepared)
177 bcm2835_i2s_start_clock(dev);
178
179 /* Stop I2S module */
180 regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG, off, 0);
181
182 /*
183 * Clear the FIFOs
184 * Requires at least 2 PCM clock cycles to take effect
185 */
186 regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG, clr, clr);
187
188 /* Wait for 2 PCM clock cycles */
189
190 /*
191 * Toggle the SYNC flag. After 2 PCM clock cycles it can be read back
192 * FIXME: This does not seem to work for slave mode!
193 */
194 regmap_read(dev->i2s_regmap, BCM2835_I2S_CS_A_REG, &syncval);
195 syncval &= BCM2835_I2S_SYNC;
196
197 regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG,
198 BCM2835_I2S_SYNC, ~syncval);
199
200 /* Wait for the SYNC flag changing it's state */
201 while (--timeout) {
202 regmap_read(dev->i2s_regmap, BCM2835_I2S_CS_A_REG, &csreg);
203 if ((csreg & BCM2835_I2S_SYNC) != syncval)
204 break;
205 }
206
207 if (!timeout)
208 dev_err(dev->dev, "I2S SYNC error!\n");
209
210 /* Stop clock if it was not running before */
211 if (!clk_was_prepared)
212 bcm2835_i2s_stop_clock(dev);
213
214 /* Restore I2S state */
215 regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG,
216 BCM2835_I2S_RXON | BCM2835_I2S_TXON, i2s_active_state);
217 }
218
219 static int bcm2835_i2s_set_dai_fmt(struct snd_soc_dai *dai,
220 unsigned int fmt)
221 {
222 struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
223 dev->fmt = fmt;
224 return 0;
225 }
226
227 static int bcm2835_i2s_set_dai_bclk_ratio(struct snd_soc_dai *dai,
228 unsigned int ratio)
229 {
230 struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
231
232 if (!ratio) {
233 dev->tdm_slots = 0;
234 return 0;
235 }
236
237 if (ratio > BCM2835_I2S_MAX_FRAME_LENGTH)
238 return -EINVAL;
239
240 dev->tdm_slots = 2;
241 dev->rx_mask = 0x03;
242 dev->tx_mask = 0x03;
243 dev->slot_width = ratio / 2;
244 dev->frame_length = ratio;
245
246 return 0;
247 }
248
249 static int bcm2835_i2s_set_dai_tdm_slot(struct snd_soc_dai *dai,
250 unsigned int tx_mask, unsigned int rx_mask,
251 int slots, int width)
252 {
253 struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
254
255 if (slots) {
256 if (slots < 0 || width < 0)
257 return -EINVAL;
258
259 /* Limit masks to available slots */
260 rx_mask &= GENMASK(slots - 1, 0);
261 tx_mask &= GENMASK(slots - 1, 0);
262
263 /*
264 * The driver is limited to 2-channel setups.
265 * Check that exactly 2 bits are set in the masks.
266 */
267 if (hweight_long((unsigned long) rx_mask) != 2
268 || hweight_long((unsigned long) tx_mask) != 2)
269 return -EINVAL;
270
271 if (slots * width > BCM2835_I2S_MAX_FRAME_LENGTH)
272 return -EINVAL;
273 }
274
275 dev->tdm_slots = slots;
276
277 dev->rx_mask = rx_mask;
278 dev->tx_mask = tx_mask;
279 dev->slot_width = width;
280 dev->frame_length = slots * width;
281
282 return 0;
283 }
284
285 /*
286 * Convert logical slot number into physical slot number.
287 *
288 * If odd_offset is 0 sequential number is identical to logical number.
289 * This is used for DSP modes with slot numbering 0 1 2 3 ...
290 *
291 * Otherwise odd_offset defines the physical offset for odd numbered
292 * slots. This is used for I2S and left/right justified modes to
293 * translate from logical slot numbers 0 1 2 3 ... into physical slot
294 * numbers 0 2 ... 3 4 ...
295 */
296 static int bcm2835_i2s_convert_slot(unsigned int slot, unsigned int odd_offset)
297 {
298 if (!odd_offset)
299 return slot;
300
301 if (slot & 1)
302 return (slot >> 1) + odd_offset;
303
304 return slot >> 1;
305 }
306
307 /*
308 * Calculate channel position from mask and slot width.
309 *
310 * Mask must contain exactly 2 set bits.
311 * Lowest set bit is channel 1 position, highest set bit channel 2.
312 * The constant offset is added to both channel positions.
313 *
314 * If odd_offset is > 0 slot positions are translated to
315 * I2S-style TDM slot numbering ( 0 2 ... 3 4 ...) with odd
316 * logical slot numbers starting at physical slot odd_offset.
317 */
318 static void bcm2835_i2s_calc_channel_pos(
319 unsigned int *ch1_pos, unsigned int *ch2_pos,
320 unsigned int mask, unsigned int width,
321 unsigned int bit_offset, unsigned int odd_offset)
322 {
323 *ch1_pos = bcm2835_i2s_convert_slot((ffs(mask) - 1), odd_offset)
324 * width + bit_offset;
325 *ch2_pos = bcm2835_i2s_convert_slot((fls(mask) - 1), odd_offset)
326 * width + bit_offset;
327 }
328
329 static int bcm2835_i2s_hw_params(struct snd_pcm_substream *substream,
330 struct snd_pcm_hw_params *params,
331 struct snd_soc_dai *dai)
332 {
333 struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
334 unsigned int data_length, data_delay, framesync_length;
335 unsigned int slots, slot_width, odd_slot_offset;
336 int frame_length, bclk_rate;
337 unsigned int rx_mask, tx_mask;
338 unsigned int rx_ch1_pos, rx_ch2_pos, tx_ch1_pos, tx_ch2_pos;
339 unsigned int mode, format;
340 bool bit_clock_provider = false;
341 bool frame_sync_provider = false;
342 bool frame_start_falling_edge = false;
343 uint32_t csreg;
344 int ret = 0;
345
346 /*
347 * If a stream is already enabled,
348 * the registers are already set properly.
349 */
350 regmap_read(dev->i2s_regmap, BCM2835_I2S_CS_A_REG, &csreg);
351
352 if (csreg & (BCM2835_I2S_TXON | BCM2835_I2S_RXON))
353 return 0;
354
355 data_length = params_width(params);
356 data_delay = 0;
357 odd_slot_offset = 0;
358 mode = 0;
359
360 if (dev->tdm_slots) {
361 slots = dev->tdm_slots;
362 slot_width = dev->slot_width;
363 frame_length = dev->frame_length;
364 rx_mask = dev->rx_mask;
365 tx_mask = dev->tx_mask;
366 bclk_rate = dev->frame_length * params_rate(params);
367 } else {
368 slots = 2;
369 slot_width = params_width(params);
370 rx_mask = 0x03;
371 tx_mask = 0x03;
372
373 frame_length = snd_soc_params_to_frame_size(params);
374 if (frame_length < 0)
375 return frame_length;
376
377 bclk_rate = snd_soc_params_to_bclk(params);
378 if (bclk_rate < 0)
379 return bclk_rate;
380 }
381
382 /* Check if data fits into slots */
383 if (data_length > slot_width)
384 return -EINVAL;
385
386 /* Check if CPU is bit clock provider */
387 switch (dev->fmt & SND_SOC_DAIFMT_CLOCK_PROVIDER_MASK) {
388 case SND_SOC_DAIFMT_BP_FP:
389 case SND_SOC_DAIFMT_BP_FC:
390 bit_clock_provider = true;
391 break;
392 case SND_SOC_DAIFMT_BC_FP:
393 case SND_SOC_DAIFMT_BC_FC:
394 bit_clock_provider = false;
395 break;
396 default:
397 return -EINVAL;
398 }
399
400 /* Check if CPU is frame sync provider */
401 switch (dev->fmt & SND_SOC_DAIFMT_CLOCK_PROVIDER_MASK) {
402 case SND_SOC_DAIFMT_BP_FP:
403 case SND_SOC_DAIFMT_BC_FP:
404 frame_sync_provider = true;
405 break;
406 case SND_SOC_DAIFMT_BP_FC:
407 case SND_SOC_DAIFMT_BC_FC:
408 frame_sync_provider = false;
409 break;
410 default:
411 return -EINVAL;
412 }
413
414 /* Clock should only be set up here if CPU is clock master */
415 if (bit_clock_provider &&
416 (!dev->clk_prepared || dev->clk_rate != bclk_rate)) {
417 if (dev->clk_prepared)
418 bcm2835_i2s_stop_clock(dev);
419
420 if (dev->clk_rate != bclk_rate) {
421 ret = clk_set_rate(dev->clk, bclk_rate);
422 if (ret)
423 return ret;
424 dev->clk_rate = bclk_rate;
425 }
426
427 bcm2835_i2s_start_clock(dev);
428 }
429
430 /* Setup the frame format */
431 format = BCM2835_I2S_CHEN;
432
433 if (data_length >= 24)
434 format |= BCM2835_I2S_CHWEX;
435
436 format |= BCM2835_I2S_CHWID((data_length-8)&0xf);
437
438 /* CH2 format is the same as for CH1 */
439 format = BCM2835_I2S_CH1(format) | BCM2835_I2S_CH2(format);
440
441 switch (dev->fmt & SND_SOC_DAIFMT_FORMAT_MASK) {
442 case SND_SOC_DAIFMT_I2S:
443 /* I2S mode needs an even number of slots */
444 if (slots & 1)
445 return -EINVAL;
446
447 /*
448 * Use I2S-style logical slot numbering: even slots
449 * are in first half of frame, odd slots in second half.
450 */
451 odd_slot_offset = slots >> 1;
452
453 /* MSB starts one cycle after frame start */
454 data_delay = 1;
455
456 /* Setup frame sync signal for 50% duty cycle */
457 framesync_length = frame_length / 2;
458 frame_start_falling_edge = true;
459 break;
460 case SND_SOC_DAIFMT_LEFT_J:
461 if (slots & 1)
462 return -EINVAL;
463
464 odd_slot_offset = slots >> 1;
465 data_delay = 0;
466 framesync_length = frame_length / 2;
467 frame_start_falling_edge = false;
468 break;
469 case SND_SOC_DAIFMT_RIGHT_J:
470 if (slots & 1)
471 return -EINVAL;
472
473 /* Odd frame lengths aren't supported */
474 if (frame_length & 1)
475 return -EINVAL;
476
477 odd_slot_offset = slots >> 1;
478 data_delay = slot_width - data_length;
479 framesync_length = frame_length / 2;
480 frame_start_falling_edge = false;
481 break;
482 case SND_SOC_DAIFMT_DSP_A:
483 data_delay = 1;
484 framesync_length = 1;
485 frame_start_falling_edge = false;
486 break;
487 case SND_SOC_DAIFMT_DSP_B:
488 data_delay = 0;
489 framesync_length = 1;
490 frame_start_falling_edge = false;
491 break;
492 default:
493 return -EINVAL;
494 }
495
496 bcm2835_i2s_calc_channel_pos(&rx_ch1_pos, &rx_ch2_pos,
497 rx_mask, slot_width, data_delay, odd_slot_offset);
498 bcm2835_i2s_calc_channel_pos(&tx_ch1_pos, &tx_ch2_pos,
499 tx_mask, slot_width, data_delay, odd_slot_offset);
500
501 /*
502 * Transmitting data immediately after frame start, eg
503 * in left-justified or DSP mode A, only works stable
504 * if bcm2835 is the frame clock provider.
505 */
506 if ((!rx_ch1_pos || !tx_ch1_pos) && !frame_sync_provider)
507 dev_warn(dev->dev,
508 "Unstable consumer config detected, L/R may be swapped");
509
510 /*
511 * Set format for both streams.
512 * We cannot set another frame length
513 * (and therefore word length) anyway,
514 * so the format will be the same.
515 */
516 regmap_write(dev->i2s_regmap, BCM2835_I2S_RXC_A_REG,
517 format
518 | BCM2835_I2S_CH1_POS(rx_ch1_pos)
519 | BCM2835_I2S_CH2_POS(rx_ch2_pos));
520 regmap_write(dev->i2s_regmap, BCM2835_I2S_TXC_A_REG,
521 format
522 | BCM2835_I2S_CH1_POS(tx_ch1_pos)
523 | BCM2835_I2S_CH2_POS(tx_ch2_pos));
524
525 /* Setup the I2S mode */
526
527 if (data_length <= 16) {
528 /*
529 * Use frame packed mode (2 channels per 32 bit word)
530 * We cannot set another frame length in the second stream
531 * (and therefore word length) anyway,
532 * so the format will be the same.
533 */
534 mode |= BCM2835_I2S_FTXP | BCM2835_I2S_FRXP;
535 }
536
537 mode |= BCM2835_I2S_FLEN(frame_length - 1);
538 mode |= BCM2835_I2S_FSLEN(framesync_length);
539
540 /* CLKM selects bcm2835 clock slave mode */
541 if (!bit_clock_provider)
542 mode |= BCM2835_I2S_CLKM;
543
544 /* FSM selects bcm2835 frame sync slave mode */
545 if (!frame_sync_provider)
546 mode |= BCM2835_I2S_FSM;
547
548 /* CLKI selects normal clocking mode, sampling on rising edge */
549 switch (dev->fmt & SND_SOC_DAIFMT_INV_MASK) {
550 case SND_SOC_DAIFMT_NB_NF:
551 case SND_SOC_DAIFMT_NB_IF:
552 mode |= BCM2835_I2S_CLKI;
553 break;
554 case SND_SOC_DAIFMT_IB_NF:
555 case SND_SOC_DAIFMT_IB_IF:
556 break;
557 default:
558 return -EINVAL;
559 }
560
561 /* FSI selects frame start on falling edge */
562 switch (dev->fmt & SND_SOC_DAIFMT_INV_MASK) {
563 case SND_SOC_DAIFMT_NB_NF:
564 case SND_SOC_DAIFMT_IB_NF:
565 if (frame_start_falling_edge)
566 mode |= BCM2835_I2S_FSI;
567 break;
568 case SND_SOC_DAIFMT_NB_IF:
569 case SND_SOC_DAIFMT_IB_IF:
570 if (!frame_start_falling_edge)
571 mode |= BCM2835_I2S_FSI;
572 break;
573 default:
574 return -EINVAL;
575 }
576
577 regmap_write(dev->i2s_regmap, BCM2835_I2S_MODE_A_REG, mode);
578
579 /* Setup the DMA parameters */
580 regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG,
581 BCM2835_I2S_RXTHR(1)
582 | BCM2835_I2S_TXTHR(1)
583 | BCM2835_I2S_DMAEN, 0xffffffff);
584
585 regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_DREQ_A_REG,
586 BCM2835_I2S_TX_PANIC(0x10)
587 | BCM2835_I2S_RX_PANIC(0x30)
588 | BCM2835_I2S_TX(0x30)
589 | BCM2835_I2S_RX(0x20), 0xffffffff);
590
591 /* Clear FIFOs */
592 bcm2835_i2s_clear_fifos(dev, true, true);
593
594 dev_dbg(dev->dev,
595 "slots: %d width: %d rx mask: 0x%02x tx_mask: 0x%02x\n",
596 slots, slot_width, rx_mask, tx_mask);
597
598 dev_dbg(dev->dev, "frame len: %d sync len: %d data len: %d\n",
599 frame_length, framesync_length, data_length);
600
601 dev_dbg(dev->dev, "rx pos: %d,%d tx pos: %d,%d\n",
602 rx_ch1_pos, rx_ch2_pos, tx_ch1_pos, tx_ch2_pos);
603
604 dev_dbg(dev->dev, "sampling rate: %d bclk rate: %d\n",
605 params_rate(params), bclk_rate);
606
607 dev_dbg(dev->dev, "CLKM: %d CLKI: %d FSM: %d FSI: %d frame start: %s edge\n",
608 !!(mode & BCM2835_I2S_CLKM),
609 !!(mode & BCM2835_I2S_CLKI),
610 !!(mode & BCM2835_I2S_FSM),
611 !!(mode & BCM2835_I2S_FSI),
612 (mode & BCM2835_I2S_FSI) ? "falling" : "rising");
613
614 return ret;
615 }
616
617 static int bcm2835_i2s_prepare(struct snd_pcm_substream *substream,
618 struct snd_soc_dai *dai)
619 {
620 struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
621 uint32_t cs_reg;
622
623 /*
624 * Clear both FIFOs if the one that should be started
625 * is not empty at the moment. This should only happen
626 * after overrun. Otherwise, hw_params would have cleared
627 * the FIFO.
628 */
629 regmap_read(dev->i2s_regmap, BCM2835_I2S_CS_A_REG, &cs_reg);
630
631 if (substream->stream == SNDRV_PCM_STREAM_PLAYBACK
632 && !(cs_reg & BCM2835_I2S_TXE))
633 bcm2835_i2s_clear_fifos(dev, true, false);
634 else if (substream->stream == SNDRV_PCM_STREAM_CAPTURE
635 && (cs_reg & BCM2835_I2S_RXD))
636 bcm2835_i2s_clear_fifos(dev, false, true);
637
638 return 0;
639 }
640
641 static void bcm2835_i2s_stop(struct bcm2835_i2s_dev *dev,
642 struct snd_pcm_substream *substream,
643 struct snd_soc_dai *dai)
644 {
645 uint32_t mask;
646
647 if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
648 mask = BCM2835_I2S_RXON;
649 else
650 mask = BCM2835_I2S_TXON;
651
652 regmap_update_bits(dev->i2s_regmap,
653 BCM2835_I2S_CS_A_REG, mask, 0);
654
655 /* Stop also the clock when not SND_SOC_DAIFMT_CONT */
656 if (!snd_soc_dai_active(dai) && !(dev->fmt & SND_SOC_DAIFMT_CONT))
657 bcm2835_i2s_stop_clock(dev);
658 }
659
660 static int bcm2835_i2s_trigger(struct snd_pcm_substream *substream, int cmd,
661 struct snd_soc_dai *dai)
662 {
663 struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
664 uint32_t mask;
665
666 switch (cmd) {
667 case SNDRV_PCM_TRIGGER_START:
668 case SNDRV_PCM_TRIGGER_RESUME:
669 case SNDRV_PCM_TRIGGER_PAUSE_RELEASE:
670 bcm2835_i2s_start_clock(dev);
671
672 if (substream->stream == SNDRV_PCM_STREAM_CAPTURE)
673 mask = BCM2835_I2S_RXON;
674 else
675 mask = BCM2835_I2S_TXON;
676
677 regmap_update_bits(dev->i2s_regmap,
678 BCM2835_I2S_CS_A_REG, mask, mask);
679 break;
680
681 case SNDRV_PCM_TRIGGER_STOP:
682 case SNDRV_PCM_TRIGGER_SUSPEND:
683 case SNDRV_PCM_TRIGGER_PAUSE_PUSH:
684 bcm2835_i2s_stop(dev, substream, dai);
685 break;
686 default:
687 return -EINVAL;
688 }
689
690 return 0;
691 }
692
693 static int bcm2835_i2s_startup(struct snd_pcm_substream *substream,
694 struct snd_soc_dai *dai)
695 {
696 struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
697
698 if (snd_soc_dai_active(dai))
699 return 0;
700
701 /* Should this still be running stop it */
702 bcm2835_i2s_stop_clock(dev);
703
704 /* Enable PCM block */
705 regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG,
706 BCM2835_I2S_EN, BCM2835_I2S_EN);
707
708 /*
709 * Disable STBY.
710 * Requires at least 4 PCM clock cycles to take effect.
711 */
712 regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG,
713 BCM2835_I2S_STBY, BCM2835_I2S_STBY);
714
715 return 0;
716 }
717
718 static void bcm2835_i2s_shutdown(struct snd_pcm_substream *substream,
719 struct snd_soc_dai *dai)
720 {
721 struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
722
723 bcm2835_i2s_stop(dev, substream, dai);
724
725 /* If both streams are stopped, disable module and clock */
726 if (snd_soc_dai_active(dai))
727 return;
728
729 /* Disable the module */
730 regmap_update_bits(dev->i2s_regmap, BCM2835_I2S_CS_A_REG,
731 BCM2835_I2S_EN, 0);
732
733 /*
734 * Stopping clock is necessary, because stop does
735 * not stop the clock when SND_SOC_DAIFMT_CONT
736 */
737 bcm2835_i2s_stop_clock(dev);
738 }
739
740 static int bcm2835_i2s_dai_probe(struct snd_soc_dai *dai)
741 {
742 struct bcm2835_i2s_dev *dev = snd_soc_dai_get_drvdata(dai);
743
744 snd_soc_dai_init_dma_data(dai,
745 &dev->dma_data[SNDRV_PCM_STREAM_PLAYBACK],
746 &dev->dma_data[SNDRV_PCM_STREAM_CAPTURE]);
747
748 return 0;
749 }
750
751 static const struct snd_soc_dai_ops bcm2835_i2s_dai_ops = {
752 .probe = bcm2835_i2s_dai_probe,
753 .startup = bcm2835_i2s_startup,
754 .shutdown = bcm2835_i2s_shutdown,
755 .prepare = bcm2835_i2s_prepare,
756 .trigger = bcm2835_i2s_trigger,
757 .hw_params = bcm2835_i2s_hw_params,
758 .set_fmt = bcm2835_i2s_set_dai_fmt,
759 .set_bclk_ratio = bcm2835_i2s_set_dai_bclk_ratio,
760 .set_tdm_slot = bcm2835_i2s_set_dai_tdm_slot,
761 };
762
763 static struct snd_soc_dai_driver bcm2835_i2s_dai = {
764 .name = "bcm2835-i2s",
765 .playback = {
766 .channels_min = 2,
767 .channels_max = 2,
768 .rates = SNDRV_PCM_RATE_CONTINUOUS,
769 .rate_min = 8000,
770 .rate_max = 384000,
771 .formats = SNDRV_PCM_FMTBIT_S16_LE
772 | SNDRV_PCM_FMTBIT_S24_LE
773 | SNDRV_PCM_FMTBIT_S32_LE
774 },
775 .capture = {
776 .channels_min = 2,
777 .channels_max = 2,
778 .rates = SNDRV_PCM_RATE_CONTINUOUS,
779 .rate_min = 8000,
780 .rate_max = 384000,
781 .formats = SNDRV_PCM_FMTBIT_S16_LE
782 | SNDRV_PCM_FMTBIT_S24_LE
783 | SNDRV_PCM_FMTBIT_S32_LE
784 },
785 .ops = &bcm2835_i2s_dai_ops,
786 .symmetric_rate = 1,
787 .symmetric_sample_bits = 1,
788 };
789
790 static bool bcm2835_i2s_volatile_reg(struct device *dev, unsigned int reg)
791 {
792 switch (reg) {
793 case BCM2835_I2S_CS_A_REG:
794 case BCM2835_I2S_FIFO_A_REG:
795 case BCM2835_I2S_INTSTC_A_REG:
796 case BCM2835_I2S_GRAY_REG:
797 return true;
798 default:
799 return false;
800 }
801 }
802
803 static bool bcm2835_i2s_precious_reg(struct device *dev, unsigned int reg)
804 {
805 switch (reg) {
806 case BCM2835_I2S_FIFO_A_REG:
807 return true;
808 default:
809 return false;
810 }
811 }
812
813 static const struct regmap_config bcm2835_regmap_config = {
814 .reg_bits = 32,
815 .reg_stride = 4,
816 .val_bits = 32,
817 .max_register = BCM2835_I2S_GRAY_REG,
818 .precious_reg = bcm2835_i2s_precious_reg,
819 .volatile_reg = bcm2835_i2s_volatile_reg,
820 .cache_type = REGCACHE_RBTREE,
821 };
822
823 static const struct snd_soc_component_driver bcm2835_i2s_component = {
824 .name = "bcm2835-i2s-comp",
825 .legacy_dai_naming = 1,
826 };
827
828 static int bcm2835_i2s_probe(struct platform_device *pdev)
829 {
830 struct bcm2835_i2s_dev *dev;
831 int ret;
832 void __iomem *base;
833 const __be32 *addr;
834 dma_addr_t dma_base;
835
836 dev = devm_kzalloc(&pdev->dev, sizeof(*dev),
837 GFP_KERNEL);
838 if (!dev)
839 return -ENOMEM;
840
841 /* get the clock */
842 dev->clk_prepared = false;
843 dev->clk = devm_clk_get(&pdev->dev, NULL);
844 if (IS_ERR(dev->clk))
845 return dev_err_probe(&pdev->dev, PTR_ERR(dev->clk),
846 "could not get clk\n");
847
848 /* Request ioarea */
849 base = devm_platform_ioremap_resource(pdev, 0);
850 if (IS_ERR(base))
851 return PTR_ERR(base);
852
853 dev->i2s_regmap = devm_regmap_init_mmio(&pdev->dev, base,
854 &bcm2835_regmap_config);
855 if (IS_ERR(dev->i2s_regmap))
856 return PTR_ERR(dev->i2s_regmap);
857
858 /* Set the DMA address - we have to parse DT ourselves */
859 addr = of_get_address(pdev->dev.of_node, 0, NULL, NULL);
860 if (!addr) {
861 dev_err(&pdev->dev, "could not get DMA-register address\n");
862 return -EINVAL;
863 }
864 dma_base = be32_to_cpup(addr);
865
866 dev->dma_data[SNDRV_PCM_STREAM_PLAYBACK].addr =
867 dma_base + BCM2835_I2S_FIFO_A_REG;
868
869 dev->dma_data[SNDRV_PCM_STREAM_CAPTURE].addr =
870 dma_base + BCM2835_I2S_FIFO_A_REG;
871
872 /* Set the bus width */
873 dev->dma_data[SNDRV_PCM_STREAM_PLAYBACK].addr_width =
874 DMA_SLAVE_BUSWIDTH_4_BYTES;
875 dev->dma_data[SNDRV_PCM_STREAM_CAPTURE].addr_width =
876 DMA_SLAVE_BUSWIDTH_4_BYTES;
877
878 /* Set burst */
879 dev->dma_data[SNDRV_PCM_STREAM_PLAYBACK].maxburst = 2;
880 dev->dma_data[SNDRV_PCM_STREAM_CAPTURE].maxburst = 2;
881
882 /*
883 * Set the PACK flag to enable S16_LE support (2 S16_LE values
884 * packed into 32-bit transfers).
885 */
886 dev->dma_data[SNDRV_PCM_STREAM_PLAYBACK].flags =
887 SND_DMAENGINE_PCM_DAI_FLAG_PACK;
888 dev->dma_data[SNDRV_PCM_STREAM_CAPTURE].flags =
889 SND_DMAENGINE_PCM_DAI_FLAG_PACK;
890
891 /* Store the pdev */
892 dev->dev = &pdev->dev;
893 dev_set_drvdata(&pdev->dev, dev);
894
895 ret = devm_snd_soc_register_component(&pdev->dev,
896 &bcm2835_i2s_component, &bcm2835_i2s_dai, 1);
897 if (ret) {
898 dev_err(&pdev->dev, "Could not register DAI: %d\n", ret);
899 return ret;
900 }
901
902 ret = devm_snd_dmaengine_pcm_register(&pdev->dev, NULL, 0);
903 if (ret) {
904 dev_err(&pdev->dev, "Could not register PCM: %d\n", ret);
905 return ret;
906 }
907
908 return 0;
909 }
910
911 static const struct of_device_id bcm2835_i2s_of_match[] = {
912 { .compatible = "brcm,bcm2835-i2s", },
913 {},
914 };
915
916 MODULE_DEVICE_TABLE(of, bcm2835_i2s_of_match);
917
918 static struct platform_driver bcm2835_i2s_driver = {
919 .probe = bcm2835_i2s_probe,
920 .driver = {
921 .name = "bcm2835-i2s",
922 .of_match_table = bcm2835_i2s_of_match,
923 },
924 };
925
926 module_platform_driver(bcm2835_i2s_driver);
927
928 MODULE_ALIAS("platform:bcm2835-i2s");
929 MODULE_DESCRIPTION("BCM2835 I2S interface");
930 MODULE_AUTHOR("Florian Meier <florian.meier@koalo.de>");
931 MODULE_LICENSE("GPL v2");
932
Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.